Vapor barriers

[xoxota]

In reference to API RP 500, 6.4, figure 3 - Enclosed area adjacent to a classified area, are
there any standards for building a vaportight barrier? I would like to install a 10' high vapor barrier at one end of a cooling tower in order to maintain the area adjacent to the barrier unclassified.

 

[rbalex]

There is no specific set of requirements - it is basically a judgment call. Truthfully though, unless the gas involved is hydrogen, almost any structurally sound solid wall or an environmentally stable membrane will do. For gasses denser than methane a good coat of paint on an otherwise slightly porous surface like wood or drywall works just fine.

Hydrogen takes a denser structural barrier like a solid metal or an aluminum- Mylar membrane; rubber or vinyl usually won’t do unless they are extremely thick (and I have no idea how thick - they usually aren't "environmentally stable" anyway).

Of course, in all cases, make sure any potential penetrations are properly sealed and any membranes or less sound barriers have adequate mechanical protection. Where paint or membranes are used scheduled inspections and repairs should be made. Annual is probably adequate but any incidentally noticed damage at any time should obviously be repaired in a timely manner.

 

[xoxota]

Bob
Thank you for the input.