Fire wall on duplex Columbus OH

14 Replies

The building department wants the wall that separates the 2 units fire rated 1hour. I have no idea where to start. I asked the city for some help and they send me to google. Any help is appreciated thanks.

I would agree the city should be able to send you some acceptable 1HR rated wall assemblies, the building division at the cities I’ve dealt with in my area have sent me pdf documents for multi family separation assemblies, I just did a multi family and the 1 hour fire separation and STC 51-54 assembly the city passed was 2X4 wall 16” o.c, 3 1/2” roxul safe n sound batts, resilient channel 24” o.c on one side, 2 layers 5/8” type x drywall on one side and 1 layer of 5/8” type x on the other. Every municipality is different so I don’t know if that’s acceptable for what you’re doing but a good “bcin designer” as we call them here should be able to point you in the right direction as well

@Rigo Monzalvo

Function

Fire resistant walls provide sufficient time to discover a fire, control it and evacuate the building if necessary. Ratings are determined using procedures developed by the American Society for Testing and Materials that simulate actual fire conditions. They can also be calculated using tables developed by the IBC.

Ratings

Fire resistance ratings are expressed in the number of minutes or hours a structure can withstand a fire simulation test. According to the Engineered Wood Association, a one-hour rating indicates that a wall constructed in a manner similar to the one tested will contain flames and high temperatures, and support its full load, for at least one hour after the fire begins.

Materials

According to the book "Commercial Drafting and Detailing," a typical one-hour fire rated wall consists of 2x4 studs spaced 16 inches from the center of one stud to the center of the next, covered by 5/8-inch, type X gypsum board. Type X gypsum board is wallboard to which non-combustible fibers have been added.

@Rigo Monzalvo According to the book "Commercial Drafting and Detailing," a typical one-hour fire rated wall consists of 2x4 studs spaced 16 inches from the center of one stud to the center of the next, covered by 5/8-inch, type X gypsum board. Type X gypsum board is wallboard to which non-combustible fibers have been added.

Originally posted by @Tanner R.:

I would agree the city should be able to send you some acceptable 1HR rated wall assemblies, the building division at the cities I’ve dealt with in my area have sent me pdf documents for multi family separation assemblies, I just did a multi family and the 1 hour fire separation and STC 51-54 assembly the city passed was 2X4 wall 16” o.c, 3 1/2” roxul safe n sound batts, resilient channel 24” o.c on one side, 2 layers 5/8” type x drywall on one side and 1 layer of 5/8” type x on the other. Every municipality is different so I don’t know if that’s acceptable for what you’re doing but a good “bcin designer” as we call them here should be able to point you in the right direction as well

If you don’t need the sound rating you may get away with less than what I had to do.. this is a good reference of tested assemblies by USG.. check pages 18-19. Best of luck! http://www.usg.com/content/dam...

First, to everyone giving building code advice and taking it from google needs to be very careful. You are opening up yourself to a lot of liability for relying straight from a google search. I'm not saying the OP is going to sue you...but he potential could. Building code, especially fire safety, is a very particular and very detailed part of the code. Inspectors are going to be very particular about this, where as they might be a bit more relaxed in more typical building codes. I'm not saying any of your are wrong either, just that referencing what you found on google is not always that reliable. Especially if you don't have actual experience detailing/design a party wall.

Secondly, my suggestion is to go back to the city with a couple examples and see what they want because there are a dozens of different ways to make a 1 hr rated wall. If you don't have the experience to figure this out on your own and defend your selection its best just to pick one and take it to them but have a couple other in your back pocket as well. Look at what @Tanner R. gave you. The link to the USG is where you will get your UL assemblies that the city is looking for. UL305 is as basic as you can get, though its probably not what you will actually want for your party wall. If you go to their website you can actually do searches by categories and types. For example, the Duplex that I am designing and building is not using UL305 for the party wall and it would not pass the city inspection if I did. Now I don't know what your city is going to want. I also don't know the design of your Duplex. The reason I point this out is there is a difference between just fire rating any wall and having a fire rated Party Wall and those are different from a Fire Wall (which you called it in your title). What you call a wall, or what the city calls your wall, is what will determine if UL305 is going to be enough or not and also the design of the duplex. My opinion is that it will not be enough. Both to meet the code of the IRC and the build quality you will want in party wall. 

I just went through this process and my firewall was approved by they city, but only after I replaced all screws with cement coated fire-rated nails.  Don't forget to add the fire-rated drywall into the joist-cavities as well and be sure to fill in any penetrations of the wall with a true fire-rated product.  The orange stuff "fire block" is not rated for this and the city knows it.

In the basement I had to build up the stone wall that separates the units into those joist cavities as well.  Reach out and I can share the plans I used..

My permits for my duplex in Columbus are almost at the finish line of being approved, except the reviewer requested that I get a design professional to add the language "UL 263" to the drawing of my fire wall.  We plan to do everything up to code, but does minor detail in a drawing really need to involve consultation with a design professional? Any advice would be appreciated. 

Also, if this helps, the building department emailed me these details in terms of what is required for a fire wall. 

Residential Code of Ohio Table 302.1 requires the common wall for two adjoined houses on separate lots to be 1 hour fire tested in accordance with ASTM E 119 or UL 263 with exposure from both sides, for each house; total combined fire rating of 2 hours. Fire-resistance-rated wall assemblies shall extend to and be tight against the exterior walls; and shall extend from the foundation, through the attic space and to the underside of the roof deck.

@Sonam Gill you should be fine if you just add the note that states fire separation walls to folllow UL 263. If he told you to have an architect or engineer sign and seal the plans then you need one of us. If not try it yourself and see what happens. He might have suggested for you to consult with an architect because not all UL rated assemblies work for every scenario.

@Sonam Gill   For our duplex, we did the drawings ourselves and add the Ul 263 to our shared wall between the units.  They approved them with no issues.  

Side note, adding the UL 263 was pointless because our property has brick in between the shared wall thus it's fire proof and didn't need the UL 263.  Best part, a city of columbus civil engineer tried to explain to me how brick is not fire proof.....  What about brick fireplaces:)?

@Ryan Mainwaring I'll add to the civil engineer's comment. A firewall is not technically rated unless it is called out as being rated. For example, in a hotel, I worked on we had numerous CMU walls. However, we only labeled a few of them as being 2-hour rated on the permit plans. Since we did not call out the other CMU walls as rated then they were not legally rated. Additionally, the same built wall was 1-hour rated in one location and 2-hours in another because that is what we labeled it as in our plans. 

A fire-rated wall is all about the entire assembly and where it is located. For example, a 1-hour rated wall has a 20-minute fire-rated door. The logic is that at a wall lots of items can be stored against it so there is more fuel. At a door, there is nothing in front of it so there is not as much fuel for the fire. Now you know. 

Finally, a brick veneer is not used for fire-rated walls. I believe it may be due to the air space behind the brick and the house structure. If it is a structural wall made from brick then it can be counted as a fire-rated wall. If the brick veneer is not included is a UL or ASTM or another agency listing then it isn't technically fire rated.