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2nd unit

C

Chad Pasquini

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Nov 4, 2009
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Thoughts please, CRC, R313.2, Exception: An automatic residential fire sprinkler system shall not be required for additions or alterations to existing buildings that are not already provided with an automatic residential sprinkler system. Have a set of plans for SFR that now wants to turn living room with addition of 180 square feet into a 2nd unit, beings there is one unit and now going to be two, would you require fire sprinklers?, we have allowed garage conversions without sprinklers because they have been within the footprint of building, this one adding additional square footage and a new unit is a first for me.
 
""""Thoughts please, CRC, R313.2, Exception: An automatic residential fire sprinkler system shall not be required for additions or alterations to existing buildings that are not already provided with an automatic residential sprinkler system. """""

Use to live in calif, but seems clear in white and black above

Addition / alternation exception
 
Still in CRC for code applicable as the end result is a two family dwelling.

Check with AHJ for any local code requirements, a lot of Cities in CA require fire sprinklers for additions over a certain size, either by area or by % increase.
 
I would say the exception applies and fire sprinklers not required.

It is not a new building, and making it into two dwelling does not change that.
 
One of the advantages (disadvantages?) of not identifying 'occupancy class' in the IRC... Of course the dwelling unit separation requirements are still there, but lacking a local amendment the IRC does not really differentiate between one-family and two-family for purposes of sprinkler requirements. Interesting post though.
 
Thanks for the replies and I am aware of some jurisdictions requiring sprinklers when additions are over 50%, due to exception, I will not be requiring them
 
the IRC does not really differentiate between one-family and two-family for purposes of sprinkler requirements.
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The IRC as published requires sprinklers in all buildings covered by the IRC

R313.1 Townhouse automatic fire sprinkler systems.

An automatic residential fire sprinkler system shall be installed in townhouses.

R313.2 One- and two-family dwellings automatic fire systems.

An automatic residential fire sprinkler system shall be installed in one- and two-family dwellings.
 
We're just working on the same issue. In my view (which is based on NFPA 101) if the building is a one family and you add a second dwelling, while you are in the same occupancy class (One and Two Family Dwelling) you still have a change of use from one family to two family. Now with a COU, do you require the new use to be brought into current compliance?
 
There are no occupancy classifications within the IRC. There are different names and requirements based on the number of dwelling units. A one family dwelling unit, a two family dwelling unit and a townhouse consisting of 3 or more dwelling units.

Adding additional dwelling units is not the same as adding an addition to an existing dwelling unit

Adding additional dwelling units may trigger sprinklers for the additional units based on the local AHJ's interpretation of the codes
 
Adding a dwelling ® unit in the IBC would drive sprinklers IMO...Not sure how Cali would treat that, I might air on the side of caution, but could see how legally it could go either way.
 
I like mtlogcabins response above, well below now as i copied and pasted it to this question. I am the local AHJ and we are getting a lot of these additions, alterations, remodels, and or conversions. We currently do not have any requirements for adding fire sprinkler systems for square foot additions and or remodels, just the good ole CRC. I have two projects that were submitted back to back, one with a 500 square foot addition above a garae for a new 2nd unit, the other is a 105 square feet addition to an existing garage creating a new 2nd unit.The neighboring city only requires a fire sprinkler system for new construction. i read the code section as they are adding a new sfr, which then requires sprinklers. "all new one and two family dwelling units are required to have a fire sprinkler system". Which then brings up a really cool situation regarding separations as Mr. Paul Sweet asked above. So with a fire sprinkler system for entire building/both units only a 1/2 hour is required, but if the applicant only wants to fire sprinkler one unit? well this is not addressed in the CRC, however in the CBC wich is based on the international code, the separation would need to be 2 hours because you would be separting buildings not occupancy. Cannot fire sprinkler only half a building. Am i on the right track here? all thoughts are appreciated. Thanks

There are no occupancy classifications within the IRC. There are different names and requirements based on the number of dwelling units. A one family dwelling unit, a two family dwelling unit and a townhouse consisting of 3 or more dwelling units.

Adding additional dwelling units is not the same as adding an addition to an existing dwelling unit

Adding additional dwelling units may trigger sprinklers for the additional units based on the local AHJ's interpretation of the codes
 
As Chad noted above, our experience is that it is not possible to get an NFPA 13D system approved in a partial building. This means we'd need a true 2 hr separation to require the sprinklers in one of the two units (the added one).

We have had some real growing pains with this as our municipality adopted the Life Safety Code in it's entirety, including sprinklers in 1 and 2 family dwellings, but the State did not, and they approve all sprinkler system plans. So our requirements state that we require all new dwelling to be sprinklered (with a few City adopted exceptions). We had a one story eatery add an apartment above, which we required to be sprinklered, but the State wouldn't allow a 13D to just the second floor unit citing a mixed use building. The problem is they would allow the project with no sprinklers at all, but denied the installation of a 13D on the second floor? The reason being is they cannot reconcile NFPA 13D with a partial non-separated building (yes commercial in this example).

We adopted policy guiding the implementation of the sprinkler requirements to allow a second unit within an existing single family, where zoning allows. The LSC lumps one and two family together so, we would end up with more issues and likely losing our sprinkler requirements if we pushed for requiring them with the added dwelling.
 
How are they getting the required fire separation between units?
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Not sure the building code side, but in NFPA 101 I think you can call it mixed use occupancy and the strictest of the two (same) occupancies apply! Actually I'm pretty confident in saying it's not even needed though, as nothing in Chapter 24 requires a fire rated separation between the two dwellings.
 
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