Intermediate handrails - minimum clear width?

[George McGerd]

IBC (2015 Ed.) requires an intermediate handrail such that all required "egress width" for a stairway be located within 30" of a handrail (1014.9) as does NFPA 101 (2015 Ed.) 7.2.2.4.1.2 (1). In addition, NFPA 101 clarifies that the minimum clear width between intermediate handrails shall be not less than 20" (7.2.2.4.1.3).

Does the IBC have a similar provision that clarifies the minimum width between handrails when an intermediate handrail is used? I couldn't find one.

Note, the building is fully sprinklered so it is my understanding that under exception (2) the 48" minimum width between handrails required for a stair to be "accessible" per 1009.3 does not apply. Correct?

Thanks.

 

[north star]

@ ~ @ ~ @

George,

I also could not find a code section related to minimum widths of

Stairways when an intermediate handrail is used.

Regarding your 2nd question, ...Section 1009.3, Exception # 2

would not apply to minimum widths, however, ...the minimum width

of an accessible Stairway must not be narrower than the calculated

width per the designed occupant load or loads for that particular

Stairway [ RE: Section 1005.3.1, Exception # 1, `15 IBC ].



@ ~ @ ~ @

 

[Francis Vineyard]

1014.8 Projections. On ramps and on ramped aisles that are

part of an accessible route, the clear width between handrails

shall be 36 inches minimum. Projections into the

required width of aisles, stairways and ramps at each side

shall not exceed 41/2 inches at or below the handrail

height. Projections into the required width shall not be limited

above the minimum headroom height required in Section

1011.3. Projections due to intermediate handrails shall not

constitute a reduction in the egress width. Where a pair of

intermediate handrails are provided within the stairway

width without a walking surface between the pair of intermediate

handrails and the distance between the pair of intermediate

handrails is greater than 6 inches, the

available egress width shall be reduced by the distance

between the closest edges of each such intermediate pair of

handrails that is greater than 6 inches.

Commentary.

The requirement for some stairways to have center

handrails (Section 1014.9) could result in a single or

double handrail down the center of the flight of stairs.

Since these stairways are 60 inches or

wider, a center handrail would typically not be an

obstruction and, therefore, would not reduce the

capacity of the stairway. Schools and large assembly

spaces commonly put in center handrails to aid in the

flow up and down the stairs during peak usage times.

If the center handrail is a double rail with a spacing of

more than 6 inches, the width of the stairway

many need to be adjusted to compensate for the

loss of available width.

 

[George McGerd]

Thanks. Regarding the second question: I have sized the stairways to exceed the calculated width per the designed occupant load, but placing an intermediate handrail (which will be required since the occupant load for each stairway exceeds 200 occupants) will result in clear widths of less than 48" between the intermediate handrail and the wall-mounted handrail. Based on everything I have read so far (above and below) this is an acceptable design solution since the building is fully sprinklered (IBC 1009.3 ex. 2)

 

[ADAguy]

It all comes down to mathematics, code minimums and risk management.

Can I get a board with firemen carrying a victim down it in less than 48" clear?

 

[JPohling]

stretcher slides down intermediate rail