It's a full 13 building because of the mixed use. 13R is not applicable. You can still do a 4 heads 13 design in the residential portion. But attics, truss spaces, closets and bathrooms all come into play now as well as a 0.1 density. And water purveyors define the backflow no matter what NFPA says.
Chris Cahill, P.E. Fire Protection Engineer Sentry Fire Protection, Inc. 763-658-4483 763-658-4921 fax Email: [email protected] Mail: P.O. Box 69 Waverly, MN 55390 Location: 4439 Hwy 12 SW Waverly, MN 55390 -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Karen Purvis Sent: Wednesday, August 12, 2009 9:29 AM To: [email protected] Subject: RE: Mixed occupancy As for the building it is an apartment building with three floors of apartments. The ground level has apartments and the front of the building has space for 6 commercial locations. I don't know what will go in those spaces. Since the majority of the building is apartments I designed as a 13R. The second question is in reference to 13R 6.7.1.6 "A listed backflow prevention assembly shall be considered a check valve, and an additional check valve shall not be required". In all my commercial builds I use a double check backflow. So I guess my confusion is because there is mixed occupancy would I use the double check because there IS commercial or just use a single check BECAUSE its 13R. Karen Purvis Senior Designer Facility Systems Consultants 713 South Central Street, Suite 101 Knoxville, TN 37902 ph.865-246-0164 fax 865-246-1084 -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of George Church Sent: Wednesday, August 12, 2009 10:23 AM To: [email protected] Subject: RE: Mixed occupancy Hmm. If the business portion of the occupancy is incidental to the residential use of the building, as in a cafeteria serving a dorm, then you drag over the couple items of #13 that 13R references for areas outside the dwelling units. If it's a restaurant serving the general public but located in a hotel, then the design is to #13 for the entire building- unless its two buildings within the definitions of building separation in your applicable building code. In either case, the riser is sized by the hydraulic demand. I cannot imagine where you'd have a situation where the backflow preventor is dependent upon 13 or 13R. In 13D you could omit the BFP in certain instances, but that doesn't seem to be in your question. Why would the occupancy change the need for backflow prevention in your mind? Water still sitting there stagnant. glc -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Karen Purvis Sent: Wednesday, August 12, 2009 10:06 AM To: [email protected] Subject: Mixed occupancy These probably are questions everyone knows the answers to but I can't find the answers: 1. If you have a mixed occupancy (residential & Business) and your design is a 13R does your riser need to be at least a certain size or just large enough to serve the hydraulic area? 2. Because there is something other than residential in the building would I not need a backflow on the riser? Karen Purvis Senior Designer Facility Systems Consultants 713 South Central Street, Suite 101 Knoxville, TN 37902 ph.865-246-0164 fax 865-246-1084 _______________________________________________ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field)
