spiral staircase and egress

[Matt Fellman]

Spiral staircase is the only means of travel from finished upper level (with bedrooms) to the main level. But there is a rear sliding door to an upper level deck with compliant stairs to the main level. There are also compliant windows in the bredrooms.

Does this comply with egress requirements?

[Markus Keller]

Don't know the IRC well enough to say for your locale. Under our Code, it would depend on how many levels above grade, square footage of upper level floor space and construction of the exterior stairs. If the rear exterior stairs are a typical/compliant porch/stair system it should be ok.
Spiral stairs are generally not considered a legit egress for several reasons such as insufficient exit width and too large openings at spindles.

[paul hardy]

From the 2006 IRC

R311.5.1 Width.

Stairways shall not be less than 36 inches (914 mm) in clear width at all points above the permitted handrail height and below the required headroom height. Handrails shall not project more than 4.5 inches (114 mm) on either side of the stairway and the minimum clear width of the stairway at and below the handrail height, including treads and landings, shall not be less than 31.5 inches (787 mm) where a handrail is installed on one side and 27 inches (698 mm) where handrails are provided on both sides.

Exception: The width of spiral stairways shall be in accordance with Section R311.5.8.

R311.5.8 Special stairways.

Spiral stairways and bulkhead enclosure stairways shall comply with all requirements of Section R311.5 except as specifie

R311.5.8.1 Spiral stairways.

Spiral stairways are permitted, provided the minimum width shall be 26 inches (660 mm) with each tread having a 7½-inches (190 mm) minimum tread depth at 12 inches from the narrower edge. All treads shall be identical, and the rise shall be no more than 9½ inches (241 mm). A minimum headroom of 6 feet 6 inches (1982 mm) shall be provided. d below.

[Matt Fellman]

Thanks guys.. I was thinking it was okay from an egress stanpoint. Basically, since it's okay with them not there (upper level apartment, etc.) it should be fine.

The stairs themself have several issues as well.

[Jerry Peck]

Spiral stairways are permitted, but not as part of a means of egress path.

[paul hardy]

Jerry
Section 311 of the IRC is the means of egress section where it includes special stairways as a means of egress. Where do you find anything that disallows them as a means of egress when this section allows them.

[Jerry Peck]

Section 311 of the IRC is the means of egress section where it includes special stairways as a means of egress.


Just because it is in the "Means of Egress" section does not mean it is allowed for a required "means of egress" item. That section covers, to a minimum point, items used in means of egress, it just means that if one of those items is installed that the item must 'at least' meet the requirements stated in the code.

For example, an EERO can be used as a 'secondary' means or egress, but you are not allowed to take the doorway out and use the window as a THE means of egress.

Likewise, you could have a second floor which is accessible by a 'regular' stairway which meets the minimum 36" width, and also has a spiral staircase. You WOULD be allowed to replace the spiral staircase with another 'regular' stair, however, you WOULD NOT be allowed to replace the 'regular' stair with another spiral staircase as the spiral staircase does not meet the requirements for a means of egress.

Follow that?

Are you allowed to install a spiral staircase in addition to a means of egress which meets the requirements for THE means of egress? Yes. Are you allowed to install a spiral staircase as THE means of egress? No.

Which is why I said it the way I did:

Spiral stairways are permitted, but not as part of a means of egress path.

THE egress path is the main stair.

Matt stated:

Spiral staircase is the only means of travel from finished upper level (with bedrooms) to the main level. But there is a rear sliding door to an upper level deck with compliant stairs to the main level.

Then Matt asked:

Does this comply with egress requirements?

The answer is, yes, that does comply with the egress requirements because there is a 'regular' (I hate using that term, which is why I put it in single quotes) stair. The spiral staircase could simply be removed as the windows are compliant for the secondary means of egress, i.e., the EERO.

The IRC does not address "means of egress" in detail, just like it does not address most other things in detail. If you want to understand more about means of egress you need to understand the IBC and how it addresses means of egress. The IRC does not even give a clue as to what 'means of egress' even means, it is not even in the definitions, for even that simple explanation you must go to the IBC:
- MEANS OF EGRESS. A continuous and unobstructed path of vertical and horizontal egress travel from any occupied portion of a building or structure to a public way. A means of egress consists of three separate and distinct parts: the exit access, the exit and the exit discharge.

[H.G. Watson, Sr.]

Depending on the clear opening of that sliding door. Many are restricted and don't afford a wide enough clear opening for the primary egress.

[paul hardy]

JERRY
I would have to disagree the code does not say that "regular" stairs must be installed to have siral stairs and comparing the IBC means of egress to the IRC requrements is like apples and oranges. Even then the IBC allows Spiral stairways as a means of egress in residential applications that fall within its scope.

1009.8

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 7.5 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 9.5 inches (241 mm). The minimum stairway width shall be 26 inches (660 mm).

[Walter Reinhaus]

In addition to 1009.8, if you consider the definition of a dwelling unit, might it be that an exterior spiral staircase providing exclusive use for the unit to discharge would be considered either: within the dwelling unit, because it is seen as within the exclusive use of the unit; or because, as an accessory feature, considered part of the unit; thereby offering required egress?