Craig, the joists are 12” deep, 16” o.c. The entire depth and width of the joist is filled with noncombustible insulation.
Sent from my iPhone > On Feb 16, 2022, at 6:55 AM, Prahl, Craig/GVL via Sprinklerforum > <sprinklerforum@lists.firesprinkler.org> wrote: > > What are the depths of the joists, the depth of the insulation and the > spacing between the joists? > > Craig Prahl | Jacobs | Group Lead/SME – Fire Protection | > craig.pr...@jacobs.com | www.jacobs.com > 1041 East Butler Road Greenville, South Carolina 29606 > CONTACT BY: email or MS TEAMS > > > > -----Original Message----- > From: Sprinklerforum <sprinklerforum-boun...@lists.firesprinkler.org> On > Behalf Of Scott Harvey via Sprinklerforum > Sent: Wednesday, February 16, 2022 12:53 AM > To: sprinklerforum@lists.firesprinkler.org > Cc: Scott Harvey <sc...@harveyplumbing.com> > Subject: [EXTERNAL] Obstructed vs Unobstructed Construction > > Hi all, I have a question for the group. > > I've got a storeroom, ceiling is open to structure. The roof structure is > solid wood joists, which are fully insulated between each joist. > > We have installed standard spray upright sprinklers with the deflectors > approx 8-10 inches below the bottom of the joist/insulation. > > In my mind, this is unobstructed construction, because per "A.8.5.4.1 Batt > insulation creates an effective thermal barrier and can be considered the > ceiling/roof deck when determining distances between deflector and ceiling." > Chapter 3 defines Obstructed Construction "Panel construction and other > construction where beams, trusses, or other members impede heat flow or water > distribution in a manner that materially affects the ability of the sprinkler > to control or suppress a fire". > > Now that I look at this again, I'm thinking I am wrong and should be > obstructed construction because although the batt insulation creates a > thermal barrier (similar to a smooth ceiling) the structure is still the > same, so I would need to keep my upright sprinklers max 6-inches below the > bottom of structure? > > Would appreciate input from the group. > > > Thanks, > > Scott Harvey, CET > > > _______________________________________________ > Sprinklerforum mailing list > Sprinklerforum@lists.firesprinkler.org > https://urldefense.com/v3/__http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org__;!!B5cixuoO7ltTeg!WNJbuEDrG9DqZDyEL512vMojwZ-VOZeVutCjsR6asnXWsu5WOOUl9NA1aE0ZoG95hg$ > > ________________________________ > > NOTICE - This communication may contain confidential and privileged > information that is _______________________________________________ Sprinklerforum mailing list Sprinklerforum@lists.firesprinkler.org http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
