As Steven said, there are a couple "ifs" in the code analysis and the biggest one is whether the code official will allow the use of 13R. NFPA 13R doesn't give prescriptive guidance but informs in A.1.1 that there may be special rules that restrict the use of 13R in mixed occupancies and that the user of the standard should:
"Refer to the adopted building code to determine whether such restrictions are applicable." This throws to the local building official. My experience in just about every (California) jurisdiction has been that a two-headed design is only allowed if there is a BUILDING separation between R and B or M occupancies. Some allow an occupancy separation between R and S-2 (parking) because if the principal use group is R, then parking is accessory to the R can be protected per 13 as specifically allowed in 13R. Podium buildings with R over other groups generally require a 3 hour horizontal assembly with all utilities and stairs shafted with 2-hour fire resistance to even consider the split design and in many jurisdictions you have to upgrade to 13 to get additional stories of Type 5 anyway. And there are area limits per floor when using a 13R that may also restrict its use; you can't just count stories or weigh building separations. The charging references are in the allowable hei ght and area tables of Chapter 5. Steve Leyton -----Original Message----- From: Sprinklerforum [mailto:[email protected]] On Behalf Of Steven Jenkins via Sprinklerforum Sent: Friday, September 18, 2020 7:43 AM To: [email protected] Cc: Steven Jenkins <[email protected]> Subject: RE: Are sprinklers required As seen in the 2015 IFC Commentary to section 903.3.1.2 "... A common question is whether a mixed occupancy building which contains a Group R occupancy could still use NFPA 13R for the design. If one of the mixed-use occupancies would require a sprinkler system throughout the building in accordance with NFPA 13, then a 13R system would not be allowed. If, however, the only reason a sprinkler system is being installed is because there is a Group R fire area, then a NFPA 13R system would be an appropriate design choice. The areas that are not classified as Group R would require protection in accordance with NFPA 13. It must be noted that although the building would be considered sprinklered throughout in accordance with NFPA 13R, not all of the code sprinkler alternatives could be applied. Any alternative that requires the installation of an NFPA 13 system would not be applicable if a portion of the building utilizes an NFPA 13R system...." Hope this helps, SJ -----Original Message----- From: Sprinklerforum <[email protected]> On Behalf Of Nick Maneen via Sprinklerforum Sent: Thursday, September 17, 2020 12:22 PM To: [email protected] Cc: Nick Maneen <[email protected]>; Thomas Reinhardt <[email protected]> Subject: Re: Are sprinklers required *** SCDLLR NOTICE *** * This email is from an external email address. Please use caution when deciding whether to open any attachments or when clicking links. * Personally Identifiable Information (PII) should not be included in e-mail text or attachments. Do not save or transmit PII unencrypted. This is supposed to be above our pay grade, but yeah. Unless the owner wants to go through all the trouble of installing rated building separations that would allow a 13R structure to sit on a 13 structure, the entire building is 13. On Thu, Sep 17, 2020 at 12:14 PM Thomas Reinhardt via Sprinklerforum < [email protected]> wrote: > Hi everyone .Thanks for taking my question. I have a old commercial > building in town with a store front only two stories. The owner would > like to convert the second floor to apartment(R-2). We currently use > the IFC where section 903.2.8 relates that yes sprinklers shall be > installed. My question is then doesn't the entire building including > the apartments shall have a NFPA 13 system instead of just a 13R system on > the second floor? > _______________________________________________ > Sprinklerforum mailing list > [email protected] > > https://linkprotect.cudasvc.com/url?a=http%3a%2f%2flists.firesprinkler > .org%2flistinfo.cgi%2fsprinklerforum-firesprinkler.org&c=E,1,qT-YuUbO_ > l8UbGHbFmTFHwUYkwB-yQ0GKFqEUcMJeEpOKg5NKb6dXvrRFOXcWP7gmkxOEj1iKKcM5Ot > -ENcUpxjcT8mkjM01v26ylD57QjKDMO5UTevb&typo=1 > -- Nick Maneen Estimator 409 W Central Ave Asheboro, NC 27203 P 336-625-2304 F 336-625-4649 C 704-791-7789 _______________________________________________ Sprinklerforum mailing list [email protected] https://linkprotect.cudasvc.com/url?a=http%3a%2f%2flists.firesprinkler.org%2flistinfo.cgi%2fsprinklerforum-firesprinkler.org&c=E,1,KcvmbQpA2WHkRp6q1fFc-t2e8aO3yibFmiIBkMs4p5O1kN5yrgMONJddlTtI_yEvxcbX_yGOAGp2VRK5JR4e8eiT2o7uuqjaykAoEw4BCmlZTXckjH_x&typo=1 _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
