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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...
Mark Heller "Well - I oughta....." -Jackie Gleason
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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?
Bob Badger Construction & Maintenance Electrician Massachusetts
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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.
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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?.
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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.
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That is a rock ceiling right? 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
Bob Badger Construction & Maintenance Electrician Massachusetts
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It is a drywall ceiling with a "spray knockdown finish" and its been that way since 1978, (the gaps around the conduits that is).
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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.
Pierre Belarge
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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.
Larry Fine Fine Electric Co. fineelectricco.com
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