Fire Wall Requirements

[MackSuniga]

I am working with a civil engineer who is putting together a set of drawings for me. The lot is small, and we are placing the structure 5' away from property line on one side of the lot. Doing this requires that we install a 1 rated hour fire wall on that side of the building. This issue is with esthetics, adding the fire wall where it sticks out 18" on both end (horizontally) and at the top (vertically) is really an eye sore. Is there any way to get around this requirement? I am assuming that installing a sprinkler system might do it. But don't really know. Also, the cost of a sprinkler system might really drive the overall cost up. Another thing I was wondering, is what if the other walls were also built with some type of fire rated material. Could that be done to meet the requirement where the fire wall does not have to extend out 18"? From another post on your web site my understanding is that the purpose of the fire wall is to contain the fire and the 18" extension is to keep the fire from creeping around the corners. So, it seems that there should be some way to design a structure to meet the fire safety code without having to sacrifice esthetics. All suggestions are greatly appreciated.

 

[classicT]

Need some more info.... but it is unlikely to be a fire wall. Most likely just a rated exterior wall is needed.

What code are you under?
What type of construction?
What is the occupancy classification?

 

[Joe.B]

Is this Bakersfield CA? As classicT says, we need more information.

Is this the first structure on the lot, or a second unit? The structure is 5' away from the property line, is there a projection (bulb-out, pop-out, extension) that then reduces the setback? Are you in a WUI zone?

I ask these questions because:
1. If you're in CA new construction will require fire sprinklers unless you meet all of the exceptions in CRC R313.2 (2.)
2. If you're 5' feet away from the property line you shouldn't need any special fire rating, unless there's some condition we are not yet aware of.

 

[classicT]

Is this Bakersfield CA? As classicT says, we need more information.

Is this the first structure on the lot, or a second unit? The structure is 5' away from the property line, is there a projection (bulb-out, pop-out, extension) that then reduces the setback? Are you in a WUI zone?

I ask these questions because:
1. If you're in CA new construction will require fire sprinklers unless you meet all of the exceptions in CRC R313.2 (2.)
2. If you're 5' feet away from the property line you shouldn't need any special fire rating, unless there's some condition we are not yet aware of.

I am pretty sure this isn't residential. Note that the OP posted in the Commercial Fire Codes section of the forum.

 

[MackSuniga]

Yes, this is Bakersfield. Address is 2014 Niles Street in case you would like to Google map it. It will be wood framing with Scocco exterior. 1850 Square Ft. @ 18 Ft high. The building use is retail space. I responded to the e-mail with copies of sheets A1 thru A3 wasn't sure how to upload them via this portal. This is a commercial lot. I can't remember the actual zone type. Can look it up if needed. I'm working with a great team. But just like getting a second opinion from a different doctor. I like being as informed as possible. What's the old saying "How do you know what you don't know?" Best answers is... "You don't, so it's a good idea to ask around." then maybe you might find some that has been there and done that.

LOL... No way do I want to roll around in the mud with an inspector. Unfortunately, sometimes they can be wrong about the interpretation of the code. So, talking to experts like you guys is a good way to keep from being bullied by them. I once worked on a project where the designer used a variance and the right code and justification where plan checkers had to refer to an engineer. he somehow always met the requirements, and his designs came out the way he wanted.

Thank you all in advance. So, glad you created this forum...

 

[classicT]

Ok, so I am going to be assuming that you are Type V-B construction, Group M occupancy, and under the 2019 CaBC.

Per Table 602, the exterior wall with 5-ft of fire separation distance will be required to be of 1-hr fire-resistance rated construction.

From there, go to Section 705 for exterior walls. Per 705.5, the wall must be rated for exposure from both sides. Per Table 705.8, openings in this wall are limited to 10% for unprotected/nonsprinkled, 25% for unprotected/sprinkled, or 25% for protected. See 705.11 for parapets (you can probably meet one of the exceptions).

Note that the 18-in horizontal continuity comes from 706.5, which is for fire walls. What you need is not a fire wall, but a rated exterior wall. Therefore, 706.5 does not apply.

 

[classicT]

I responded to the e-mail with copies of sheets A1 thru A3 wasn't sure how to upload them via this portal.

In order to upload files, you have to be a paid member (a Sawhorse). If you join via a membership, you can upload from within the message/post.