API hammer union

[seraph3333]

Do anybody know is there some API standard mentioned hammer union (high pressure, eg. Fig 1002, Fig 1502)?
To me, I have no idea if there is an API Spec about that, to my knowledge, only screw been mentioned.
Thanks!

 

[DraftingMan]

xuhaotomato,

Hammer unions are not standardized through API or any other group.

They are only standardized by manufacturer practice, some of the units of differing pressure ratings can screw together and fail, so no standards body wants to touch them.

John H. Dunten, CD
Certified Drafter

 

[jbeckhou]

API has had meetings regarding hammer union specifications. According to API, this is an ongoing item.

DraftingMan is correct about some of the hammer unions being able to screw together, they are 1502 and 602. see attached warnings from FMC (weco).

I had a project which I reversed engineered 2" thru 4" hammer unions, the 602 union thread was designed in a way that the 1502 would not screw on.

Petrotrim Services

 

[DrillerNic]

I'll back up the warnings given above of various hammer unions appearing to mate up but not actually being pressure tight.

In the North Sea, common practice is to ONLY allow 1502 unions on a rig or platform, to remove any possiblilty of mis-matching different unions. But there are still occasional safety alerts about mis-matched unions blowing off, sometimes resulting in injury.