Fisher ET - Manual (Page 6)

ED, ET, EZ, HP, HPA Valves w/ 657/667 Actuator
SIL Safety Manual
July 2010
6
Physical Location and Placement
The Fisher ED, ET, EZ, HP, or HPA valve shall be
accessible with sufficient room for the actuator,
pneumatic connections, and any other components
of the final control element. Provisions shall be made
to allow for manual proof testing.
Pneumatic piping to the actuator shall be kept as
short and straight as possible to minimize the airflow
restrictions and potential clogging. Long or kinked
pneumatic tubes may also increase the valve
closure time.
The ED, ET, EZ, HP, or HPA valve shall be mounted
in a low vibration environment. If excessive vibration
can be expected special precautions shall be taken
to ensure the integrity of pneumatic connectors or
the vibration should be reduced using appropriate
damping mounts.
Operation and Maintenance
Suggested Proof Test
The objective of proof testing is to detect failures
within an ED, ET, EZ, HP, or HPA valve that are not
detected by any automatic diagnostics of the
system. Of main concern are undetected failures
that prevent the Safety Instrumented Function from
performing its intended function.
The frequency of proof testing, or the proof test
interval, is to be determined in reliability calculations
for the Safety Instrumented Functions for which an
ED, ET, EZ, HP, or HPA valve is applied. The proof
tests must be performed more frequently than or as
frequently as specified in the calculation in order to
maintain the required Safety Integrity of the Safety
Instrumented Function.
The proof test shown in table 1 is recommended.
The results of the proof test should be recorded and
any failures that are detected and that compromise
functional safety should be reported to Emerson
Process Management. The suggested proof test
consists of a full stroke of the ED, ET, EZ, HP, or
HPA valve.
The person(s) performing the proof test of an ED,
ET, EZ, HP, or HPA valve should be trained in SIS
operations, including bypass procedures, valve
maintenance and company Management of Change
procedures. No special tools are required.
Repair and replacement
Repair procedures in the appropriate valve
instruction manual must be followed.
Manufacturer Notification
Any failures that are detected and that compromise
functional safety should be reported to Emerson
Process Management. Please contact Emerson
Process Management customer service or your local
Emerson Process Management service
representative.
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