Protection of Rated Crawlspace Floor

[Dr. J]

2009 IBC, 716.6.1 states in part:

"...a duct constructed of approved materials in

accordance with the International Mechanical Code that penetrates

a fire-resistance-rated floor/ceiling assembly that connects

not more than two stories is permitted without shaft

enclosure protection, provided a listed fire damper is installed

at the floor line or the duct is protected in accordance with Section

713.4."

Section 713.4.1.1, exception 1 states in part:

"Penetrations by steel, ferrous or copper conduits,

pipes, tubes or vents or concrete or masonry items

through a single fire-resistance- rated floor assembly

where the annular space is protected with materials

that prevent the passage of flame and hot gases sufficient

to ignite cotton waste when subjected to ASTM

E 119 or UL 263 time-temperature fire conditions

under a minimum positive pressure differential of

0.01 inch (2.49 Pa) of water at the location of the penetration

for the time period equivalent to the

fire-resistance rating of the construction penetrated."

What materials are suitable for either a 1 or a 2 hour fire resistive floor? Is this just mineral wool?

 

[zigmark]

Dr J-

Are your asking what constitutes a 1-2 hour rated floor assembly? To many options to list if so and having seen previous posts of yours I'm pretty certain you know that. If you are asking about the "materials that prevent the passage of flame and hot gases sufficient to ignite cotton waste when subjected to ASTM E 119 or UL 263" there are nearly as many options for that application, mineral wool on its' own would typically not meet the requirement. 3m and other manufacturers make materials specific to an application i.e. 1/2"-1" plastic pipe penetrating a rated floor/ceiling assembly with concentric annular space. it usually shakes out something like;

1) Hour Rating being maintained

2) Membrane or Through penetration

3) type of material being penetrated (drywall, CMU etc.)

4) type and size of penetrating item (copper tubing, plastic pipe, wiring, ducting)

5) concentric or offset annular space

Protection of rated penetrations are very specific in application and must be securely fixed in place especially in industrial settings where vibration can wreak havoc on certain types of materials.

Hope it helps,

ZIG

 

[zigmark]

After reading what I wrote previously I wasn't very happy with what it says. Items 1-5 of my previous post would be used in specifying the type of protection a manufacturer would have available for use in that application. The material is typically an intumescent product (expands when subjected to heat) that is either field applied out of a tube/spray container or a preassembled product that has a collar/ring/escutcheon type plate for holding it in place or a tape/adhesive backed flat rope material that is affixed per the installation detail. Many times the installations require backing (often mineral wool). Check out this site;

Firestop solutions from 3M Fire Protection Products.

Good luck

ZIG

 

[High Desert]

I think Dr. J was asking about the provision "materials that prevent the passage of flame and hot gases sufficient to ignite cotton waste when subjected to ASTM E 119 or UL 263." I ask for the material information sheet showing it meets the ASTM or UL test. Most mineral wool products meet this.

 

[zigmark]

High Desert-

Per the application that the OP stated where we are omitting a rated shaft and protecting the opening/penetration by a duct I would humbly disagree that mineral wool installed at the perimeter of the duct would suffice. If it is a through penetration then It must meet the requirements of IBC 713.4.1.1.2 for a Through Penetration Fire Stop System.

ZIG

 

[steveray]

Exception 1 gets them out of the "listed penetration"......mineral wool should work...the question is...how much?....

 

[Paul Sweet]

A metal collar or escutcheon might also be necessary to prevent the pressure difference from forcing hot gasses through the mineral wool. If it's penetrating a slab, I'd vote for the thickness of the slab. Things get tricikier if it's penetrating a rated wood-framed assembly. An inch or so (the thickness of subfloor plus finish floor) of mineral wool probably won't suffice.

 

[peach]

There are several intumescent sleeves for larger penetrations; for smaller (3/4" - 1") we generally see rock wool WITH the spray on Hilti (or equivalent) firestop. (Don't I sound like a designer?)

 

[Dr. J]

Steveray is on to what I am asking. I know about protecting floor openings with dampers, shafts, and listed Firestopping Systems. What 713.4.1.1, exception 1 seems to be saying is that I can just pack the annular space with some stuff. What is that stuff? What are the annular space limitations? Listed firestop systems are very prescriptive on depth, gaps, backing, max size, min gauge, etc. What is the criteria for "stuff"?

 

[zigmark]

I suppose whatever has met the codes prescription. "Stuff" in this case would be a product that has been tested per ASTM E 119 or UL 236 and will stay in place under the given pressure difference. Has mineral wool been tested to one of these standards? What keeps it in place? How thick does it need to be? Does it need to be thicker in a 2-hour rated situation or does it perform equally in either instance?

Now there are products out there that will meet all of these requirements and they are listed and rated for the very application, but they are not simply mineral or rock wool stuffed into a gap.

ZIG

 

[High Desert]

Most mineral or rock wool meets the ASTM E 119 test. This is one of those nebulus code provisions that you need to fill comfortable making a decision on. The code cannot detail every type of product installation. Ask for the manufacturer's specs and they will show how to install it to meet the testing criteria. The code outright permits it.

 

[globe trekker]

If the (fire) rated floor assembly has a 1 hr. or 2 hr. rating, wouldn't the "stuff" being installed

in to the opening need to meet or exceed the fire rating of that assembly? Also, in this

jurisdiction, we have allowed the use of mineral wool to be "stuffed" in to these types of spaces,

and then sealed with an approved fire rated caulk, or on gypsum walls, to use gypsum mud to

seal over the mineral wool.

.

 

[Builder Bob]

Gypsum mud is a no go... it does not allow for any movement after it cures... then it cracks and drops down or off..... leaving an opening that would allow the fire and / or smoke gasses to travel through.