stair landing dimensions

[metalfab]

I am confused on the stair and landing width codes. The codes imply that the landing width be the same or greater than the stair width, but there are no real clarifications of where they are measuring from. For example, we have a commercial building with a interior stair consisting of MC12x10.6 stringers that also wrap around the landing. The guardrails are 1 1/4" std. pipe (1 5/8" od) with 1 1/4" std. pipe offset handrail that is 3 1/4" from center of post to center of handrail. The wall rails are 2 1/2" from wall to center of pipe. What is the minimum stair width and where exactly are they measuring to? Also where do you measure to in calculating the landing width? Is it from the last nosing or the end of the stringers and is to the wall or the inside of the wall stringer? I would appreciate any input on this.

Thanks

 

[fatboy]

Welcome!

A drawing would most helpful.

A simple answer would be the clear interior dimension.

Every landing shall have a minimum depth, measured parallel to the
direction of travel, equal to the width of the stairway or 48
inches (1219 mm), whichever is less.

 

[metalfab]

Welcome!

A drawing would most helpful.

A simple answer would be the clear interior dimension.

Every landing shall have a minimum depth, measured parallel to the
direction of travel, equal to the width of the stairway or 48
inches (1219 mm), whichever is less.

I understand that, but what I'm after is how the stair width is established. Is the measurement between the handrails, between the stringers, to the wall etc.? The same question for the landing. Is the measurement from the nosing, the end of the stringer, or the handrail over to the wall or stringer face? Basically, what surfaces are they measuring from to get these minimums?

 

[fatboy]

Width of the stair above the hand rail(s) is wall to wall, handrails may encroach into that width, and below can be reduced.

Projections into the required width of aisles, stairways and ramps at each side
shall not exceed 4 1/2 inches (114 mm) at or below the handrail height.

So the stairway itself, since it is below the handrail, could be reduced 9". And the associated landing, is the width of the stairway.

 

[ICE]

I understand that, but what I'm after is how the stair width is established. Is the measurement between the handrails, between the stringers, to the wall etc? The same question for the landing. I the measurement from the nosing, the end of the stringer, or the handrail over to the wall or stringer face? basically what surfaces are they measuring from to to get these minimums.

The width of a stairway is the width of the tread between stringers or walls. The width of a landing is the same. The depth of a landing includes the nosing per the definition of a nosing.

THE NOSING: The leading edge of treads of stairs and of landings at the top of stairway flights.

 

[ICE]

Width of the stair above the hand rail(s) is wall to wall, handrails may encroach into that width, and below can be reduced.

Projections into the required width of aisles, stairways and ramps at each side
shall not exceed 4 1/2 inches (114 mm) at or below the handrail height.

So the stairway itself, since it is below the handrail, could be reduced 9". And the associated landing, is the width of the stairway.

Please clarify the landing width required. Can a landing be reduced 9" to match the stairway served. So for example, a 36" wide stairway that has been reduced to 27" below the handrail can have a 27" wide landing?

I wouldn't think so but the way you worded it some might take it the wrong way.

 

[fatboy]

Every landing shall have a minimum depth, measured parallel to the
direction of travel, equal to the width of the stairway or 48
inches (1219 mm), whichever is less.

Every landing shall have a minimum depth, measured parallel to the
direction of travel, equal to the width of the stairway or 48
inches (1219 mm), whichever is less.

I've never been asked the question, but that it is what the code says.

At the landing, above the handrail the there needs to be the required width, below the handrail the section speaks to depth of landing, why wouldn't it apply to the landing width, IF there are handrails present.

Where do you get otherwise?

 

[bill1952]

The OP said landing width, and several posts have quoted landing depth. Just checking.

 

[tbz]

The clear minimum width of the stairway, that meets the reduction in the IBC to be only 36 inches wide is measured above the handrails.

Thus the landing does not follow below the clear width [ i.e. - the reduced width between handrails ]. It follows minimum width/width above handrails, hence wall to wall.

What sets the minimum width of the stairways is based on the occupancy load for M.O.E., hence 36", 44", 48" or other if larger and or for non-M.O.E. stairs which require 36" between the handrails.

So the Architect is going to specify the required width, hopefully correctly in the plans, this translates to the landing.

Metalfab, with a wrap around landing the designer should be specifying from nosing to back for the landing depth, but the width will be based on the 2 stair flights and the distance between them, hence the minimum width could be 72 + ? or 88 + ? or even another, as the 2 landings and the mid distance combine to be one large landing.

However, the minimum is the required minimum width, or larger based on the stair flights required M.O.E. 50 or less or more than 50 what's the number and also is the building sprinklered.

Thus the number will fluctuate, but the measuring point is Minimum above handrails and or larger.

Then you have stairways with wrap around continuous handrails, were the width between the stringers is allowed to be the same on the landing, since there is no clear break below.

 

[fatboy]

"Then you have stairways with wrap around continuous handrails, were the width between the stringers is allowed to be the same on the landing, since there is no clear break below."


That is what I was picturing.

 

[Joe.B]

I'll just add a little salt to the stew. All of these measurements should be checked at rough framing inspection so there wouldn't be handrails, wall board, etc... At that point it would be simpler to decide where you're measuring from, I would think anyways.