AGA XFO-277 and API-500 Natural Ventilation Building Size Limits

[Natfuelbilll]

Natural ventilation building size limits on page B1 of AGA XFO-277 and in paragraph 6.3.2.4.5 of API-500 are mismatched.

AGA recommends that natural ventilation can be used for "...building up to 2000 square feet..."; whereas, API recommends "...1,000 cubic feet or less."

For a building that has 10' tall walls, the API limit is a 100 square foot building - twenty times more restrictive than the AGA limit!

What am I missing?

 

[bobgorno]

Different organizations, different committees....AGA hasn't been updated since 1992 the last time I looked. API is on a more standard revision or re-affirmation schedule. AGA is specifically for gas utility areas whereas API covers oil and gas production, storage, transportation, etc. Large buildings just don't work well with natural ventilation. Might as well just leave out the walls.

 

[rbalex]

?Adequate ventilation? has long been a topic of conversation since I entered the business. It has been defined and redefined several times. AGA XF0277 cites API RP500 (1991) for greater than the 2000sqft. My 1991 API RP500 edition is safely buried - probably about 2-3 boxes deep in my garage.

Both the current editions of AGA XF0277 (1992) and RP500 (2002) cite NFPA 30 as the ?standard? for actually determining adequate ventilation. Unfortunately it is NFPA 30 that has kept the ball bouncing as is more or less documented in RP500, Annex C. And sad to say, NFPA 30 now tends to deal with ventilation as a function of specific installations. Some ?general? concepts are maintained, such as below 25 percent LEL is adequate, but how to achieve it varies by application.

 

[rbalex]

From what I understand, API RP500 is undergoing a major rewrite that should be published in 2010 or sooner. API typically likes to revise or reaffirm their standards every 5-7 years, sooner if possible. RP 500 is a major revenue stream.