Stairs Ventilation

[Mech]

2009 IBC & IMC

Group R-2, Type 5B construction, 3 story building

Is ventilation required in a fire-rated stairwell? Pressurization / smoke control is not required per sections 403 & 405. I am not 100% on the lingo, but this might be an exit access stairs because the occupants must leave the stair tower and enter a corridor on the level of discharge prior to getting out of the building.

The second stair tower opens to the exterior and can claim natural ventilation (if ventilation is required.)

Thanks in advance?

 

[Builder Bob]

I don't believe so... I believe the building is to low for a pressurized stairway to be required. sprinkler systems do funny things to buildings in the ICC.

 

[Mech]

The peak of the roof is less than 35 ft above ground due to the zoning ordinance. No way to reach the 75 ft mark to be a high rise. I was unsure if stairs are lumped with corridors requiring 0.06 cfm /sq ft or not.

 

[jeffc]

I would refer to IMC Section 401.1, This chapter shall govern the ventilation of spaces within a building intended to be occupied. Using the definition of occupied space in chapter 2, I would condider this space occationally occupied and for short periods of time. Therefore, I think the stair shaft would be unoccuped space and not ventilated.