2012 IBC 703.4 Sprinklers v. Prescribed FR

[AegisFPE]

With the first line of this new code section referring specifically to the "prescriptive fire resistance requirements of the IBC" does this automatic sprinkler provision only apply to assemblies in Section 721 Prescriptive Fire Resistance?

703.4 Automatic sprinklers. Under the prescriptive fire resistance requirements ofthe International Building Code, the fire resistance rating of a building element,

component or assembly shall be established without the use of automatic sprinklers

or any other fire suppression system being incorporated as part of the assembly

tested in accordance with the fire exposure, procedures, and acceptance criteria

specified in ASTM E119 or UL 263. However, this section shall not prohibit or limit

the duties and powers of the building official allowed by Sections 104.10 and

104.11.

 

[Frank]

I believe that the prescriptive fire resistance they are referring to is the required fire resistance prescribed in the code.

This is a counter to some of the sprinklered glass walls that have been labled depending on a continued water supply to provide the required fire resistance.

However the fallaciy of this approach is if the sprinklers work then you don't need the fire resistance rated construction, and if the sprinklers did not work then you don't have the water for the active fire resistance depending on the sprinkler or water spray cooling the barrier.

 

[Architect1281]

Fire Resistane (passive) in CH 7 is always tested and rated without the application of water (fire supression active)

as regulate by CH 9

CH 7 is related to constructed; (Masonry, gypsum, applied coatings,) fire RESISTIVE assemblies 1/2 hour 1 hour 2 + n so on

and the construction is tested burning and the hit with a hose stream at the appropriate hour to determine rating.

 

[Builder Bob]

Aegis FPE, to answer your question (IMHO) Yes.......

This section is eleiminating a designer the ability to argue a reduction in a prescriptive fire rated assembly when using the prescriptive section of the code when a reduction in the required rating may be used when a sprinkler option is added....

For example, a prescriptive design is stated for a 2 hour interior non-rated fire barrier in a sprinklered building, the designer would have to use a prescriptive design for the two hour wall and could not reduce the rating to one hour if using otherr means.

I assume that 721 is the table and chart for prescriptive design ..... instaed of UL or other third party listed assemblies. ( I do not have the 2009 or 2012 to reference)

 

[Frank]

This code change came about because TYCO got an ES report ESR-2397 for using a special sprinkler head model WS to get a two hour rating on a nonbearing 1/4 inch heat strengthened or tempered butt glazed glass wall.

http://docs.approvalzoom.com/PDF/icc_products/ESR-2397/Evaluation%20Report.pdf

ICC ES response was to call a committee meeting--not sure of the results of this meeting

http://www.icc-es.org/Criteria_Development/1106-pre/22_AC385.pdf

 

[JustReid]

Since it is at the beginning of 703, I see this as addressing any rated assembly that is proposed to be used. This seems to be addressing rated assemblies using sprinklers to achieve the rating. Specifically the Tyco WS (window sprinkler) which can give a rated wall up to 2-hours and has been tested IAW ASTM E 119. Another example would be the common use of sprinklers for 3/4 hour opening protection "water curtains". Notice they gave an out with the sections 104.10 and 104.11 referenced (The Tyco WS has a research report). An interesting add to the new edition of the code.

 

[TJacobs]

This is a great addition and clarification. We are on the 2006 though...