Management of Change Guide: Replacing Fisher CP Valves with Fisher GX Control Valves
Table of contents
Loading...Fisher Management of Change Guide: Replacing Fisher CP Valves with Fisher GX Control Valves Manuals & Guides
Replacement of CP Valves with
Fisher™ GX Control Valves
Table of Contents
Management of Change ..................................2
Background ....................................................2
Question & Answer Checklist ..........................2
Management of Change Guide
September 2018 / D352214X012
Fisher CP Valve and GX Valve Comparison .......4
Capabilities by Size ............................................................. 4
Alloy Material Comparison .................................................. 6
ISA Long Face-to-Face Dimension ....................................... 6
Bellows Comparison ........................................................... 7
Valve and Actuator Features ............................................... 7
Conclusion ......................................................8
Additional Resources ......................................9
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.
Background
The Fisher CP valve was developed to meet the specic requirements of the
chemical industry and was the primary offering for the industrial process application
segment of the chemical industry until 2005. The CP was a globe-style, single-port
valve with integral anges, stem guiding, and a clamped-in seat ring. The CP valve is
an obsolete Fisher product and spare parts support for it will end in 2015.
The Fisher GX is a compact, multi-spring actuator and globe valve system that
can meet the requirements of the chemical market. The GX valve is rugged,
reliable, and easy to select. It requires no actuator sizing—the actuator selection is
automatic once the valve body construction and available plant air supply pressure
are selected. A key feature of the GX valve is the ability to integrally mount the
FIELDVUE™ DVC2000 or DVC6200 digital valve controller for linkage-less position
feedback. With a global installed base of nearly 100,000 units, the GX is a proven
and reliable control valve solution for a wide array of applications across a broad
range of industries.
MOC: Replacement of CP with GX Valves
September 2018 / D352214X012
Contained in the following sections are design comparisons between the current
Fisher GX control valve and obsolete Fisher CP control valve. These comparisons are
intended to help end users complete MOC approval documents to understand the
similarities and differences between GX and CP valves to effectively transition to the
GX valve.
Question & Answer Checklist
Q: Does the proposed modication cause any changes to the piping and
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instrumentation diagram (P&ID)?
A: No.
Q: Does the proposed modication change process chemistry,
technology, or operating and control philosophies?
A: No.
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Q: Does the proposed modication change how the existing plant is
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operated?
A: Possibly. Review capacity information to help ensure no issues will
take place.
Q: Does the proposed modication change process ows?
A: Possibly. Review capacity information to help ensure no issues will
take place.
Q: Does the proposed modication change existing pressure relief cases?
A: Possibly. If the GX replacement selection exceeds the maximum rated
Cv of the existing CP valve, then pressure relief cases will require
review. Pressure relief valve sizing when sizing and selecting Fisher
control valves for end user applications is not considered. If the control
valve is determined to affect upstream or downstream safety relief
cases, review by the end user or third party is recommended.
MOC: Replacement of CP with GX Valves
September 2018 / D352214X012
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.
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 previous equipment items.
Q: Does the proposed modication change existing operator training
requirements?
A: No.
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