2hr stair shaft constructed of ICF

[doregan]

Hi all,

SBCCI 1999

We are building a 4 storey office building - type V - non sprinklered - ICF exterior walls

One stairwell is built against the exterior wall - and I wanted to get input on if you deem leaving the inner wall of ICG (2-1/2" EPS) acceptable.

We would provide the required thermal barrier on the interior face - but would there be an issue with the requirement to have stairways constructed of non combustible materials? Can the EPS with sheetrock applied over be viewed as an applied finish?

Thanks in advance for your input.

Daniel

 

[brudgers]

Wouldn't SBCCI require an ES report for ICS?

 

[TheCommish]

seem to me that the foam should be covered to maintain the rating of the stair shaft

 

[Builder Bob]

doregan, check with the manufacture of the ICF, this issue has been raised on numerous occasions and something tickles my memory of testing performed on these forms that would indicate comformance with flame spread - but I believe they fail on smoke development. that may the issue to address.

As far as combustible verus combustible vs. non-combustible wording of the code - check the definitions to see what is defined as combustible........otherwise, in a true sense of the word, drywall is combustible but as NFPA defines it - it is limited combustible. The combustibility of drywall comes from the paper backing that is used to make the drywall.

However, that was when they were first introduce to the code people years ago.......

 

[mtlogcabin]

Gypsum board is by definition combustible under the IMC.

COMBUSTIBLE MATERIAL. Any material not defined as noncombustible.

NONCOMBUSTIBLE MATERIALS. Materials that, when tested in accordance with ASTM E 136, have at least three of four specimens tested meeting all of the following criteria:

1. The recorded temperature of the surface and interior thermocouples shall not at any time during the test rise more than 54ºF (30ºC) above the furnace temperature at the beginning of the test.

2. There shall not be flaming from the specimen after the first 30 seconds.

3. If the weight loss of the specimen during testing exceeds 50 percent, the recorded temperature of the surface and interior thermocouples shall not at any time during the test rise above the furnace air temperature at the beginning of the test, and there shall not be flaming of the specimen.

 

[cda]

Interior finish requirements????

 

[doregan]

Thanks to all for your input.

I have some documentation from manufacturer showing acceptable results after ASTM 119 testing. I think this will stand up to scrutiny. This leaves me thinking along the same lines as cda - do I comply with interior finish requirements - and the short answer in my interpretation is yes. I will run by the authorities and let you all know the outcome