Exception 1 in Section 1005.3.1 allows for a reduction in size when a building is equipped with an automatic fire sprinkler system and an emergency voice/alarm communication system, except for when serving an occupancy group H and I-2. There are a few exceptions worth mentioning. If it was calculated to be less, such as 40 inches for example, a width of 44 inches must be used since that is the minimum as noted above per Section 1011. In this example you can see that the minimum width for this stairway is 60 inches. In order to best understand this, let us take a quick look at an example:Ī stairway serves an occupant load of 200.įactor per Section 1005.3.1 is 0.3 inch per occupant.Ģ00 occupants x 0.3 inch per occupant = 60 inches If you are interested to learn how the Occupant Load of a room or space is calculated, be sure to check out this POST. It states that the means of egress for stairs is calculated by multiplying the occupant load served by the stairs by a factor of 0.3 inch per occupant. Section 1005.1 outlines several egressing components, which is a topic of its own to discuss, but you can find the requirements specifically for stairways in Section 1005.3.1. For example if a stairway serves a room as a way of exiting, it must be wide enough to accommodate the number of occupants exiting the space. I stairway can be used as a component of a means of egress. Remember what was said before? These stair requirements are for stairs that serve an occupied building or space.
Stair rail code open riser at the bottom how to#
But what is Section 1005.1? This section explains how to size a portion of a mean of egress system. Section 1011 refers us to Section 1005.1 to size the width of stair. Now lets look at how the width is calculated.
The reason for this is that if it is determined per section 1005.1 that the width is less than 44, 44 inches shall be used as the minimum. In order to determine this the code refers us to Section 1005.1, but before we look at this section the code does say that the minimum width shall not be less than 44 inches. Unlike residential stairs per the IRC, where the width is just a given measurement, commercial stair width per the IBC is based on capacity. With that said, let’s get into what those commercial stair requirements are… COMMERCIAL STAIR WIDTH Section 1011 of the International Building Code establishes the code requirements for stairs that serve an occupied building or space. Looking for Residential Stair Requirements? Be sure to check out this POST. What’s the difference between the IBC and IRC? Be sure to check out this POST. In this post we will be looking at the code standards related to commercial stairs in accordance with the International Building Code (IBC). Note that when looking for residential stair standards, one must look at the International Residential Code (IRC). Several components are looked at such as stair width, headroom, riser and tread heights. Non-circular handrails should have a perimeter dimension of at least 4 inches, and no greater than 6.25 inches, with a maximum cross-section dimension of 2.25 inches.Īlso keep in mind that guardrails are required along stairways more than 30 inches above grade, and should be a minimum of 42 inches high.When it comes to commercial stair standards, the International Building Code (IBC) establishes the minimum requirements for stairs to insure a level of safety to the public. Circular handrails should have an outside diameter of at least 1.25 inches, and no greater than 2 inches. At the bottom, the extension should continue to slope for a distance of the depth of one tread from the bottom riser the remainder of the extension should be horizontal.Įxceptions include handrails within dwelling units that are not required to be accessible, and aisle handrails in Group A occupancies.Ĭlear space between handrails and wall surfaces are required to be a minimum of 1.5 inches.
At the top, the handrail extension should be parallel to the ground.
Stair rail code open riser at the bottom plus#
If handrails are not continuous, they should extend a minimum of 12 inches beyond the top riser, and a minimum of 12 inches plus the depth of one tread beyond the bottom riser. Handrails should return to a wall, guardrail or walking surface, or should be continuous to the handrail of an adjacent stair flight or ramp run. Handrail extensions are required for all commercial stairs.