SFPE Discussions

Ladder fire protection?

I have a simple commercial building with a small intermdiate floor provided with 30-minute FRR to the underside and supporting structure. (no supporting walls)
The intermediate floor is accessed via ladder.
All appropriate escape route multiplication factors are applied and travel distances comply within the limitations afforded by the Type 3 fire alarm system to be installed.

An RFI has been received from the Consenting Authority stating:
Mezzanine floor, all timber framed walls including steel element which support floor joists shall be fire rated to 30min as per fire report. wall holding the escape ladder shall be fire rated to 30min.
please clarify this on the architectural drawings.

My response to RFI was:
**We have reviewed the NZBC C/AS2 document in regards to all references for Ladders, and find there is no requirement anywhere that specifies the walls to which ladders are affixed must be of fire rated construction. Paragraph 4.13.3 only states: “intermediate floors, including their supporting primary elements and stairs, shall have FRRs of at least 30-minutes.*”

The consenting officer has replied with:
*In respect of the fire design to the mezzanine floor, I have different opinions with the fire designer. *
*The fire rated mezzanine floor does not provide real fire separation as the entire complex is a single fire cell. *
It is supposed to provide fire protection to the fire escape route from the mezzanine and this fire escape route contains two parts: 1. horizontal route provided by the mezzanine floor. 2. vertical route provided by the steel ladder.
The vertical fire escape route also need fire protection as the mezzanine floor already has. That’s why the wall the ladder attached must be fire rated

Looking for guidance please…

a step type ladder or a rung type ladder? recommend to check out D1 first to see if the proposed access is suitable. rung type ladders are only suitable for access to IA spaces so if it is you may be able to use paragraph 4.13.9 C/AS2 to negate altogether? if your proposing a rung type ladder to an occupied space you may need to change to a stair or step type ladder of which are easily protected

vertical rung type ladder - intermediate floor is IA with 0.3 occupant load assessed (30m2/person)
thanks for your comment