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2006 ibc 405

M

MechinspMi

Member
Joined
Oct 17, 2009
Messages
14
Location
Michigan
Would you interpret the exception of fully sprinklered in 405 to eliminate the rest of the entire 405 subsections when the building is more than 80' deep? This is an underground parking garage. It does have an accessory office in the lowest level (6) levels down. Thanks for any insight, It makes no sence that smokeproof enclosures for stairwells and pressurization, smoke control etc including the alarm paging system would be eliminated with only having a sprinkler system that won't stop the spread of smoke.

One thought we had in our dept. was that parking garages by themselves don't pose the same risk as an underground occupied building but the commentary seems to state differently.
 
No need for interpretation, it is very clear - "The provisions of this section apply ... except... Parking garages with automatic sprinkler systems". Can't get more straightfoward than that.

However, your situation is not straightforward. You have a B occupancy down there, and that part is not exempted. No matter what, UG building features will be required for that area. The real question to decide (if they don't just move the stoopid thing upstairs) is whether just the office (and it's egress path) needs compartmentalization, smoke control, smokeproof enclosures, etc. or if the entire garage needs it. Once confronted with this, the designers should just move the office to 29' below grade.
 
Thanks Dr. J

That is what we suggested regarding the office, but the owner thinks it will be a safety factor if people using the garage see the attendants accessing this space from open stairways.

So back to the point you made. Would you think that the egress stairwell for this area would meet the same provisions for pressureization/smoke control at the lowest level only?

Vern
 
Well, you woulkd have to go for a variance/equivalency. If it were my project, I might suggest a dedicated egress stair and elevator for the office, directly accessible from the office without having to enter the garage, and that this stair be pressurized. This could be looked at like an upside down aircraft control tower – limited to somewhat trained personnel, not the general public, and a very small occupant load. See 412.
 
it's an underground mid-rise; all the below grade parking garages here have pressurized stairs. The commentary has a note: Note that a smoke control system is required. Automatic sprinkler systems are essential systems of any smoke control system. Also look in 406 which will refer you to 509. Why can't we write some of the explatory material into the body of the code?
 
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