• Welcome to The Building Code Forum

    Your premier resource for building code knowledge.

    This forum remains free to the public thanks to the generous support of our Sawhorse Members and Corporate Sponsors. Their contributions help keep this community thriving and accessible.

    Want enhanced access to expert discussions and exclusive features? Learn more about the benefits here.

    Ready to upgrade? Log in and upgrade now.

New sprinkler in existing mixed use....

R

Robert

REGISTERED
Joined
Jan 29, 2016
Messages
348
Location
Pinole, CA
Hello. I am analyzing an old, existing mixed use, unseparated occupancy building (non-conforming). Ground floor B, with a common entry/enclosed stairs to the R-3 above..... upper 2 floors R-3. If I add a sprinkler system, I can get the separation to 1 hour instead of 2 based on CBC 508.4. Does the sprinkler system need to be all 3 floors or just the most restrictive occupancy (ground floor B)? Footnote to the table says "buildings equipped throughout.....". And if so, is this a NFPA 13R or 13D? Thank you.
 
Always get your. Scope out

NFPA 13d



1* Scope. A.1.1 NFPA13D is appropriate for protection against fire hazards only in one- and two-family dwellings and manufactured homes. Residential portions of any other type of building or occupancy should be protected with residential sprinklers in accordance with NFPA 13 or in accordance with NFPA 13R. Other portions of such buildings should be protected in accordance with NFPA 13 or NFPA 13R as appropriate for areas outside the dwelling unit. The criteria in this standard are based on full-scale fire tests of rooms containing typical furnishings found in residential living rooms, kitchens, and bedrooms. The furnishings were arranged as typically found in dwelling units in a manner similar to that shown in Figure A.1.1(a), Figure A.1.1(b), and Figure A.1.1(c). Sixty full-scale fire tests were conducted in a two-story dwelling in Los Angeles, California, and 16 tests were conducted in a 14 ft (4.3 m) wide mobile home in Charlotte, North Carolina. Sprinkler systems designed and installed according to this standard are expected to prevent flashover within the compartment of origin where sprinklers are installed in the compartment. A sprinkler system designed and installed according to this standard cannot, however, be expected to completely control a fire involving fuel loads that are significantly higher than average for dwelling units [10 lb/ft2 (49 kg/m2)] and where the interior finish has an unusually high flame spread index (greater than 225) when tested in accordance with ASTM E 84, Standard Test Method for Surface Burning Characteristics of Building Materials, or ANSI/UL 723, Standard for Test for Surface Burning Characteristics of Building Materials. (For protection of multifamily dwellings, see NFPA 13 or NFPA 13R.) ****INSERT FIGURE HERE**** FIGURE A.1.1(a) Bedroom. ****INSERT FIGURE HERE**** FIGURE A.1.1(b) Manufactured Home Bedroom. ****INSERT FIGURE HERE**** FIGURE A.1.1(c) Living Room. 1.1.1 This standard shall cover the design, installation, and maintenance of automatic sprinkler systems for protection against the fire hazards in one- and two-family dwellings and manufactured homes. 1.1.2 This standard shall not provide requirements for the design or installation of water mist fire protection systems, which are not considered fire sprinkler systems and are addressed by NFPA 750. 1.1.3 This standard shall be based on the concept that the sprinkler system is designed to protect against a fire originating from a single ignition location.
 
The first sentence sounds like 13D is only for residential 1 & 2 family dwellings. The building I'm working on contains a single family dwelling, but also contains a commercial space, so by default it appears 13R is the correct system.

The next sentence then states residential portions of other buildings (ie: mixed occupancy?) needs to be 13R. Then to further confuse me...it states all other areas outside the dwelling unit also need to be 13R....so 13R for both commercial floor and residential floor?
 
Read the footnotes to tables. To be able to use the sprinklered “S” ratings, the sprinkler system must be per Section 903.3.1.1, which is a NFPA 13 system. You could split the building with a NFPA 13R system for the residential and a NFPA 13 system for the commercial below, but per NFPA this is only permitted if the residential and the commercial are separated using the horizontal separation allowance per Section 510.2. If a building’s primary function is residential, you can use NFPA 13R throughout (per NFPA), but you would not be able to reduce the fire rating per Table 508.4.
 
That about sums it up::

13d mainly 1-2 family with its limits

13R residential with its limits


13. All other


states residential portions of other buildings (ie: mixed occupancy?) needs to be 13R. Then to further confuse me...it states all other areas outside the dwelling unit also need to be 13R....so 13R for both commercial floor and residential floor?[/QUOTE]
 
You must log in or register to reply here.
Back
Top