i need some help on penetrations through a two hour fire wall for mechanical including ducting and gas piping and also electrical and plumbing.
the wall is in bellevue a suburb of seattle. the wall is common to the main house and what the city calls an accessory dwelling unit ,ADU( a two bed one bath apartment). the two residences have been connected with a 12’x12′ addition. the ADU used to be a 3bay garage. the wall is of 2×8 studs sheeted with 1/2″ply covered with two layers of 5/8″ gwb on both sides (no gwb on interior of ADU yet)
the electrical inspector called for the two hour wall, now i’m trying to figure out how and what exactly can be used for penetrations.
for gas—can i run black iron? yellow flex?
for plumbing—-copper ok? metal box for wash machine?
electrical— my panel will be in 12×12 room. is there a limit to wires through penetration?
ducting—???
for all—are metallic sleeves required/the best way? fire tape and mud the hole and call it good?
i know the building dept. should be able to help but aside from the electrical inspector nobody seems to care about this two hour wall for a residential use.
i’m working my way through irc 2006 and washington energy codes and washington fire but would appreciate any help i can get. thanks.
Replies
I'm guessing that for the ducting you need to have a fire shutter in the duct.
As an engineer, all I can offer not being registered in that state, is to look at the USG website. If memory serves there is a detail there that shows a two hour wall. I also believe that the 3M website might show a similar detail. Again, if memory serves, there are more than a few disclaimers on each site.
Might be a good idea to print it (they were pdf files) and pass it by the BI.
Good Luck!!
I could be wrong but I think small penetrations aren't that big of a deal.
I did small hospital renovations as a carp once apon a time. They are real sticklers about fire in hospitals.
But I would think they would want steel pipe for the gas and emt (Steel) conduit for the electrical.
Steel or cast iron is the way to go.
We used fire dampers for ductwork. It will have a tag that says 2 Hr.
Any doors?
yeah, one door, with a 10 1/4" jamb at a cost of $350. i'm happy with that # because my first reaction was it would cost a lot more.
will keep all cuts to bare minimum and use the fire caulking. will check the websites as soon as i'm done here. didn't even think about the louvre in the duct. that's why i asked. thanks for the thoughts...
I can only tell you what I saw done for a two hour wall around a stairwell in an apartment building.
Black gas pipe
bare romex was ok to penetrate
cpvc supply was okay to penetrate
there weren't any in the 2 hour wall but in the 1 hour walls UL listed dampers had to be used on ducts
in the 1 hour walls UL listed metal washer box
the main hang up our inspector had was UL listings for fire rated, and that copious amounts of fire caulk be used on all penetrations
typically Romex will not be used in building with fire walls, smoke walls maybe but not fire walls. Most buildings that require fire walls are steel, block, and sprinklered construction. Romex not allowed here. Wire will most likely be EMT conduit, some MC.
"typically Romex will not be used in building with fire walls, smoke walls maybe but not fire walls. Most buildings that require fire walls are steel, block, and sprinklered construction. Romex not allowed here. Wire will most likely be EMT conduit, some MC."
Definitely not true - common to have multiple single-family townhouses with 2-hour fire walls in between - and with Romex.
Jeff
true if the building is a residential classified structure, which then there usually aren't very penetrations into the fire walls because most items are individually contained per unit. IME, which is mostly commercial, the scenario I spoke of would be true. Thus if original poster were working on a condo building of multi story, then romex would not be allowed. perhaps that was clarified and I missed it, but my experiences are different than yours, obviously. Two people might look at the same wording slightly different based on experiences.
Do yourself a favor, stop in to the inspectors office in the AM before they leave, Maybe even bring a box of donuts to sweeten him up. Explain your job & ask what HE wants to see for the penetrations, Ultimately he is the one who will either approve or knock it down. Most inspectors will take the time to spend a few minutes w/ you if you ask & most will give you a little lea way if the see you have tried to do it the way the he wanted. All the being said hopefully the inspector is not an A** & being unreasonable, but then again there are a few out there.
Good Luck
The duct will need a fire damper and an access panel. The fire damper will need to be installed in a sleeve, probably 16ga steel. The duct connections will need to be made with breakaway hardware. The fire damper/sleeve assembly will need to be anchored and flashed in the wall opening.
Pipe penetrations, in my experience, need to be run through a larger sleeve of Sch 40 pipe. The gap between the pipe and the sleeve is then filled with intumescent caulking.
Best bet is to sit down with the inspector and ask what they want. Make sure that the person you talk to is the same one doing the inspecting.
Danski, although you may be right out of dumb luck, the reality is that you have no idea what the the local code requires for a 2 hour penetration. You have no idea how big the penetration is and wether or not a fire damper is required (size matters as does the mterial od the duct). I respect your knowledge on some levels, but this one is not included. Your experience as a trade worker in the Chicagoland area may be extensive, but this is a question beyond the technician level. In my opinion, any advice without a lot more specifics is irresponsible at best.
Ok, whatever.
Notice the bottom sentence of my post... I guess you missed it.
I have never seen a piece of duct, no matter large or how small, penetrate a fire wall *without* a fire damper. Said duct needs an access door to both inspect and reset the fire damper linkage (note that the fire damper needs to be installed correctly so it can be reset). Said ductwork needs to be connected with breakaway hardware (plastic bolts, special clips or special cleats) so *if* the duct falls, the fire damper within the opening is not pulled out with the ducting, preserving the integrity of the fire wall.
Wall openings need to be flashed closed (flashing secures the damper assembly in the wall), closing gaps with mortar or drywall is also good. Holes should be sealed with high temperature silicone *not* intumescent caulk as the intumescent material expands and will interfere with fire damper operation.
Fire dampers in the factory 22ga sleeve (or installed in like thickness ducting without the sleeve) have a 1 hour fire rating. Thicker metal is needed for a longer rating.
Fire dampers and smoke dampers are *not* the same thing.
Typically, fire damper, damper flashing type/material, access door size and somtimes location, and pipe penetration specifications *should* be given somewhere in the drawings or job specs. If not, the smart person asks and gets an approved drawing from the engineer.
Shortcuts are usually at the direction of the contractor because someone missed something during the bid process and they are hoping to get away with it.
I have seen piping (sprinkler/water) and conduit (electrical) penetrations mudded in with drywall material, wall openings oversprayed with intumescent material, wall openings plugged with intumescent "clay bricks" or piping encased in a larger SCH 40 sleeve and then packed with intumescent material.
But, you are correct that I do not know everything. Nor do I claim to.
There is nothing wrong with the information I have provided. I did a job placing over 100 fire and smoke damper assemblies. I have also been told to leave stuff out at the direction of an employer.
What would be wrong is for anyone responsible to take *any* construction advice without checking local conditions. There is plenty of advice given on the web, but one still must decide what to do with it. This forum would be quite boring if all the replys were "check local codes".
He11, sometimes you can't get a straight answer from the GC, project engineer, architect or the boss because they all have competing interests.
Edited 4/2/2009 7:49 am ET by danski0224
Fair enough, the last line qualified the post. Still
"I have never seen a piece of duct, no matter large or how small, penetrate a fire wall *without* a fire damper. "
Because you haven't seen it or don't understand it proves my point. This is where knowing the rating of the wall, the guage of the duct and the area of the penetration come into play. Knowing the code(s) and how it applies is critical. I have seen (and designed) systems that included exactly what you haven't, many times, that were fully compliant with the applicable code at the location. The point is that you worked at the direction of knowledgeable, responsible people that made the evaluation and decisions for you.
In a 1 hour rated wall, a fire damper is a waste of time and money. The duct, if standard gauge or thicker, is understood by the NFPA (and most AHJs) to have an equal or greater rating. In some states, ducts that have a cross section of less than 1 square foot do not, but larger ducts are required to have a fire damper installed. In a 3 hour wall, then what you saw, installed and related applies.
Ok, whatever.
Edited 4/2/2009 8:30 am by Tim
The ELECTRICAL inspector called for a two hour wall? That just doesn't sound right.
When a building is built, the plans specify what fire rating,if any, the walls need to have. In certain situations, particular codes may require a fire rated wall; for example, the electrical code requires a rated wall for transformer vaults. Those specific exceptions aside, the rating is determined by the architect.
Now, when you run a pipeor duct through a rated wall, you need to preserve the rating of that wall. Exactly what you need to do depends on how the wall achieves it's rating.
"Just fire tape" isn't enough. For the rating to be preserved, you need to FILL the hole -not just tape over it. For example, a wall with two layersof 5/8 drywall needs to have the holes filled to the complete thickness of the drywall.
Pipes and electrical conduits need not be of anyparticular material; the opening just needs to be properly sealed. Since applying the correct amount of 'mud' can be a challenge - and for materials other than drywall - there are all manner of specialty caulks, and other products, out there.
Air ducts will almost always require an automatic fire damper to be installed in the duct, right where the duct passes through the wall.
Keep in mind that walls are rated as complete assemblies, and may be rated for the fire exposure on one face only.
Where you set a box into a wall, you need to take steps to maintain the rating of the wall. You can make the appropriate drywall 'box' around these things, or you may use the various specialty products that are out there.
There are no limits on the number, or size, of penetrations. Where it is expected that many items will pass through the wall, it is common to construct a 'chase' for them, with the chase being sealed at the end of the job.
Careful now.
Soon, Tim will be along stating you do not know what you are talking about.
:)
sorry for the delay in responding, i was in bellevue... i'm doing this for my mother. she will move into the ADU my sister will take over the house.
to all: thanks for the insights and your time. also, i can assure you i asked this question only to gain information which may or may not help in my situation. i will be checking with any authorities necessary before committing to anything....
in response to your q about the electrical inspector requiring the wall.... yes, he did verbally when i went to see him at city for preliminary discusssion. he said this was code (not sure if he speced whose) if i was to run electric through that wall.
yes, there were plans, drawn by me.... (first attempt at architect, maybe last) plans were approved and got all the stamps.... including one, the biggest boldest, stamp requiring a one hour fire wall that says... (Caps are theirs not mine) IMPORTANT NOTE: 1 HR RATED FIRE RESISTANCE WALL BETWEEN LAUNDRY AND ADU SHALL EXTEND TO UNDERSIDED OF ROOF SHEATHING OR CEILING OF ADU AND HWH CLOSET SHALL BE OF 5/8" TYPE-X GWB AND ALL OPENINGS SHALL BE PROTECTED PER CHAPTER 7 OF 2006 IRC. That is all that is said about wall other than usual disclaaimer that all work done in conformance with all codes.
plans did not show electrical, mechanical, plumbing...
i believe this all would be avoided if i were to bring a separate electrical service from the hand hold or transformer (another issue....) to the ADU. however, i am hoping to upgrade existing panel in house and pull subpanel over to feed ADU.
thanks again
I'm with renosteinke, unanswered yet. What is elect. inspect. doing calling for structural fire rating requirements when not directly involving life safety devices, signal wires of, or em. power?
I'm with renosteinke, unanswered yet. What is elect. inspect. doing calling for structural fire rating requirements when not directly involving life safety devices, signal wires of, or em. power?
Did you have a pre-con? Who brought this up? Jan? Have you had the BI thru yet?
Edited 4/5/2009 8:16 am ET by McMark
don't know if i want to name names but it was electrical who brought it up after constructiuon began. pre-con didn't include two hour wall. we talked about one hour wall as per plans.
several framing inspections and also had my framing inspector bring out his boss whose name eludes me, to tell me how to construct fire wall as they saw it. ask too many questions, get too many answers not always meshing. just trying to do what needs done to make everyone happy and get my project completed.
thanks
At that point, I would penetrate the wall with the electrical and plumbing you need, and fire caulk as per your UL rated assemblies. I hope you don't have to penetrate the wall with a duct. Call for cover and final.
i don't have an answer to the question "why electrical inspector is calling for two hour wall" <paraphrased>
i just know he told me it was required if i went through that wall, common to both living units with electrical. perhaps, i need to revisit with him, as to why. at this point though i've paid for and installed the door, the sheetrock,the washing machine box, got the plumbing signed off. may as well keep going, yes??
To answer the question of why " the electrical inspector is saying a 2 hour wall is necessary" . In WA state the electrical inspector is a State L&I Inspector not a member of the Building Dept. He can supercede the locality @ anytime as long as he is going above the rating. In other municipalities Electrical inspectors are a local muni. inspector. It happens all the time up here where the Elec. Inspect. calls out for something not per plan or spec , you just have to roll with it .As for your firestopping details call your local Hilti Rep. your area has some very knowledgeable Reps and they will come out and take a look for free, help w/ the submittals, and get engineered judgments stamped for free to fit your particular issues if there is not a drawing for your EI. They have always been very helpful, especially now they are really hungry. Feel free to email me if you need some help getting to the right pe
Trace
I read these posts and kept asking myself, HUH. L&I(labor and industry) does all electrical inspection inspections and that permit is separate from the building permit
Then you responded. With the info he needed.
It seems that he hasn't pulled his electrical permit yet.
No electrical final, no building final.
L&I inspectors don't like unlicensed homeowners. They will make you jump through hoops. They are amazingly thorough. I believe this is what all inspections should be.
The one benefit of their inspections they will give you the exact code and violation of what is wrong. It makes disagreeing with them difficult.
I just smile and wave and say thank you
In Bellevue, electrical inspections are done by the city, not L&I.
Mark,
That's funny, on my side of the state it is a state official that does the inspections as well as a state inspector for both Commercial and Residential everywhere I have worked in Eastern WA which is just about all the decent towns. It should not surprise me though this state has some goofy rules anyhow. I have never had to deal with the inspection process in W. Washington, I have only done 2 projects MountainStar @ Roslyn and the Casino @ Tulalip, neither did I deal w/ inspections. Sorry for the misunderstanding.
Trace
Does Spokane do their own electrical inspections? How about Yak, 'Burg, and the Tri-Cities.
In Western Washington, the state L&I does inspection in rural areas, and a lot of smaller towns. But Seattle, Redmond, Bellevue, Everett, etc etc do their own electrical inspections
Edited 4/24/2009 8:04 am ET by McMark
Edited 4/24/2009 9:07 am ET by McMark
Nope, All of the cities you mentioned and just about any other I can think of all have State L&I EI's. The Firestopping issue rears its ugly head all the time, and no one can ever get on the same page. I have many times set up jobsite meetings w/ the BI, EI and Firestopping Rep to hammer out exactly what will work and you never get the same answer twice. To answer some of the product issues Electrical boxes in ADU demising wall should be metal and padded w/ putty pads, pipe penetrations can be caulked, conduit can be dealt with the same though you are going to have to research an engineered judgement as I cant find a UL drawing, but I have fairly dated material for a 2 hour wall in a wood framed structure(2007), residential is not my bag. The head of wall on the plate to Ceiling joist would be stuffed w/ 4# mineral wool safing and GWB up to the deck. This demising wall will probably have to extend to the roof structure then caulked @ the top. The through wall sleeves are excellent for pulling through wires but have spotty approval. The Ducting should be able to be handled though a system of galv plate and putty blocks.
Trace
Do you really need to make "holes" in the wall?
Would it be easier to set it up with its own system and supply of gas and electric?
Sorry if this seems to be a dumb question.
definitely not dumb and definitely an option. however, i do not want to meter separately. i guess that's part of the reason for my question.... i had one plan in mind to upgrade existing house panel and pull sub from there. and to t-off after gas meter and run line through house roof system. house was built in 1950's slab on grade. simple, easy enough....
to complicate this some more i have 100 amp panel serviced by 1/0 aluminum conductor. 1/0 is direct bury until meter sweep where it's in 1 1/2" conduit :( power company says drawings show hand hold on my property... finding it is another problem. don't have numbers right in front of me but i think i could squeeze in a 200 amp service off that conductor. but to pull a sub off that is going to put me right at the treshhold as far as my allowed load. to go back to the transfromer is approx. 200' across two driveways. work to be done in right of way by utility co. with permits from city and power.
separate meters are not required and are expensive. now, i need to figure out what makes the most sense for me to proceed.
obviously in over my head, but that's the best way to learn to swim... or drown :)
My experience in MI has been that you can run PVC drain lines through such a wall, but home-made "pipe sleeves filled with intumescent caulk” won’t fly. We have used intumescent COLLARS which trap an intumescent belt inside a tight metal sleeve, with “fingers” that fold in at the ends to contain the expansion. EMT, sprinkler line penetrations, etc. are fine with intumescent caulk alone, since the metal won’t fail in a fire the way PVC will.
Ditto on the donuts, too.
AitchKay
Both USG and Hilti have web-sites which will show UL rated assemblies for one- and two-hour walls. You should be able to discern if NM cable is OK from Hilti's fire caulking book. If NM isallowed in your building for new construction, and Hilti has an assembly for NM, romex is OK.
Fire dampers are common in One-hour walls. Regardless of what other posters claim, they want to see them in Bellevue. Dampers do require a framing detail specific to that damper, and a seperate framing inspection by the mechanical or building inspector.
My question is, why wasn't this brought up in any of the required pre-cons?
i don't have a good answer to that. thanks for the input.
Bob,
Bellevue is big into Pre-cons, I'm surprised that the building inspector didn't bring it up then.
As far as what you need to do, it really isn't thaat big of a deal, except for (possibly) ducts.
Here is a Hilti submittal http://www.us.hilti.com/data/techlib/docs/ul%20firestop%20drawings/wl/WL2084_112905.pdf
Go to Hilti USA's website, and you should be able to find assemblies that will do what you need done. Hilti's website is different than I have used in the past, and I couldn't find one using NM (romex) and a one-hour wall assembly, but I am sure their is one in there.
Regardless, your building inspector is the one to talk to, they are the ones who typically inspect fire rated penetrations
thanks, this looks like what i was after
Bob,
If your looking for a way to pass Romex or cabling through this firewall, take a look at the EZ-Path.
http://www.stifirestop.com/ezpath/installation_selector/22_index.html
Here's what the smaller unit looks like.
View Image
We use at our healthcare facility mainly for cabling, but I noticed in the tech sheet that you can get up to 3 No. 8 AWG Romex cable thru one of these units.
These are very easy to install, and once there in, all you do is push the wiring through and your done. No fire caulking necesary.
Need to make an addition at a later date? No problem, just continue to add until youv'e reached the max fill for this size.
Here's a link to the tech and installation sheet in case your interested.
http://sti.fmpdata.net/ftp/UL_System_Cards/wl3271.pdf
http://sti.fmpdata.net/ftp/Estimation_Installation/ZIS1007_Install_Sheet.pdf
interesting, I haven't seen that. What do they run?
Not sure, as I'm not in the buying department. I can check Monday and see what they cost.