T601 rated assembly alternative

[Sifu]

Sorry, this plan is wearing me out. Two indoor pools in a type IIA, two story building. The floor/ceiling and primary frame above is supposed to be a 1-hr assembly (it is less than 20' above) , but they include a vague note for an alternate design using closely spaced sprinklers to protect the beams and purlins. The plans are very good, just introducing me to a couple of things I haven't encountered. Anybody encountered this before? Having trouble finding any info on it.

 

[RLGA]

Well, you are or represent the code official, so you have the authority to accept or deny an alternate material, design, or method of construction. I suggest that you deny it until they can prove performance via Section 104.11. I assume your jurisdiction has a policy regarding code modification submissions.

 

[steveray]

Seen it for glass and atriums I believe, not for structure.....

404.6 Enclosure of atriums. Atrium spaces shall be separated
from adjacent spaces by a 1-hour fire barrier constructed
in accordance with Section 707 or a horizontal
assembly constructed in accordance with Section 711, or
both.
Exceptions:
1. A fire barrier is not required where a glass wall
forming a smoke partition is provided. The glass
wall shall comply with all of the following:
1.1. Automatic sprinklers are provided along
both sides of the separation wall and doors,
or on the room side only if there is not a
walkway on the atrium side. The sprinklers
shall be located between 4 inches and 12
inches (102 mm and 305 mm) away from
the glass and at intervals along the glass
not greater than 6 feet (1829 mm). The
sprinkler system shall be designed so that
the entire surface of the glass is wet upon
activation of the sprinkler system without
obstruction;

 

[Sifu]

Seen it for glass and atriums I believe, not for structure.....

404.6 Enclosure of atriums. Atrium spaces shall be separated
from adjacent spaces by a 1-hour fire barrier constructed
in accordance with Section 707 or a horizontal
assembly constructed in accordance with Section 711, or
both.
Exceptions:
1. A fire barrier is not required where a glass wall
forming a smoke partition is provided. The glass
wall shall comply with all of the following:
1.1. Automatic sprinklers are provided along
both sides of the separation wall and doors,
or on the room side only if there is not a
walkway on the atrium side. The sprinklers
shall be located between 4 inches and 12
inches (102 mm and 305 mm) away from
the glass and at intervals along the glass
not greater than 6 feet (1829 mm). The
sprinkler system shall be designed so that
the entire surface of the glass is wet upon
activation of the sprinkler system without
obstruction;

Yes, I have too several times, just never for this application. Didn't know if it was common.

 

[Sifu]

Well, you are or represent the code official, so you have the authority to accept or deny an alternate material, design, or method of construction. I suggest that you deny it until they can prove performance via Section 104.11. I assume your jurisdiction has a policy regarding code modification submissions.

I have asked for clarification, just trying to figure out if there was an exception somewhere I didn't know about in anticipation of the response. Just looking to see if there was some code prescribed path before it goes further.

 

[steveray]

Actually....Now that my brain is working....They did it in the Pittsburgh convention center where the ABM was last year....Don't know that I can find a pic though.....Rated structural type 1 or IIA construction I assume, but the (large) cable supports run through the occupied space....Above the ceiling, they used the shaft/duct wrap, steel anchors below was sprayed with some type of intumescent paint, but the cables likely would not have taken kindly to that, so they had some weird looking suppression above the cables....You can't see the suppression on this one....

 

[Sifu]

Interesting. Had I not cancelled my trip I might have seen it, though I'm not sure my sometimes less than keen eye would have even noticed.