Stair Width and Handrails

[rosegamble]

Hi All. Need some help finding where in the code it is stated that stair width is measured from wall-to-wall, not handrail-to-handrail like ramps.

I searched IBC 1011 and 1014. Can't find where this is stated explicitly.

Thanks!

 

[TheCommish]

Section 1011.2 stair width, section 1014.8 projections into the the required width (see 1011.2 ) shall not exceed 4 1/2 inches at or below the handrail height.

So by design the stairway must be the required width and the handrails can project into the width 4 1/2 inches.

Code is fun languages, it tells us things and does not read like a novel where they state things.

 

[Inspector Gift]

Section 1011.2 stair width, section 1014.8 projections into the the required width (see 1011.2 ) shall not exceed 4 1/2 inches at or below the handrail height.

So by design the stairway must be the required width and the handrails can project into the width 4 1/2 inches.

Code is fun languages, it tells us things and does not read like a novel where they state things.

Our Building Division has come to understand the required width as being the clear space measured between the handrails, based upon the language in the 2018 IBC for stairs and ramps. We would rather error on being more accessible than less.

Stairs:
IBC 1011.2 Width and capacity. The required capacity of stairways shall be... <snip> not less than 44 inches. See Section 1009.3 for accessible means of egress stairways.
IBC 1009.3.2. Accessible Stairways. Stairways shall have a clear width of 48 inches minimum between the handrails.

Ramps:
IBC 1012.6.2 Width and capacity. The minimum width and required capacity of a means of egress ramp shall be not less than that required for corridors by Section 1020.2. The clear width of a ramp between handrails, if provided, or other permissible projections shall not be less than 36 inches minimum.

 

[tbz]

Our Building Division has come to understand the required width as being the clear space measured between the handrails, based upon the language in the 2018 IBC for stairs and ramps. We would rather error on being more accessible than less.

Stairs:
IBC 1011.2 Width and capacity. The required capacity of stairways shall be... <snip> not less than 44 inches. See Section 1009.3 for accessible means of egress stairways.
IBC 1009.3.2. Accessible Stairways. Stairways shall have a clear width of 48 inches minimum between the handrails.

Ramps:
IBC 1012.6.2 Width and capacity. The minimum width and required capacity of a means of egress ramp shall be not less than that required for corridors by Section 1020.2. The clear width of a ramp between handrails, if provided, or other permissible projections shall not be less than 36 inches minimum.

You forgot the exceptions, if the building is sprinklered, then 48 between is not required.

 

[TheCommish]

 

[Yikes]

1. “Stair-way“ width is the width of the stair tread.
2. Handrails are an allowable encroachment in that stairway tread width. One way to visualize it is that a frail person who doesn’t have much arm leverage may grab the handrail by rotating their body slightly towards the wall, thus their toes are utilizing the space underneath the handrail. So the tread space under the handrail still has practical usefulness for egress width.
3. The accessible stairway width of 48” min. clear only comes into play when the designer has selected the stair as a component to achieve code-required accessible means of egress. The extra clear width is deemed necessary to help carry someone out down the stairs. If a designer chooses another method (such as an elevator) to comply with code AMOE, then the 48” clear is not required.

 

[mtlogcabin]

Generally speaking, most people are wider above the waist then below the waist so the protruding handrail should have little impact on egress.

 

[bill1952]

Generally speaking, most people are wider above the waist then below the waist so the protruding handrail should have little impact on egress.

At least that was the case 75 or so years ago when these dimensions were codified.

 

[anaparke]

2018 commentary shows it measured beyond the 4.5" max. projection. You can also see that other things below the handrail can project into this space as well.

 

[Paul Sweet]

The only places I know of where width has to be measured between handrails are accessible stairs (IBC 1009.3.2) and intermediate handrails on wide stairs (1014.9).

 

[bill1952]

The only places I know of where width has to be measured between handrails are accessible stairs (IBC 1009.3.2) and intermediate handrails on wide stairs (1014.9).

in assembly also: 1030.9.1 (2018) Minimum Aisle Widths

 

[brokenkeys]

At least that was the case 75 or so years ago when these dimensions were codified.

Which is one of my favorite code sections (NFPA 101 Appendix 7.3.3.2):



The section is much bigger than this but the code lingo version of "sure people are bigger and slower nowadays, but we don't have data about it, so we'll stick with what we got!", part is chef's kiss

 

[bill1952]

There will eventually be a large loss of life incident where this issue is determined to be a factor, and then the codes will react and change. Like after the Station fire and so many other large loss of life incidents.