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Use of Suspended Ceiling for Fire Separation

jar546

jar546

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I know we have had this topic before but I would like to start fresh on this one without being specific to create a more informative, varying discussion on this topic. Here it goes:

On a multi-use building that is more than one story, is it acceptable to utilize a fire rate suspended ceiling to separate occupancies?

Keep in mind that electrical and other equipment for the lower use will be above the drop or suspended ceiling.
 
Typically that would be a fire barrier which would be required to be supported by construction with the same rating, I don't see it as being possible.....

707.3.8 Separated occupancies. Where the provisions of Section 508.4 are applicable, the fire barrier separating mixed occupancies shall have a fire-resistance rating of not less than that indicated in Table 508.4 based on the occupancies being separated.

707.5.1 Supporting construction. The supporting construction for a fire barrier shall be protected to afford the required fire-resistance rating of the fire barrier supported. Hollow vertical spaces within a fire barrier shall be fireblocked in accordance with Section 717.2 at every floor level.
 
Since we generally look to tested/listed assemblies for guidance and require the installed construction to comply with all the assembly design parameters, it is more than difficult to get a suspended ceiling to comply (my experience). I don't know if there are any horizontal assemblies still in the UL and other fire design directories that have "rated" suspended ceilings as part of the assembly. Then there is the 'ol maintenance issue, as soon as the tenancy below the rated ceiling needs to do any work on something in or above the suspended grid, the clips or anchor straps or ballast get taken out and never put back in causing a "non" rated assembly.
 
interesting, because you can do a suspended ceiling in a rated corridor.

But I am taking that would be a "barrier"
 
Find a UL assembly using rated cieling tiles?

Will ceilings alone provide me with a 1-hour rating?

No, Fire resistance ratings apply to a floor/ceiling or roof/ceiling assembly in its entirety. Individual components, such as ceiling panels or suspended grid systems, are not assigned fire resistance ratings. If your architect has not yet determined which UL design should be followed for your specific project, you may have to select a UL Design for code official approval. If so, here is how to select the correct UL fire-rated assembly:

•Establish the hourly rating needed to meet code requirements.

•Determine the existing or planned building elements, including structural, mechanical,electrical and finish materials, in the fire-rated assembly.

•Refer to the Fire Resistive Rating Summary in the back of the Armstrong ceilings catalog to determine which UL design numbers resemble your building. The summary is divided into categories based on construction type and components.

•Submit the chosen UL design to the code official for approval.

Which Armstrong ceilings and grid can I use if a fire-rated assembly is required?

Only Armstrong "FireGuard" ceilings and grid can be used in fire-rated assemblies. These products are identified by our FireGuard icon.

http://www.armstrong.com/commceilingsna/article21342.html
 
Typically that would be a fire barrier which would be required to be supported by construction with the same rating, I don't see it as being possible.....
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The supporting construction for a rated ceiling is being protected by the rated ceiling

I don't like rated ACT system for the very reasons jdfruit mentioned. I see no problems with gypsum board suspended ceilings using the iron channel. GA FC 1290 comes to mind
 
mtlogcabin said:
The supporting construction for a rated ceiling is being protected by the rated ceiling I see no problems with gypsum board suspended ceilings using the iron channel. GA FC 1290 comes to mind
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How about the walls it is attached to and when the floor ceiling above burns?
 
Yes the support walls or columns and beams

Ceiling assemblies are rated only from one side which is the room side not from the floor above.

See Table 720.1(3) for a number of different systems depending on the floor or roof system

712.4 is horizontial assemblies. 707.5 was for walls

712.4 Continuity.

Assemblies shall be continuous without openings, penetrations or joints except as permitted by this section and Sections 708.2, 713.4, 714 and 1022.1. Skylights and other penetrations through a fire-resistance-rated roof deck or slab are permitted to be unprotected, provided that the structural integrity of the fire-resistance-rated roof assembly is maintained. Unprotected skylights shall not be permitted in roof assemblies required to be fire-resistance rated in accordance with Section 704.10. The supporting construction shall be protected to afford the required fire-resistance rating of the horizontal assembly supported.

Exception: In buildings of Type IIB, IIIB or VB construction, the construction supporting the horizontal assembly is not required to be fire-resistance-rated at the following:

1. Horizontal assemblies at the separations of incidental uses as specified by Table 508.2.5, provided the required fire-resistance rating does not exceed 1 hour.

2. Horizontal assemblies at the separations of dwelling units and sleeping units as required by Section 420.3.

3. Horizontal assemblies at smoke barriers constructed in accordance with Section 710.
 
"Yes the support walls or columns and beams

Ceiling assemblies are rated only from one side which is the room side not from the floor above."

Is there anything that allows a fire rated assembly separating occupancies to be rated from only one side?
 
Is there anything that allows a fire rated assembly separating occupancies to be rated from only one side?
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Is there anything that requires a fire rated floor ceiling assembly separating occupancies to be rated from both sides?

722.6.2.4 Floors and roofs.

In the case of a floor or roof, the standard test provides only for testing for fire exposure from below. Except as noted in Section 703.3, Item 5, floor or roof assemblies of wood framing shall have an upper membrane consisting of a subfloor and finished floor conforming to Table 722.6.2(4) or any other membrane that has a contribution to fire resistance of at least 15 minutes in Table 722.6.2(1).
 
Hunh....I don't have 722 in my antiquated codes, it does make some sense that you only need one sided protection when separating uses.....but I will have to mull that one over a bit more...
 
steveray said:
Hunh....I don't have 722 in my antiquated codes, it does make some sense that you only need one sided protection when separating uses.....but I will have to mull that one over a bit more...
Click to expand...
That's how they test in the ovens??
 
steveray said:
Hunh....I don't have 722 in my antiquated codes, it does make some sense that you only need one sided protection when separating uses.....but I will have to mull that one over a bit more...
Click to expand...
That's how they test in the ovens??
 
So I just received another submission again yesterday. Guess what he change it to?Nothing. I received the specs for a Chicago grid system and for the panels. Oh yeah, and this:
attachment.php


View attachment 1172
 
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& + & + &

Dear Drafter,

Your recent document submittal did not clearly indicate exactly which compliant,

appropriately rated, ceiling \ floor assembly will be installed in this project.

So that we can continue with, and complete our Review Process of the project

plans, ...please submit information \ documents that state exactly which

rated ceiling \ floor assembly will be installed on this project.

Regards,

XXXXXX

& + & + &
 
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