I think “for the building being calculated” doesn’t take into account the potential arrangement of a single water line supplying domestic and fire protection to multiple buildings. If I was the AHJ, I would require the fixture load allowance of both buildings to be added to the sprinkler demand of the subject building for that portion of the piping that is common to both buildings. So if you’re coming in from a meter to the main building and call that Section A, then you have Section B going to the Satellite building, I would calculate Satellite sprinkler demand + Satellite domestic allowance in Section B, then at the point where the line branches off to the main building I would add the Main building plumbing allowance so that Section A includes Satellite sprinkler demand plus Satellite domestic + Main Building domestic.
I hope that makes sense. Steve L. From: Sprinklerforum [mailto:[email protected]] On Behalf Of J H via Sprinklerforum Sent: Monday, September 09, 2019 3:17 PM To: [email protected] Cc: J H Subject: 13R Fixture Units for Multiple Buildings I've got a Bed & Breakfast (sprinklered per 13R) that is building a second detached suite which is to likewise be sprinklered to 13R. The existing yard line supplies both the domestic and fire demands for the existing building and the new building is planned to also tap into this yard line. Question: In determining the fixture units for the new building would we also have to account for the existing building's fixture units when calculating back to the city tap? 13R states: "9.6* Domestic Demand Domestic demand for the building being calculated shall be included as part of the overall system demand for systems with common domestic/fire mains where no provisions are made to prevent thedomestic waterflow upon sprinkler system activation." I think the keywords are "for the building being calculated" and we would not have to account for anything else but I'm also thinking that if the intent is to account for water losses due to domestic usage and we are daisy chaining off of a relatively small, private, water line that it would be wise to account for these losses. Any thoughts? JH
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