SIL Safety Manual for Fisherr ED, ES, ET, EZ, HP

SIL Safety Manual for Fisherr ED, ES, ET, EZ, HP
SIL Safety Manual
ED, ES, ET, EZ, HP, HPA Valves w/ 657/667 Actuator
D103401X012
November 2011
SIL Safety Manual for Fisherr ED, ES, 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, ES, ET, EZ, HP, or HPA valve with 657/667 actuator.
Introduction
This manual provides information that is necessary for meeting the IEC 61508 or IEC 61511 functional safety
standards.
Figure 1. Fisher Valve with 667 Actuator
W2174-3
W1916-2
ED or ET Valve
www.Fisher.com
W8120A-2
ES Valve
X0183-1
HP Valve with FIELDVUE
EZ Valve with FIELDVUEt
DVC6200 Digital Valve Controller DVC6200 Digital Valve Controller
ED, ES, ET, EZ, HP, HPA Valves w/ 657/667 Actuator
November 2011
SIL Safety Manual
D103401X012
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
safety­related systems.
Fail­Safe State: State where valve actuator is de­energized and spring is extended.
Fail Safe: Failure that causes the valve to go to the defined fail­safe 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
fail­safe 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 safety­related system is no
greater than twice the proof test frequency.
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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.
PFDAVG: Average Probability of Failure on Demand
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 safety­related 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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November 2011
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Related Literature
Hardware Documents:
51.1:ED, Fisher ED, EAD, and EDR Sliding-Stem Control Valves Bulletin: D100017X012
Fisher ED and EAD easy-et Valves CL125 through CL600 Instruction Manual: D100390X012
51.1:ES, Fisher ES and EAS Sliding-Stem Control Valves Bulletin: D100021X012
Fisher ES and EAS easy-et Valves CL125 through CL600 Instruction Manual: D100397X012
51.1:ET, Fisher ET, EAT, and ETR Sliding-Stem Control Valves Bulletin: D100022X012
Fisher ET and EAT easy-et Valves CL125 through CL600 Instruction Manual: D100398X012
51.1:EZ, Fisher EZ Sliding-Stem Control Valve Bulletin: D100025X012
Fisher EZ easy-et 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 Safety Integrity Level Selection — Systematic Methods Including Layer of Protection Analysis, ISBN 1­55617­777­1,
ISA
D Control System Safety Evaluation and Reliability, 2nd Edition, ISBN 1­55617­638­8, ISA
D Safety Instrumented Systems Verification, Practical Probabilistic Calculations, ISBN 1­55617­909­9, ISA
Reference Standards
Functional Safety
D IEC 61508: 2000 Functional safety of electrical/electronic/ programmable electronic safety­related systems
D ANSI/ISA 84.00.01­2004 (IEC 61511 Mod.) Functional Safety — Safety Instrumented Systems for the Process Industry
Sector
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SIL Safety Manual
ED, ES, ET, EZ, HP, HPA Valves w/ 657/667 Actuator
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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 ES single-port valves (figure 1) have cage guiding, quick-change trim, and unbalanced push-down-to-close valve
plug action. Valve configurations are as follows:
ES--Globe-style valve with metal-to-metal seating as standard for all general applications over a wide range of pressure
drops and temperatures, and metal-to-PTFE seating is optional for more stringent shutoff requirements.
EAS--Angle version of ES, 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.
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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Designing a SIF Using Fisher ED, ES, ET, EZ, HP, or HPA Valve
Safety Function
When the valve's actuator is de­energized, the actuator and valve shall move to its fail­safe position. Depending on
which configuration is specified fail—closed or fail­open, the actuator will move the valve plug to close off the flow path
through the valve body or open the flow path through the valve body.
The ED, ES, ET, EZ, HP, or HPA valve is intended to be part of final element subsystem as defined per IEC 61508 and the
achieved SIL level of the designed function must be verified by the designer.
Pressure and Temperature limits
The designer of a SIF must check that the product is rated for use within the expected pressure and temperature limits.
Refer to the ED, ES, ET, EZ, or HP and HPA valve product bulletin for pressure and temperature limits.
Application limits
The materials of construction of ED, ES, ET, EZ, HP, or HPA valves are specified in the product bulletins. A range of
materials are available for various applications. The serial card will indicate what the materials of construction are for a
given valve. It is especially important that the designer check for material compatibility considering on­site chemical
contaminants and environmental conditions. If the ED, ES, ET, EZ, HP, or HPA valve is used outside of the application
limits or with incompatible materials, the reliability data provided becomes invalid.
Diagnostic Response Time
The ED, ES, ET, EZ, HP, or HPA valve does not perform any automatic diagnostic functions by itself and therefore it has
no diagnostic response time of its own. However, automatic diagnostics of the final control subsystem may be
performed such as Partial Valve Stroke Testing (PVST). This typically will exercise the valve over a small percentage of
its normal travel without adversely affecting the flow through the valve. If any failures of this PVST are automatically
detected and annunciated, the diagnostic response time will be the PVST interval time. The PVST must be performed
10 times more often than an expected demand in order for credit to be given for this test.
Design Verification
A detailed FMEDA report is available from Emerson Process Management. This report details all failure rates and failure
modes as well as the expected lifetime.
The achieved SIL of an entire SIF design must be verified by the designer via a calculation of PFDAVG considering
architecture, proof test interval, proof test effectiveness, any automatic diagnostics, average repair time and the
specific failure rates of all products included in the SIF. Each subsystem must be checked to assure compliance with
minimum HFT requirements.
When using an ED, ES, ET, EZ, HP, or HPA valve in a redundant configuration, a common cause factor of at least 5%
should be included in the Safety Integrity calculations.
The failure rate data listed in the FMEDA report is only valid for the useful lifetime of an ED, ES, ET, EZ, HP, or HPA valve.
The failure rates will increase after this time period. Reliability calculations based on the data listed in the FMEDA
report for mission times beyond the useful lifetime may yield results that are too optimistic, i.e. the calculated Safety
Integrity Level will not be achieved.
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SIL Capability
Systematic Integrity
Figure 2. exida SIL 3 Capable
Fisher ED, ES, ET, EZ, HP, and HPA valves have met manufacturer design process requirements of SIL 3. These are
intended to achieve sufficient integrity against systematic errors of design by the manufacturer. A SIF designed with
this product must not be used at a SIL level higher than stated without “prior use” justification by the end user or
diverse technology redundancy in the design.
Random Integrity
The ED, ES, ET, EZ, HP, or HPA valves are classified as Type A devices according to IEC 61508, having a hardware fault
tolerance of 0. The complete final element subsystem, with a Fisher valve as the final control element, will need to be
evaluated to determine the Safe Failure Fraction of the subsystem. If the SFF for the entire final element subsystem is
between 60% and 90%, a design can meet SIL 2 @ HFT=0.
Safety Parameters
For detailed failure rate information refer to the Failure Modes, Effects and Diagnostic Analysis Report for the ED, ES,
ET, EZ, HP, or HPA valve.
Connection of the Fisher ED, ES, ET, EZ, HP, or HPA Valve to the SIS
Logic-solver
The final element subsystem (consisting of a positioner, actuator, and ED, ES, ET, EZ, HP, or HPA valve) is connected to
the safety rated logic solver which is actively performing the Safety Function as well as any automatic diagnostics
designed to diagnose potentially dangerous failures within the ED, ES, ET, EZ, HP, or HPA valve , actuator and any other
final element components, (i.e. Partial Valve Stroke Test).
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General Requirements
The system's response time shall be less than process safety time. The final control element subsystem needs to be
sized properly to assure that the response time is less than the required process safety time. The ED, ES, ET, EZ, HP, or
HPA valve will move to its safe state in less than the required SIF's safety time under the specified conditions.
All SIS components including the ED, ES, ET, EZ, HP, or HPA valve must be operational before process start­up.
The user shall verify that the ED, ES, ET, EZ, HP, or HPA valve is suitable for use in safety applications.
Personnel performing maintenance and testing on the ED, ES, ET, EZ, HP, or HPA valve shall be competent to do so.
Results from the proof tests shall be recorded and reviewed periodically.
The useful life of the ED, ES, ET, EZ, HP, or HPA valve is discussed in the Failure Modes, Effects and Diagnostic Analysis
Report for the Fisher ED, ES, ET, EZ, HP, or HPA valve.
Installation and Commissioning
Installation
WARNING
To ensure safe and proper functioning of equipment, users of this document must carefully read all instructions, warnings,
and cautions in each applicable instruction manual.
The Fisher ED, ES, ET, EZ, HP, or HPA valve must be installed per standard practices outlined in the appropriate
instruction manual.
The environment must be checked to verify that pressure and temperature conditions do not exceed the ratings.
The ED, ES, ET, EZ, HP, or HPA valve must be accessible for physical inspection.
Table 1. Recommended Full Stroke Proof Test
Step
Action
1
Bypass the safety function and take appropriate action to avoid a false trip.
2
Interrupt or change the signal/supply to the actuator to force the actuator and valve to perform a full stroke to the Fail­Safe state and
confirm that the Safe State was achieved and within the correct time.
3
Restore the supply/signal to the actuator and confirm that the normal operating state was achieved.
4
Inspect the ED, ES, ET, EZ, HP, or HPA valve and the other final control element components for any leaks, visible damage or contamination.
5
Record the test results and any failures in your company's SIF inspection database.
6
Remove the bypass and restore normal operation.
Physical Location and Placement
The Fisher ED, ES, 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.
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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, ES, 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, ES, 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, ES, 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, ES, ET, EZ, HP, or HPA valve.
The person(s) performing the proof test of an ED, ES, 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.
Status of the Document
Releases
Version History:
(Version, Status, Date)
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SIL Safety Manual
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November 2011
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Appendix A
Sample Startup Checklist
This appendix provides a Sample Start­up Checklist for a Fisher ED, ES, ET, EZ, HP, or HPA valve. A start­up checklist will
provide guidance during the final control element's employment.
Start-Up Checklist
The following checklist may be used as a guide to employ the ED, ES, ET, EZ, HP, or HPA valve in a safety critical SIF
compliant to IEC61508.
#
Activity
Result
Verified
By
Design
Target Safety Integrity Level and PFDAVG determined
Correct valve mode chosen (Fail­closed, Fail­open)
Design decision documented
Pneumatic compatibility and suitability verified
SIS logic solver requirements for valve tests defined and documented
Routing of pneumatic connections determined
SIS logic solver requirements for partial stroke tests defined and
documented
Design formally reviewed and suitability formally assessed
Implementation
Physical location appropriate
Pneumatic connections appropriate and according to applicable codes
SIS logic solver valve actuation test implemented
Maintenance instructions for proof test released
Verification and test plan released
Implementation formally reviewed and suitability formally assessed
Verification and Testing
Electrical connections verified and tested
Pneumatic connection verified and tested
SIS logic solver valve actuation test verified
Safety loop function verified
Safety loop timing measured
Bypass function tested
Verification and test results formally reviewed and suitability formally
assessed
Maintenance
Tubing blockage / partial blockage tested
Safety loop function tested
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Date
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ED, ES, ET, EZ, HP, HPA Valves w/ 657/667 Actuator
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Neither Emerson, Emerson Process Management, nor any of their affiliated entities assumes responsibility for the selection, use or maintenance
of any product. Responsibility for proper selection, use, and maintenance of any product remains solely with the purchaser and end user.
Fisher, FIELDVUE, and easy-e are marks owned by one of the companies in the Emerson Process Management business division of Emerson Electric Co.
Emerson Process Management, Emerson, and the Emerson logo are trademarks and service marks of Emerson Electric Co. All other marks are the property
of their respective owners.
The contents of this publication are presented for informational purposes only, and while every effort has been made to ensure their accuracy, they are not
to be construed as warranties or guarantees, express or implied, regarding the products or services described herein or their use or applicability. All sales are
governed by our terms and conditions, which are available upon request. We reserve the right to modify or improve the designs or specifications of such
products at any time without notice.
Emerson Process Management
Marshalltown, Iowa 50158 USA
Sorocaba, 18087 Brazil
Chatham, Kent ME4 4QZ UK
Dubai, United Arab Emirates
Singapore 128461 Singapore
www.Fisher.com
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EFisher Controls International LLC 2010, 2011; All Rights Reserved
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