Fisher Safety Manual: Fisher SS-263 Volume Booster for Safety Instrumented System (SIS) Solutions Manuals & Guides

Instruction Manual Supplement

D103985X012

SS-263 Volume Booster

October 2017

Safety manual for Fisher™ SS-263 Volume
Booster for Safety Instrumented System (SIS)
Solutions

When the Fisher SS-263 volume booster is used in a Safety Instrumented System (SIS) the design process should follow
a safety lifecycle as described in several international standards (IEC 61508, ANSI/ISA 84.01, etc.) The following check
list must be thoroughly reviewed and implemented as part of the safety lifecycle. This is in addition to regular
installation procedures and warnings listed in the latest version of the Fisher SS-263 Volume Booster Instruction
Manual (D103542X012

WARNING

This instruction manual supplement is not intended to be used as a stand-alone document. It must be used in conjunction
with the following manual: Fisher SS-263 Volume Booster Instruction Manual (D103542X012)

Failure to use this instruction manual supplement in conjunction with the above referenced manual could result in personal
injury or property damage. If you have any questions regarding these instructions or need assistance in obtaining this
document, contact your Emerson sales office

).

or Local Business Partner.

Check List

A. Safety Instrumented System Design

1. The volume booster is suitable for use in applications up to a maximum Safety Integrity Level of 3 (SIL3).

2. The SIS application of the volume boosters is limited to low demand mode.

3. The safe state can be either Exhaust on Trip (0 psig input to the volume booster) or Supply on Trip (input pressure to
the volume booster as required to fully stroke safety valve).

4. The volume booster is a 1:1 device with a designed deadband. Input pressure to the volume booster produces an
identical output pressure within limits of the booster deadband.

5. The design must meet all interface requirements and environmental limits given in the SS-263 Volume Booster
instruction manual (D103542X012). Temperature and humidity limits are class D1 per ANSI/ISA-S71.01-1985.

6. Safety Instrumented Function (SIF) design verification must be done for all components in the SIF including the
SS-263 volume booster. The SIF must fulfill the requirements according to the Safety Integrity Level (SIL). Failure
rates for the volume booster appropriate for SIL verification calculations are given in the FMEDA Report (exida
report no. FCI 10/06-083 R001), available from your Emerson sales office.

www.Fisher.com

SS-263 Volume Booster

October 2017

Instruction Manual Supplement

D103985X012

B. Volume Booster Installation

1. Maximum supply pressure is 150 psig. The supply medium must be a clean, dry, non-corrosive gas that meets the
requirements of ISA standard 7.0.01.

2. After completion of pressure connections and prior to applying pressure, the bypass restriction must be properly
adjusted.

a. If the unit is used in a SIF without Partial Valve Stroke Testing (PVST), the bypass should be closed (turned fully
clockwise). If the bypass is open, stroking time following a fail-safe command will be slowed.

b. If the unit is used in a SIF with PVST that does not utilize valve stem position feedback, the bypass can likely be
closed (turned fully clockwise). Test the PVST function to ensure that it operates properly with no resulting valve
instability. If the bypass is open, stroking time following a fail-safe command will be slowed.

c. If the unit is used in a SIF with PVST utilizing valve stem position feedback (e.g. a DVC6000 SIS digital valve
controller) the bypass restriction must be tuned to both optimize valve stroking speed when a fail-safe command
is received and maintain smooth operation and stable control during PVST. If the bypass is excessively open, the
stroking time following a fail-safe command will be slowed. If the bypass is excessively restricted, the control
loop response during PVST may be unstable, causing unacceptable process deviations and PVST failure. See the
Operating Information section in the SS-263 Volume Booster Instruction Manual (D103542X012

3. The safety function of the SIF must be tested after installation.

).

C. Volume Booster Operation and Maintenance

1. Volume booster preventative maintenance consists, at minimum, of replacing all critical elastomeric seals and
diaphragms in the device and a visual inspection of moving components to verify satisfactory condition. Spare parts
kits to replace these parts are available through your local Emerson sales office.

2. A conservative approach is taken in estimating the service interval for volume booster in Safety Instrumented
Systems. For SIS applications, preventative maintenance must be performed on the volume booster at ten year
intervals from the date of shipment. If the volume booster is exposed to the upper or lower extremes of the
environmental limits, the interval for preventative maintenance may need to be reduced.

3. If air leakage from the volume booster is detected when at steady-state conditions, take immediate corrective
action by performing preventative maintenance or replacing the volume booster. To ensure continuous
improvement and accurate reliability prediction, the user must also work with their Emerson sales office
Business Partner to see that all failures are reported.

or Local

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