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exposed wood joists and stringers inside the stairwell

Ryan Schultz

Ryan Schultz

SAWHORSE
Joined
Apr 2, 2012
Messages
283
Location
Madison, WI
I have a 3 story sprinklered Type VB R-2.

The stair wells have a 2hr enclosure.

I assume, since Table 601 allows floors with 0 rating, that we can have exposed wood joists and stringers inside the stairwell, correct?
 
Ryan Schultz said:
I have a 3 story sprinklered Type VB R-2.

The stair wells have a 2hr enclosure.

I assume, since Table 601 allows floors with 0 rating, that we can have exposed wood joists and stringers inside the stairwell, correct?
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How do you get or maintain the two hour enclosure, With exposed wood ?
 
Just my thoughts, take with a grain of salt. I would say the "stair" is within the 2 hour enclosure (read, protected from fire) and therefore requires no protection. An analogy would be an unprotected steel stair in an enclosure of a Type IIA building, which is used 90% of the time.

Ken
 
The walls around the stairwell are 2hr.

I'm assuming the stair landings and stringers can be 0 rated in this circumstance.
 
1011.7 Stairway Construction

Stairways shall be built of materials consistent with the types permitted for the type of construction of the building, except that wood handrails shall be permitted for all types of construction.
 
I presume that this is within an interior exit stairways (i.e. a part of the exit)?

If so, 1023.2 only specifies the construction of the enclosure. The stairs themselves should be of appropriate materials given the type of construction per 1011.7. The challenge can be in finding the appropriate detail for a membrane penetration to bear the beam/girder to the enclosure wall. But, sounds like you have this covered.

1011.7 Stairway Construction
Stairways shall be built of materials consistent with the types permitted for the type of construction of the building, except that wood handrails shall be permitted for all types of construction.

1023.2 Construction
Enclosures for interior exit stairways and ramps shall be constructed as fire barriers in accordance with Section 707 or horizontal assemblies constructed in accordance with Section 711, or both. Interior exit stairway and ramp enclosures shall have a fire-resistance rating of not less than 2 hours where connecting four stories or more and not less than 1 hour where connecting less than four stories. The number of stories connected by the interior exit stairways or ramps shall include any basements, but not any mezzanines. Interior exit stairways and ramps shall have a fire-resistance rating not less than the floor assembly penetrated, but need not exceed 2 hours.

Exceptions:
  1. Interior exit stairways and ramps in Group I-3 occupancies in accordance with the provisions of Section 408.3.8.
  2. Interior exit stairways within an atrium enclosed in accordance with Section 404.6.
 
steveray said:
I doubt it.....If the wood penetrates the rating, it is a problem, but wood treads and risers and stringers are the norm in VB construction even inside a rated enclosure..
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How about other exposed wood in the rated enclosure::::


"""""""joists/stringer/sheathing black--an industrial look.""""
 
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