A couple of sources come to mind: The Compressed Gas Association and the National Fire Prevention Association. Also, have you checks the OSHA site for rules for welding? The problem with OSHA regulations is they rarely tell one how to comply with the requirements.

Best regards - Al

AWS and AISC have safety manuals for fabricators that give guidelines for cylinder storage and transportation.  Both have bookstores where these can be purchased.  I would have to take time to look it up beyond that.  Bottom line, direct sunlight for all day in high temp climates can cause expansion of gases which would then blow the safety valves.  Low time, lower temps, other factors will contribute to how much pressure is built up as heat causes expansion. 

He Is In Control, Have a Great Day,  Brent

Read OSHA Subpart H - Hazardous Materials, 1910.102 (Acetylene). The first subsection (a) Cylinders - it talks about in-plant transfer, handling, storage and use. It also says employers are to comply with CGA Pamphlet G-1-2009, which was incorperated by reference (and referenced by Al in his post). Depending on your specific situation and set up, NFPA 51A- 2001 or 2006 may need a looking at as well. Not having the CGA provisions in front of me, and if memory serves me right, it will give you the information you are looking for.

Oxygen is found in 1910.104 of the OSHA Standards.

Hope this helps...