2012 IMC fire partition/corridors

[klarenbeek]

Doing a plan review for a project that will be under the 2012 IMC. In the 2012 code, exception 3 under fire barriers (607.5.2) allowing for no fire dampers if the duct system contains no flex has been extended to the fire partion section (607.5.3) as well, as exception 4. The new exeption is identical word for word to the existing exception for fire barriers.

Here's the situation--1 hour rated corridor where the walls are fire partions partitions. If there is no flex in the system, a smoke damper only, no fire, is required at the wall penetration because of the new exception. This corridor also has duct registers in the floor, coming from the lower level.

Question- Do the floor penetrations require smoke dampers only or fire/smokes? Does the exception apply to the walls only or the floor/ceiling assembly as well?

 

[rgrace]

This is the way I read the requirements for your given information .... Starting at the beginning, 607.5 states that fire, smoke, or combination fire/smoke dampers shall be provided at the locations specified in 607.5.1 through 607.5.7.

IBC 1018.1 confirms that corridor walls are "fire partitions", so section 607.5.3 would apply for duct and air transfer opening penetrations.

607.5.3 (fire partitions) states that duct and air transfer openings that penetrate a fire partition shall be protected with a listed fire damper (not a smoke damper - a smoke damper would only be required under 607.5.4, and you made no mention that this corridor enclosure required smoke and draft control doors).

Under exception 4 of 607.5.3, a fire damper is not required if all three of these situations apply; (1) the system is what I like to call "fully" ducted, which means that this exception would not apply to air transfer openings for a return air plenum since they are not "fully" ducted, but would apply to the fully ducted supply air system; (2) the required rating of the partition is 1 hour or less; and (3) the building is equipped throughout with an automatic sprinkler system per the IBC. (we can get into discussions later as to why this exception was identical to that of fire barriers).

As far as your question, this section would not apply to any floor, floor/ceiling, or ceiling membrane penetrations into this corridor. IMC 607.7 would apply. I’m sorry, there is not nearly enough information contained within your post to give a response to these penetrations.

 

[rgrace]

As far as your question, this section would not apply to any floor, floor/ceiling, or ceiling membrane penetrations into this corridor. IMC 607.7 would apply. I’m sorry, there is not nearly enough information contained within your post to give a response to these penetrations.

My apologies, the quoted section should be 607.6, not 607.7

 

[klarenbeek]

Thanks rgrace.

I probably should have said so, but 607.4 does apply, so the smoke dampers are required. This is in a boarding school/children's shelter and this is a corridor with sleeping rooms off it. All of the requirements of exception 4 of 607.3 are met so we've already determined that the walls require smoke only not fire dampers. We were having a discussion in our office of wether the floor penetrations would need fire as well as smoke dampers. Floor penetrations in the sleeping rooms will have fire dampers. What other information would you need?

BTW our interpretation of item 1 of that exception is not just fully ducted, but no flex duct in the system. It states duct must be a minimum ..019, or 26 gauge.