Spiral stair outside main exit/entrance

Voting section related to Minnesota building codes.

Can a spiral stair be used outside of a residential structure at the main exit door?

Poll ended at Sun Aug 31, 2008 2:49 pm

Yes
16
94%
No
1
6%
 
Total votes : 17

Spiral stair outside main exit/entrance

Postby forumadmin » Mon Aug 04, 2008 10:52 am

Can a spiral stair be used outside of a residential structure at the main exit door?
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Re: Spiral stair outside main exit/entrance

Postby Patrick Parsley » Mon Aug 04, 2008 11:08 am

Yes according to R311.5.8-a complying spiral stair is allowed as part of the exit path.
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Re: Spiral stair outside main exit/entrance

Postby JimW » Mon Aug 04, 2008 3:54 pm

Yes, if you read only the IRC. I have always questioned how good that book was put together. As some of you may recall in the UBC days there was a limit to where and when spiral stairways could be used. So I turned to both the IRC and IBC commentary to see what it had to say. Below is some of the IBC. I personal belive if one book is not clear or doing something that is really off base you should try to find the intent of the section before you make your judgement.

So in close I Vote NO if this is the main exit. Yes if this is a secondary exit.


1009.8 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.

Spiral stairways are generally constructed with a fixed center pole that serves as either the primary or the only means of support from which pie-shaped treads radiate to form a winding stairway.

The commentary to Section 1009.3.1 regarding the eccentricity of movement on stairways with winders also applies to spiral stairways. The nature of stairway construction is such that it does not serve well when used in emergencies that require immediate evacuation, nor does a spiral stairway configuration permit the handling of a large occupant load in an efficient and safe manner. Furthermore, it is impossible for fire service personnel to use a spiral stairway at the same time and in a direction opposite that being used by occupants to exit the premises, possibly causing a serious delay in fire-fighting operations. Therefore, this section allows only very limited use of spiral stairways when part of a required means of egress. Spiral stairways may be used in any occupancy as long as such stairways are not a component of a required means of egress. Spiral stairways are required to have dimensional uniformity. Treads must be at least 26 inches (660 mm) wide and the depth of the treads must not be less than 71/2 inches (191 mm) measured at a point that is 12 inches (305 mm) out from the narrow edge. Riser heights are required to be the same throughout the stairway, but are not to exceed 9 ½ inches (241 mm). Minimum headroom of 6 feet 6 inches (1981 mm) is required.
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Re: Spiral stair outside main exit/entrance

Postby Patrick Parsley » Mon Aug 04, 2008 4:00 pm

Let me qualify my answer.
Yes: A spiral stairway is acceptible as a part of the exit system from a residence built under the 2006 IRC. I assumed the question was only asking about IRC installations.
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Re: Spiral stair outside main exit/entrance

Postby RDavidson » Wed Aug 06, 2008 10:29 am

I regret that I must agree with the Imperial Potentate from Fairmont. Since the IRC only requires that you have an exit door and that door must have a landing (no stair or ramp required to grade), it would then seem that you could use any stair or ramp permitted by the IRC to get to grade. If you choose not to put in a stair, that is your choice to. So once again, there is a wealth of truth and common sense coming out of Fairmont.
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Re: Spiral stair outside main exit/entrance

Postby Patrick Parsley » Wed Aug 06, 2008 11:21 am

Thank you for the affirmation-I think :o
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Re: Spiral stair outside main exit/entrance

Postby Peter » Mon Aug 18, 2008 6:56 am

It is my staff opinion that a spiral stair constructed per 2006 IRC Section R311.5.8 can be used for any exit for the dwelling, whether it is the required exit (Section R311, Means of Egress) or otherwise. Peter Kulczyk
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