# Size of roof Hatch



## liarchitect (Jun 24, 2010)

i have a new 2 story commercial building approximately 25 feet height, non occupied with parapets, what is the min, size of a roof hatch to provide access the roof

As per section 1009.12.1 Roof Access Exception:

in buildings without an occupied roof, access to the roof shall be permitted to be a roof hatch or trap door not less than 16 square feet in area and having a min. distance of 2 feet

Does this meet the roof hatch has to be 16 square feet, or a trap door needs to be that min. size

A 16 sf roof hatch seems a bit to large

Good old code, each time i read it i interpret it a difference way

thank in advance


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## Gene Boecker (Jun 24, 2010)

You say that the building is 2-stories in height.  The threshold for when access to the roof is required is at 4 stories according to 1009.12 (2006 IBC).  As such, any access you provide can be as you wish it to be.

The 16 SF is for fire fighters access needs (breathing gear and special equipment take up space).  In buildings up to 4 stories access is possible from an external ladder.  Higher than that the roof access is necessary from the interior.  On a 2-story structure you don't need an internal roof access.


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## mtlogcabin (Jun 24, 2010)

Agree with Gene don't forget about 1013.6

1013.6 Roof access.

Guards shall be provided where the roof hatch opening is located within 10 feet (3048 mm) of a roof edge or open side of a walking surface and such edge or open side is located more than 30 inches (762 mm) above the floor, roof or grade below. The guard shall be constructed so as to prevent the passage of a 21-inch-diameter (533 mm) sphere.


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## georgia plans exam (Jun 24, 2010)

If fuel burning appliances are located on the roof, the threshold for permanent access is 16' per IFGC Section306.5. See also IMC Section 306.5. (2006 codes)

GPE


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## liarchitect (Jun 24, 2010)

thank you

thank you for all of your insightful input


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## Examiner (Jun 24, 2010)

OSHA will require a railing system around the roof hatch also.  Check BILCO roof scuttles out for the railing and the telescoping pole.

The Code Commentary has good graphics regarding the other guardrailing requried if the roof opening is 10-feet or less from a roof edge.


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