Non Required Winder Stair

[tbz]

Ok, this is a RFI request about a tread and riser issue on a project, from what I am reading the person answering the question is stating that non-required stairs need not comply. Am I reading something wrong?

From what I understand 2006 IBC does not allow winder treads to be part of the MOE, thus the fact that they are covered for min/max requirements makes wonder how they can even think this, but what do you all think of this answer?

Thank you - Tom

 

[Francis Vineyard]

Tom I believe a code change in the 2012 edition section 1009.1 clarified the dimensions applied to all stairs including convenience stairs that served occupied portions of the building.

 

[TheCommish]

408.3.4 Spiral stairways. Spiral stairways that conform to
the requirements of Section 1009.9 are permitted for access
to and between staff locations.

1009.9 Spiral stairways. Spiral stairways are permitted to be
used as a component in the means of egress only within dwelling
units or from a space not more than 250 square feet (23 m2)
in area and serving not more than five occupants, or from galleries,
catwalks and gridirons in accordance with Section
1015.6.
A spiral stairway shall have a 71/2-inch (191 mm) minimum
clear tread depth at a point 12 inches (305 mm) from the narrow
edge. The risers shall be sufficient to provide a headroom of 78
inches (1981 mm) minimum, but riser height shall not be more
than 91/2 inches (241 mm). The minimum stairway clear width
at and below the handrail shall be 26 inches (660 mm).

 

[tbz]

Tom I believe a code change in the 2012 edition section 1009.1 clarified the dimensions applied to all stairs including convenience stairs that served occupied portions of the building.

Thanks Francis for the response,

Yes as you stated it was clarified in later additions, my question is if Chapter 10 says you can't have "winder treads" in a MOE stair flight, and then in that same chapter it spells out what winder treads must comply to, then why are the requirements in the code? The respondent in the letter is simply saying non-required stairs are not covered by the code in chapter 10 because they are not part of the required MOE plan and chapter 10 only applies to the MOE plan. and since there is no other notation in any other chapter you can do what ever you want.

The code says you can't have winders within the MOE, but then defines them for construction. It just seems odd that we have a requirement for something that is not allowed.

My understanding of the difference between required MOE stairs and non-required "convenience" stairs is that they are not required to be in the building. however, if you install them they still need to comply and since they are not part of the main MOE traffic flow we will allow you a little more freedom with the design and construction with allowing the following and here are the base requirements.

By the logic of the letter, exterior viewing balconies are not required for the MOE plan, so why are they required to install guards on them?

Do you concur that the under 2006 the stair tread & riser config is required to meet the code as spelled out in chapter 10 or because of a flaw in the code it can go the other way?

 

[tbz]

408.3.4 Spiral stairways. Spiral stairways that conform to
the requirements of Section 1009.9 are permitted for access
to and between staff locations.

1009.9 Spiral stairways. Spiral stairways are permitted to be
used as a component in the means of egress only within dwelling
units or from a space not more than 250 square feet (23 m2)
in area and serving not more than five occupants, or from galleries,
catwalks and gridirons in accordance with Section
1015.6.
A spiral stairway shall have a 71/2-inch (191 mm) minimum
clear tread depth at a point 12 inches (305 mm) from the narrow
edge. The risers shall be sufficient to provide a headroom of 78
inches (1981 mm) minimum, but riser height shall not be more
than 91/2 inches (241 mm). The minimum stairway clear width
at and below the handrail shall be 26 inches (660 mm).

Thanks Commish,

I limited the post to Winder treads in the heading because the stairs are winders not a spiral and the letter is about requirements on winder construction.

I do get your note that spirals are allowed in limited use in a MOE, thought thanks

Tom

 

[Francis Vineyard]

. . . Do you concur that the under 2006 the stair tread & riser config is required to meet the code as spelled out in chapter 10 or because of a flaw in the code it can go the other way?

Yes

 

[TheCommish]

Oh, sorry I missed that. I would still follow the path stair geometry is covered by the code for stair construction by type, with the additional burden if it is MOE stair it has to meet those requirements

 

[Mr. Inspector]

It's interesting according to IBC 1012 that you only need to go by the code for stairways serving an occupied space in a building. That would leave out any stairways outside of a building that do not serve a building, like a stairway between to parking lots at different levels. So the accessible ramp between the parking lots would have to be by code but if there are stairs also, the stairs are not required to be to code. Or any other extra stairway outside, like a stairway from a school to a playground as long as you have the required accessible ramp to it?

I guess the stairway to the basement which only has a heater (not a occupied space) won't need to be to code either since it has a walk out door in the basement for egress. But there are steps outside of the basement door that go the ground level. I guess they would not need to be to code since the basement is not a occupied space?