IBC 2006 Section 1009 Stairways Exception 1- 36" width allowed for occupant load less than 50

[Jean Tessmer-HI]

This is an existing apartment complex going through remediation repair for existing stairways. Each building is 3 stories high, with two-2 bedroom dwellings on each floor and each floor is served by two stairways one at each end. Each floor occupant load is based on R-2 occupancy of 200 sf per person. The discharge load is 10 for the ground floor and 8 each for the second floor and third floor. Total occupant load number for all three floors including ground floor exit discharge is 26. The ground floor units exit pathways utilizes the existing stairways ground floor landings as a part of the exit discharge walkways. The landings are are not less than 6' by 6' wide clear and attached to the walkways going to the ground floor units and the exit walkways leading out to an open parking area away from the buildings.

An inspector is saying that the step tread has to be 36 inches wide. The width on the existing stairway assemblies between the structural posts and balusters is 36 inches.
The step tread are existing concrete units each with contiguous rise and run surfaces, to be reused after the rotting stringers are replaced.

Where is the net 36 inch wide stairway assembly measured? Is it measured between the inside faces of the structural component or each step tread which is manufacture to fit between the stairway 36 inch net clear width (which means they are made to fit inside a finished 36" wide stairway assembly so are about an inch shy)?

I do realize that under 1012.7 Projections: that the projections into the required width of the stairways at each handrail shall not exceed 4.5 inches at or below the handrail height. Does below handrail height mean anything under the handrails like a vertical side edge guard placed at each outside left and right edges of the step tread making the width under the handrail less than 36 inches wide is ok? Is having the stairway nine inches narrower under the handrails ok?

Thanks for the consideration.

 

[mtlogcabin]

The code uses the terms "width" and "clear width" in Chapter 10."Width" will allow projections into the required minimum width. "Clear width" is absolute and is typically used with regards to an accessible route.
A 35" tread width does not reduce the function or capacity of your stair and it does not make the means of egress "less safe".

IEBC
701.2 Conformance.
An existing building or portion thereof shall not be altered such that the building becomes less safe than its existing condition.

IBC
1011.2 Width and capacity.
The required capacity of stairways shall be determined as specified in Section 1005.1, but the minimum width shall be not less than 44 inches (1118 mm). See Section 1009.3 for accessible means of egress stairways.

Exceptions:

1. Stairways serving an occupant load of less than 50 shall have a width of not less than 36 inches (914 mm).

1009.3 Stairways.
In order to be considered part of an accessible means of egress, a stairway between stories shall comply with Sections 1009.3.1 through 1009.3.3.

1009.3.2 Stairway width.
Stairways shall have a clear width of 48 inches (1219 mm) minimum between handrails.

 

[Jean Tessmer-HI]

Thanks for the response. I appreciate it. These stairs even though a part of Multifamily Housing are not covered by the Fair Housing Act so are not required to be accessible. Do you also happen to know how IBC 2006 1012.7 applies? Does it really mean anything under the handrails can project into the space up to 4.5"?

 

[mtlogcabin]

2006 IBC 1012.7 Projections.
On ramps, the clear width between handrails shall be 36 inches (914 mm) minimum. Projections into the required width of stairways and ramps at each handrail shall not exceed 4.5 inches (114 mm) at or below the handrail height. Projections into the required width shall not be limited above the minimum headroom height required in Section 1009.2.

​

Measuring Stair Egress Width​

How do I measure the “egress” width of a stair?

IBC Section 1014.8 permits handrails to project up to 4½ inches into the required width of aisles, stairways, and ramps on each side. Therefore, the egress width of a stair is measured as the clear width above the handrails (between obstructions such as a wall, guard, etc.), unless handrails project more than 4 ½ inches into the stair, in which case the stair width is the measurement between the interior surface of the handrails plus 4 ½ inches on each side.

This measurement typically results in stair egress width being measured from outside stringer to stringer as this aligns with adjacent walls and guards, but this can vary depending on wall or guard offsets from the stair. In many cases, there is a gap between the outside portion of the stringer and the adjacent wall or guards which can be counted towards egress width. Alternatively, the guard is sometimes located on top of the stringer, in which case the stringer width would not be counted towards your egress width.

Are You Measuring Egress Widths Correctly? - Code Red Consultants

How to measure the widths of egress components like doors and stairs is one of those questions that code consultants get on a weekly basis. In many cases, there seems to be confusion on the minimum sizes of certain components and how to properly measure their widths properly. Stair egress...

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1012.7 is referring to the minimum clear distance required between the inside of the handrail and the surface to which it is attached. Basicall it keeps the user from scraping their knuckles' on the wall.

 

[bill1952]

Basicall it keeps the user from scraping their knuckles' on the wall.

It more importantly allows a hook grip, important in preventing falls.

 

[Jean Tessmer-HI]

Thanks MTLOGCABIN and Bill 1952 - very good information

2006 IBC 1012.7 Projections.
On ramps, the clear width between handrails shall be 36 inches (914 mm) minimum. Projections into the required width of stairways and ramps at each handrail shall not exceed 4.5 inches (114 mm) at or below the handrail height. Projections into the required width shall not be limited above the minimum headroom height required in Section 1009.2.

​

Measuring Stair Egress Width​

How do I measure the “egress” width of a stair?

IBC Section 1014.8 permits handrails to project up to 4½ inches into the required width of aisles, stairways, and ramps on each side. Therefore, the egress width of a stair is measured as the clear width above the handrails (between obstructions such as a wall, guard, etc.), unless handrails project more than 4 ½ inches into the stair, in which case the stair width is the measurement between the interior surface of the handrails plus 4 ½ inches on each side.

This measurement typically results in stair egress width being measured from outside stringer to stringer as this aligns with adjacent walls and guards, but this can vary depending on wall or guard offsets from the stair. In many cases, there is a gap between the outside portion of the stringer and the adjacent wall or guards which can be counted towards egress width. Alternatively, the guard is sometimes located on top of the stringer, in which case the stringer width would not be counted towards your egress width.

Are You Measuring Egress Widths Correctly? - Code Red Consultants

How to measure the widths of egress components like doors and stairs is one of those questions that code consultants get on a weekly basis. In many cases, there seems to be confusion on the minimum sizes of certain components and how to properly measure their widths properly. Stair egress...

coderedconsultants.com

1012.7 is referring to the minimum clear distance required between the inside of the handrail and the surface to which it is attached. Basicall it keeps the user from scraping their knuckles' on the wall.