NFPA 99 - Dedicated Exhaust for Med Gas Storage Room

[PagoMitch]

I am designing a couple small Med Gas Storage Rooms in a Hospital; (4) K cylinders each of N2 and CO2 (about 300 ft^3 each tank, 1200 ft^ 3 each room, 2400 ft^3 on this floor). These will be in separate rooms, although it is technically not required.

NFPA 99 2018 requires 1-hr walls, with 45-minute door and opening protection. This is in spite of 1-hr walls NOT needing protection (fire dampers) per NFPA. OK, so be it.

My question is on the exhaust:
Ducts down to one foot from the floor - no problem.
Exhaust at 1 CFM/5 ft^3 tank volume - no problem.
Non-combustible Exhaust Duct - no problem.

However... "Para 9.3.6.5.3.5: Dedicated exhaust systems shall not be required, provided that the system does not connect to spaces that contain combustible or flammable materials". OOPS, problem. This was going to connect to the Central Exhaust System, a nominal 5000 CFM Fan that serves roughly 16000 SF.

I cannot think of any enclosed area, anywhere (except for maybe an empty prison cell), that would not contain "combustible or flammable materials". Papers on a desk, a wall calendar, seat cushions, a wooden desk, wooden filing cabinets, manilla folders, the paper covering on an exam table, paper towels in the bathroom, cardboard boxes in the Janitors Closet holding cleaning supplies, and even the paper bags from In-N-Out burger would all be combustible, with the In-N-Out bag in particular (probably) being flammable due to the grease coating.

The way this is written, EVERY Med Gas Storage Room, even those at a miniscule 12 SF would require a dedicated Exhaust System.
I did try looking at definitions for "combustible or flammable materials" in NFPA, hoping it would be defined as Types of Construction - no such luck.

Am I missing something, or is this paragraph as literal - and inane - as it appears?

TIA.

 

[PEDARRIN2]

From the commentary.

 

[PagoMitch]

Pedarrin2 - Thanks for the response.

I understand the Code - I quoted it.
However... the way it is written is appalling.
"... cannot interconnect with other facility air-handling systems that serve locations containing combustible or flammable materials".

For pete's sake... An employee in a Hospital of concrete and/or steel construction, with a concrete floor and steel furniture - that may reasonably be construed as NOT containing combustible or flammable materials (assuming it is a true paperless office, and no one brought in today's copy of the Wall Street Journal to read at their desk), would VIOLATE that construal by bringing back a hamburger and fries in a paper bag, or (if she smokes), leaving her Zippo in her purse. Most codes are written with a little less arbitrariness, with violations not dependent upon the packaging of what someone brings for lunch.

I had hoped... that as this code has been in place since at least 2012, that ...someone... may have challenged this, or got an interpretation a little more rationally written. This could have been on defining "materials" as "construction materials", and defining their performance per ASTM E-84 "Flame Spread Rating", or E-119 "Fire Rating". THAT... would have made a lot more sense. Alas, apparently not.

In this case, the facility is in the tropics, and having an opening from tank gases (which cool appreciably as they are being used) to the very high humidity ambient temperature is a recipe for lots of mold. So I will need to provide conditioned (and dehumidified) are as make-up. Which we have.

There is another line of thought... are we really concerned with inert gases in industry standard pressurized containers bursting into flame? Sigh.

Regards.

 

[3DDave]

It would seem that contacting the issuing authority for clarification or remediation of this section would be the most effective approach.