Gas Storage Ventilation

Q: In the 1999 Edition of NFPA 99, it mentions for medical gas storage systems more than 3,000 cubic feet, if the door opens to an exit access corridor, louvered openings shall not be used and a mechanical ventilation system shall be required. I cannot find that requirement in the 2012 edition of NFPA 99 regarding not using a louvered door in an exit access corridors. Has it been eliminated, or am I just missing it? If it was eliminated, do you know why?

A: In a way they eliminated it and in another way they did not. Yes, they did delete the language that says doors that open onto an exit access corridor cannot have louvers for ventilation. But that does not mean you can now have louvers in doors to exit access corridors. Section 5.1.3.3.2 of the 2012 NFPA 99 is the section for central storage in quantities greater than 3,000 cubic feet of compressed medical gas, and for gas manifold systems.

You will notice that ventilation requirements are no longer under section 5.1.3.3.2. You will find ventilation requirements for medical gas storage under section 9.3.7, and specifically section 9.3.7.5.2 describes natural ventilation which now limits the ventilation openings to be directly to the outside atmosphere without ductwork. This precludes the possibility of louvers in a door to an exit access corridor.

And, NFPA 99 requires a fire-rated door for medical gas storage rooms and gas manifold rooms. Louvers are not permitted in fire-rated doors.

There is still an option of using natural ventilation or mechanical ventilation, and plenty of rules for both.