Stairwell Roof Fire Rating

06 06 2003 edition issued.

Stairwell roof fire rating.

Vertical exit enclosures four stories or mor e shall be 2 hour fire resistance rat ed. Fire resistance rated construction section 706 4 ibc interpretation no. In buildings four or more stories or more than 40 feet 12 192 mm in height above grade one stairway shall extend to the roof surface through a stairway bulkhead complying with section 1509 2 unless the roof has a slope steeper than 20 degrees 0 35 rad access to setback roof areas may be through a door or window opening to the roof. 05 31 06 706 4 co ntinuity o f fire ba rrier w alls.

Interior exit stair ways shall be enclosed. Fire ba rri er wal ls shall ext end f rom the top of the floor cei ling assembly below t o the under side of the floo r or roof slab or deck abo ve and shall be securely attached thereto. Astm e119 standard test methods for fire. Openings in the roof shall not be located within 4 feet 1220 mm of the fire wall.

Ver tical exit enclosur es les s than f our stor ies shall be 1 hour f ire resistance rated. On this building the ibc allows for a rated lid as long as it matches the rating of the vertical walls ibc 2009 section 708 12. Fire and sound selector fire and sound ratings fire ratings fire resistance is the ability of an assembly constructed in a laboratory to contain a fire in a carefully controlled test setting for a specified period of time. Can you rate the ceiling or lid of a stair or elevator enclosure thus avoiding the expense and complication of taking the rated walls to the bottom of the roof.

What i found is still somewhat inconclusive. 3 every exit shall be separated from the remainder of the building by a fire separation having a fire resistance rating not less than that required by subsection 3 2 2 but not less than 45 min for a the floor assembly above the storey or b the floor assembly below the storey if there is no floor assembly above. The lower roof assembly within 4 feet 1220 mm of the wall has not less than a 1 hour fire resistance rating and the entire length and span of supporting elements for the rated roof assembly has a fire resistance rating of not less than 1 hour. Over non combustible roof decks such as steel poured gypsum or concrete only the spread of flame on the top surface of the roof system is evaluated.

The number of stories shall be co mp uted as al l f loor lev els i ncludi ng bas ements but ex cludi ng mezzan ines. If stairwell doors do not allow for reentry and a stairwell becomes impassible it can jeopardize the lives of those using the stairwell as a means of egress.