Mezzanine in Type IIA construction Type, Single Story, Sprinklered Building. Are Rated Floor Penetrations Required?

[jrtecharch]

We are in for permit review and the AHJ asked why our mezzanine floor is not rated. The mezzanine floor is rated, but we do not have any rated penetrations, because vertical openings are permitted per NCBC 2018 712.1.11, and we are not separating any spaces below and above the mezzanine. Am I wrong in not providing rated floor penetration details?

 

[Yankee Chronicler]

IMHO, you are not wrong. A mezzanine is a raised area within a room or space. I don't think there is anything in the code that requires a room to be separated from itself by rated assemblies.

 

[jrtecharch]

IMHO, you are not wrong. A mezzanine is a raised area within a room or space. I don't think there is anything in the code that requires a room to be separated from itself by rated assemblies.

I just didn't know if my interpretation for assemblies required to be rated based on Table 601 would assume even their openings and penetrations would be rated. But there isn't a %percent unprotected openings in a rated floor assembly the way there is for unprotected openings in an exterior rated wall.

 

[Yankee Chronicler]

I just didn't know if my interpretation for assemblies required to be rated based on Table 601 would assume even their openings and penetrations would be rated. But there isn't a %percent unprotected openings in a rated floor assembly the way there is for unprotected openings in an exterior rated wall.

Table 601 is for the structural requirements. That's why your mezzanine floor is a rated assembly. There's nothing in Chapter 6 that says anything about fire separations between spaces or about rated penetrations. By definition, a mezzanine does not constitute a story -- it's an elevated level within a room or space. Unless there's a code section that says a floor within a space needs to have penetrations protected, I don't think you need rated penetration assemblies.

 

[steveray]

They made this really confusing when they separated horizontal assemblies and just speak of them as fire rated or non-fire rated I believe when they could just have said "fire rated per Ch. 7" but I think you have to bounce around until you end up at openings not required to be in a shaft....