• Welcome to the new and improved Building Code Forum. We appreciate you being here and hope that you are getting the information that you need concerning all codes of the building trades. This is a free forum to the public due to the generosity of the Sawhorses, Corporate Supporters and Supporters who have upgraded their accounts. If you would like to have improved access to the forum please upgrade to Sawhorse by first logging in then clicking here: Upgrades

Firestopping

O

Oscar

Registered User
Joined
Aug 24, 2018
Messages
14
Location
New York
I have a concrete slab that is separating two spaces. The fire resistance needed is 2 hours between spaces. The existing conditions have many penetrations from our mezzanine space to the tenant above.
Some penetrations go through to the space above and in some instances the space is larger than 6 inch. diameter. The GC does not want to firestop every penetration due to costs and suggested we could do a drop ceiling.

I am correct in my understanding that even if I install a UL listed 2 hour rated assembly system for a suspended ceiling, I would still need to close gaps from the existing pipe penetrations since at these locations it is not a 2 hour rated assembly since the assembly includes the deck/slab?
 
For walls, the fire-protection rating is bidirectional: the wall would provide protection from a fire on either side of the wall, with some exterior walls being an exception. A floor-ceiling assembly, on the other hand, is unidirectional, providing protection from the ceiling side only.

If the suspended ceiling provides the required 2-hour rating (which includes prevention of the passage of hot gases per ASTM E 119), then the section of the concrete floor above the rated ceiling assembly is removed from the fire-rating equation and is just a support system for the rated ceiling.

From what I can see, UL only provides two assemblies that provide a 2-hour rating protecting a concrete floor.
 
Oscar said:
Which UL assembly would those be? The one's I see all include the concrete floor as part of the assembly.
https://www.usgdesignstudio.com/floor-selector.asp?framingType=18709&fireRating=2&orderby=firerating
Click to expand...
Yes, the concrete is part of the assembly because it provides the support for the ceiling. The ceiling itself is the fire-rated barrier, which also blocks the passage of hot gases. The assembly is intended to provide protection for a concrete floor assembly that cannot provide protection on its own because of the slab thickness being too thin or there is a lack of concrete coverage over the reinforcing steel.

However, this brings up another question that is not code-related: How does the contractor get to choose which method to use or not? Doesn't the contract documents require that all penetrations--new and existing--be protected with through-penetration assemblies? if so, then the contractor is required to provide what is in the contract documents--the GC cannot make substitutions without the owner's approval. If not, then the owner should be making the decision on which method to use and pay for the added work.
 
RLGA, could mineral wool stuffed around the pipes from above suffice?
 
Pcinspector1 said:
RLGA, could mineral wool stuffed around the pipes from above suffice?
Click to expand...

I was thinking the same thing. At least for NYC BC we are working in 1968 code and the following section is noted:
(a) Firestopping materials.- In buildings of construction group I, firestopping or fill shall be of noncombustible material that can be shaped, fitted, and permanently secured in position. In buildings of construction group II, firestopping may be of combustible material consisting of wood not less than two inches nominal thickness with tight joints, two layers of one inch nominal thickness assembled so that there are no through joints or of one-half inch exterior type plywood with joints backed, except that noncombustible firestopping shall be used in concealed spaces of fire divisions and where in contact with fireplaces, flues, and chimneys. Noncombustible firestopping may be masonry set in mortar, concrete, three-quarter (3/4”) inch thick mortar or plaster on noncombustible lath, plasterboard at least three-eighths (3/8”) of an inch thick, fire-rated wallboard at least five-eighths of an inch thick, sheet metal at least No. 14 U.S. std. gage thick, solid web metal structural members, asbestos-cement board at least one-quarter of an inch thick, or equivalent rigid noncombustible material. Mineral, slag, or rockwool may be used for firestopping when compacted to a density of at least three and one-half pounds per cubic foot into a confined space of least dimension not more than one-third its second dimension.

(1) The performance of through-penetration fire stops shall be measured and specified according to reference standard RS 5-19.

(2) The commissioner may accept reference standard RS 5-19 test data results from an independent laboratory acceptable to the commissioner pursuant to subdivision

(c) of section 27-131, when such data is submitted by a registered architect or licensed professional engineer to justify the usage of fire stops or the details of their installation not specified herein.




On another note: I actually called USG and they suggested I use assembly K-504 http://database.ul.com/cgi-bin/XYV/...n=versionless&parent_id=1073984818&sequence=1 however this seems like overkill for a mezzanine ceiling with a low height already and I would run into headroom issues.
 
Look at Hilti speed sticks for 2-hr applications, don't know if that would work or not?
 
Oscar said:
Table 3-4 in 1968 NYCBC for a Class I-B building requires 2 hour Floor construction requirement.
Click to expand...

Even with the rated ceiling below the floor structure I would think that any penetrations through the existing floor would need to be fire stopped to maintain the rating. I also cant see how firestopping the existing floor penetrations can be cheaper than installing a new 2 hour rated ceiling.

If this is a tenant fit out, I would make the landlord pay for all of the missing firestopping at the existing floor penetrations.
 
Tim Mailloux said:
Even with the rated ceiling below the floor structure I would think that any penetrations through the existing floor would need to be fire stopped to maintain the rating. I also cant see how firestopping the existing floor penetrations can be cheaper than installing a new 2 hour rated ceiling.

If this is a tenant fit out, I would make the landlord pay for all of the missing firestopping at the existing floor penetrations.
Click to expand...

That's exactly the situation we are in. It is a tenant fit-out but the Landlord is refusing to provide any firestopping and saying it is the tenants responsibility. There is nothing in the lease the tenant signed that says legally the landlord is responsible.
 
Try the UL product spec site. It may have most of the penetrations in your assembly. I have found it to be incredibly helpful. Just input the info and pick one that will work. Unfortunately, it doesn't have a "who will pay for it" section.

http://productspec.ul.com/index.php
 
You must log in or register to reply here.
Top