3
Valtek ShearStream SB Ball Valves VLENDS4152-00-A4 05/15
1 Introduction
1.1
Scope and purpose of the Safety Manual
This safety manual provides the information necessary to design, install, verify and maintain a Safety Instrumented Function
(SIF) utilizing the Shearstream SB Ball Valve. This manual provides necessary requirements to enable the integration of
the Shearstream SB Ball Valve when showing compliance with the IEC 61508 or IEC 61511 functional safety standards.
This Safety Manual indicates all assumptions that have been made on the usage of the Shearstream SB Ball Valve. If these
assumptions cannot be met by the application, the SIL capability of the Shearstream SB Ball Valve may be adversely
1.2
Skill level required
System design, installation and commissioning, and repair and maintenance shall be carried out by suitably qualified
personnel. affected.
1.3
Terms, abbreviations and acronyms
Basic Safety
Freedom from unacceptable risk of harm.
BPCS
Basic Process Control System - a system which responds to input signals from the
process, its associated equipment, other programmable systems and/or an operator and
generates output signals causing the process and its associated equipment to operate in
the desired manner but which does not perform any safety instrumented functions with
a claimed SIL
≥
1.
Fail-safe State
State where solenoid valve is de-energized and spring is extended.
Fail Annunciation Detected
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 Undetected 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 Dangerous
Failure that does not respond to a demand from the process (i.e. being unable to go to
the fail-safe state).
Fail Dangerous Detected
Failure that is dangerous but is detected as part of partial valve stroke testing.
Fail Dangerous Undetected
Failure that is dangerous and that is not detected as part of partial valve stroke testing.
Fail No Effect
Failure of a component that is part of the safety function but that has no effect on the
safety function.
Fail Safe
Failure that causes the valve to go to the defined fail-safe state without a demand from
the process.
FMEDA
Failure Modes, Effects and Diagnostics Analysis.
Functional safety
Part of the overall safety relating to the process and the BPCS which depends on the
correct functioning of the SIS and other protection layers.
HFT
Hardware Fault Tolerance.
Low demand
Mode of operation, where the frequency of demands for operation made on a safety-
related system is no greater than twice the proof test frequency.
MOC
Management Of Change - specific procedures often done when performing any work
activities in compliance with government regulatory authorities.
PFDAVG
Average Probability of Failure on Demand.
