I have a two story type V-B construction building with B-occupancy.
I am allowed unenclosed stairs.
I have one unenclosed stairway in U-shape.
I have a storage area under one run of stairs and under the stair mid-level landing.
the next run passed over two adjacent small offices.
I have the storage area with 1-hour rated walls with fire rated doors.
The stair soffit under the mid-level landing is similar to a floor/ceiling assembly so is easy to rate for 1-hour.
The reviewer does not agree with just applying two layes 5/8 type x board to the bottom of the stairs as this
is not a the same as a floor/ceiling assembly. E.g. I need to double up with 2x4 framing, osb or ply on top with 2 layes type 'x' board.
A little difficult to construct with the osb or ply on top but is is doable. (although not necessary in my view)
In addition the reviewer wants to fire rate the walls and ceilings of the two adjacent offices because one run of the stairs crosses these two rooms. The Code Commentary specifically mentions that the concern is regarding storage under the stairs. The code also mentions "useable space" under stairs. I believe what the reviewer is requesting is not the intend of this code requirement.
Imagine a small section of stairs crossing a large office area, you would have to rate all the walls, ceilings and doors?
Also, if I have within the fire rated wall of the storage area a wood post (4x6) to support the stair opening trimmers.
Of course the reviewer classifies these as columns and need to be independently rated from the wall.
E.g. I need to wrap the posts.....note: there is no tested system for wood column fire rating.
I am allowed unenclosed stairs.
I have one unenclosed stairway in U-shape.
I have a storage area under one run of stairs and under the stair mid-level landing.
the next run passed over two adjacent small offices.
I have the storage area with 1-hour rated walls with fire rated doors.
The stair soffit under the mid-level landing is similar to a floor/ceiling assembly so is easy to rate for 1-hour.
The reviewer does not agree with just applying two layes 5/8 type x board to the bottom of the stairs as this
is not a the same as a floor/ceiling assembly. E.g. I need to double up with 2x4 framing, osb or ply on top with 2 layes type 'x' board.
A little difficult to construct with the osb or ply on top but is is doable. (although not necessary in my view)
In addition the reviewer wants to fire rate the walls and ceilings of the two adjacent offices because one run of the stairs crosses these two rooms. The Code Commentary specifically mentions that the concern is regarding storage under the stairs. The code also mentions "useable space" under stairs. I believe what the reviewer is requesting is not the intend of this code requirement.
Imagine a small section of stairs crossing a large office area, you would have to rate all the walls, ceilings and doors?
Also, if I have within the fire rated wall of the storage area a wood post (4x6) to support the stair opening trimmers.
Of course the reviewer classifies these as columns and need to be independently rated from the wall.
E.g. I need to wrap the posts.....note: there is no tested system for wood column fire rating.