FWIW, I agree with Mike's assessment. "Unobstructed CEILING construction".
It should be recognized that the above is my opinion as a member of the NFPA, and has not been processed as a formal interpretation in accordance with the NFPA Regulations Governing Committee Projects and should therefore not be considered, nor relied upon, as the official position of the the NFPA, nor any of their technical committees. Sincerely, Cecil Bilbo Academy of Fire Sprinkler Technology Champaign, IL 217.607.0325 www.sprinkleracademy.com<http://www.sprinkleracademy.com> [email protected]<mailto:[email protected]> ?? OUR STUDENTS SAVE LIVES!! ________________________________ From: Sprinklerforum <[email protected]> on behalf of Mike Morey via Sprinklerforum <[email protected]> Sent: Wednesday, February 16, 2022 8:39 AM To: [email protected] <[email protected]> Cc: Mike Morey <[email protected]> Subject: RE: [EXTERNAL] Obstructed vs Unobstructed Construction 13 2019 edition states: 9.5.4.1.3 For ceilings that have insulation installed directly against underside of the ceiling or roof structure, the deflector distance shall be measured from the bottom of the insulation and shall be in accordance with 9.5.4.1.3.1, 9.5.4.1.3.2, and 9.5.4.1.3.3. 9.5.4.1.3.1 Insulation used to measure sprinkler deflector distance shall be batt insulation or insulation that withstands 3 lb/ft2 (0.13 kg/m2) uplift force. 9.5.4.1.3.2 For insulation that is installed directly against the ceiling or roof structure and is installed flat and parallel to the ceiling or roof structure, the deflector distance shall be measured to the underside of the insulation. To me up to 12" would be a compliant installation as long as the insulation is batt type which I presume it would have to be based on description. Mike Morey CFPS 3229 • NICET S.E.T. 123677 Project Manager • Fire Protection Group Shambaugh & Son, LP an EMCOR Company 7614 Opportunity Drive • Fort Wayne, IN • 46825 direct 260.487.7824 / cell 260.417.0625 / fax 260.487.7991 email [email protected] -----Original Message----- From: Sprinklerforum <[email protected]> On Behalf Of Scott Harvey via Sprinklerforum Sent: Wednesday, February 16, 2022 9:18 AM To: [email protected] Cc: Scott Harvey <[email protected]>; Prahl, Craig/GVL <[email protected]> Subject: Re: [EXTERNAL] Obstructed vs Unobstructed Construction BE ADVISED - This email originated outside EMCOR. 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 > <[email protected]> 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 | > [email protected] | > https://urldefense.com/v3/__http://www.jacobs.com__;!!FaxH778!NpU3BJxYKauVH0bhPEdX1FAnTug5yROhXr9YqwVi7O2ZEKWL_FHKv8ML1fPCtDke$ > 1041 East Butler Road Greenville, South Carolina 29606 > CONTACT BY: email or MS TEAMS > > > > -----Original Message----- > From: Sprinklerforum <[email protected]> On > Behalf Of Scott Harvey via Sprinklerforum > Sent: Wednesday, February 16, 2022 12:53 AM > To: [email protected] > Cc: Scott Harvey <[email protected]> > 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.https://urldefense.com/v3/__http://8.5.4.1__;!!FaxH778!NpU3BJxYKauVH0bhPEdX1FAnTug5yROhXr9YqwVi7O2ZEKWL_FHKv8ML1eJeTxOh$ > 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 > [email protected] > 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 [email protected] https://urldefense.com/v3/__http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org__;!!FaxH778!NpU3BJxYKauVH0bhPEdX1FAnTug5yROhXr9YqwVi7O2ZEKWL_FHKv8ML1Rr_halt$ This message is for the named person's use only. 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