Valve Design Features

[sonkimloai]

Dear my all Friends and Specialists*
I have some troubles when prepare datasheets for trunnion mounted ball valves related to DBB function and sealant injection system complete with the valves* no code and standard mention to or specify an exact requirements for these design features.
I just found some Oil/Gas specifications* standard(API 6D) which had some guidelines for above concerns but they are just a guideline/optional point!
Could you please help me to clarify these things*not limited to the followings:
1. which code/standard clearly require these requirement and are they mandatory requirement for trunnion mounted ball valves or NOT?
Can we ignore these design feature when we buy a valve from Manufacturer?
2. Normally* what size and rating of valves will be required for 2 mentioned requirements?
Thank you so much for your support!
Erik

[mej]

Here is an article that may be helpful in applying double block and bleed* which needs to be understood to begin to answer your questions

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[mej]

Also see this valve manufacturer's info for some details

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