Management of Change Guide: Replacement of Fisher A-Body Control Valves with easy-e Control Valves
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Management of Change Guide
September 2018 / D352308X012
Replacement of Fisher™ Double-Ported
A-Body Control Valves with Fisher easy-e™
Sliding-Stem Control Valves
Table of Contents
Management of Change ..................................2
Background ....................................................2
Question & Answer Checklist ..........................3
A-Body and easy-e Control Valve
Comparison ...................................................5
Capacities (Cv) by Size ........................................................ 5
Face-to-Face Dimensions .................................................... 7
Shutoff Class ....................................................................... 8
Trim Materials ..................................................................... 8
Product Features ................................................................ 9
Approximate Control Valve Assembly Weights .................... 9
Conclusion .....................................................10
Additional Resources .....................................10
Management of Change
Management of Change (MOC) is a procedure used to proactively manage changes
that have the potential to impact safety or the process within a plant. Evaluating
new techniques for improving MOC approval procedures can have an impact on
plant efciency. Historically, upgrading obsolete products or replacing existing
process control equipment had been delayed or abandoned due to the extensive
paperwork involved in completing a complex MOC approval sheet.
Contained in the following sections are design comparisons between inactive
Fisher double-ported A and AR control valves, and current Fisher easy-e ED and ET
control valves. Fisher double-ported A and AR control valves will be referenced as
“Fisher A-body” throughout this document; Fisher easy-e ED and ET control valves
will be referenced as “Fisher easy-e.” These comparisons are intended to help endusers understand the similarities and differences between Fisher A-body and Fisher
easy-e control valves and to complete MOC approval documents for an efcient
and safe transition.
MOC: A-Body to easy-e Valves
September 2018 / D352308X012
Background
Fisher A-Body control valves are double-ported balanced designs with a variety of
characteristics, valve plug guiding options, and material offerings allowing them
to be used in a wide range of industrial applications as rugged, high-capacity
globe valves. Direct-acting Fisher A-body or reverse-acting (AR) control valves are
compatible with many spring-and-diaphragm or piston actuators. NPS 1, 1 ¼ and
1 ½ Fisher A-body control valves are obsolete products and the 10-year guarantee
of recommended spare parts availability for these products ended in 2000. NPS 2
thru 16 Fisher A-body control valves are inactive Fisher products, with limited parts
availability and increased lead time for new assembly orders.
Fisher A-body control valves have been general service control valves for
several decades, still used within various service applications. Due to modern
advancements in control valve technology, which allow for smaller actuation,
tighter shutoff, and more material choices, Fisher A-body control valves have been
declared obsolete to transition to recently developed control valves. Fisher easy-e
control valves are offered as replacements for Fisher A-body control valves based on
shared actuation platforms and the wide ranges of trim and material options.
The Fisher easy-e series is comprised of ED, ES, ET, EZ, and EW constructions; this
document will specically discuss ED and ET control valves. Fisher ED control valves
most closely match the capabilities of Fisher A-body control valves within a wide
range of operating temperatures. Fisher ET control valves are also similar, but offer
PTFE trim seals and seat options, and tighter shutoff at lower temperatures. Fisher
easy-e control valves are cage guided, single-port globe valves, with balanced valve
plugs in a quick change trim design that simplies maintenance. These control
valves are generally used for throttling or on-off control applications for a wide array
of liquids and gases. For more information regarding other Fisher easy-e control
valves, please contact your local Emerson sales ofce.
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Question & Answer Checklist
Q: Does the proposed modication cause any changes to the piping and
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instrumentation diagram (P&ID)?
A: Possibly. If the control valve size changes, concentric reducers to the
control valve inlet and outlet may need to be added to the P&ID.
Q: Does the proposed modication change process chemistry,
technology, or operating and control philosophies?
A: No.
Q: Does the proposed modication change how the existing plant is
operated?
A: Possibly. Review capacity information (page 7, Table 1) to ensure no
issues will take place.
MOC: A-Body to easy-e Valves
September 2018 / D352308X012
Q: Does the proposed modication change process ows?
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A: Possibly. Review capacity information (Table 1) to ensure no issues will
take place.
Q: Does the proposed modication change the process description?
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A: No.
Q: Have the codes and standards to which the new equipment was
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designed changed?
A: No, although they may have been updated since Fisher A-body control
valves were installed.
Q: Does the proposed modication change the materials of construction,
such as a change in material form (cast, forged, or alloy)?
A: No.
Q: Does the proposed modication introduce new equipment items that
require periodic predictive maintenance?
A: No. The new equipment items will require the same periodic
maintenance as required by the revious equipment items.
Q: Does the proposed modication change existing operator training
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requirements?
A: No.
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