# Stair roof fire rating?



## Mech (Sep 27, 2019)

2015 IBC
3 story building; 2B construction, 0 hr fire resistance rating requirements per Table 601.

The interior exit stairways are located outside the building as shown below.

…...____________
…..|...……….…...|
…..|...…….……...|________
…..|...…….………|...……….|
…..|...…….……...| stairs..|
…..|...….…………|_______|
…..|...….…………|
…..|...….…………|
…..|___________|​The wall common to the building and stairway is rated one hour.

Does the roof of the stairway need to be fire rated if it is lower than the main building roof?  The stairs roof could be 15 - 20 feet lower than the building roof.

Thanks


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## RLGA (Sep 27, 2019)

No. Roofs of enclosed stairways comply with the requirements for the type of construction


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## classicT (Sep 27, 2019)

Separation from the building, yes; enclosed by rated assembly at roof, no.

As indicated by Ron, roofs for exterior exit stairways do not need to be rated unless required per Table 601 and the given the type of construction.

*1027.6 Exterior Exit Stairway and Ramp Protection*
_Exterior exit stairways _and _ramps _shall be separated from the interior of the building as required in Section 1023.2. Openings shall be limited to those necessary for egress from normally occupied spaces. Where a vertical plane projecting from the edge of an _exterior exit stairway _or _ramp _and landings is exposed by other parts of the building at an angle of less than 180 degrees (3.14 rad), the exterior wall shall be rated in accordance with Section 1023.7.
*
Exceptions:*

Separation from the interior of the building is not required for occupancies, other than those in Group R-1 or R-2, in buildings that are not more than two stories above _grade plane _where a _level of exit discharge _serving such occupancies is the first story above _grade plane_.
Separation from the interior of the building is not required where the _exterior exit stairway _or _ramp _is served by an _exterior exit ramp _or balcony that connects two remote _exterior exit stairways _or other _approved exits _with a perimeter that is not less than 50 percent open. To be considered open, the opening shall be not less than 50 percent of the height of the enclosing wall, with the top of the openings not less than 7 feet (2134 mm) above the top of the balcony.
Separation from the open-ended _corridor _of the building is not required for _exterior exit stairways _or _ramps_, provided that Items 3.1 through 3.5 are met:
The building, including open-ended _corridors_, and _stairways _and _ramps_, shall be equipped throughout with an _automatic sprinkler system _in accordance with Section 903.3.1.1 or 903.3.1.2.
The open-ended _corridors _comply with Section 1020.
The open-ended _corridors _are connected on each end to an _exterior exit stairway _or _ramp _complying with Section 1027.
The _exterior walls _and openings adjacent to the _exterior exit stairway _or _ramp _comply with Section 1023.7.
At any location in an open-ended _corridor _where a change of direction exceeding 45 degrees (0.79 rad) occurs, a clear opening of not less than 35 square feet (3.3 m2) or an _exterior stairway _or _ramp _shall be provided. Where clear openings are provided, they shall be located so as to minimize the accumulation of smoke or toxic gases.

*1023.2 Construction*
Enclosures for _interior exit stairways _and _ramps _shall be constructed as _fire barriers _in accordance with Section 707 or _horizontal assemblies _constructed in accordance with Section 711, or both. _Interior exit stairway _and _ramp _enclosures shall have a _fire-resistance rating _of not less than 2 hours where connecting four stories or more and not less than 1 hour where connecting less than four stories. The number of stories connected by the _interior exit stairways _or _ramps _shall include any _basements_, but not any _mezzanines_. _Interior exit stairways _and _ramps _shall have a _fire-resistance rating _not less than the floor assembly penetrated, but need not exceed 2 hours.

*Exceptions:*​
1. _Interior exit stairways _and _ramps _in Group I-3 occupancies in accordance with the provisions of Section 408.3.8.
2. _Interior exit stairways _within an _atrium _enclosed in accordance with Section 404.6.​


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## RLGA (Sep 27, 2019)

Ty J. - The OP doesn't indicate it's an exterior stair. It states "interior exit stairways" which are located in enclosures, thereby are not required to conform to the exterior exit stairway requirements.

However, the exterior walls of an enclosed interior exit stairway are required to comply with Section 1023.7.


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## classicT (Sep 27, 2019)

RLGA said:


> Ty J. - The OP doesn't indicate it's an exterior stair. It states "interior exit stairways" which are located in enclosures, thereby are not required to conform to the exterior exit stairway requirements.
> 
> However, the exterior walls of an enclosed interior exit stairway are required to comply with Section 1023.7.


Agree, that's what he states, but the second half of his post sounds a lot more like an exterior exit stairway.


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## Mech (Sep 30, 2019)

So if I have my understanding correct between stair types, this is an interior exit stair as it is enclosed with 4 walls and a roof.


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## classicT (Sep 30, 2019)

If the stair and three of the four associated walls are on the exterior as suggested by the OP pictogram, then an exterior stair may allow greater benefit as the (3) walls would not need to be rated if appropriate setbacks are allowed. Would no longer require construction as a shaft.


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## steveray (Sep 30, 2019)

Yep...and like Ron said....Watch for this:

1023.7 Interior exit stairway and ramp exterior walls.
Exterior walls of the interior exit stairway or ramp shall comply
with the requirements of Section 705 for exterior walls.
Where nonrated walls or unprotected openings enclose the
exterior of the stairway or ramps and the walls or openings
are exposed by other parts of the building at an angle of less
than 180 degrees (3.14 rad), the building exterior walls
within 10 feet (3048 mm) horizontally of a nonrated wall or
unprotected opening shall have a fire-resistance rating of not
less than 1 hour. Openings within such exterior walls shall be
protected by opening protectives having a fire protection rating
of not less than 3/4 hour. This construction shall extend
vertically from the ground to a point 10 feet (3048 mm)
above the topmost landing of the stairway or ramp, or to the
roof line, whichever is lower.


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