Management of Change Guide
Fisher™ NotchFlo™ DST Control Valves
Table of Contents
Management of Change ..................................2
Background ....................................................2
Question & Answer Checklist ..........................2
D351980X012 / September 2018
Fisher NotchFlo DST and Masoneilan
LincolnLog Valve Comparison .........................4
Face-to-Face Dimensions .................................................... 4
Allowable Particle Size ........................................................ 5
Weight ............................................................................... 5
Valve Performance with Positioner ...................................... 5
Trim Materials ..................................................................... 6
Conclusion ......................................................7
Additional Resources ......................................7
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
With an installed base over one thousand units, the Fisher NotchFlo DST control
valve has proven to be the valve of choice for critical service applications containing
entrained particulate. In many cases the Fisher NotchFlo DST outperforms existing
control valves by providing improved control and reliability for critical service valve
applications. The purpose of this document is to simplify the transition from existing
control valve technologies, which are beyond their service life or no longer provide
the control and reliability required, to the proven reliable Fisher NotchFlo DST.
MOC: NotchFlo DST Control Valves
D351980X012 / September 2018
Contained in this document are two sections. First there is a Question and Answer
section to help end users complete Management of Change approval documents
when upgrading to a Fisher NotchFlo DST control valve. Then there is a side by side
comparison of the Fisher NotchFlo DST and the Masoneilan LincolnLog. In this section,
in addition to the similarities between these two valves, you will see a number of
advantages the NotchFlo DST design has compared to the LincolnLog design. These
comparisons demonstrate how the NotchFlo DST can allow users to safely and
efciently replace existing problematic control valves for critical service applications.
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. There will be no change in the existing P&IDs.
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: No.
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Q: Does the proposed modication change process ows?
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A: No. The modication doesn’t change the process ow direction.
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: Have the operating and design conditions (ow, temperature,
pressure, process uids) of the proposed modication changed?
A: No.
MOC: NotchFlo DST Control Valves
D351980X012 / September 2018
Q: Does the proposed modication change the materials of construction
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such as a change in material form (cast, forged) or alloy?
A: Not generally, but there are certain isolated cases, where the material
form (cast to forged bodies) changes. Be sure to review trim material
comparison thoroughly to assure there are no compatibility issues.
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 old equipment items.
Q: Does the proposed modication change existing operator training
requirements?
A: Yes. The Emerson network of Local Business Partners offers local
training and support to ensure operators; maintenance personnel,
and instrument technicians are fully trained on the Fisher NotchFlo
DST control valve.
Q: Does the proposed modication change existing pressure relief cases?
A: No, as long as the replacement selection doesn’t exceed the
maximum rated Cv of the existing valve.
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