It is not defined in the normative text of API 6A, so you have freedom to define it as you want, although you should be reasonable.

One way to meet the requirement is to imitate API 6A Annex F (which is informative and does not create requirements for the normative body of the standard), which has the following cycle test for chokes in section F.2.4.4.:

The rated working pressure shall be applied, and the stem cycled at rated working pressure a minimum 160 times open-close-open. The mating parts shall be free of all lubrication not specified in the manufacturer's part or assembly specifications or maintenance procedures. The acceptance criteria shall be within the manufacturer's written specifications. Adjust the internal pressure to compensate for expansion and contraction of the test fluid chamber.

Hi,

Operating cycle is nothing but valves fully opened from close then again to close.
table 57 testing is mandatory one and it is part of design requirement. but Annex F is just an informative.
for table 57, you can write your own established procedures for complying "200 operation cycles and 3 seat to body sealing requirements". it should be documented and follwed as per the same.

you can find some useful information related to your query in official API 6A interpretation document which was published in API community..
herewith i have attached the link for your quick info. refer the page 32 query no 30. which is related to operating cycles test for valves.

http://mycommittees.api.org/standards/techinterp/e...

Good Day!!!

Dinu...

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