Fisher ED, ET User Manual

124.83 Kb

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	W6848-1
	W6848-1
	W8120A-1

ED or ET Valve	EZ Valve	HP Valve with FIELDVUEt
		DVC6000 Digital Valve Controller
	Figure 1. Fisher Valve with 667 Actuator

www.Fisher.com

SIL Safety Manual

ED, ET, EZ, HP, HPA Valves w/ 657/667 Actuator

July 2010

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 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.

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 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).

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 Sliding Stem Control Valves Bulletin: D100017X012

Fisher ED and EAD easy et Valves CL125 through CL600 Instruction Manual: D100390X012

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:

DSafety Integrity Level Selection – Systematic Methods Including Layer of Protection Analysis, ISBN 1-55617-777-1, ISA

DControl System Safety Evaluation and Reliability, 2nd Edition, ISBN 1-55617-638-8, ISA

DSafety 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

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.

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.

SIL Safety Manual

ED, ET, EZ, HP, HPA Valves w/ 657/667 Actuator

July 2010

Designing a SIF Using Fisher ED, ET, EZ, HP, or HPA Valve

Safety Function

When the valve’s actuator is de-energized, the actuator and valve shall move to its fail-safe position. Depending on which configuration is specified fail–closed or fail-open, 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, 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.

Environmental limits

The designer of a SIF must check that the product is rated for use within the expected environmental limits. Refer to the ED, ET, EZ, or HP and HPA valve product bulletin for environmental limits.

Application limits

The materials of construction of ED, 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 on-site chemical contaminants and environmental conditions. If the ED, 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, 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, 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, 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.

SIL Capability

Systematic Integrity

Figure 2. exida SIL 3 Capable

The product has 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

SIL Safety Manual

July 2010

ED, ET, EZ, HP, HPA Valves w/ 657/667 Actuator

user or diverse technology redundancy in the design.

Random Integrity

The ED, 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, ET, EZ, HP, or HPA valve.

Connection of the Fisher ED, ET, EZ, HP, or HPA Valve to the SIS Logic-solver

The final element subsystem (consisting of a positioner, actuator, and ED, 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, ET, EZ, HP, or HPA valve , actuator and any other final element components, (i.e. Partial Valve Stroke Test).

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, 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, ET, EZ, HP, or HPA valve must be operational before process start-up.

The user shall verify that the ED, ET, EZ, HP, or HPA valve is suitable for use in safety applications.

Personnel performing maintenance and testing on the ED, 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, ET, EZ, HP, or HPA valve is discussed in the Failure Modes, Effects and Diagnostic Analysis Report for the Fisher ED, ET, EZ, HP, or HPA valve.

Installation and Commissioning

Installation

The Fisher ED, 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 environmental conditions do not exceed the ratings.

The ED, 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 Fail-Safe 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, 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.

SIL Safety Manual

ED, ET, EZ, HP, HPA Valves w/ 657/667 Actuator

July 2010

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.

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.

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

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)

SIL Safety Manual

July 2010

ED, ET, EZ, HP, HPA Valves w/ 657/667 Actuator

Appendix A

Sample Startup Checklist

This appendix provides a Sample Start-up Checklist for a Fisher ED, ET, EZ, HP, or HPA valve. A start-up 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, ET, EZ, HP, or HPA valve in a safety critical SIF compliant to IEC61508.

#	Activity	Result		Verified

			By		Date

	Design
	Target Safety Integrity Level and PFDAVG determined
	Correct valve mode chosen (Fail-closed, Fail-open)

	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

SIL Safety Manual

ED, ET, EZ, HP, HPA Valves w/ 657/667 Actuator

July 2010

Note

Neither Emerson, Emerson Process Management, nor any of their affiliated entities assume responsibility for the selection, use, or maintenance of any product. Responsibility for the selection, use, and maintenance of any product remains 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. Neither Emerson, Emerson Process Management, nor any of their affiliated entities assume 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.

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