Fujitsu M10 Series, SPARC Enterprise Series, PRIMEQUEST Series Installation Planning Manual

Front Cover

C120-H007-08EN

Fujitsu M10/SPARC Servers/
SPARC Enterprise/
PRIMEQUEST

COMMON INSTALLATION PLANNING
MANUAL

FOR SAFE OPERATION

Handling of This Manual

This manual contains important information regarding the use and handling of this

product. Read this manual thoroughly. Use the product according to the instructions

and information available in this manual. Keep this manual in hand for further

understanding.

Fujitsu makes every effort to prevent users and bystanders from being injured or from

suffering from damages to their property. Use the product according to this manual.

ABOUT THIS PRODUCT

This Product is designed, developed and manufactured as contemplated for general

use, including without limitation, general office use, personal use and household use,

but is not designed, developed and manufactured as contemplated for use

accompanying fatal risks or dangers that, unless extremely high safety is secured,

could lead directly to death, personal injury, severe physical damage or other loss

(hereinafter "High Safety Required Use"), including without limitation, nuclear

power core control, airplane control, air traffic control, mass transport operation

control, life support, weapon launching control. You shall not use this Product without

securing the sufficient safety required for the High Safety Required Use. If you wish

to use this Product for High Safety Required Use, please consult with sales

representatives in charge before such use.

RADIO FREQUENCY INTERFERENCE STATEMENT

The following notice is for EU users only.

WARNING: This is a product which meets Class A of EN55022. In a domestic
environment this product may cause radio interference in which case the user may
be required to take adequate measures.

The following notice is for USA users only.

This equipment has been tested and found to comply with the limits for a Class A
digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to
provide reasonable protection against harmful interference when the equipment is
operated in a commercial environment. This equipment generates, uses, and can
radiate radio frequency energy and, if not installed and used in accordance with the
instruction manual, may cause harmful interference to radio communications.
Operation of this equipment in a residential area is likely to cause harmful
interference in which case the user will be required to correct the interference at his
own expense.

C120-H007-08EN

TRADEMARKS ACKNOWLEDGEMENTS

 UNIX is a registered trademark of The Open Group in the United States and other

countries.

The contents of this manual shall not be disclosed in any way or reproduced in any

media without the express written permission of Fujitsu Limited.

All Rights Reserved, Copyright  FUJITSU LIMITED 2002-2014, 2016

C120-H007-08EN

Revision History

(1/1)

Edition Date

Revised section

(Added/Deleted/Altered)

Details

01 2002-10-31 

02 2005-09-15 Entire manual (Altered)

• Technical brush-up

• Modification of the manual title

• Addition of PRIMEQUEST

Section 3.3.2

(Altered/Added)

• Modification of the concept of units
operational grouping

• Addition of description for concentration
of small equipment

Section 5.2.2 (Added)

• Addition of conditions for using mobile
phones

03 2008-04-16 Entire manual (Altered) • Modification of manual title

• Addition of description for SPARC
Enterprise

• Deletion of description for
PRIMEPOWER

04 2009-12-15 Section 4.3.5 (Altered) • Modification of tolerable limit of

Hydrogen sulfide gas

05 2011-11-25 Entire manual (Altered)

• Technical brush-up

Section 2.2.1

(Altered)

• Modification of the value for vibrations
during earthquakes

Section 4.3.5 (Altered)

Section 4.3.6 (Added)

• Modification of Table4.4

• Addition of the seawater (salt damage)

• Modification of the value for withstanding
a horizontal seismic intensity

Section 8.2.2 (Added)

• Addition of consulting department of an
earthquake preparedness

Reader's Comment Form
(Altered)

• Modification of the address for sending
back of the form

06 2012-11-15 Entire manual (Altered) • Modification of manual title

• Addition of description for Fujitsu M10/
SPARC M10 Systems

C120-H007-08EN

Edition Date

07 2014-03-25 Section 6.1.1 (Altered) • Modification of Table6.1

08 2016-05-17 Entire manual (Altered) • Modification of the name of the target

Revised section

(Added/Deleted/Altered)

Details

equipment from "SPARC M10 systems" to
"SPARC Servers"

Note: In this table, devised section is indicated by its section number in the

current edition.

An asterisk (*) indicates a section in the old edition.

C120-H007-08EN

Preface

1

This manual describes the requirements and concepts of installation and facility

planning that pertain to the setup of Fujitsu M10/SPARC Servers, SPARC Enterprise

and PRIMEQUEST. Installation and facility planning requires full review with

Fujitsu representatives in charge according to the instructions presented herein.

This manual is intended for site planners preparing for the server system installation.

Use this manual to review server system installation plans or to run and administer the

server system. The reader is assumed to have some knowledge or experience in the

server system installation planning.

SPARC Servers include the SPARC M10 and SPARC T7/M7/T5.

Contents and Organization of This Manual

This manual consists of 8 chapters, one appendix, one acronyms and abbreviations

section, and one index as below:

The manual contains general information and precautions required for the server

system installation plans. For information about specific Fujitsu M10/SPARC

Servers, SPARC Enterprise models and PRIMEQUEST models, refer to the

respective Installation Planning Manual.

CHAPTER 1 Installation Planning Overview

This chapter describes general requirements for the server system installation

planning and for the facilities used to house the server systems.

CHAPTER 2 Installation Sites

This chapter describes the recommended sites and structures and the buildings in

which the server systems can be installed, and the structures of the computer rooms.

CHAPTER 3 Equipment Layout

This chapter describes the procedures and precautions to take in laying out the server

system equipment.

CHAPTER 4 Air Conditioning

This chapter describes the available computer room air conditioning methods, along

with their features, conditions of air conditioning, and precautions.

C120-H007-08EN i

Preface

CHAPTER 5 Electromagnetic Environment and Static Electricity

This chapter describes the electromagnetic environmental conditions relevant to

server systems, and electrostatic effects.

CHAPTER 6 Power Supply Facilities

This chapter describes the power supply requirements, power supply facilities,

grounding plans, power distribution boards, and power distribution routes for the

server systems.

CHAPTER 7 Protection Against Lightning

This chapter describes the safeguards necessary to protect server systems against

destructive lightning surge voltages.

CHAPTER 8 Security Actions

This chapter describes the actions necessary to ensure server system security.

Appendix A Conversion Information

This appendix provides quick reference tables for measure units conversion and

fractional decimal equivalent conversions.

Acronyms & Abbreviations

This acronyms and abbreviations provides complete word(s) of acronyms and

abbreviations used in this manual.

Index

This index provides the keywords, along with the reference page numbers so that

users can find the necessary information at a glance.

ii C120-H007-08EN

Preface

Other Reference Manuals

When installing the SPARC Enterprise or PRIMEQUEST, read the installation guide

for each model first.

For the readers

• If you find any inconvenience with the description or incorrect explanation in this manual, please
fill in the "Comment Form" sheet at the back of this manual and forward it to the address
described on the sheet.

• This manual is subject to be revised without prior notice.

C120-H007-08EN iii

Contents

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i

CHAPTER 1 Installation Planning Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.1 Office Installation and Computer Room Installation . . . . . . . . . . . . . . . . . . . 1

1.1.1 Office installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.1.2 Computer room installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.2 Computer Room Installation Planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.2.1 Device support planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.2.2 Support staff assignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.3 Preparing Building and Facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1.3.1 Building and facilities needed to install a server system . . . . . . . . . . 4

1.3.2 Furnishings accompanying a server system . . . . . . . . . . . . . . . . . . . 4

1.3.3 Rooms needed to run the server system . . . . . . . . . . . . . . . . . . . . . . 5

1.4 Scheduling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

CHAPTER 2 Installation Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.1 Building Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.1.1 Sites convenient for systems development and administration . . . . . 7

2.1.2 Utility services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.1.3 Secure sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.2 Buildings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.2.1 Building structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.2.2 Computer room location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

2.2.3 Spaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

2.2.4 Facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

2.2.5 Access routes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

2.2.6 Water and fuel stocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

2.3 Computer Room Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

2.3.1 Computer room structural requirements . . . . . . . . . . . . . . . . . . . . . . 16

2.3.2 Free-access flooring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

2.3.3 Interiors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

CHAPTER 3 Equipment Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

3.1 Proposed Computer Room Top View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

3.2 Equipment Templates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

3.3 Precautions in Preparation of an Equipment Layout . . . . . . . . . . . . . . . . . . . 26

C120-H007-08EN v

Contents

3.3.1 Hardware constraints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

3.3.2 Operational considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

3.4 Air Conditioners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

3.4.1 Air conditioning units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

3.4.2 Air conditioning piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

3.4.3 Heat distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

3.4.4 Air circulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

3.4.5 Dusting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

3.5 Power Supply Facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

3.5.1 Power supply facilities for server system . . . . . . . . . . . . . . . . . . . . . . 30

3.5.2 Power supply facilities for air conditioners . . . . . . . . . . . . . . . . . . . . . 31

3.5.3 Facility control panels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

3.6 Line and Signal Wiring Facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

3.6.1 Line facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

3.6.2 Signal wiring facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

CHAPTER 4 Air Conditioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

4.1 Characteristics of Computer Room Air Conditioning . . . . . . . . . . . . . . . . . . . 33

4.1.1 Constant temperatures and humidities . . . . . . . . . . . . . . . . . . . . . . . . 33

4.1.2 Air conditioning conditions and capacities . . . . . . . . . . . . . . . . . . . . . 34

4.1.3 Service time and reliability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

4.2 Styles of Air Conditioner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

4.2.1 Direct blowing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

4.2.2 Duct blowing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

4.2.3 Underfloor ventilation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

4.2.4 Combined use of direct or duct blowing and underfloor ventilation . . 37

4.3 Air Conditioning Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

4.3.1 Permissible temperature and humidity ranges for server systems . . 38

4.3.2 Recommended temperatures and humidities for computer rooms . . 39

4.3.3 Temperature and humidity recommendations for computer rooms . . 40

4.3.4 Dust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

4.3.5 Corrosive gases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

4.3.6 Seawater (salt damage) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

4.4 Thermal Load and Cooling Capacities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

4.4.1 Thermal load imposed on air conditioner . . . . . . . . . . . . . . . . . . . . . . 45

4.4.2 Example of cooling capacity calculations for room air conditioning . . 46

4.4.3 Underfloor ventilation air conditioning . . . . . . . . . . . . . . . . . . . . . . . . . 49

4.4.4 Convenient formulas for air conditioning capacities . . . . . . . . . . . . . . 50

4.5 Precautions Pertaining to the Installation of Air Conditioners . . . . . . . . . . . . 52

4.5.1 Humidifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

4.5.2 Air conditioner filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

vi C120-H007-08EN

Contents

4.5.3 Installing temperature/humidity sensors . . . . . . . . . . . . . . . . . . . . . . . 54

4.5.4 Taking in fresh air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

4.5.5 Preventing dew condensation in underfloor ventilation . . . . . . . . . . . 55

4.5.6 Preventing water leaks and installing detectors . . . . . . . . . . . . . . . . . 56

4.5.7 Installing a backup unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

4.5.8 Preventing freezing of cooling water . . . . . . . . . . . . . . . . . . . . . . . . . 57

CHAPTER 5 Electromagnetic Environment and Static Electricity. . . . . . . . . 59

5.1 Magnetic Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

5.1.1 Allowable magnetic field intensities of displays . . . . . . . . . . . . . . . . . 59

5.1.2 Sources of magnetic fields and fault symptoms . . . . . . . . . . . . . . . . . 60

5.1.3 Magnetic field control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

5.2 Electric Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

5.2.1 Allowable electric field intensities for server systems . . . . . . . . . . . . 62

5.2.2 Conditions for using mobile phones . . . . . . . . . . . . . . . . . . . . . . . . . . 62

5.3 Static Electricity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

5.3.1 Recommended electrostatic voltage for a computer room . . . . . . . . 63

5.3.2 Electrostatic control in the computer room . . . . . . . . . . . . . . . . . . . . . 63

CHAPTER 6 Power Supply Facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

6.1 Input Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

6.1.1 Input power requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

6.1.2 Calculating the power required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

6.1.3 Calculating the rush current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

6.2 Power Supply Facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

6.2.1 Kinds and uses of power supply facilities . . . . . . . . . . . . . . . . . . . . . . 67

6.2.2 Selecting power supply facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

6.3 UPS Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

6.4 Grounding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

6.4.1 Grounding equipment in the computer room . . . . . . . . . . . . . . . . . . . 77

6.4.2 Grounding other equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

6.4.3 Grounding LAN devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

6.4.4 Grounding-plate method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

6.5 Distribution Panels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

6.5.1 Distribution panel location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

6.5.2 Distribution panel breakers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

6.5.3 Distribution panel structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

6.6 Distribution Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

6.6.1 Induced noise control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

6.7 Share of Responsibility for Construction in a Computer Room . . . . . . . . . . . 88

6.8 Distribution Line Insulation Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

C120-H007-08EN vii

Contents

6.8.1 Test voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

6.8.2 Phase and grounding cable insulation test . . . . . . . . . . . . . . . . . . . . . 89

6.8.3 Interphase insulation testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

CHAPTER 7 Protection Against Lightning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

7.1 Protection of AC Line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

7.2 Protection of Signal Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

CHAPTER 8 Security Actions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

8.1 Basic Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

8.1.1 Levels of security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

8.1.2 Objects of security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

8.1.3 Kinds of disasters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

8.2 Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

8.2.1 Fire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

8.2.2 Earthquakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

8.2.3 Water damage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

8.2.4 Burglary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

8.2.5 Rat damage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

8.3 Maintenance and Management of Disaster Control Facilities . . . . . . . . . . . . 106

Appendix A Conversion Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

A.1 Units of Measure Conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

A.2 Fraction to Decimal Equivalence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

Acronyms & Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

viii C120-H007-08EN

Contents

Figures

Figure 2.1 Slit floor panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Figure 2.2 Floor panels with an airflow control damper . . . . . . . . . . . . . . . . . . . . 21

Figure 2.3 Air flow control panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Figure 3.1 Concept of units operational grouping . . . . . . . . . . . . . . . . . . . . . . . . . 27

Figure 4.1 Direct blowing setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Figure 4.2 Duct blowing setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Figure 4.3 Underfloor ventilation setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Figure 4.4 Schematic view of a combined system . . . . . . . . . . . . . . . . . . . . . . . . . 38

Figure 4.5 Psychrometric chart applicable to changing the room temperature 41

Figure 4.6 Psychrometric chart applicable to lowering the underfloor

temperature

Figure 4.7 Typical air conditioner characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Figure 4.8 Air condition in a psychrometric chart (for a typical air conditioner) 46
Figure 4.9 Air condition in a psychrometric chart (underfloor-ventilation air) . . 49

Figure 4.10 Dike . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Figure 6.1 System based on a UPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Figure 6.2 System based on a UPS and an independent power generator . . . 69

Figure 6.3 Commutating load circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

Figure 6.4 Method of grounding equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Figure 6.5 Typical 100 Base-T connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Figure 6.6 Grounding-plate method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

Figure 6.7 Distribution panel (free-standing) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

Figure 6.8 Distribution panel (wall-mounted) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

Figure 6.9 Round crimp terminal dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Figure 6.10 Space around output terminal boards . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Figure 6.11 Grounding connections within a distribution panel . . . . . . . . . . . . . . . 87

Figure 6.12 Share of responsibility for construction in a computer room . . . . . . 88

Figure 7.1 Surge absorber (power outlet connected type) . . . . . . . . . . . . . . . . . . 93

Figure 7.2 Install surge absorber on the distribution panel's input side . . . . . . . 93

Figure 7.3 Lighting control action when using external modem . . . . . . . . . . . . . 94

Figure 7.4 Lightning control action for LAN cables . . . . . . . . . . . . . . . . . . . . . . . . 94

Figure 8.1 Designating alarm zones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

C120-H007-08EN ix

Contents

Tables

Table 2.1 Ceiling heights. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Table 2.2 Raised floor heights of free-access floors . . . . . . . . . . . . . . . . . . . . . . . 18

Table 2.3 Strengths and surface materials of free-access floor panels . . . . . . 19

Table 3.1 Kinds, uses, and locations of power supply facilities . . . . . . . . . . . . . 30

Table 4.1 Recommended temperatures and humidities for computer rooms . 40

Table 4.2 Temperature and humidity recommendations (changing the room

temperature)

Table 4.3 Temperature and humidity recommendations (lowering the underfloor

temperature)

Table 4.4 Tolerable limits for corrosive gases . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Table 4.5 Sources of overload and amount of heat dissipation . . . . . . . . . . . . . 45

Table 4.6 Examples of typical air conditioner cooling capacity calculations . . 47

Table 4.7 Examples of underfloor-ventilation air conditioner cooling capacity

calculations

Table 4.8 Convenient formulas for air conditioner capacity . . . . . . . . . . . . . . . . . 50

Table 5.1 Sources of magnetic fields and fault symptoms. . . . . . . . . . . . . . . . . . 60

Table 6.1 Input power requirement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Table 6.2 Types of available power supply facilities and usage . . . . . . . . . . . . . 67

Table 6.3 Transformers for 200 V server systems. . . . . . . . . . . . . . . . . . . . . . . . . 70

Table 6.4 Transformers dedicated to 400 V server systems . . . . . . . . . . . . . . . . 71

Table 6.5 Specification of the grounding trunk cable for server systems

(in the buildings complying to the IEC standards)

Table 6.6 Requirements for other equipment grounding facilities . . . . . . . . . . . 79

Table 6.7 Details of the separation of the LAN transmission line signal

ground (SG)

Table 6.8 Output terminal board dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Table 7.1 Specification of power control box (F9710PW2) . . . . . . . . . . . . . . . . . 92

Table 7.2 Recommended surge absorber for external modem. . . . . . . . . . . . . . 94

Table 8.1 Characteristics of fire extinguishing agents . . . . . . . . . . . . . . . . . . . . . 99

Table A.1 Units-of-measure conversion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

Table A.2 Fractions to decimal-equivalent conversion . . . . . . . . . . . . . . . . . . . . . 108

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

. . . . . . . . . . . . . . . 78

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

C120-H007-08EN xi

CHAPTER 1 Installation Planning Overview

1

This chapter defines the general requirements for server system installation planning

and for the facilities used to house server systems. Successful planning ensures

system installation efficiency now and in the future, assuring system reliability,

convenience, and functionality.

The users wishing to install a server system must make both the site and associated

facilities available, and also develop meticulous installation plans to ensure that all of

the facilities prerequisite to operating the server system into service are ready before

equipment are delivered to the site.

1.1 Office Installation and Computer Room Installation

Installation site of server system can be classified into two types as described below.

The decision of installation site depends on the unit size and specific conditions of

use.

 Office installation

 Computer room installation

The following are overview of each case:

1.1.1 Office installation

Computer equipment appropriate for office space installation is:

 Compact server units

 I/O devices

These equipments are more appropriate for office space installation than are

equipment that must be installed in a computer room, because they make less noise,

have lower power requirements, dissipate less heat and are operable over wider

temperature and humidity ranges. Office installation does not require free-access

floors or special electrical facilities. As a rule, the building's existing air conditioning

system can be shared.

C120-H007-08EN 1

CHAPTER 1 Installation Planning Overview

A server system involving equipment that is too large to fit into the available office

space or a mixture of equipment having a combined heat dissipation over about 21

MJ/h (20000 Btu/h) would need to be installed in facilities meeting the computer

room installation requirements.

(1) Equipment suitable for office installation

Equipment meeting any of the following requirements is suitable for office

installation.

 Equipment that operates from a power supply of single-phase, and that can be

plugged in

 Equipment whose noise level is low enough to permit installation in a general

office environment

(Equipment with a height of 1 m or lower: Noise level of 47 dB (A) or less;

equipment with a height of 1 m or higher: Noise level of 50 dB (A) or less)

 Equipment with permissible ranges of temperature and humidity that meet

installation requirements in a general office environment

(Indoor temperature: 5 to 35°C; indoor humidity: 20 to 80% RH (operating) or 8 to

80% RH (not operating))

(2) Air conditioning and power requirements of equipment subject to

office installation, and associated facilities

The amount of heat dissipated by equipment subject to installation in an office, the

power requirements, and the number of equipment items installed may require

improvements to the air conditioning and power supply facilities in the office in

question. In installing equipment in an office space, it is important to review

beforehand the air conditioning facilities of the office and the ratings of the power

supplies available.

1.1.2 Computer room installation

Computer equipment appropriate for computer room installation is:

 A server system involving equipment that is too large to fit into the office space

 A mixture of equipment having combined heat dissipation over about 21 MJ/h

(20000 Btu/h)

2 C120-H007-08EN

1.2 Computer Room Installation Planning

1.2 Computer Room Installation Planning

Computer room installation requires prior device support planning and support staff

assignment.

1.2.1 Device support planning

Regarding the method of supporting device, the following items must be planned:

(1) Configuration of the server system and equipment to be added

 Environmental specifications for each room (such as dimensions, mass, voltages,

power requirements, heat dissipation, and temperature and humidity conditions)

 Scale templates for planning device layouts

 Kinds, numbers, and length limitations of signal cables used to connect devices

installed between rooms

(2) Quantities of storage media to be stored

CD, DVD, MO, magnetic tapes, floppy disks, printed forms, etc.

(3) Quantities of supplies and consumables to be stored

Print forms, ink ribbons, toner, photo-conductive drums, etc.

(4) Quantities of spare parts and maintenance tools to be stored

(5) Storage space for user's manuals

(6) Staff and visitor access management scheme

(7) Policy on carrying media and supplies in and out of the computer

room

1.2.2 Support staff assignment

To proceed the installation planning smoothly, an installation planning group

comprises the appointed staff of the user organization and Fujitsu is needed to be

organized.

C120-H007-08EN 3

CHAPTER 1 Installation Planning Overview

Regarding the required staff in the installation planning group, consider the following:

 An installation planning group and a supervisor within the user organization

 An installation consultant from a Fujitsu or agent

1.3 Preparing Building and Facilities

Review the building and facilities needed to install a server system, ancillary

furnishings accompanying the server system, and the rooms needed to run the server

system.

1.3.1 Building and facilities needed to install a server system

Regarding the building and facilities needed to install a server system, consider the

following:

 Building

 Power supplies

 Air conditioning

 Signal line, telecommunication facilities

 Fire extinguishers, fire extinguishing facilities

1.3.2 Furnishings accompanying a server system

Review the following furnishings accompanying in use of a server system:

 Cabinets and lockers

- Small equipment

- Storage media

- Supplies

- Spare parts and maintenance tools

- Instructions manuals

 Warehouses

- Storage media

 Trucks

4 C120-H007-08EN

1.4 Scheduling

1.3.3 Rooms needed to run the server system

Regarding the rooms needed to run the server system, review the following:

 Offices

 Meeting rooms

 System administrator rooms

 System developer rooms

 Backup maintenance engineer and other related rooms

1.4 Scheduling

In installing a server system in a computer room, the scheduling of the following

activities is recommended:

 Development of an overall installation planning schedule

 Facility design verification

 Verification of the status of ongoing facility construction

 Final preparations for installing the server system, facility and interior finish

checks, and, where appropriate, facility test runs

C120-H007-08EN 5

CHAPTER 2 Installation Sites

1

This chapter details the recommended sites and structures and the buildings in which

server systems can be installed, and the structures of the computer rooms.

Server systems setups can be classified into two broad forms: one in which a server

system is installed in a computer room for message collection and distribution

processing and perform calculation processing, and one in which a server system is

installed conveniently in an office for use as a stand-alone machine or as one

connected to a communications network.

This chapter presents a variety of tips and hints for determining the most appropriate

locations for server systems. The importance of the individual tips and hints, however,

depends on the intended use of the server system. Alternative or corrective actions

may be available for particular items. The server system department of the user's

organization is recommended to hold in-depth consultations on requirements for

determining a server system's location with its department in charge of construction or

with a building contractor.

2.1 Building Location

The building in which a server system is to be installed should be conveniently

located for systems development and administration, afford good access to utility

services, such as electricity, water, and telephone lines, and ensure security.

2.1.1 Sites convenient for systems development and administration

When selecting sites conveniently located for systems development and

administration, take the following factors into consideration:

 Commutation of the management and employees

 Communication with the related departments

 Traffic to and from subcontractors

C120-H007-08EN 7

CHAPTER 2 Installation Sites

2.1.2 Utility services

When selecting sites that afford good access to utility services, take the following

factors into consideration:

 Satisfactory availability of electric power

 No suspension or failure of water supplies, or the availability of alternate measures

for water supply

 Access to telecommunication lines

2.1.3 Secure sites

When selecting sites that offer a high degree of security, take the following into

consideration. (Among these factors, those that threaten security will be described

later.) The adverse effects of these factors can be minimized if the structural

requirements for buildings or computer rooms are met.

 Little occurrence of earthquakes, with the effects therefrom minimal

 No danger of damage from flooding and snow

 Little occurrence of lightning

 Easy implementation of fire preventive measures

 No high-level electromagnetic radiation influence

 Little presence of dust and corrosive gases

 Procedures in place for dealing with riots and trespassing, break-ins, etc.

2.2 Buildings

The buildings in which server systems can be installed are broadly classified into the

following forms:

 Dedicated server system centers

 Office rooms converted to dedicated computer rooms

 General office rooms in which server systems are installed for convenience's sake

Except for the last form of installation mentioned above, server system centers and

dedicated computer rooms would best benefit from structural safety considerations,

because they are intended to house server systems handling large amounts of data.

Particularly, the more important a server system center is, the more strict safety

considerations are required.

8 C120-H007-08EN

2.2 Buildings

2.2.1 Building structures

Structural considerations for buildings in which server systems are to be installed are

summarized below.

(1) Floor strength

The floor of the building in which a server system is to be installed should be strong

enough to withstand the combined weight of the server and its component devices. An

equipment layout superimposed with weight distributions should be presented to the

building designer or installation engineer as a means of determining whether the

server system can be installed.

a) Base floor strength of the computer room

The base floor loading strength of the computer room including the strength of the

floor itself, beams, and columns should be sufficient to accept the installation of a

server system.

• Loading strength of the floor itself

The base floor of the computer room, like the floor of a general office room, must

have a loading strength of 2.9 kN/m2 (61 lbf/ft2) or greater.

• Loading strength of beam and column

A loading strength of 2.9 kN/m2 (61 lbf/ft2) or greater is recommended for the

beams and columns that support the floor of the computer room.

Although a loading strength of 1.8 kN/m2 (38 lbf/ft2) or greater is recommended for

the beams and columns used to support the floor of a general office room, this could

restrict the equipment layout of large chained devices or heavy devices.

b) Verification by the building designer or the building constructor

Even if the base floor strength of the computer room meets the value suggested

above, the structure of the building, its secular changes, or the location of the server

system may not accept its installation. For these reasons, an equipment layout

superimposed with weight distributions should be presented to the building designer

or the building constructor as a means of determining whether the server system can

be installed.

c) Rooms used to install heavy devices

Power supply rooms and media storage rooms may require reinforcement even

when they provide a loading strength of 2.9 kN/m2 (61 lbf/ft2).

C120-H007-08EN 9

CHAPTER 2 Installation Sites

d) Newly constructed buildings

If a server system is to be installed in a newly constructed building, it is

recommended that loading strength of the floor itself, beam, and column is 4.9 kN/

m2 (100 lbf/ft2) or greater for such computer room.

(2) Vibration and earthquake-proofing

Recent years have witnessed the emergence of earthquake-free buildings mounted on

earthquake-free foundations that absorb the effects of earthquakes and computer

rooms with earthquake-free floors as safeguards against earthquakes. Because the

higher floors in an ordinary building are more susceptible to the effects of earthquakes

than the lower floors, it is recommended that server systems be installed on lower

floors.

Regarding the floor on which the server system is to be setup, special consideration

should be given to the following:

 As little vibration as possible in the steady state

 Vibrations during earthquakes not exceeding 2.5m/S2 (8.2ft/S2)

 If vibrations during earthquakes exceed 2.5m/S2 (8.2ft/S2), study the available

safeguards against earthquakes. The safeguards against earthquakes include

earthquake-free method, securing method, or clamping devices in position.

(3) Water damage

a) Drainage

The basement or the first floor of a building should be avoided as a site for installing

a server system because these floors can be flooded during floods. If installing a

server system on such floors is unavoidable, embankments or drainage facilities

should be provided to ensure uninterrupted functionality of the server system.

b) Structure

The building in which a server system is installed must be so structured to protect

the server system from the effects of the following:

 Damage from storms and flooding

 Fire fighting water

 Water leaking from the roof

 Water flowing from stairways

 Water leaking from water facilities in the upper floor(s)

 Water leaking from the water pipelines above the ceiling

10 C120-H007-08EN

2.2 Buildings

 Water leaking due to clogged drainage pipelines on the roof or in the upper floor(s)

c) Preventing water leakage from air conditioning facilities

Because air conditioning facilities commonly involve the use of water, as in coolant

pipelines, humidifying feed water, and water generated as a result of dehumidifying,

they would require measures to prevent water leakage. These measures include:

 Embankments surrounding air conditioning facilities and detection of water

leakage inside the embankments

 Detection of water leakage from water pipes

(4) Fires

a) Fireproofing

Buildings should be made fireproof.

b) Buffer zones

Buffer zones should be provided to avoid the effects of fires in the neighborhood.

c) Effects of fires in the neighborhood

Regarding the effects of smoke and heat caused by fires in the neighborhood,

following circumstances must be reviewed:

 From the standpoint of security, computer rooms and media storage rooms should

be windowless or have double walls to provide protection from fire, etc.

 The air intake duct in the computer room should be capable of being cut off

immediately during outbreaks of fires.

(5) Disasters caused by human neglect

Things to consider with regard to disasters caused by human neglect are summarized

below:

 Markings that clearly point to the presence of a server system should be avoided.

Such signboards would include those attached to a building.

 Computer rooms should be at locations where access can be limited to only

authorized personnel.

 Areas surrounding buildings housing server systems should be guarded by

patrolling, for example.

 Rooftop facilities and ground facilities on the premises visible from outside the

premises should be removed from view with screens or fences.

 Computer rooms should also not be visible externally.

C120-H007-08EN 11

CHAPTER 2 Installation Sites

2.2.2 Computer room location

Things to consider with regard to location of the computer room are summarized

below.

(1) Operability

The computer room should be conveniently located for access to communication with

related departments and for data receipt, issue, and relocation.

(2) Security

From a security standpoint, the computer room should be located on the lower middle

floor of a building, rather than the top floor or a basement. The first floor facing the

street should also be avoided. In addition, the top floor is not suitable since top floor

would be influenced by the effects of heat from the rooftop and ambient-air

temperatures.

(3) Sunshine requirements

Computer rooms do not have any special sunshine requirements because they

typically house a limited staff of operators and a large set of devices.

(4) Power supply

Computer rooms installed in buildings should be so located to afford access to the

required power source.

(5) Air conditioning

Computer rooms installed in buildings should be so located to afford access to air

conditioning.

2.2.3 Spaces

Regarding the spaces pertaining to buildings in which server systems are to be

installed, the following items, among others, should be considered:

 The space in which the server system is to be installed

 The space through which the server system will be moved

 The space where additional peripheral equipment or other server systems will be

installed

12 C120-H007-08EN

2.2 Buildings

 The space used for signal and telecommunication lines in the building

 Recording media storage room

 Office room needed for systems administration and development

 Storage rooms for supplies and spare parts

 Access control room

2.2.4 Facilities

Considerations pertaining to facilities are summarized below:

(1) Power supply facilities

The power supply facilities should distribute enough power to meet the requirements

of the server systems and associated facilities. A dedicated transformer or

uninterruptible power supply is required as a power supply facility for the server

systems.

When the computer room is selected, the route of the main power cable to the

computer room must be determined, and a power distribution board and grounding

cable facilities must be prepared.

(2) Air conditioning facilities

a) Types of air conditioning facilities

Review the use of following air conditioning facilities as dedicated air conditioning

facilities for computer rooms, for within power supply rooms, or for neighboring air

conditioning rooms:

 Packaged air conditioner

 Air-handling unit

Regarding air conditioning for other locations, review the following facilities:

 Cooling tower

 Outdoor unit

 Chiller

Following the selection of the computer room, determining the location of the air

conditioning facilities and routing of the pipeline will be required:

C120-H007-08EN 13

CHAPTER 2 Installation Sites

b) Purpose of air conditioning

In a computer room, there are many heat sources such as dissipation from server

systems, heat from surrounding circumstances, and heat generated by lighting and

operators' bodies that increase instability of air conditions in the room. Air

conditioners are required in order to improve stability of air conditions in the room.

c) Precautions

Regarding the selection of air conditioning facilities, the following items require

consideration:

 Air conditioning facilities needed to keep the server system running successfully

 For water-cooled air conditioners, the location of the cooling tower and coolant

piping to the air conditioner

 For air-cooled air conditioners, the location of the air-cooled outdoor unit and

refrigerant piping to the air conditioner

 Cooling water capacity to provide year-round cooling, for cases where only chilled

water is available for cooling the building, and no locations are available for

installing a cooling tower or outdoor unit

(3) Telecommunications equipment

The area or telecommunications equipment room in which telecommunications

equipment is to be installed need to be reviewed.

(4) Fire extinguishing facilities

If fire extinguishing facilities are to be installed, a particular area is needed to install

them.

2.2.5 Access routes

The process of installing a server system involves frequent carrying-in and out of

equipment, at initial system setup, the addition of more equipment, upgrading, and so

on. Before equipment is carried in, consideration should be given to the surrounding

conditions of the building, the location where the equipment is to be unpacked, how

the equipment is to be carried in, and temporary floor reinforcement along the access

route. To this end, the user needs to review the access route from the opening in the

building through which the equipment is carried into the computer room where the

equipment is to be set up. The Fujitsu shipping coordinator may take a preliminary

tour of the access route and conduct consultations with the user beforehand.

The items that require consideration are listed as follows:

14 C120-H007-08EN

2.2 Buildings

 Where the equipment is to be unloaded from the transport vehicle

 How the equipment is to be carried in and out the building

 Where the equipment is to be temporarily stored and unpacked

 The size of the elevator and its loading capacity

 The carry-in access route to the computer room

 Whether floor protection along the access route is required

The access route from the building delivery entrance to the computer room is

described below:

(1) Building delivery entrance

a) Carrying in equipment in a wooden crate or box

When the server system to be carried in is enclosed in a wooden crate or box as is

the case when shipped from the factory over a long distance to a user overseas, the

building delivery entrance should generally have the following dimensions:

 Height: 2.5 m (8.2 ft) or more

 Width: 1.6 m (5.2 ft) or more

Because the wooden crate or box packaging dimensions for specific users depends

on the kind of equipment to be packaged and the transportation method, the field

representative in charge confers with the shipping department and notifies the user

accordingly.

b) Carrying in equipment with a crane

Difficulties may be experienced in carrying equipment into the middle floor of a

building directly with a crane, depending on the structure of the delivery entrance of

the building and the surrounding conditions of the building. Prior consultation with

the Fujitsu shipping coordinator is recommended.

(2) Computer room entrance and building passages

The delivery entrance of the building into which equipment is to be carried in

unpacked, the intermediate passages of the access route, and the entrance of the

computer room must have the values specified below.

 The entrance of the computer room and the building passages should have a height

of at least 20 cm (8 in.) more than the assumed equipment height.

 The entrance of the computer room and the building passages should have a width

of at least 30 cm (12 in.) wider than an equipment width.

Besides this, the followings need to be taken into consideration.

 Enough space for negotiating corners along building passages

 Whether the elevator(s) of the building is available

C120-H007-08EN 15

CHAPTER 2 Installation Sites

(3) Withstand load and protection of the access route

The withstand load of the access route should be large enough to support the mass and

transportation activity concerning the server system.

At the time of transportation, the floor and wall surfaces along the access route may

require protection.

2.2.6 Water and fuel stocks

The quantities of water and fuels to be kept in stock should be calculated by taking

into account the number of hours for which server service should be sustained, a

factor that should be determined before proceeding with stock quantity calculation.

Primary considerations involved in the determination of stock quantities are as

follows:

 Cooling water for air conditioning facilities and emergency power generation

facilities

 Living utility water

 Fuels for emergency power generation facilities

 Fuels needed to heat or cool office rooms and rooms occupied by people

2.3 Computer Room Structure

This section describes the structural requirements of computer rooms, free-access

floors, and interior furnishings.

2.3.1 Computer room structural requirements

The following items are requirements that should be taken into account at the time of

computer room selection.

 Base floor strength and surface finishing

 Free-access floor

 Ceiling height

 Floor vibration

 Room location and access route

 Power supply

 Air conditioning facilities and external water chilling facilities

16 C120-H007-08EN

2.3 Computer Room Structure

 Security and disaster prevention considerations

(1) Base floor strength

The base floor on which the server system is to be set up must have enough strength to

support a raised floor and facilities and equipment, as well as the server system itself.

A floor top view with an equipment layout superimposed with equipment weights for

each lockers must be presented to the building designer or the building constructor as

a means of determining whether the server system can be installed on the floor in

question.

For base floor strength, see Section 2.2.1, "Building structures."

(2) Dustproof finishing

If the surface of the base floor is left unfinished, equipment may be adversely affected

by calcium carbonate scattered as dust from the concrete surface. The concrete

surface must be finished with a dustproof coating to prevent the buildup of dust.

(3) Free-access floor construction

Server rooms covering an area of about 30 m

floor structure as far as circumstances allow. A raised floor structure with a free-

access floor that allows floor plate removal is recommended to facilitate equipment

installation and relocation, cabling, and underfloor ventilation. Requirements for the

raised floor height of a free-access floor and the floor panel strength are described in

Section 2.3.2, "Free-access flooring."

(4) Ceiling height

The ceiling of the computer room must be high enough to allow for the circulation of

cold air up from under the free-access floor to the heated equipment which it cools

down before flowing unrestrained within the room back to the air conditioner. The

ceiling height is measured from the surface of the free-access floor (raised floor) to

the bottom layer of the double ceiling. The values specified in Table 2.1 are required

depending on the equipment height.

Table 2.1 Ceiling heights

2

(320 ft2 ) or more should have a raised

Equipment height Ceiling height

Up to 1.8 m (5.9 ft

Above 1.8 m (5.9 ft) but not exceeding 2.0 m (6.6 ft) 2.5 m (8.2 ft

C120-H007-08EN 17

) 2.3 m (7.5 ft ) or higher

) or higher

CHAPTER 2 Installation Sites

2.3.2 Free-access flooring

The construction of free-access floors is reviewed with respect to the following items:

 Raised floor height

 Strength and surface material of free-access floor panels

 Opening for server-system-use

 Installation of floor panels for a building air conditioner

Each item is described as follows:

(1) Raised floor height

Regarding the raised floor height of a free-access floor, the following factors require

consideration:

 Availability of underfloor ventilation

 Cabling height

 Safeguards against earthquakes

Table 2.2 lists suggested raised floor heights for free-access floors.

Table 2.2 Raised floor heights of free-access floors

Condition Raised floor height

Room
ventilation

Underfloor
ventilation

Erected directly on the free-access floor
Optional earthquake-free legs that absorb the
energy of earthquakes installed to protect
against earthquakes

Clamped from under the free-access floor to
protect against earthquakes

Erected directly on the free-access floor
Optional earthquake-free legs that absorb the
energy of earthquakes installed to protect
against earthquakes

Clamped from under the free-access floor to
protect against earthquakes

180 mm (7 in.) or higher

250 mm (10 in.)

300 mm (12 in.)

400 mm (16 in.)

or higher

or higher

or higher

18 C120-H007-08EN

2.3 Computer Room Structure

(2) Strength and surface material of free-access floor panels

Table 2.3 lists the strengths and surface materials suggested for free-access floor

panels.

Table 2.3 Strengths and surface materials of free-access floor panels

Item Condition

Floor-panel strength Deflection not exceeding 1.5 mm (0.05 in.) under a

concentrated load of 4.9 kN (1100 lbf)

6

9

Surface
material

Suppression of
static electricity

Oil resistance and
ease of cleaning

Dust buildup
characteristics

Volume resistivity falling 10

Resistant to oils used during maintenance and easy to clean

Resistant to dust buildup

to 10



(3) Opening for server-system-use

That area of the free-access floor in which a server system is installed requires a floor

panel opening, an auxiliary support and a slit floor panel.

When Fujitsu receives a free-access floor allocation plan from the user after the

finalization of an equipment layout, it will furnish an opening diagram marked with

an opening pattern, an auxiliary support position, and a slit floor panel position.

The user then proceeds with construction of the floor panel opening, an auxiliary

support, and slit floor panel on the basis of this opening diagram.

a) Floor panel opening

That area of the free-access floor in which an equipment is installed must have an

opening in the floor panel to facilitate equipment cabling and underfloor cold

ventilation.

b) Auxiliary supports

Depending on the shape of the floor panel opening, an auxiliary support may be

required to augment panel strength and to secure the panel in a firm position. In

installing equipment, such as a magnetic tape unit, on a floor panel, an auxiliary

support should be used to reinforce the floor panel so that the equipment can be kept

level by offsetting panel deflection.

c) Slit floor panels

Depending on the heat dissipation and the air intake/exhaust structures of the

equipment installed, a slit floor panel for cold ventilation may have to be installed in

the service area.

C120-H007-08EN 19

CHAPTER 2 Installation Sites

Figure 2.1 shows the outer view of a slit floor panel.

Figure 2.1 Slit floor panel

d) Preventing the free-access floor from being collapsed because of the opening

Horizontal forces applied to the free-access floor during earthquakes or when heavy

equipment is carried in could cause the floor panel to shift, depending on the structure

of the free-access floor and the shape of the floor panel opening, leading to free-

access floor collapse. When such an opening is built, the free-access floor should be

reinforced with bolts or brackets to guard against possible collapse.

(4) Installation of a floor panel for a building air conditioner

A floor panel must be installed only for buildings air conditioned by underfloor

ventilation. When underfloor ventilation and room air conditioning are jointly used,

the floor panel is not required.

a) Underfloor ventilation

If only underfloor ventilation is used to air condition the computer room, floor

panels with an airflow control damper or airflow control panels must be installed to

allow cold air to rise up from under the free-access floor to circulate outward into

the room. This is proceeded to enable the air thus circulated may cool the heat

penetrating the computer room, and heat generated by room lighting and by the

operators' bodies.

20 C120-H007-08EN

2.3 Computer Room Structure

The number of floor panels with an airflow control damper or number of airflow

control panels required should be determined by the air conditioning facility or the

free-access floor construction designer on the basis of the concerned heat load in the

room.

Figure 2.2 Floor panels with an airflow control damper

Figure 2.3 Air flow control panel

b) When underfloor ventilation and room air conditioning are combined

When underfloor ventilation is used to cool the equipment, with room air

conditioning available to air condition the building in which the server system is

housed, floor panels for the building's air conditioning system are not required.

(5) Slopes and stairways

If there is a difference in levels between the base floor and the free-access floor, either

a slope or stairway must be built at the entrance of the computer room to facilitate

traffic or physical transportation.

C120-H007-08EN 21

CHAPTER 2 Installation Sites

(6) Base floor and free-access floor cleaning

The base floor and the free-access floor require cleaning before the server system is

installed. The following cleaning procedures are recommended, including those for

cleaning the free-access floor surface periodically:

1 Remove dust on the surface of the panels.
2 Clean with a mop or cloth dipped in a solution having an anti-static agent,

then squeeze the mop tightly before proceeding with mopping.

Never use polishing powder or solid or water-soluble waxes to clean computer rooms.

They may become deposited in gaps in the floor surface or floor panels, then scattered

by underfloor ventilation, penetrating inside the computers and affecting equipment

adversely.

2.3.3 Interiors

Server rooms require more strict temperature and humidity control than common

office rooms. Essential things to consider with regard to such air conditioning include

insulation against heat, prevention from entry of outside air, and shielding from direct

sunlight. Cutting out heat from external sources would lessen the heat load of the

building on the air conditioning facilities, leading to savings on expenditures on

power required for air conditioning.

Other factors to consider with regard to computer room interiors include sounds

absorption and insulation to suppress room noise, room lighting, and maintenance

outlets.

(1) Heat insulation

The computer room should have a heat-insulating structure to cut heat penetrating

through the walls, ceiling, windows, and other locations and to facilitate air

conditioning. Heat insulation may be effected, for example, by the use of wind-free

double walls and by finishing the walls, ceiling, and the ceiling of the floor

immediately below with heat insulators of a noncombustible kind.

22 C120-H007-08EN

2.3 Computer Room Structure

(2) Prevention of entry of outside air

Outside air penetrating through gaps in a window could threaten successful

temperature and humidity control of the air conditioning facilities.

Moreover, outside air might contain dust and harmful gases. From this standpoint, the

windows in the computer room should be made airtight or semi-airtight. Openings

that may allow the direct inflow of air from outside, from the floor right above or

below, from passages, and elsewhere should be sealed. Outside air that is taken in

must have its temperature and humidity regulated by an air conditioner before it can

be fed into the computer room.

(3) Shielding from direct sunlight

When direct sunlight enters the room through a window, it could produce local

temperature increases in the room or in the equipment, adversely affecting the

performance of such equipment. These windows must have blinds affixed to shield

the room from direct sunlight.

(4) Sound absorption and insulation

Appropriate sound absorption is recommended in the computer room to ease operator

fatigue that may be caused by various kinds of noises generated in the room. Among

all areas of the computer room, the ceiling and walls will make for the most effective

sound absorbers when modified to this end. The use of noncombustible sound

absorbers is recommended. The walls of the computer room should have a sound

insulation structure to prevent noise from traveling imparted to adjoining offices,

meeting rooms, etc.

If the floor is to be covered with carpeting as a sound absorber, such carpeting must be

free of static electricity and dust.

(5) Lighting

It is recommended that the computer room be illuminated to provide an illuminance

of 400 to 600 lx at a point 85 cm (33 in.) above the floor for server system operation

and maintenance purposes. Each lighting fixture should be furnished with a switch to

turn off the light when it is not necessary.

C120-H007-08EN 23

CHAPTER 2 Installation Sites

(6) Maintenance outlets

The computer room requires maintenance outlets to power instruments for

maintaining the server system or to clean the floor. Maintenance outlets should be

provided on column or wall surfaces 5 to 7 m (16 to 23 ft) apart at a height of about 30

cm (12 in.) above the floor. An extension cord is required where the outlet spacing

exceeds 7 m (23 ft). Power leading to the outlets may be fed from a common general

power source.

(7) Dust

It is recommended to provide preventive action for generation of dust within the room

in which the equipment is installed, and for entering of dust from the windows and

entrances of the room. Most equipment applies mandatory cooling method. If dust

particles adhere over the vent to shut down the airflow, the temperature inside the

equipment ascends. Such conditions may cause equipment fault or system down. Dust

may become a cause of readout malfunction when dust covers over magnetic tapes,

optical disks, or such media. Planning of media warehousing is also important.

24 C120-H007-08EN

CHAPTER 3 Equipment Layout

1

This chapter describes the items which considerations require for when laying out

equipment. Equipment layout deserves special consideration, because it has a

significant bearing on the efficiency of system operation and maintenance.

3.1 Proposed Computer Room Top View

A top view of the proposed computer room must be prepared.

(1) Top view

A precise top view of the proposed computer room must be prepared to aid

in reviewing the equipment layout.

(2) Scale

The top view of the proposed computer room prepared on a scale of one-fiftieth

is recommended.

3.2 Equipment Templates

Equipment templates at a scale of one-fiftieth are recommended. Prepare templates

for the following kinds of equipment:

 Server system main unit

 Console tables

 Equipment installation shelves

 Cabinets used to house small floor-mounted equipment

 Air conditioners

 Power supply facilities

C120-H007-08EN 25

CHAPTER 3 Equipment Layout

3.3 Precautions in Preparation of an Equipment Layout

In preparing an equipment layout, take into account hardware constraints, operational

considerations, and installation equipment constraints.

3.3.1 Hardware constraints

(1) Cable length limitations

Each signal cable or power control cable has a limitation on its length. In laying out

equipment, be careful not to exceed these limitations.

(2) Wiring volumes and routes

a) Small systems

In small systems involving a relatively low volume of wiring, equipment may be

installed in an I, L or E-shaped layout to simplify the wiring routes on or under the

floor.

Cover any wires or connections that are laid on the floor so that they do not interfere

with traffic.

b) Larger systems

In larger systems with an increased volume of wiring, a free-access floor is required.

This is a raised floor structure in which the floor plates are removable.

(3) Heat dissipation from equipment

If devices that dissipate a high amount of heat are used, they must not be concentrated

within the same area considering air conditioning capability (1 or 2 kW/m2).

3.3.2 Operational considerations

(1) Equipment functionality and operability

The components that make up a server system each have a specific functional goal to

serve and should be grouped for ease of system operation.

26 C120-H007-08EN

3.3 Precautions in Preparation of an Equipment Layout

File units

CPUs Line units

I/O devices

Consoles

Even if a single device has multiple functions, it should be grouped according to the

degree to which it can be run with or without manual intervention.

Generally, devices may be divided into the following groups:

 Consoles for visual monitoring

 I/O devices requiring interchangeable and portable storage media

 Connection equipment that has a long service life and seldom requires replacement

 Data processing devices (such as CPUs and file units) that normally do not require

manual operation

Figure 3.1 shows a conceptual view of grouping.

Figure 3.1 Concept of units operational grouping

(2) Concentration of small equipment

Concentrate small devices, such as modems and LAN units, on shelves.

For a large number of small, floor-mounted devices, such as display controllers, LAN

controllers, link adapters, and optical channel adapters, consider erecting a single

cabinet to house them all.

(3) Entrance and passage

Lay out the equipment to facilitate human traffic and the movement of supplies and

storage media through the entrance. Allow also for human traffic and the movement

of media, equipment, and instruments when locating the passages in the room.

(4) Maintainability

Provide service clearance around server systems, air conditioners, and power supply

facilities to allow access for inspection or maintenance.

C120-H007-08EN 27

CHAPTER 3 Equipment Layout

(5) Acoustic noise

A general-purpose server system is generally made up of a mix of equipment, each of

which generates its own acoustic noise. Because the acoustic noises from individual

equipment may result in a very high noise-level, it is recommended that these

equipment be installed in an unattended zone.

a) Distinction between an attended zone and an unattended zone

Install consoles and I/O equipment in a single attended zone, and data processors and

file storage units in an unattended zone.

b) Attended zone

Make sure that an attended zone is not surrounded by equipment on all sides. A wall

may be erected on one side or it may be partitioned for sound insulation.

(6) Furniture and fixtures

Provide locations for furniture and fixtures that are needed during operations.

Furniture and fixtures include:

 Cabinets used to store media

 Lockers used to store spare parts and documentation

 Forms storage stands

(7) Handling of vents

Keep the inlet and outlet for air circulation and cooling equipment free from clogging

up.

28 C120-H007-08EN

3.4 Air Conditioners

3.4 Air Conditioners

Factors to be considered when laying out air conditioning are described below:

3.4.1 Air conditioning units

Do not simply install a single, high-capacity central air conditioning unit in the

computer room or an adjoining air-conditioning room. Considering possible device

failures and the need for regular maintenance of air conditioning units, Fujitsu

recommends installing multiple small-capacity air conditioning units (having a

cooling power between 15 kW and 50 kW) at locations throughout the computer

room. Ensure that the installation area, including maintenance space, is not

unnecessarily large.

3.4.2 Air conditioning piping

When installing an underfloor-ventilation air conditioning unit, be careful to keep the

piping from interfering with the underfloor ventilation or wiring. Construct the air

conditioning piping upright from the floor above, below the ceiling, or on the back of

the air conditioning unit.

3.4.3 Heat distribution

Devices that generate high heat should be installed at the place where the devices are

cooled sufficiently by cold air from an air conditioner. Install air conditioners matched

to the required heat dissipation in each area.

3.4.4 Air circulation

When installing air conditioners in the computer room, lay out the equipment to allow

the air blown out from the air conditioner to circulate all around the equipment and

then back to the air conditioner steadily so that stagnant air will not exist. Because

airflow tends to stop around tall equipment, pay special attention to the relation

between the location of tall equipment and the air outlet of the air conditioner.

In a system using underfloor ventilation for air conditioning, consider the paths of

both hot and cold airflow.

C120-H007-08EN 29

CHAPTER 3 Equipment Layout

3.4.5 Dusting

Units that use paper or toner in operation, such as line printers and laser printers,

produce dust. The relation between dust-producing devices and device that should be

dust-free requires special consideration. For example, dust-free devices can be

installed near the air outlet, while the dust-producing devices can be near the air

intake.

3.5 Power Supply Facilities

This section describes power supply facilities.

3.5.1 Power supply facilities for server system

The power supply facilities required for a server system include transformers, voltage

regulators, and distribution panels. Some of these are installed in the server room.

Table 3.1 summarizes the kinds, uses, and locations of the power supply facilities.

Table 3.1 Kinds, uses, and locations of power supply facilities (1/2)

Power supply Use Location

High-voltage transformers
(dedicated to server systems or
shared by other facilities)

Voltage regulators such as an
uninterruptible
power supply (UPS)

Transforms a high transmission
voltage into a commercial voltage.

Compensates for momentary
interruptions or voltage variations
in commercial power.

Installed in a power user's
electrical facility room, in a power
company's transformer room, or
on a pole.

Installed in a power user's
electrical facility room or
computer room.
Generally, a UPS is installed in a
dedicated electrical facility.
A UPS rated at less than 100 kVA
may be installed in a computer
room.

30 C120-H007-08EN

3.5 Power Supply Facilities

Table 3.1 Kinds, uses, and locations of power supply facilities (2/2)

Power supply Use Location

Separate transformers Low-voltage transformers used

when:

• The supply voltage available to

the building and the voltage
required by the server system
differ.

• A voltage regulator, such as a

UPS, is installed in a separate
building or at a remote location.

• Power is fed from a high-

voltage transformer that is
shared by other facilities,
without using a voltage
regulator.

Step-down transformers
(200 V to 100 V)

Distribution panels Distributes power to server

Grounding facilities Used to ground server system. The grounding cable is led to the

Transforms 200 V, from a high­voltage transformer and voltage
regulator, to suit certain
equipment which operates
at 100 V.

system.

Separator transformers, when
used, are typically installed in a
computer room.

Step-down transformers, when
used, are typically installed in a
computer room.

Installed in a computer room.

distribution panel for distribution.

3.5.2 Power supply facilities for air conditioners

Air conditioners or air conditioning control panels must be located for correct and

efficient operation of the computer room.

3.5.3 Facility control panels

Facility control panels, which are used to run facilities in auto mode or shut them off

immediately in an emergency, must be located to allow easy access.

C120-H007-08EN 31

CHAPTER 3 Equipment Layout

3.6 Line and Signal Wiring Facilities

This section describes line and signal wiring facilities.

3.6.1 Line facilities

When line terminal boards and line terminals are installed, they must be located to

allow for easy connection with any line units in the computer room.

3.6.2 Signal wiring facilities

Signal cabling with devices that are installed outside the computer room requires

wiring facilities, such as pipelines, ducts, and cable racks. Even though these units are

located in an adjoining room, a through hole in the wall would still be necessary.

Examine these wiring facility requirements and the location of any through holes

during layout preparation and mark the top view of the proposed computer room

accordingly.

32 C120-H007-08EN

CHAPTER 4 Air Conditioning

1

This chapter describes which items require considerations when laying out air

conditioning facilities.

4.1 Characteristics of Computer Room Air Conditioning

Computer room air conditioning is characterized by:

 Constant temperatures and humidities

 Air conditioning conditions and capacities

 Service time and reliability

These are detailed as below:

4.1.1 Constant temperatures and humidities

While most server system has wide permissible temperature and humidity ranges as

described later, it is recommended that the computer room be maintained at a constant

temperature and humidity to provide operational stability, fewer media effects, and a

good operator environment. A stable environment is important because the computer

room houses semiconductor devices, which are easily affected by thermal shocks,

precision mechanical parts, which are liable to thermal expansion due to temperature

changes, and print forms, toner, OMR and OCR forms, paper tape and other kinds of

media, which are susceptible to the effects of humidity changes. A computer room

requires temperature and humidity regulation, while guarding against electrostatic

effects at low humidities and dew condensation caused by underfloor ventilation at

lower temperatures and humidities.

C120-H007-08EN 33

CHAPTER 4 Air Conditioning

4.1.2 Air conditioning conditions and capacities

The air conditioning system must have the capacity to be able to process the amount

of heat dissipated from the computer equipment to cool the computer room. A server

system

rated or listed capacity of the air conditioning facilities may have been measured for a

general office for human beings as specified by the relevant industrial standards or the

like and may not be readily applicable to a server room environment. Consultation or

design by a professional engineer is required for determining the capacity of an air

conditioner to be used in a computer room.

4.1.3 Service time and reliability

The air conditioning facilities for a computer room must be kept operable at all times.

A large number of relatively low-capacity units are recommended. Maintain the room

air at a somewhat lower temperature, so that even if one unit fails, there would still be

time to take corrective action before a critical temperature is reached. The installation

of spare units to back up the primary units is also recommended.

generates heat from the Power Supply Unit, semiconductor devices, etc. The

4.2 Styles of Air Conditioner

Air conditioner installations for computer rooms can be grouped into four broad styles

as listed below. Choose from them to suit the user's architectural requirements, the

size of the system installation, layout constraints, etc.

 Direct blowing

 Duct blowing

 Underfloor ventilation

 Combined use of direct or duct blowing and underfloor ventilation

These methods are detailed as below:

34 C120-H007-08EN

4.2 Styles of Air Conditioner

4.2.1 Direct blowing

In the direct blowing setup, air conditioner(s) are installed in the computer room to

blow air directly into the room.

This setup is economical, permits easy room temperature and humidity regulation,

and is less susceptible to dew condensation. Moreover, the air conditioner(s), free

from blowing temperature constraints, offer high working efficiency. However, while

this setup is easier to install, cold air could be poorly distributed. Hence, a facility

layout should be such as to ensure unrestricted flow of cold air. Another drawback is

that where a high cooling capacity is required, rapid drafts of cold air could chill

operators.

Generally, a unit installed in a direct blowing setup should include a draft fan, a

cooling coil, a heater for the winter time, a humidifier, and a filter.

Figure 4.1 shows a schematic view of the direct blowing setup.

4.2.2 Duct blowing

In the duct blowing setup, air duct is connected to an air conditioner so that cold air is

blown from grille or spot in the computer room.

Figure 4.1 Direct blowing setup

This setup features offering uniform blowing, permitting easy room temperature and

humidity regulation, and lessening operator health effects. Its drawbacks, however,

are the need for ducting in the ceiling, possible collision of air blowing from the

ceiling with upward exhaust from the equipment, restricted equipment layout, and the

difficulty of using centralized blowing against equipment which requires high heat

dissipation.

C120-H007-08EN 35

CHAPTER 4 Air Conditioning

An air conditioner installed in the duct blowing setup should include a cooling coil, a

heater for the winter and temperature control, a humidifier, and a filter.

Figure 4.2 shows a schematic view of the duct blowing setup.

Figure 4.2 Duct blowing setup

4.2.3 Underfloor ventilation

In the underfloor ventilation setup, air blown out of the air conditioner is fed into the

clearance between the free-access floor and the base floor, and is blown through

openings in the free-access floor into the space at the bottom of the server system or

the surrounding space.

This setup is useful in the following cases:

 Larger server systems including high heat dissipation volume unit(s)

 Intricate layout including tall equipment

36 C120-H007-08EN

4.2 Styles of Air Conditioner

This setup features the ability to keep operators less chilled because this lessens direct

exposure to drafts of air blown out of the air conditioner. Because underfloor

ventilation blows air directly against equipment, the air must be filtered for dust by

the air conditioner beforehand. The lower the air temperature is, the greater the

chance for dew condensation becomes because of increased humidity. Hence, the air

requires regulation of both its temperature and humidity. A special underfloor-

ventilation air conditioner dedicated to computer room use, which permits

temperature and humidity regulation, is usually used. An air handling unit that uses a

water-based cooling coil must be controlled to maintain the humidity, as well as the

temperature, within a prescribed range. Regulation of the temperature and humidity in

this setup is generally accomplished by cooling and dehumidifying the room air to a

temperature lower than the target temperature and then heating and humidifying it to

some degree to attain the target temperature and humidity. The cooling capacity of an

air conditioner installed in this setup will be lower than its rating because of the

internal heating process involved.

In the winter time, heating to a predetermined temperature is required.

Figure 4.3 shows a schematic view of the underfloor ventilation setup.

Figure 4.3 Underfloor ventilation setup

4.2.4 Combined use of direct or duct blowing and underfloor ventilation

If direct blowing or duct blowing is combined with underfloor ventilation, the server

system is cooled down by the air blown from under the floor, while the air in the room

is conditioned to a temperature suitable for the operator by room air conditioning.

The underfloor-ventilation air conditioner dehumidifies the air by overcooling before

regulating the temperature and humidity by heating and humidifying.

C120-H007-08EN 37

CHAPTER 4 Air Conditioning

Sometimes the underfloor-ventilation air conditioner does not perform heating and

humidifying but only cools the room air to the target temperature. In this situation,

regulation of the temperature and humidity of the air in the room and under the floor

can be accomplished by heating and humidifying the room air and the outside air after

it has been dehumidified by overcooling by the underfloor air conditioner.

Figure 4.4 shows a schematic view of a combined system.

Figure 4.4 Schematic view of a combined system

4.3 Air Conditioning Conditions

This section describes air conditioning conditions.

4.3.1 Permissible temperature and humidity ranges for server systems

Each component of a server system has its own permissible temperature and humidity

ranges, within which its operability is guaranteed. The prescribed temperature and

humidity are those at the air vents of the component. For the permissible temperature

and humidity ranges, see the Installation Planning Manual for each device.

38 C120-H007-08EN

4.3 Air Conditioning Conditions

4.3.2 Recommended temperatures and humidities for computer rooms

Keep the ambient temperature in the computer room at a level that feeds comfortable

to the human body or somewhat lower. This precaution will not only prevent local

temperature rises in the computer room, such as those caused by equipment which

requires high heat dissipation, or stagnant air circulation, but will also allow some

time before the upper-limit temperature is reached even if the air conditioner fails.

In underfloor ventilation, humidity considerations require special consideration.

Normal air contains vapor. The higher the temperature is, the lower the relative

humidity is; the lower the temperature is, the higher the relative humidity is. For

example, air at a temperature of 24C (75F) with a relative humidity of 45% would

have a relative humidity of 65% at a temperature of 18C (64F) and could have a

still higher relative humidity as the temperature falls.

Air conditioners are not designed to detect subtle changes in temperature and

humidity in the entire computer room space. Generally, air conditioning is controlled

by detecting and regulating the temperature and humidity at the main unit or at each

of multiple air outlets. An air conditioner installed for underfloor ventilation detects

and regulates the temperature and humidity at a point near each air outlet. As such, a

nonuniform distribution of temperature and humidity may occur in the computer

room.

Table 4.1 lists recommended temperatures and humidities for computer rooms.

C120-H007-08EN 39

CHAPTER 4 Air Conditioning

Table 4.1 Recommended temperatures and humidities for computer rooms

Air

conditioning

setup

Direct
blowing or
duct blowing

Underfloor
ventilation

Combined
direct
blowing or
duct blowing
and
underfloor
ventilation

Near the underfloor air outlet Detection and regulation point

Temperature

C F



181 C 642 F 655% Targeted

181 C 642 F655% 24 2 C754F455% 

  24 2 C754F455% 

Humidity %

Temperature

C

at
24 C

F

Targeted
at
75F

Humidity %

About 45%
at 24C
(75F)

The
temperature
and
humidity
depend on
the thermal
load.

Remarks

4.3.3 Temperature and humidity recommendations for computer rooms

Practical temperature and humidity recommendations that apply to changing the room

temperature from the basic recommendations or to lowering the underfloor

temperature in unattended areas where paper is not used are explained below.

(1) Changing the room temperature

Before changing the room temperature of a computer room from the basic

recommendations consider the following:

 Keep the room humidity constant when direct blowing or duct blowing is used.

 If underfloor ventilation and room air conditioning is combined, keep the absolute

temperature, which is a measure of the water content of the room air, equivalent to

a temperature of 24C (75F) and a humidity of 45%. Do not change the flow rate

even if the underfloor temperature is changed.

Table 4.2 summarizes the practical temperature and humidity recommendations that

apply to changing the temperature from the basic recommendations.

40 C120-H007-08EN

4.3 Air Conditioning Conditions

Table 4.2 Temperature and humidity recommendations (changing the room

temperature)

Air conditioning

setup

Direct blow or
duct blow

Underfloor
ventilation

Combined use of
direct blowing or
duct blowing
and underfloor
ventilation

Near the underfloor air

outlet

Temperature

C F C F

   Setting:

181 C 642 F655% Targeted at

191 C 662 F625% Targeted

20 1 C 682 F585% Targeted

181 C 642 F655% 242 C754F 40 to 50% Do not

191

C 662 F625% 252 C774F 40 to 48%

20 1 C 68 2 F585% 262 C794F 40 to 45%

Humidity

%

Detection and regulation

point

Temperature

Setting:
Between 21
and 26 Width
of variation:
2 C

24 C

between
24 and 25C

between
24 and 26 C

Between 70

and 79 Width

of variation:

4F

Targeted at

75F

Targeted

between

75 and 77F

Targeted

between

75 and 79F

Humidity

%

455% 

About 45% at
24C (75F)

About 43% at
24C (75F)

About 40% at
26C (79F)

The
temperature
and humidity
depend on
the thermal
load.
Do not
change the
flow rate
even if the
underfloor
temperature
is changed.

change the
flow rate
even if the
underfloor
temperature
is changed.

Remarks

Figure 4.5 is an air-line diagram depicting the relationships between the dry-bulb

temperature, relative humidity, and absolute temperature.

Figure 4.5 Psychrometric chart applicable to changing the room temperature

C120-H007-08EN 41

CHAPTER 4 Air Conditioning

(2) Lowering the underfloor temperature

In unattended areas where paper is not used and where only those devices that have

broad permissible underfloor and room temperature and humidity ranges are installed,

the underfloor temperature may be lowered. As an example, in an unattended room

associated with a large system installation involving multiple computer rooms, hold

the underfloor relative humidity to 70% or below to keep the room humidity at a

lower level.

Table 4.3 summarizes the practical temperature and humidity recommendations that

apply to lowering the underfloor temperature.

Table 4.3 Temperature and humidity recommendations (lowering the underfloor

temperature)

Air

conditioning

setup

Underfloor
ventilation

Combined use
of direct
blowing or duct
blowing and
underfloor
ventilation

Figure 4.6 is an air-line diagram applicable to lowering the underfloor temperature.

Near the underfloor air outlet Detection and regulation point

Humidity

C F C F

171 C 632 F655% Targeted

161 C 612 F655% Targeted

171 C 632 F655% 242 C754F425% 

161 C 612 F655% 242 C754F405%

%

Temperature Humidity

at 24 C

at 24 C

Targ eted
at 75F

Targ eted
at 75F

About 42%
at 24C (75F)

About 40%
at 24C (75F)



The
temperature
and humidity
depend on
the thermal
load.

RemarksTemperature

Figure 4.6 Psychrometric chart applicable to lowering the underfloor temperature

42 C120-H007-08EN

4.3 Air Conditioning Conditions

4.3.4 Dust

(1) Airborne dust

Ensure that airborne dust does not exceed 0.15 mg/m3 (0.004 mg/ft3). Most server

systems are designed to withstand this level of airborne dust. This is the same as the

permissible level for airborne dust in a general office and should be easily attainable

in a computer room where there is little inflow of outside air and smoke.

(2) Removing dust

Airborne dust is collected by air filters in the air conditioner. For air filter, see Section

4.5.2, "Air conditioner filters." The computer room must be periodically cleaned to

remove dust on and under the floor. For cleaning procedures, see (6), "Base floor and

free-access floor cleaning," in 2.3.2, "Free-access flooring."

Cleaning is required in the following situations:

 When the construction of the computer room has just been completed, and it is

ready to house equipment.

 When the computer room has been repaired.

 When equipment already in position in the computer room has been relocated.

Areas surrounding printers and for forms handling require periodic cleaning.

4.3.5 Corrosive gases

Corrosive gases must be removed and kept out by using appropriate air cleaning

facilities. Maintaining positive pressure in the computer room with filtered air will

serve as a safeguard against the entry of corrosive gases or dust from an outside

source.

Table 4.4 lists the tolerable limits for different kinds of corrosive gases.

Table 4.4 Tolerable limits for corrosive gases (1/2)

Gas name Tolerable limit

Hydrogen sulfide (H

Sulfur dioxide (sulfur oxide) (SO

Hydrogen chloride (HCI) Up to 6.6 ppb

Chlorine (CI

Hydrogen fluoride (HF) Up to 3.6 ppb

C120-H007-08EN 43

) Up to 3.4 ppb

2

S) Up to 7.1 ppb

2

) Up to 37 ppb

2

CHAPTER 4 Air Conditioning

Table 4.4 Tolerable limits for corrosive gases (2/2)

Gas name Tol er ab le li mi t

Nitrogen dioxide (nitrogen oxide) (NO2) Up to 52 ppb

Ammonia (NH

Ozone (O

Oil vapor

) Up to 420 ppb

3

) Up to 5 ppb

3

4.3.6 Seawater (salt damage)

The air in the vicinity of coastal areas contains large amounts of airborne sea salt

particles. If these particles remain inside computers, substances are formed by a

condensation reaction of chemicals. These substances and the humidity lead to

insulation failure and the corrosion and deterioration of components and materials.

Therefore, computers should be installed in locations at a distance from coastal areas.

The following outlines installation criteria for preventing salt water damage due to

airborne sea salt particles.

Criteria: The installation site shall not be within 0.5 km of the ocean or coastal areas

(unless the computer room uses air conditioners to filter out airborne sea salt particles

from outside air).

Up to 0.2 mg/m

3

44 C120-H007-08EN

4.4 Thermal Load and Cooling Capacities

4.4 Thermal Load and Cooling Capacities

The thermal load imposed on an air conditioner must include those coming from the

power supply facilities and from the building, as well as heat from the server system

itself.

Air conditioning of computer rooms in comparison with normal offices is

characterized by the following:

 Sensible heat accounts for a greater percentage of the heat which causes

temperature rises, with lesser latent heat relating to outside air and vapor from

human bodies. The flow rate of the air conditioner needs to be able to cool sensible

heat.

 While the common room temperature and humidity requirements are 24C (75F)

(dry-bulb temperature) and 45% (relative humidity), the ratings of air conditioners

are usually stated at 27C (81F) and 50%.

Hence, it is more desirable to determine the cooling capacity of an air conditioner on

the basis of its test data, rather than its stated ratings. Possible sources of thermal load

that are imposed on air conditioners, examples of cooling capacity calculations, and

convenient formulas to work out air conditioning capacities are described below:

4.4.1 Thermal load imposed on air conditioner

The thermal load that is imposed on an air conditioner in a server room can generally

be calculated by summing up the amount of heat dissipation listed in Table 4.5.

Table 4.5 Sources of overload and amount of heat dissipation

Source of heat Amount of heat dissipation

Heat from the server system

Heat from the power supply
facilities

Heat from outside the room
(walls, partitions, windows,
ceiling, floor, etc.)

Heat from outside air taken in,
from natural ventilation, etc.

Heat from lighting fixtures

Heat from human bodies

Amount of heat dissipation calculated from the
specification of the individual devices.

Amount of heat dissipation from the stepdown
transformer, automatic voltage regulator (AVR), or
uninterruptible power supply (UPS).

A computer room in a steel-framed reinforced
concrete building built in Japan typically has a heat

dissipation of about 420 kJ/h per 1m

2

per 1 ft
This approximate value depends on the district in
which the building exists, its structure, the
orientation of the room, and other relevant
conditions.

).

2

(36.9 Btu/h

C120-H007-08EN 45

CHAPTER 4 Air Conditioning

4.4.2 Example of cooling capacity calculations for room air conditioning

Examples of cooling capacity calculations for an air conditioner, flow rate 135 m3/min

(4770 ft3/min), running in a room air conditioning setup are given below.

The following values have been determined with respect to the rated capacity of 167.4

MJ/h (158,700 Btu/h):

 The cooling capacity is 145.6 MJ/h (138,000 Btu/h), 87% of the capacity rating.

 The sensible heat capacity is 124.4 MJ/h (117,900 Btu/h), 74% of the capacity

rating.

Figure 4.7 shows typical air conditioner characteristics, and Figure 4.8 shows the air

condition in a psychrometric chart.

Figure 4.7 Typical air conditioner characteristics

Figure 4.8 Air condition in a psychrometric chart (for a typical air conditioner)

Table 4.6 summarizes procedures that can be used to calculate the cooling capacities

of a typical air conditioner from its characteristics and psychrometric chart.

46 C120-H007-08EN

4.4 Thermal Load and Cooling Capacities

The values in the table involve certain characteristic curve and air-line diagram read

errors.

Table 4.6 Examples of typical air conditioner cooling capacity calculations (1/2)

Item Calculated value Calculation method

Enthalpy of the air at the
conditioner inlet

Enthalpy difference
between the air conditioner
coil inlet and the coil
surface

Enthalpy on the air
conditioner coil surface

Air conditioner bypass
factor

Enthalpy of the air coming
out of the air conditioner

Temperature and humidity
at the inlet

Enthalpy on the air
conditioner coil surface

Temperature and humidity
of the air coming out of the
air conditioner

Air conditioner cooling
capacity

i

=45.4 kJ/kg

1

(19.6 Btu/lb)

i=16.7 kJ/kg

(7.2 Btu/lb)

i

=28.7 kJ/kg

2

(12.4 Btu/lb)

Determine the enthalpy at 24C (75.2F)and
45%RH from the air-line diagram

Determine the difference from typical air
conditioner characteristics.

Determine the enthalpy from the air-line
diagram.

BF=0.095 Determine the bypass factor from typical air

conditioner characteristics.

i

=30.3 kJ/kg

3

(13.1 Btu/lb)

Calculate the enthalpy by solving the bypass
factor relation BF= (i

- i2) / (i1 - i2).

3

24C (75.2F) 45% Setup condition

9.7C (49.5F)
100%

Determine the temperature and humidity
from the point of intersection between the
enthalpy (i

) on the air conditioner coil

2

surface and 100% relative humidity in the
air-line diagram.

11.1C (52F) 92% Determine the temperature and humidity
from the point of intersection of a line
segment, between the status point at the
conditioner inlet and that on the air
conditioner coil surface, and the enthalpy of
the air coming out of the air conditioner in
the air-line diagram.

145.6 MJ/h

(138,029 Btu/h)

(i

- i3)  Flow rate/Specific volume

1

3

3

3

/kg)

/lb)

/min) 

3

/min) 

=15.1 (kJ/kg)  135 (m

60 (min/h) / 0.84 (m

=6.5 (Btu/lb)  4770 (ft

60 (min/h) / 13.5 (ft

C120-H007-08EN 47

CHAPTER 4 Air Conditioning

Table 4.6 Examples of typical air conditioner cooling capacity calculations (2/2)

Item Calculated value Calculation method

Air conditioner sensible
heat cooling capacity
(when calculated on the
basis of sensible heat
enthalpy differences)

Air conditioner sensible
heat cooling capacity
(when calculated on the
basis of temperature
differences)

124.4 MJ/h
(117,931 Btu/h)

124.4 MJ/h
(117,931 Btu/h)

(i

- i3)  Flow rate/Specific volume

4

3

=12.9 (kJ/kg) 135 (m

3

0.84 (m

/kg)

=5.5 (Btu/lb)  4770 (ft

60 (min/h) / 13.5 (ft

(T

- T3)  Specific heat  Flow

1

/min)  60 (min/h) /

3

/min) 

3

/lb)

rate/ Specific volume
=(24-11.1)(C)  1[kJ/(kg  C)]

 135 (m

/ 0.84 (m

3

/min)  60 (min/h)

3

/kg)

=(75.2-52)(F)  0.24[Btu/(lbF)]  4770

(ft3/min)  60 (min/h) / 13.5 (ft3/lb)

48 C120-H007-08EN

4.4 Thermal Load and Cooling Capacities

4.4.3 Underfloor ventilation air conditioning

Figure 4.9 shows the air condition for underfloor ventilation in a psychrometric chart.

Table 4.7 summarizes procedures for calculating the cooling capacities of an

underfloor-ventilation air conditioner, flow rate 220 m3/min (7770ft3/min).

The values in the table involve certain characteristic curve and psychrometric chart

read errors.

Figure 4.9 Air condition in a psychrometric chart (underfloor-ventilation air)

Table 4.7 Examples of underfloor-ventilation air conditioner cooling capacity

calculations (1/2)

Item Calculated value Calculation method

Temperature and
humidity at the inlet

Temperature and
humidity of the air
coming out of the air
conditioner

Air conditioner sensible
heat cooling capacity
(when calculated on the
basis of temperature
differences)

Enthalpy of the air at the
conditioner inlet

24C (75.2F) 45% Setup condition

18C (64.4F) 65% Setup condition

94.3 MJ/h (89400 Btu/h) at a flow

rate of 220 m

3

/min (7770ft3/min)

(T

- T5)  Specific heat  Flow rate/

1

Specific volume
=(24-18)(C) 1[KJ/(kg C)]220 (m
min) 60 (min/h) / 0.84 (m
=(75.2-64.4)(F) [Btu/(lbF)] 

ft3/min) 60 (min/h) / 13.5 ft3/lb)

i

=45.4 kJ/kg

1

(19.5 Btu/lb)

Determine the enthalpy at 24C (75.2°F)
and 45% RH from the air-line diagram.

3

/kg)

3

/

C120-H007-08EN 49

CHAPTER 4 Air Conditioning

1.0/0.84 (24 C-11 C) 0.9 60

Thermal load (kJ/h)

0.24/13.5 (75.2 F-52 F) 0.9 60

Thermal load (Btu/h)

=

.

.

=

.

.

Flow rate (m /min)

3

Flow rate (ft /min)

3

1.0/0.84 (24 C-18 C) 60

Thermal load (kJ/h)

0.24/13.5 (75.2 F-64.4 F) 60

Thermal load (Btu/h)

=

.

.

=

.

.

Flow rate (m /min)

3

Flow rate (ft /min)

3

Table 4.7 Examples of underfloor-ventilation air conditioner cooling capacity

calculations (2/2)

Item Calculated value Calculation method

Enthalpy of the air
coming out of the air

i5 =39.3 kJ/kg

(16.9 Btu/lb)

Determine the enthalpy at 18C (64.4°F)

and 65% RH from the air-line diagram.
conditioner

Air conditioner sensible
heat cooling capacity
(when calculated on the
basis of sensible heat
enthalpy difference)

95.9 MJ/h(90900 Btu/h) at a flow

rate of 220 m

3

/min (7770ft3/min)

(i

- i5)  Flow rate/Specific volume

1

=6.1(kJ/kg)  220 (m

 60 (min/h) / 0.84 (m

=2.6(Btu/lb)  ft

60 (min/h) / 13.5 ft

3

/min)

3

/kg)

3

/min)

3

/lb)

4.4.4 Convenient formulas for air conditioning capacities

Table 4.8 lists convenient formulas for the capacity of air conditioners installed in a

computer room. Because a proportion of the thermal load comes from sensible heat,

the capacity and number of air conditioners required can be determined by calculating

the flow rate requirement relating to sensible heat. Actual air conditioning design

should allow for air conditioner characteristics, building thermal load calculations,

etc.

Table 4.8 Convenient formulas for air conditioner capacity

Air conditioning setup

Room air conditioning

Underfloor ventilation

Flow rate calculation formula

50 C120-H007-08EN

4.4 Thermal Load and Cooling Capacities

Sensible heat from thermal load

Temperature difference

Specific

heat/Specific vol

----------------------------------------------------------------------------------------------------------------------------------------------------------

=

The formula terms are:

 Flow rate: Sensible heat from the thermal load divided by the temperature

difference and the heat removed to cool a unit volume by 1C (34F).

 Thermal load: While the thermal load is a sum of sensible heat and latent heat,

sensible heat accounts for such a large proportion of the thermal load in a computer

room that the thermal load is assumed to be equal to the sensible heat.

Thermal load = Sensible heat + Latent heat Sensible heat

• 1.0 or 0.24: Specific heat of the air [kJ/(kg  C )] or [Btu/(lb  F)]

• 0.84 or 1.35:

Specific volume of the air (m

3

/kg) or (ft

•24C or 75.2F: Air conditioner inlet air temperature

•11C or 52F: Approximate temperature of the air on the coil surface
of a room air conditioner

• 0.9: Approximate bypass factor of a room air conditioner

• 60: Conversion to minutes (min/h)

•18C or 64.4F: Outlet air temperature of an underfloor-ventilation air
conditioner

3

/lb)

C120-H007-08EN 51

CHAPTER 4 Air Conditioning

4.5 Precautions Pertaining to the Installation of Air Conditioners

Air conditioners that are installed in computer rooms differ in many ways from those

installed in general offices. Precautions specific to installing air conditioners in a

computer room are summarized below.

4.5.1 Humidifier

The reason a humidifier is needed, types of humidifiers available, and humidifiers

used with underfloor-ventilation air conditioners are described below.

(1) Why a humidifier is needed?

In the winter time, drops in the relative humidity of the air in the computer room make

it more susceptible to the generation of static electricity. To prevent this, a humidifier

must be installed to raise the relative humidity of the room air.

(2) Types of humidifiers and replacement water

Use of a humidifier that generates steam by boiling water is recommended.

Using a boiling humidifier will cause impurities in the water to be precipitated and

should have automatic or periodic discharge and replacement of the water.

A spraying humidifier (for example, ultrasonic humidifier, water spray, or centrifugal

sprayer) discharges fine drops of water into the air in vapor form. With this type of

humidifier, impurities in the water could adhere to the equipment or supplies as white

powder. This white powder can be a source of numerous problems, including

defective insulation, rusting, clogged filters, or poor contact, and might also scratch

the surfaces of magnetic disks, resulting in loss of data.

When using spray humidifiers including ultrasonic humidifier, be sure to maintain the

purity of distilled water.

The following conditions must be considered when using purifiers.

 Let distilled water pass the ion exchange resin of the purifier. The conductivity of

water after passing a purifier must not exceed 2 S/cm.

 Use a purifier that detects problems in the ion exchange resin automatically to

sustain the performance of the purifier. When problems are detected, replace the

ion exchange resin.

52 C120-H007-08EN

4.5 Precautions Pertaining to the Installation of Air Conditioners

(3) Humidifiers used with underfloor-ventilation air conditioners

Certain types of underfloor-ventilation air conditioners have a boiling humidifier and

a draft fan installed at adjacent locations such that drops of boiling water from the

humidifier can enter the draft fan for aerial dispersion. If this occurs, impurities in the

drops of water can adhere to the air inlet of the equipment as white powder or turn

into sandy particulate under the floor and cause corrosion.

Care should be taken in selecting or designing an air conditioner to prevent the

dispersion of drops of boiling water from a boiling humidifier. In scheduled facility

checkouts, check for white powder on the draft fan, sandy particulate under the floor,

and white powder on the air inlets of the equipment and any resultant corrosion to

ensure that the air conditioner is working correctly.

4.5.2 Air conditioner filters

Use filters that provide a high collection efficiency and that do not have any adverse

effects on the server system. Also install a filter at the outside air inlet to remove dust

from the outside air.

(1) Filter collection efficiency

Use of a filter with a collection efficiency of 95% or higher as measured by the

gravimetric method is recommended.

(2) Filter types

Filters must be mechanical ones made of a nonwoven cloth or similar material. Do not

use electrostatic dust collectors as they generate ozone gases, which could degrade

rubber parts.

C120-H007-08EN 53

CHAPTER 4 Air Conditioning

4.5.3 Installing temperature/humidity sensors

Temperature/humidity sensors used to regulate the temperature and humidity of an air

conditioner are installed at different positions according to the ventilation method.

(1) Location of temperature/humidity sensors for a room air

conditioner

Location to install temperature/humidity sensors for a room air conditioner is:

 At a height of about 1 to 1.5 m (3.3 to 4.9 ft) above the floor

 Where measuring the mean temperature and humidity is available

 Where they are not exposed to direct drafts of cold air from the air conditioner or

air emissions from the equipment

(2) Location of temperature/humidity sensors for an underfloor-

ventilation air conditioner

Location to install a temperature/humidity sensor for a underfloor-ventilation air

conditioner is:

 Under the floor 1 to 1.5 m (3.3 to 4.9 ft) from the air outlets

 Where they are readily accessible for inspection

4.5.4 Taking in fresh air

Fresh air needs to be drawn into the computer room for operators.

(1) Volume of fresh air

Fresh air should be taken in at a rate of about 30 m3/h (1100 ft3/h) per operator present.

Where outside air is taken in through a duct, and not by natural ventilation through

ventilation, dust must be removed and its temperature and humidity regulated before

it can be fed into the room or under the floor.

(2) Preventing natural inflow of outside air

Install a closing damper at the outside air intake duct. Keep it closed to prevent the

natural inflow of outside air while the air conditioner is shut down. Prevent natural

inflow of outside air through ventilation.

54 C120-H007-08EN

4.5 Precautions Pertaining to the Installation of Air Conditioners

4.5.5 Preventing dew condensation in underfloor ventilation

In underfloor ventilation, provisions should be made to prevent dew condensation

inside and outside of devices installed in the computer room as they are exposed to

direct drafts of cold air from the air conditioner. Devices are susceptible to dew

condensation if they are at a low temperature while the room temperature is low and

also if the air inside and outside the room is at a high temperature and a high humidity.

Further, where both the temperature and humidity are regulated from the beginning,

the underfloor air could be dampened and cause dew condensation.

The air conditioning control scheme must be examined and established on the user's

own responsibility to meet their own needs. Typical air conditioning control schemes

are described below.

(1) If the room temperature is low

If the room is in low temperature, the devices installed in the computer room is also

cool. When this occurs, follow the procedure below to start the humidifiers.

1 Stop the humidifier of the air conditioner(s).
2 After reaching the target temperature only with the air conditioner in heating-drive

mode, turn on the server systems.

3 Change the drive mode of the air conditioner to cooling-drive.
4 When room temperature reaches stable circumstance, start operating the

humidifiers.

(2) If the room air is at a high temperature and a high humidity

If the room air is at a high temperature and a high humidity, the room humidity will

rise sharply when the air conditioner starts to deliver low-temperature air. When this

occurs, follow the procedure below to start operating the air conditioning.

1 Bring the room air to the target temperature and humidity points slowly while

dehumidifying the air with a high blow temperature setting and a low humidity
setting. Keep the dehumidifier stopped in the meantime.
If the room humidity does not fall below its target point before the dehumidifier is
run, the following are conceivable:

 Failing to dehumidify the air because reheater that regulates the temperature after

room air has been cooled may not operate.

 Outside air penetrating the room through gaps.

In this case, the facilities and building must be checked.

C120-H007-08EN 55

CHAPTER 4 Air Conditioning

2 When temperature reaches the target range, turn on the server system. The

humidifier may operate after the room temperature reaches a stable state.

(3) Example of stopping humidifier upon starting up of the server

system

In underfloor ventilation, if heat dissipation from server system during startup of the

equipment leads transition of drive condition of the air conditioners, and the room is

dampened heavily so that the room is brought to high humidity, dew condensation

may be caused in the server system. In such case, to prevent high humidity or dew

condensation, stop the humidifier before turning on the server system, restart the

humidifier when the temperature is stabilized after server system is turned on.

4.5.6 Preventing water leaks and installing detectors

Ensure that water leaks, resulting from failures in the air conditioner or water piping

or clogged drain pipes, will not spread to under the raised floor or over the floor

surface. When water leaks occur, they should be detected immediately. It is

recommended that dikes or similar fences be made around the air conditioner and that

leak detectors be installed inside the dike and around the water pipeline.

Figure 4.10 is a schematic view of a dike.

Figure 4.10 Dike

56 C120-H007-08EN

4.5 Precautions Pertaining to the Installation of Air Conditioners

4.5.7 Installing a backup unit

It is recommended that the air conditioner be backed up. Without a backup unit, if the

air conditioner fails, the resultant rise in the computer room temperature would

demand a shutdown of the server system to correct the failure. A backup unit also

facilitates scheduled inspections.

4.5.8 Preventing freezing of cooling water

The air conditioner for a server system is generally run for cooling year round. If a

water-cooled air conditioner is used, care should be taken to prevent the water in the

cooling tower from freezing.

C120-H007-08EN 57

CHAPTER 5 Electromagnetic Environment

and Static Electricity

1

This chapter explains the electromagnetic environment conditions and electrostatic

effects relevant to server systems.

5.1 Magnetic Fields

CRT displays could be influenced by the magnetic fields generated by nearby power

transformers, electric wires carrying large current, or any magnetized metallic objects.

5.1.1 Allowable magnetic field intensities of displays

CRT displays vary in allowable magnetic field intensity depending on the size of the

CRT, resolution, etc.

Typical values are:

 Allowable AC magnetic field intensity: About 1 

 Allowable DC magnetic field intensity: About 50 to

C120-H007-08EN 59

CHAPTER 5 Electromagnetic Environment and Static Electricity

5.1.2 Sources of magnetic fields and fault symptoms

Table 5.1 lists the possible sources of magnetic fields and the associated display

screen faults.

Table 5.1 Sources of magnetic fields and fault symptoms (1/2)

Magnetic field

component

AC magnetic field
components

Source of magnetic field Fault symptom

1 Power supply facilities, such as an uninterruptible

power supply and a transformer, or any electrically
driven equipment, such as a motor: Magnetic fields are
generated by current flowing through the equipment.
Example: AC magnetic field of 8.2 at a point 4 m
(13 ft) away from a transformer rated at 100 kVA.

2 Indoor electrical connections: A separation of 2 m (7 ft)

from connections rated at 30 A or so will eliminate their
effects.
Example: AC magnetic field of 2.5 at a point 1 m (3
ft) away from a connection that is not enclosed in a steel
pipe.

3 High-voltage transmission lines, electric car overhead

lines
Example: A high-voltage transmission line rated at
about 280 A will affect the display images of displays
installed 5 m (16 ft) away with a magnetic field of 2.4
, but will not affect those of a display device installed
10 m (33 ft) away with only 0.6 

4 Adjacent equipment: Magnetic fields generated from

the adjacent equipment could exert adverse effects.
Example: AC magnetic field of 3  at a point 200 mm
(8 in.) away from a display device.

5 Mutual interference among display devices: Magnetic

fields generated from the deflection yoke in each device
may have an interfering effect.
Example: AC magnetic field of 3 at a point 200 mm
(8 in.) away from a display device.

Fluctuating display
images

60 C120-H007-08EN

5.1 Magnetic Fields

Table 5.1 Sources of magnetic fields and fault symptoms (2/2)

Magnetic field

component

DC magnetic field
components

1 Electrically welded metallic exterior sheets, etc.:

Magnetism may remain as a result of metallic
magnetization.

2 Magnets used in acoustic equipment: Speaker magnets,

etc.

3 Steel-framed prefabricated columns, etc. moved by an

electromagnetic on a crane
Example: DC magnetic field of 100 at a point 0.5 m
(1.6 ft) away from the steel frame.

4 Equipment operating on a DC magnetic field principle,

a magnetic paper holder, etc.
Example: DC magnetic field of 500 at a point 2 m (7
ft) away from a nuclear magnetic resonance unit

Source of magnetic field Fault symptom

5.1.3 Magnetic field control

Displays may require the following actions to control nearby magnetic fields in

Color misconvergence,
display distortion

excess of their allowable magnetic field intensities:

(1) Separating the display

Keep the display farther away from sources of magnetic fields. Magnetic fields will

be lessened in a range between the value divided by separation to the third power and

the value divided by separation to the second power.

(2) Changing the display type

Change the display from a CRT display to a liquid-crystal or plasma display.

(3) Magnetic shielding

Special permalloy parts or cases can provide a shield against magnetic field effects.

Certain display models are available with internal fitting magnetic shied options.

For information on magnetic shielding of a display as a whole, consult a shielding

case manufacturer.

C120-H007-08EN 61

CHAPTER 5 Electromagnetic Environment and Static Electricity

5.2 Electric Fields

This section describes electric fields.

5.2.1 Allowable electric field intensities for server systems

Each equipment has an allowable electric field intensity of 3 V/m, where 1 V/m is 120

dB/V.

An electric field intensity of 1 V/m is a typical level encountered in a low-level

electromagnetic radiation environment. For the example purpose:

 In transmissions from a typical radio or TV station located 1 km (3000 ft) away or

farther

 In transmissions from a low-power transceiver

5.2.2 Conditions for using mobile phones

Keep the main unit doors closed and stay 1.7 m (5 ft) away from the main unit before

using mobile phones.

Moreover, since mobile phones automatically emit electromagnetic waves in response

to incoming messages, Fujitsu recommends keeping mobile phones switched off near

the computing equipment.

62 C120-H007-08EN

5.3 Static Electricity

5.3 Static Electricity

Static electricity may be charged and kept in a person's body by the following

conditions.

 Through friction between shoes and floor as a result of his or her walking.

 Through friction between clothes and body.

 Also, carts may be charged as a result of their movement.

When this static electricity is discharged to server system at a high charge voltage, it

could cause a malfunction. Hence, take steps to make the computer room less

susceptible to electrostatic generation.

5.3.1 Recommended electrostatic voltage for a computer room

It is best if the static electricity charge on human bodies or carts be kept at such level

or lower that there is no discomfort to the people when there is a discharge. For

example it will not cause pain in the skin at discharge. This is variable from one

individual to another, but it is generally about 2.0 kV (kilovolt). An electrostatic

discharge of 2.0 kV or lower should not affect the server system.

5.3.2 Electrostatic control in the computer room

To inhibit the generation of static electricity, choose flooring that is rarely charged

with static electricity and use humidity control. For computer room flooring surface

materials, see Table 2.3 For suggested computer room humidities, see Table 4.1 and

Section 4.3.3, "Temperature and humidity recommendations for computer rooms."

C120-H007-08EN 63

CHAPTER 6 Power Supply Facilities

1

This chapter deals with input power requirements, power supply facilities,

uninterruptible power supplies (UPS), grounding, distribution panels, distribution

lines, and the share of responsibility for construction work.

Operational stability of a server system requires a good-quality power supply. Power

supply facilities that match the power requirements of the server system must be

selected to suit the importance of the server system's operation.

6.1 Input Power Requirements

This section describes input power requirements, power requirement, and a method

for calculating rush current.

6.1.1 Input power requirements

Input power at the input power terminals of equipment must satisfy the requirements

listed in Table 6.1. For unit-specific input voltage, power requirement, and rush

current specifications, refer to the relevant Installation Planning Manual.

C120-H007-08EN 65

CHAPTER 6 Power Supply Facilities

Table 6.1 Input power requirement

Item Requirement

Input voltage Number of phases Abroad

Single-phase two-wire 100 V, 110 V, 115 V, 120 V

Single-phase two-wire 200 V, 208 V, 220 V, 230 V, 240 V

Three-phase three-wire 200 V, 208 V,220 V, 230 V, 240 V

Three-phase four-wire 380 V, 400 V, 415 V neutral conductor

connected to ground

Voltage regulation From +10% to -10% of the input voltage or less

Instantaneous input voltage
variation

Instantaneous input
interruption

Input frequency 50 Hz or 60 Hz

Frequency regulation +2% to -4% of the input frequency

Input voltage imbalance 5% or less (three-phase input)

Voltage waveform distortion 10% or less

Power capacitance Depends on each unit specifications

Rush current Depends on each unit specifications

+15% to -20% of the input voltage or less in 0.5 second or
shorter

10ms or less

6.1.2 Calculating the power required

For the purpose of selecting the kind of power supply facilities required, calculate the

total power requirement of every unit in the system by consulting the relevant

Installation Planning Manual.

6.1.3 Calculating the rush current

The rush current calculation assists with selecting a UPS. Calculate the rush current in

the power-on sequence by consulting the documentation for each component. The

case that more than one device may turn on at the same time should also be

considered.

If the UPS is started up rapidly, the UPS startup could occur as rush current flows

from the server system line filter and before the server system power controller begins

to properly supply power to the server system. In this case, the UPS may detect

overcurrent. Try to use an UPS that allows for a slow startup.

66 C120-H007-08EN

6.2 Power Supply Facilities

6.2 Power Supply Facilities

Select power supply facilities after considering the input power requirements of the

server system (see Section 6.1), the availability of a power source at the installation

site, and the operational importance of the server system.

6.2.1 Kinds and uses of power supply facilities

Power supply facilities are used for converting voltages, reducing leakage current,

keeping a server system free from power failures, shaping waveforms, converting

frequencies, and reducing harmonic currents.

Table 6.2 lists the kinds of power supply facilities available, and their fitness for

particular uses.

Table 6.2 Types of available power supply facilities and usage

Use

Type of power

supply facility

Commercial power
source

Transformer 

UPS:
Constant commercial
type

UPS:
Constant inverter type

Voltage

conversion







Freedom

from power

failures

Waveform

shaping

Reduction

of

harmonic

current

Note: means fit.

means not fit.

Among the uses of power supply facilities, the reduction in leakage current and

freedom from power failures are highlighted below.

C120-H007-08EN 67

CHAPTER 6 Power Supply Facilities

(1) Reduction in leakage current

Computers are equipped with a line filter in their power input terminals to absorb both

external and internal electric noise. If a common commercial power source is

connected to a computer, leakage current will flow to the grounding cable of the

computer.

In a system built by connecting multiple computers with one another, the total leakage

current flowing to ground across the system must be compliant with IEC60435 and

IEC60364.

Notes:

Leakage current can be classified as follows:

 Equipment leakage current:

This equipment-inherent current is observed at equipment grounding terminals

when power with the frequency/voltage characteristics of a commercial power

supply is applied. The values of the current must be in accordance with the

operating manuals for the respective equipment.

 Ground leakage current:

This current flows to ground in actual system operation, and it differs from the

total equipment leakage current depending on the method of distribution line

grounding. The floating current of the system has an effect on this current.

The rules of ground leakage current in the system must meet the rules of each country

and be compliant with IEC60435 and IEC60364.

(2) Freedom from power failures

Use of a UPS is recommended to keep the server system safe from power failures,

instantaneous voltage drops, or instantaneous interruptions in the commercial power

supply.

68 C120-H007-08EN

6.2 Power Supply Facilities

6.2.2 Selecting power supply facilities

Select power supply facilities to suit the available power source at the installation site,

and the operational importance of the server system.

(1) Systems that cannot tolerate service disruption

a) Power failure-free system

Use of a UPS is mandatory for server systems that cannot tolerate service disruption

at any time even the instantaneous interruption or power failure of commercial

power supply.

Figure 6.1 shows the configuration example of a server system which uses a UPS.

Note: Secondary side of UPS is isolated or neutral.

Figure 6.1 System based on a UPS

b) Long-duration power failure-free system

A UPS combined with an independent power generator provides a solution for

longer term power failures as shown in Figure 6.2.

Figure 6.2 System based on a UPS and an independent power generator

C120-H007-08EN 69

CHAPTER 6 Power Supply Facilities

(2) Systems that can tolerate a service disruption

If a server system can tolerate a service disruption caused by power interruption or

voltage variation, install a transformer dedicated to that system, isolated from the

secondary terminals if the system runs at 200 V or grounded to a neutral phase wire if

it runs at 400 V.

a) Transformers dedicated to 200 V server systems

Table 6.3 contains descriptions of the types of transformers dedicated to 200 V

server systems and their schematic views.

Table 6.3 Transformers for 200 V server systems

Case

A dedicated high-to-low-voltage
transformer can be installed.

High-to-low-voltage
transformer that is shared with
other power supplies.

Transformer dedicated

to a server system

Install a contact
prevention transformer
that has an output voltage
of 200 V and is dedicated
to the server system. The
secondary terminal of the
transformer shall be
isolated.

Install a separate
transformer that has an
output voltage of 200 V
and is dedicated to the
server system near the
distribution panel. The
secondary terminal of the
transformer shall be
isolated.

Schematic view

High-voltage line

High-voltage line

70 C120-H007-08EN

6.2 Power Supply Facilities

b) Transformers dedicated to 400 V server systems

Table 6.4 describes the types of high-to-low-voltage transformers that can be

dedicated to 400 V server systems and those that can be shared with other power

supplies.

Table 6.4 Transformers dedicated to 400 V server systems

Transformer

Case

A dedicated high-to-low-voltage
transformer can be installed.

A high-to-low-voltage
transformer that is shared with
other power supplies.

dedicated to a server

system

Install a transformer in
the power receiving/
transformer room. If the
power receiving/
transformer room is not
close to the computer
room, install a separate
transformer near the
distribution panel in the
computer room.
The secondary terminal
of the separate
transformer shall be
grounded to a neutral
phase wire.

Install a separate
transformer near the
distribution panel in the
computer room, with its
secondary terminal
grounded to a neutral
phase wire.

Schematic view

High-voltage line

High-voltage line

C120-H007-08EN 71

CHAPTER 6 Power Supply Facilities

6.3 UPS Requirements

An Uninterruptible Power Supply system (UPS) supplies power to server systems

constantly under power failures even in a huge magnitude of power failures.

Instantaneous voltage drop of commercial power generally occur by thunder. The

chance of occurrence of instantaneous voltage drop depends on the location of the site

(in Japan, three to four times in a year). The typical interruption time of power supply

is said between 0.07 to 2 seconds.

Generally, power distribution circuits of server systems can maintain the performance

under power interruption at magnitude of 0.01 second. When the lower power supply

or power interruption sustains over 0.01 seconds, operation of server systems is

disabled, and this may lead to system down. It is important to avoid instantaneous

system down since longer time must be spent to reactivate the server systems, and

applications may interrupt for long time accordingly. Not only that, important files

may be destructed. Use UPS to prevent such instantaneous power failures. UPS

distributes to components in the server system in operation by its built-in batteries

under such interruption of commercial power supply.

UPS examination items are explained below.

Note that if the UPS is installed regardless of the following requirements, the

requirements of the server system and the performance of the UPS mismatch, and the

user's server system may be damaged, or significant data may be destroyed.

 UPS load specifications

 Prediction of rush current and load variation of the equipment

 UPS terminating requirements

 Effect of high-frequency noise

 Life-span of a UPS built-in battery

 Discharge of UPS built in battery

 Requirements for power interruption

 Leakage current

 Load rating

 Power rating (for printer connection)

 Checking the UPS environmental specifications and the warranty term

72 C120-H007-08EN

6.3 UPS Requirements

(1) UPS load specifications

Some server systems adopt condenser-input type rectifier circuit (commutating load)

as shown in Figure 6.3.

Figure 6.3 Commutating load circuit

Rectifier of this type turns the current waveform of a server system into a distorted

waveform containing harmonics. The amplified crest (peak value) of distorted

waveform containing harmonics is about 2.8 times to the effective value.(It means

that if effective value is 10 A, the peak value is 28 A.) If the UPS is so designed that

output voltage is regulated by resistor, driving at 50% or less of the UPS's deliverable

output voltage is needed. Make sure that the rectifier has a mechanism that lowers the

distortion (peak value is about 2.8 times) current passing the rectifier to 10%

(distortion factor) at peak wave (crest factor). Also check this point for loads of

transformers and motors (linear amplifier).

As the conclusion, the recommendable UPS rectifier load specification is:

 Linear load or Peak-to-valley ratio (at peak) must not exceed 2.8

(2) Prediction of rush current and load variation of the equipment

Turning on the power to connected devices generates rush current. For example, a

component operating at a steady-state current of 3 A may generate a current of

0-P

30 A

UPS output voltage fluctuation must stay within ±15%. Special attention must be

paid to cases where multiple devices are connected, since the rush current generated

by each connected device at its power-on time may cause a UPS voltage drop, and

other components in operation may stop operating. Therefore, the rush current and

load variability of the components must be reviewed together with the overcurrent

detection specifications of the UPS.

when it is turned on. Even when connected devices generate rush current, the

C120-H007-08EN 73

CHAPTER 6 Power Supply Facilities

(3) UPS terminating requirements

UPS terminates when incorrect current is loaded (overload). When such circumstance

is made, the output cutoff circuit (which prevents distribution of current exceeding the

specification) activates to drop voltage, and the UPS stops. Some components may

generate higher load to stop UPS. If this occurs, input power to the components is

switched to direct commercial power since UPS stops when overloaded. As switching

back input power to UPS, rush current is generated, then UPS stops again. As such,

power supply can not be steady. To avoid this, review the specified overload value

that UPS activates the circuit (the mean and peak values), and make sure to operate

under the value.

(4) Effect of high-frequency noise

Normally, UPS uses microwave switching method. For this reason, output noise and

input noise around the components and reflection noise are generated. These noises

may cause components failure and data destruction of the nearby recording media.

Therefore, following must be reviewed when selecting a UPS.

 Input and output noise around the component is 4 V

 Reflection noise is 70 dB or less

 Do not place magnetic tapes and floppy disks on the UPS

(5) Life-span of a UPS built-in battery

The main type of battery built into a UPS is a lead-acid battery. Lead-acid batteries

have their own life-spans, and therefore Fujitsu recommends a service support

agreement for immediate battery replacement.

(6) Discharge of UPS built in battery

Once a lead-acid battery is completely discharged, sufficient voltage cannot be

generated even when recharged. If this occurs, replace the battery. The battery in a

UPS that supplies its control power from the battery may be in the discharged state if

left on but not used for about five days because a power failure occurred or because it

P-P

or less

was in storage. To prevent this, the battery switch must be turned off when the UPS is

not in use. Some UPSs automatically turn off the battery switch when they stop

operating.

74 C120-H007-08EN

6.3 UPS Requirements

8

kW

10

kVA

-------------------

0.8=

8

kW

power factor of load

------------------------------------------------------------

load kVA

=

(7) Requirements for power interruption

The following specifications must be checked for selection of a UPS.

 Most of UPS cannot be started up under circumstance of power interruption. If

such startup is required, request the UPS manufacturer for modification.

 When part of system components are connected to UPS, and the rest of the

components are connected directly to the commercial power, the components

connected to commercial power supply may generate incorrect signals, and the

components malfunction may occur.

(8) Leakage current

If commercial power supply facilities have leakage shut-off unit, leak current from a

UPS may activate the shut-off unit. In such case, the following actions must be

considered.

 Increase the trigger voltage of the shut-off unit.

 Use a shut-off unit which does not trip easily by microwave leakage current.

 Install an insulation transformer between the UPS and the commercial power

outlet.

(9) Load rating

When operating UPS in higher power factor than its rated power factor, use the UPS

in reduced output voltage. For example, a rating power factor of a 10 kVA/8 kW rated

UPS is 0.8.

When connecting load lower than 0.8 power factor to the UPS, up to 10 kVA load can

be connected. When connecting load grater than 0.8 power factor, reduce the load to

the calculated value by the formula below.

C120-H007-08EN 75

CHAPTER 6 Power Supply Facilities

(10)Power rating (for printer connection)

If a printer is connected to a UPS, selecting a UPS whose power capacitance is

sufficient to connect a printer is needed, by taking account of the following

precautions.

 Input voltage variation of a printer depends on the printing mode.

 Some laser printers requires few times higher than their rated power in toner

fixing.

(11)Checking the UPS environmental specifications and the warranty

term

Other precautions and requirements:

 UPS environmental specification

- Input capacity

- Grounding phase in input one-line grounding

- External dimensions

- Mass

- Amount of heat dissipation

- Earthquake-proofing actions

- Noise level

- Input/output terminals (connector)

 Warr anty term

6.4 Grounding

Grounding should be planned to suit the following:

 Grounding equipment in the computer room

 Grounding other equipment

 Grounding LAN devices

 Grounding-plate method

 Grounding of surge absorbers

For the last, see Chapter 7, "Protection Against Lightning."

76 C120-H007-08EN

6.4 Grounding

6.4.1 Grounding equipment in the computer room

For grounding equipment, connect a protective grounding conductor to the dedicated

grounding electrode.

Transformer

Protective grounding conductor

Secondary single
wire ground of
the transformer

Flow of leakage current

Line filter

Equipment

Figure 6.4 Method of grounding equipment

If possible, do not connect an equipment cabinet to the ground built into the floor of

the computer room (such as a mesh ground) through a separate wire. This could

cause stray current to flow into the system and cause a malfunction.

The grounding method for the server systems depends on whether the computer room

is in a building that conforms to the Grounding Regulation Types or the International

Electrotechnical Commission (IEC) standards.

(1) Grounding in the buildings in conformance with the Grounding

Type :

The grounding conditions for the server systems to be installed in the domestic or

others' buildings which are in conformance with the Grounding Type with A to D type

are as follows:

To run the server systems in the computer room stable, the dedicated grounding cable

facility must be prepared for each server system to prevent extraneous noise coming

from the distribution line or other grounding system lines.

The grounding cable facilities to be installed in the computer room must have

dedicated grounding electrode. Primarily, the wiring from the dedicated grounding

electrode through the distribution panel in the computer rooms must be implemented

by the metal conduit installation method using the special insulated cables. This

ground wiring facility must not be shared with other facilities.

The grounding resistance of the dedicated grounding electrode and the grounding

trunk cable must be as follows:

 Grounding resistance of the dedicated grounding electrode: 10  or less

 Size of the grounding trunk cable: 22 mm2 (AWG 4) or more

C120-H007-08EN 77

CHAPTER 6 Power Supply Facilities

S 16 (AWG5)

16 (AWG5) < S 35 (AWG2)

S > 35 (AWG2)

S

16 (AWG5)

S/2

(2) Grounding in the buildings conforming with the IEC standards.

In the installation of server systems to the buildings based on the equal potential

bonding principal of the IEC standards, the server systems must be grounded using

grounding facility shared with other facilities.

Because the ground is not the dedicated one, the grounding trunk cables for the server

systems are preferably branched from the grounding box near the grounding electrode

(the main grounding terminal).

If there is no way other than branching from the omnibus grounding cable nearest to

the server systems, please consult with Fujitsu Facility section because noise

countermeasure which requires expertise is required in most cases.

Primarily, the wiring of grounding trunk cable must be implemented by the metal

conduit installation method using special insulated cables. Follow Table 6.5 for the

cable size.

Table 6.5 Specification of the grounding trunk cable for server systems

(in the buildings complying to the IEC standards)

Cross section of the phase

conductor of the facilities

S (mm2)

Minimum cross section of the

grounding trunk cable

Sp (mm2)

Note: The term "the phase conductor of the facilities"

represents a conductor of a phase of a power supply

cable which is led into the distribution panel.

78 C120-H007-08EN

6.4 Grounding

6.4.2 Grounding other equipment

Table 6.6 summarizes the requirements for other equipment grounding facilities.

Table 6.6 Requirements for other equipment grounding facilities

Item Requirements

Grounding electrode • A dedicated grounding electrode for other equipment is recommended.

If a dedicated grounding electrode is not available, a grounding trunk
cable may be branched from a shared grounding electrode.

• The grounding resistance must not exceed 100 .

• Keep the grounding electrode at least 10 m (33 ft) apart from the lightning
arrester grounding electrode.

Grounding trunk
cable

Distribution panel
grounding terminal

• Use an insulated wire at least 5.5 mm

• Use the grounding trunk cable dedicated to other equipment. Do not share
with other facilities.

• Isolate the primary grounding terminal and branch grounding terminals
for other equipment from the distribution panel frame.

2

(AWG10).

C120-H007-08EN 79

CHAPTER 6 Power Supply Facilities

6.4.3 Grounding LAN devices

Grounding LAN devices which share the same signal ground to the same grounding

system and those which have different signal ground to different grounding systems.

The method for grounding LAN devices, details of the separation of the LAN

transmission line signal ground from the connected devices, and typical modes of

LAN connection and grounding are described below.

(1) Grounding LAN devices

The signal ground of each device signal line is separated at the point of connection

with the LAN transmission line for both optical and metal cables.

A coaxial cable transmission line must be grounded at one point per segment.

LAN devices may be grounded to different grounding systems individually or in

groups.

A group of devices connected to the same transceiver must be grounded to the same

grounding system.

(2) Separation of the LAN transmission line signal ground from the

connected devices

The LAN transmission line signal ground is separated from the ground of the

connected devices. Table 6.7 details the separation of the signal ground.

Table 6.7 Details of the separation of the LAN transmission line signal ground (SG)

Transmission line Cable type Details

Fibre Optical fibre Separation by opto-electrical and

10Gigabit Ether Optical fibre

Gigabit Ether Optical fibre

FDDI Optical fibre

100BASE-T Paired Separation by transceiver's signal

Gigabit Ether Optical fibre

electrical-opto-signal converters

transformer

(3) Typical modes of LAN connection and grounding

Typical LAN connections and grounding are described below with regard to

100Base-T.

Figure 6.5 shows a typical 100Base-T connection. The transmission route of a twisted

pair cable is not to be grounded.

80 C120-H007-08EN

6.4 Grounding

Figure 6.5 Typical 100 Base-T connection

6.4.4 Grounding-plate method

In shared ground facilities complying with the International Electrotechnical

Commission (IEC) standards, noise generated by other electronic facilities such as

electronic devices, air conditioning facilities and elevators may penetrate the server

systems through the shared ground facilities' cables. In some cases, this can be

prevented by the grounding-plate method. In the grounding-plate method, a

grounding plate (see note below) is laid under the raised floor near the power

distribution panel, as shown in Figure 6.6. This reduces electrical noise from other

equipment. For whether the site requires implementation of grounding-plate, consult

with the Facility section.

Note: Grounding-plate conducts by high-capacitance conductive sheet covering

over copper plate.

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CHAPTER 6 Power Supply Facilities

Figure 6.6 Grounding-plate method

82 C120-H007-08EN