Fisher ED, ET User Manual
SIL Safety Manual
D103401X012
July 2010
ED, ET, EZ, HP, HPA Valves w/ 657/667 Actuator
SIL Safety Manual for Fisherr ED, ET, EZ,
HP, or HPA Valves with 657 / 667 Actuator
Purpose
This safety manual provides information necessary
to design, install, verify and maintain a Safety
Instrumented Function (SIF) utilizing the Fisher ED,
ET, EZ, HP, or HPA valve with 657/667 actuator.
Introduction
This manual provides necessary requirements for
meeting the IEC 61508 or IEC 61511 functional
safety standards.
W1916-2/IL
www.Fisher.com
ED or ET Valve
W8120A-1
EZ Valve
Figure 1. Fisher Valve with 667 Actuator
W6848-1
HP Valve with FIELDVUEt
DVC6000 Digital Valve Controller
SIL Safety Manual
ED, ET, EZ, HP, HPA Valves w/ 657/667 Actuator
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
injury 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 the facts - of the safety
achieved by safety-related systems.
Fail-Safe State: State where valve actuator 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 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.
Acronyms
FMEDA: Failure Modes, Effects and Diagnostic
Analysis
HFT: Hardware Fault Tolerance
MOC: Management of Change. These are specific
procedures often done when performing any work
activities in compliance with government regulatory
authorities.
PFD
: Average Probability of Failure on Demand
AVG
July 2010
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.
SFF: Safe Failure Fraction, the fraction of the overall
failure rate of a device that results in either a safe
fault or a diagnosed unsafe fault.
SIF: Safety Instrumented Function, a set of
equipment intended to reduce the risk due to a
specific hazard (a safety loop).
SIL: Safety Integrity Level, discrete level (one out of
a possible four) for specifying the safety integrity
requirements of the safety functions to be allocated
to the E/E/PE safety-related systems where Safety
Integrity Level 4 has the highest level of safety
integrity and Safety Integrity Level 1 has the lowest.
SIS: Safety Instrumented System – Implementation
of one or more Safety Instrumented Functions. A
SIS is composed of any combination of sensor(s),
logic solver(s), and final element(s).
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SIL Safety Manual
July 2010
ED, ET, EZ, HP, HPA Valves w/ 657/667 Actuator
Related Literature
Hardware Documents:
51.1:ED, Fisher ED, EAD, and EDR SlidingStem
Control Valves Bulletin: D100017X012
Fisher ED and EAD easyet Valves CL125 through
CL600 Instruction Manual: D100390X012
51.1:ET, Fisher ET, EAT, and ETR SlidingStem
Control Valves Bulletin: D100022X012
Fisher ET and EAT easyet Valves CL125 through
CL600 Instruction Manual: D100398X012
51.1:EZ, Fisher EZ SlidingStem Control Valve
Bulletin: D100025X012
Fisher EZ easyet Control Valve Instruction
Manual: D100401X012
51.2:HP, Fisher HP Series Control Valves Bulletin:
D101635X012
Fisher HP and HPA Control Valves Instruction
Manual: D101634X012
Guidelines/References:
D ANSI/ISA 84.00.01-2004 (IEC 61511 Mod.)
Functional Safety – Safety Instrumented Systems for
the Process Industry Sector
Device Description
Fisher ED single-port valves (figure 1) have cage
guiding, quick-change trim, and balanced
push-down-to-close valve plug action. Valve
configurations are as follows:
ED--Globe-style valve with metal-to-metal seating for
all general applications over a wide variety of
pressure drops and temperatures.
EAD--Angle version of ED, used to facilitate piping
or in applications where a self-draining valve is
required.
Fisher ET single-port valves (figure 1) have cage
guiding, quick-change trim, and balanced
push-down-to-close valve plug action. Valve
configurations are as follows:
ET--Globe-style valve with metal-to-PTFE seating
(standard for all except Cavitrol III cages) for
stringent shutoff requirements, or metal-to-metal
seating (standard for Cavitrol III cages, optional for
all others) for higher temperatures.
D Safety Integrity Level Selection – Systematic
Methods Including Layer of Protection Analysis,
ISBN 1-55617-777-1, ISA
D Control System Safety Evaluation and
Reliability, 2nd Edition, ISBN 1-55617-638-8, ISA
D Safety Instrumented Systems Verification,
Practical Probabilistic Calculations, ISBN
1-55617-909-9, ISA
Reference Standards
Functional Safety
D IEC 61508: 2000 Functional safety of
electrical/electronic/ programmable electronic
safety-related systems
EAT--Angle version of ET, used to facilitate piping or
in applications which require a self-draining valve.
Fisher EZ valves (figure 1) are globe-style with
integral end connections, post guiding, and
quick-change trim. These valves are used in
chemical or hydrocarbon processing applications or
in applications that require control of nonlubricating,
viscous, or other hard-to-handle fluids.
Fisher HP Series high-pressure globe and angle
valves (figure 1) have metal seats, cage guiding,
quick change trim, and push-down-to-close valve plug
action. HPD, HPAD, HPT, and HPAT valves use
balanced valve plugs. HPS and HPAS valves use an
unbalanced valve plug. To provide a seal between
the cage and a balanced valve plug, the HPD and
HPAD valve plugs use piston rings; the HPT and
HPAT valve plugs use a pressure-assisted seal ring.
A Whisper Trim cage can be used with an HPD,
HPAD, HPS, HPAS, HPT, or HPAT valve plug. A
Cavitrol III cage can be used with an HPS, HPAS,
HPT, or HPAT valve plug.
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