Flowserve Valtek Mark, Safety Manual

Page: 3 / 13

1. Introduction
This Safety Manual provides information necessary to design, install, verify and maintain a Safety
Instrumented Function (SIF) utilizing a Flowserve Valtek Mark Series Valve and Cylinder Actuator.
This manual provides necessary requirements for meeting the IEC 61508 or IEC 61511 functional
safety standards.
1.1 Terms and Abbreviations
Safety:
Freedom from unacceptable risk of harm
Functional Safety:
The ability of a system to carry out the actions necessary to achieve or to maintain a defined safe
state for the equipment / machinery / plant / apparatus under control of the system
Basic Safety:
The equipment must be designed and manufactured such that it protects against risk of damage to
persons by electrical shock and other hazards and against resulting fire and explosion. The protection
must be effective under all conditions of the nominal operation and under single fault condition
Safety Assessment:
The investigation to arrive at a judgment - based on evidence - of the safety achieved by safety-
related systems
Fail-Safe State:
State where solenoid valve is de-energized and spring is extended
Fail Safe:
Failure that causes the valve to go to the defined fail-safe state without a demand from the process
Fail Dangerous:
Failure that does not respond to a demand from the process (i.e. being unable to go to the defined
fail-safe state)
Fail Dangerous Undetected:
Failure that is dangerous and that is not being diagnosed by automatic stroke testing
Fail Dangerous Detected:
Failure that is dangerous but is detected by automatic stroke testing
Fail Annunciation Undetected
Failure that does not cause a false trip or prevent the safety function but does cause loss of an
automatic diagnostic and is not detected by another diagnostic.
Fail Annunciation Detected:
Failure that does not cause a false trip or prevent the safety function but does cause loss of an
automatic diagnostic or false diagnostic indication
Fail No Effect:
Failure of a component that is part of the safety function but that has no effect on the safety function
Low demand mode:
Mode, where the frequency of demands for operation made on a safety-related system is no greater
than twice the proof test frequency