Class 1 Division 2 Ventilation

[John_187]

There is a code that states adequate ventilation for Class 1 Division 2 buildings that is open ended. NFPA 497 section 3.3.1 states adequate ventilation is 6 air changes per hour, or 1 CFM/SF. Do you select whatever number is larger?

In the American Petroleum Institute Guidelines for Class 1 Division 2 section 6.3.2.4.2, it says that it's 6 air changes per hour. I am just curious if anyone else has dealt with this discrepancy, and what you did?

Thanks

 

[chicopee]

Calculate with each one of those two options and the highest value should be your selection.

 

[GT-EGR]

Do the larger one, which in an 8 foot ceiling roomn is the CFM/ft2 number. This essentially ensures that a room with very high ceilings and a lot of room volume doesn’t end up with a low airflow.

But the basis of those numbers we’ll probably never know.