61334872

You need to be a little more specific in your post.  

If I assume by the forum, this is for offshore work, and the tubing is for structural and piping for pressure, then you may/will encounter:

API RP 1111 - Design, Construction, Operation, and Maintenance of Offshore Hydrocarbon Pipelines
API RP 14C - Recommended Practice for Analysis, Design, Installation, and Testing of Basic Surface Safety Systems for Offshore Production Platforms
API SPEC 5L - Specification for Line Pipe
ASME B31.4 - Pipeline Transportation Systems for Liquid Hydrocarbons and other Liquids
ASME B31.8 - Gas Transmission and Distribution Piping Systems
30 CFR 250 - Oil and Gas and Sulphur Operations in the Outer Continental Shelf
49 CFR 192 - Transportation of Natural and Other Gas by Pipeline–Minimum Federal Safety Standards
49 CFR 195 - Transportation of Hazardous Liquids by Pipeline
DNV RP E305 - On Bottom Stability Design of Submarine Pipelines
NACE MR0175 - Sulfide Stress Cracking Resistant Metallic Materials for Oilfield Equipment

I've never worked North Sea, so don't know what codes are used there.  

Also, if you are talking about jacket & subsea structures, then there are a host of others, rather than list them, if you need a listing for subsea structures & appertunences, respond back and I can give you a long, but probably not exhaustive list.

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website: www.oil-gas-consulting.com