Thanks to NORCAL for these:

How would you seal around these conduit penetrations?
The larger conduits are 4", and the ceiling is supposed to be rated.







(The void runs the full length between the 1st and 2nd rows)

[This message has been edited by electure (edited 03-27-2006).]

Block up the bottom and pour cement back in from above.

Can't you use UL listed fire rated Caulk? They also have UL listed fire collars that shrink when they are heated up and provide protection.

Caulk it...seriously. Use the red hilti stuff you see in the top picture - pipe bank on right.

You can get a tube of caulk as big as a salami...or you can get the bucket and trowel it in...we do it all the time - by "we", I mean the apprentices and not "me"

Just remembered...someone (maybe Hilti ??? , I forget)...makes a a sheet metal product that has the fireproofing sandwiched in it. It helps to lay the sandwich out BEFORE you run the pipes.

Just something to keep in the back of the cranium for next time.

Stuff it...


Try a Internet search for--3M Fire Barrier Pillows


[This message has been edited by Redsy (edited 03-27-2006).]

You guys all have money to 'burn'

Yes all those products will work, but you can buy a few 100 lbs of 'crete for the price of a Hiti salami.

Bob

Bob,
If the ceiling is required to be fire rated, can you just use cement and meet the requirements?
Don

Probably, Don. Not too many ceilings have a better fire rating than an equivalent amount of cement, mortar, joint compound, etc. And- with all those pipes passing through, so close to each other- the issue of bonding this patch to the ceiling is kind of moot!

Indeed, for most such penetrations, I suspect simply packing the spaces with fiberglass, then taping over, would probably pass the fire test.

I suppose that ultimately, its' an engineering call, based upon trade practices, comparison to specific ceiling designs, and the acceptance of the AHJ.

Not to be overlooked is the way the pipe itself will conduct heat through the wall, no matter how you seal it. There's only so much a patch can do.

Sealing with concrete will work okay...as long as neither the floor nor the conduits ever move. There's no way for anything to expand with concrete. I had problems with a bus riser bending in a 5 story building because they poured concrete around it.
Also, if you're using the red firestop goop be sure and check the installation instructions. The goop itself isn't the firestop; it's just a part of a UL Listed 'system'. If UL lists it with 2" of packing and 1" of goop, cramming in 3" of goop is a waste of money (that stuff ain't cheap).
I've seen foam or cardboard cut around the conduits to support the packing material and then the right amount of goop on top of it. That seems to pass muster in most places.

Pack the cavity with mineral wool or pillows, then chalk or puddy. Yu can also use the fireboard stuff too, in the recent past I cut all the holes, then cut a slit across them all so it was strips then pieced it back together between the pipes

Bob, some of the inspectors around here would want to see an approved section drawing sheet for the assembley listing of using concrete for penitrations. And allowable distances between them... I wonder if the concrete associations out there have such a drawing? RECTORSEAL makes a fire rated mortar...

I am definitely surprised to hear that restoring the original material may not be adequate.

Leaves me wondering why.

If I had the pipe there before the pour would I need an approved drawing?

If these are entering or passing through fire-resistive construction (fire walls, fire barriers, smoke barrier walls, fire partitions) and you are under the UBC or the IBC, you must meet the requirements of those codes. Basically, you must use a listed (ASTM E814 or UL1479) fire stop system or an alternative (concrete, ...)that has been approved by the Building AHJ. The fire stop systems all have, as part of their installation instructions; specific components, spacing, thicknesses, number of conduits and diameters, sleeving, and other requirements that must be followed to achieve the proper result---that of stopping fire, combustion gases, heat and/or smoke. Please don't just throw some red gunk up there and call it good.
Hilti and the other manufacturers will even come to the job site and help you get the right product and get it installed per the Listing.
We take great pride in this Forum in doing safe installations, per their electrical listings, and discuss all the in's and out's of getting it right; and accept criticism when we're brave enough to put photos of our work up. Let's get the fire-stopping details right. In a fire situation, it makes a big, big difference on the spread of fire, gases, etc.

Over here in NZ, you'd have to use something like Dow-Corning Fire-Stop 300 compound around them conduits.
BTW Rollie,
Is it my eyesight or are them two larger conduits to the right of the front bunch, on a slant?.

First, let me apologise for the length of this post; I think you wil find I've been doing some homework!

Let's assume that you are able to make a perfect hole, one snug enough to the pipe that it can just slip through. What's required there?
I say absolutely nothing- as long as the area of the penetrations does not exceed the % allowed by the ceiling design.

Using that approach, I would say that restoring the original construction, and filling small gaps with a similar thickness of gypsum (ie: joint compound), you've met the design requirements.

Now, joint compound has its' problems- especially whae you start applying large amounts. It drips, it sags, it may shrink or dry. I requires tools, and may require you to have water available.
How about packing the voids with, say, mineral wool? Sure, but then there is the question of whether you've really stopped any drafts. A plumber, testing his patch (made from expanding foam) with a candle ("watch the flame for draft-induces movement) started a fire that almost destroyed the Brown's Ferry Nuclear plant in the '70's.

This accident directly led to the invention, and marketing, of assorted fire stop compounds. In turn, this led to a frenzy of testing, and the listing of the products.

Keep in mind, it was NEVER intended that restoring the original structure be outlawed. These fancy products were simply an attempt to make the job easier! All of the products are tested in comparison to the original structure, and required to be at least as good.

UL publishes several "Fire Resistance Directories." I am sure that there are other references out there as well. Volume 2 addresses the use of firestopping materials.
Many, many systems use mortar as the "fill, void, or cavity sealant." While there is usually a specific product mentioned, the range of products mentioned is so broad as to include virtually every type of mortar there is. (For contrast, the Hilti product is referred to as a "sealant")
Many, many systems use mineral wool as the "packing material."

As for gypsum...5/8 is 5/8 is 5/8...etc. What is important to realise is that if you use joint compound, it is essential that you apply the full thickness. Most of the specially listed materials do not require this full thickness.

Likewise, whether you use gypsum, caulk, or other sealant, you are generally quite limited in the size of the gap you may fill, without having additional support.

The most common form of support used in these designs is filling the cavity with mineral wool. Another method often used is a wire mesh. If you're pouring a mortar, the support is often nothing more than a sheet of cardboard, removed as soon as the stuff has set.

Note in the UL books also stress that it is not a specific product that is evaluated, but an entire construction system. It is quite possible that a material used improperly, or in the wrong ceiling type, will not perform as you'ld expect.

That is a rock cieling right? What would hold a bag of cement or two up there, the conduit? You might wind up with an even larger opening, and a big mess....

Not all concrete or cement will act the same when heated, hold a blow torch to some. (Remember to wear safey glasses...)

There are apparently some people who study this type of thing... http://fire.nist.gov/bfrlpubs/fire99/PDF/f99010.pdf
http://www.pmengineer.com/CDA/Archives/306a2d8d26298010VgnVCM100000f932a8c0____

DOH!

I assumed it was poured concrete with a spray finish applied, a common method around here in buildings that have gear and feeders of that size.

Now I understand why a cement patch would be questionable.

Bob

It is a drywall ceiling with a "spray knockdown finish" and its been that way since 1978, (the gaps around the conduits that is).

If this was a concrete floor, using concrete or cement to patch the hole for firerated/firestopping would not be permitted. The cement patch when heat from the fire is applied to the patch would shrink and not adhere to the original concrete floor opening.

There are products on the market that are specifically listed for this "Firerated Assembly".

The "Assembly" depends on several factors, such as the floor material, pipe, and the annular space around the opening of the floor.

Not everyone knows that fire-stop materials expand when heated, so they fill the holes left when cables burn away and open holes. That's why it's a 'system', and not just puttying closed an opening.

If the cable can burn away then the fire will travel thru the wall along the cable to the other side, making the whole exercise of installing fire-stop a waste of time.

These 'fire stop systems' incorporate an intumescent compound, usually based on melamine. Upon heating above a critical temperature, the compound expands, without sagging and produces a foamed-char product, based on carbon, when ignition temperatures pertain. This foam-char then acts as a heat shield, a smoke and fume seal and a gap-filler, replacing burned or melted components like wire insulation or pvc conduit. But only for a limited period. That's because eventually the carbonised char burns through. Hopefully, the delay in smoke and heat propagation gives occupants time to escape a fire.

Alan

ps. I might add that steel conduits might need to have an intumescent seal on their inside diameters where they penetrate a wall or floor in certain arrangements, as they could conduct combustion products or fire.

[This message has been edited by Alan Belson (edited 04-05-2006).]