Ball Valves Rated to 10,000 and 15,000 psi

[Angsi2]

Location: Offshore production platform
Service: Hydrocarbon gas


The project has several ball valves located on the flowlines of high pressure gas well christmas trees. The flowlines are rated to API 10k and 15k (PSL3G), in accordance with API 6A.

API 6A applies to wellhead equipment i.e. the christmas tree, associated wing and choke valves. It does not cover ball valves.

What will be the best approach for the design of the subject ball valves?

A) Maintain API 6D/ASME B16.34 requirements and ensure pressure casing and componnets are rated for 10k and 15k psi

OR

B) Request valve manufacturers to design the valves completely to API 6A requirements meeting, materials, testing and PSL 3G (though API 6A does not cover ball valves?) in view of the extreme high pressure?

Thanks in advance.

 

[jbeckhou]

API-6A covers ball valves.

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[Angsi2]

jbeckhou,

1. AP 6A could be applied to ball valves by extension maybe but I really dont think API 6A addresses ball valves.

2. Also if API 6A is applied then all material requirements such as minimum 75ksi material yield strength for 15k psi valves are expected to be met. So, duplex stainless steel for pressure housing might be inappropriate unless its strength is increased. This is in accordance with API 6A. So, is this the extend of conformance we expect from the ball valves in order to meet API 6A?

 

[jbeckhou]

Correct. You would need to follow the guidelines of API-6A when choosing materials. Do a search on the internet for API-6A ball valve manufactures. Most of the sites will provide material guidelines. Some of the ball valves which I have seen rated at 15k, were 4130 75k, with inconel overlay.

You may want to talk your customer into buying a gate valve, it would be cheaper in the end.

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