jb:
API 6A aplies to wellheads and christmas trees:
1.1 Purpose
This International Standard specifies requirements and gives recommendations for the performance, dimensional
and functional interchangeability, design, materials, testing, inspection, welding, marking, handling, storing,
shipment, purchasing, repair and remanufacture of wellhead and christmas tree equipment for use in the petroleum
and natural gas industries.
Also I checked AWHEMS website, my problem is usually to make my contractor to do things thta are not in the contract or the standards... but finally they are making the correction, thanks a lot