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Exclusion of valve options
- Jun 22, 2018 -

Gold-plated specs tend to eliminate less expensive options, often requiring more expensive solutions with no corresponding operational improvements. Some of these include:

  • Threaded seat rings are not acceptable.

  • Bonnet bolts shall not be used to attach actuators or mounting brackets.

  • Reverse-acting spring diaphragm actuators that incorporate seals or glands should be avoided.

  • Valve yokes may be cast iron for fluid operating temperatures up to 800ºF, but shall be cast steel for temperatures exceeding 800ºF.

The threaded seat ring exclusion and the no-bonnet-bolts spec drive a user to more expensive valves by eliminating cost-saving alternatives. Stating that reverse-acting spring diaphragm actuators incorporating seals or glands should be avoided is incorrect. If a valve must fail open, it needs a reverse-acting actuator.

Specifying that valve yokes may be cast iron or cast steel for various temperatures is an incomplete spec because it does not state if extension bonnets can help with high-temperature applications, which is often a more cost-effective solution.

It is difficult to capture all the options offered by valve manufacturers, and it is hard to know if something put into a specification will eliminate an option that could bring the overall project cost down. This is why early review and optimization of specifications and requirements is critical. If valve vendor technical personnel can review specs before the project is bid, they can walk users through the specs and identify problematic areas.