Emerson H800 Instruction Manual

Instruction Manual
Form 5187

March 2009

Type H800 Relief Valve

WARNING

!

Failure to follow these instructions or to
properly install and maintain this equipment

could result in an explosion, re and/or

chemical contamination causing property
damage and personal injury or death.

Fisher® relief valves must be installed, operated
and maintained in accordance with federal,
state, and local codes, rules and regulations,
and manufacturer’s instructions.

If a leak develops or if the outlet continually
vents gas, service to the unit may be required.

Failure to correct trouble could result in a

hazardous condition. Only a qualied person

must install or service the unit

Type H800

W3618

Figure 1. Type H800 Relief Valve

Installation, operation, and maintenance

procedures performed by unqualied personnel

may result in improper adjustment and unsafe
operation. Either condition may result in
equipment damage or personal injury. Use

qualied personnel when installing, operating,

and maintaining the Type H800 relief valve.

Introduction

Scope of the Manual

This manual provides installation, maintenance, and parts
ordering information for the Type H800 relief valve. Information
for other equipment used with this relief valve is contained in
separate manuals.

Product Description

(1)

The Type H800 relief valve
Direct-Operated relief valve. It is used primarily between a
pneumatic instrument and its supply pressure regulator to limit
the instrument supply pressure to 50 psig (3,4 bar) should
the supply pressure regulator fail open. The Type H800 relief
valve can also be mounted on other equipment, such as an air

compressor, where limited relief capacity is desired.

(See Figure 1) is a compact,

Specications

Specications for the Type H800 relief valve are given on
page 2. Additional specications for 67 Series regulators used

with Type H800 relief valves are shown in Table 1.

Installation

Upon receipt, inspect the relief valve to be sure it is free of
foreign material.

WARNING

!

Installing a Type H800 relief valve where its
capabilities can be exceeded or where proper
operation might be impaired may cause
personal injury, property damage, or leakage
due to bursting of pressure-containing parts or
explosion of accumulated gas. To avoid such

conditions, install a Type H800 relief valve where:

• Service conditions are within the unit
capabilities are specied in specications

section and Table 1, and

• The relief valve is protected from

exposure to physical damage and/or
corrosive substances.

1. Relief valve dened in ANSI Standard B95.1-1972. Not all codes or regulations permit these valves to be used as nal overpressure protection devices.

www.emersonprocess.com/regulators

D100405X012

Type H800

Specications

Body Size and End Connection Style

NPS 1/4, NPT (internal)

Maximum Allowable Inlet (Relief) Pressure

(1)

250 psig (17,2 bar)

Relief Pressure Ranges

Non-adjustable, Start-to-discharge between

39 and 44 psig (2,7 and 3,0 bar)

Reseat Pressure

(1)

35 psig (2,4 bar) or higher

Wide-Open Flow Coefcients for Relief Valve Sizing

Maximum Temperature Capabilities

-20° to 150°F (-29° to 66°C)

IEC Sizing Coefcients

XT: 0.775
FD: 0.50

FL: 0.89

Vent Connection

1/2 NPT (internal)

Approximate Weight

5 ounces (140 grams)

(1)

Cg: 55

1. The pressure/temperature limits in this Instruction Manual or any applicable standard limitation should not be exceeded.

Table 1. Maximum Allowable Inlet Pressure to 67 Series Regulators (with Type H800 Relief Valve)

to Prevent Instrument Supply Pressure from Exceeding 50 psig (3,4 bar)

TYPE H800 INSTALLATIONS

FROM FIGURE 2

A

B

1. Limit vent piping to 30 equivalent feet (9,14 equivalent meters) of 1/2-inch (13 mm) piping. Lower vent piping may reduce the maximum allowable inlet pressure to supply

pressure regulator.

SUPPLY PRESSURE
REGULATOR TYPES

67, 67R, 67R, 67FR,

67CF, or 67CFR

67, 67R, 67CF, or 67CFR

67FR or 67F

REMOTE

VENT PIPING

(1)

Yes

No

Yes 100 (6,9)

No 250 (17,2)

Yes 100 (6,9)

No 200 (13,8)

MAXIMUM ALLOWABLE INLET PRESSURE TO

SUPPLY PRESSURE REGULATOR, PSIG (bar)

250 (17,2)

The relief valve may be shipped already mounted on other
equipment; if so, install that equipment by referring to its

Instruction Manual.

WARNING

!

This relief valve vents gas from the connection

marked “vent”. In hazardous or ammable

gas service, the vented gas may accumulate,
causing personal injury or equipment damage

due to re or explosion. Provide piping or

tubing to vent the gas to a safe, well-ventilated
location, and protect all vent openings from
condensation, freezing, or any substance that

could clog the vents.

The 1/2 NPT vent connection must face down in any installation.
Also, the screen (key 7) and disk restriction (key 6) must either

remain in the relief valve body (key 1) or be replaced by remote
vent piping or tubing that is as short and as straight as practical.

The piping or tubing should be 1/2-inch (13 mm) in diameter to

avoid the effects of backpressure build-up on relief performance.

Provide a screened vent for the open end of the remote vent

piping or tubing.

Figure 2 illustrates two typical methods of connecting a Type H800

relief valve to a 67 Series regulator. A yoke-mounted supply

pressure regulator and pneumatic instrument are shown in

Figure 2; however, the two methods of connecting a Type H800

relief valve to a 67 Series regulator also apply to pneumatic

instruments mounted on other equipment in other orientations.

Table 1 lists the conditions for the two typical methods of
installing a Type H800 relief valve. Whenever possible, use
installation A since a Type H800 relief valve with or without
remote vent piping will limit instrument supply pressure to 50 psig

(3,4 bar) when a 67 Series regulator fails open with 250 psig

(17,2 bar) inlet pressure.

For installation A, install the relief valve in the instrument
supply tubing between the supply pressure regulator and the
pneumatic instrument. Apply pipe compound to the male

threads of the pipe nipple and the tting for the instrument

supply pressure tubing.

For installation B, connect the relief valve with a pipe nipple to

the outlet pressure gauge connection of the 67 Series regulator.

Install a pipe plug or pressure gauge as shown in Figure 2. Apply
pipe compound to the male threads of the pipe nipple and pipe

plug or pressure gauge.

Maintenance

Relief valve parts are subject to normal wear and must be

inspected and replaced as necessary. The frequency of inspection
and parts replacement depends on the severity of service
conditions and the requirements of local, state, and federal rules
and regulations.

2