NFPA 72 does not define “Area Coverage”. However, they do define partial or selective coverage. From NFPA 72, 2016 Handbook
17.5.3.2* Partial or Selective Coverage. Where other governing laws, codes, or standards require the protection of selected areas only, the specified areas shall be protected in accordance with this Code. A.17.5.3.2 If there are no detectors in the room or area of fire origin, the fire could exceed the design objectives before being detected by remotely located detectors. When coverage other than total coverage is required, partial coverage can be provided in common areas and work spaces such as corridors, lobbies, storage rooms, equipment rooms, and other tenantless spaces. The intent of selective coverage is to address a specific hazard only. Where a specific area is to be protected, all points within that area should be within 0.7 × the adjusted detector spacing for spot-type detectors as required by 17.6.3<http://codesonline.nfpa.org/a/c.ref/handbook_2016_ID072_chap17_72/sec> and 17.7.3.2<http://codesonline.nfpa.org/a/c.ref/handbook_2016_ID072_chap17_145/sec>. Note that an area does not necessarily mean an entire room. It is possible to provide properly spaced detectors to provide detection for only part of a room. Similarly, the Code permits protection of a specific hazard. In that case, detectors within a radius of 0.7 × the adjusted detector spacing from the hazard provide the required detection. An example of protection of specific risk is the smoke detector required by Section 21.3<http://codesonline.nfpa.org/a/c.ref/handbook_2016_ID072_chap21_20/sec> to be within 21 ft (6.4 m) of an elevator, where elevator recall is required. It should also be noted that fire detection by itself is not fire protection. Also, protection goals could be such that detection being provided for a specific area or hazard might require a form of total coverage for that particular area or hazard. That is, it might be necessary to provide detectors above suspended ceilings or in small closets and other ancillary spaces that are a part of, or an exposure to, the area or hazard being protected. 72 also doesn’t mention anything about being Listed “FOR AREA PROTECTION”. However, it does mention against using duct detectors as substitutes for open area coverage. 17.7.4.3* Detectors placed in environmental air ducts or plenums shall not (Emphasis by me) be used as a substitute for open area detectors. Where detectors are used for the control of smoke spread, the requirements of 17.7.5<http://codesonline.nfpa.org/NFPA/a/c.html/nfpa_72_hbk/handbook_2016_ID072_part1/part_one___i_nfpa_72_sup___x00ae___sup___national_fire_alarm_and_signaling_code__i___2016_edition__with_commentary__span__div_class__bookmarksec____div_#handbook_2016_ID072_chap17_207> shall apply. Where open area protection is required, 17.7.3<http://codesonline.nfpa.org/NFPA/a/c.html/nfpa_72_hbk/handbook_2016_ID072_part1/part_one___i_nfpa_72_sup___x00ae___sup___national_fire_alarm_and_signaling_code__i___2016_edition__with_commentary__span__div_class__bookmarksec____div_#handbook_2016_ID072_chap17_139> shall apply. In most buildings, there are periods when the HVAC system is not moving significant quantities of air from the compartments it serves. As a result, the fire detection system cannot be designed to rely on the HVAC system operation for the transport of smoke to smoke detectors. A.17.7.4.3 Smoke might not be drawn into the duct or plenums when the ventilating system is shut down. Furthermore, when the ventilating system is operating, the detector(s) can be less responsive to a fire condition in the room of fire origin due to dilution by clean air. They both point out smoke dilution and delayed activation. Kind Regards, mike Mike Henke CET Sprinkler Product Manager ___________________________________________________ [cid:image001.jpg@01D21332.08789B20] Potter Electric Signal Company, LLC 1609 Park 370 Place, St. Louis, MO 63042 phone: 800-325-3936 | direct: 314-595-6740 mi...@pottersignal.com<mailto:mi...@pottersignal.com> | www.pottersignal.com<http://www.pottersignal.com/> From: Sprinklerforum [mailto:sprinklerforum-boun...@lists.firesprinkler.org] On Behalf Of craig.pr...@ch2m.com Sent: Tuesday, September 20, 2016 10:43 AM To: sprinklerforum@lists.firesprinkler.org Subject: RE: Pre-action detection Define “Area Coverage”. The duct detector covers or senses within the same AREA the air handling system serves. Does it say in either NFPA 13 or NFPA 72 that a detector has to be listed “FOR AREA PROTECTION”? Actually a detector isn’t really protecting anything, just sensing and alarming. Craig L. Prahl Fire Protection Group Lead/SME CH2M 200 Verdae Blvd. Greenville, SC 29607 Direct - 864.920.7540 Fax - 864.920.7129 CH2MHILL Extension 77540 craig.pr...@ch2m.com<mailto:craig.pr...@ch2m.com> From: Sprinklerforum [mailto:sprinklerforum-boun...@lists.firesprinkler.org] On Behalf Of michael G Sent: Tuesday, September 20, 2016 11:16 AM To: sprinklerforum@lists.firesprinkler.org<mailto:sprinklerforum@lists.firesprinkler.org> Subject: RE: Pre-action detection [EXTERNAL] Bruce, They don’t make a Duct detector that is listed for area of protection. Also our other major concern. Michael Goodis Estimator, Project Manager IL#000635 NICET#135586 Key Fire Protection Enterprises LLC 3200 Mike Padgett HWY Augusta, GA 30906 Office- (706)790-3473 Cell- (706) 220-8822 Fax: (706) 738-2119 From: Sprinklerforum [mailto:sprinklerforum-boun...@lists.firesprinkler.org] On Behalf Of Bruce Verhei Sent: Tuesday, September 20, 2016 11:01 AM To: sprinklerforum@lists.firesprinkler.org<mailto:sprinklerforum@lists.firesprinkler.org> Subject: Re: Pre-action detection Guess I'll be the angel's advocate. Is the duct detector listed for area coverage? That said, I think (51%) that a detector in the exhaust from each one-person cell was used as the detection for such a system in Kent WA. I was not the plan reviewer for this project so I am not sure. Operator is King Co. Constructed as King County Regional Justice Center, renamed Norm Maleng Regional Justice Center. I don't have a current contact. Best Bruce Verhei On Sep 20, 2016, at 07:04, <craig.pr...@ch2m.com<mailto:craig.pr...@ch2m.com>> <craig.pr...@ch2m.com<mailto:craig.pr...@ch2m.com>> wrote: Playing devil’s advocate here for a minute, how does the duct detector differ from a room detector with regards to its listing for this application? How does a duct detector sensing room smoke conditions differ from a VESDA system which samples air from a room? Does the HVAC unit serve only the same area as the preaction system covers? Is there specific verbiage cited within NFPA 13 or NFPA 72 which does not allow the use of an HVAC return air smoke detector as an initiating device for a preaction system? Craig L. Prahl Fire Protection Group Lead/SME CH2M 200 Verdae Blvd. Greenville, SC 29607 Direct - 864.920.7540 Fax - 864.920.7129 CH2MHILL Extension 77540 craig.pr...@ch2m.com<mailto:craig.pr...@ch2m.com> From: Sprinklerforum [mailto:sprinklerforum-boun...@lists.firesprinkler.org] On Behalf Of Gregg Key Sent: Tuesday, September 20, 2016 9:28 AM To: sprinklerforum@lists.firesprinkler.org<mailto:sprinklerforum@lists.firesprinkler.org> Subject: Pre-action detection [EXTERNAL] Greetings, First of all, what a great convention. Good speakers and fellowship. Nashville was awesome as well. I am in serious need of some technical assistance. I have posted this a few times with some response but this has become a three ring circus between the architect ,fire marshal and us . The Architect specified a double interlock pre-action system with the detection being provided with a duct detector in the return duct at the unit. We have refused to certify the system due the fact that the detector not being listed for this application. State is asking me to hang a partial certification ( yellow tag) . has anyone else dealt with this detection being used for a pre-action system in a detention center? Any help would be appreciated Gregg Key General Manager Key Fire Protection Enterprises,LLC 3200 Mike Padgett Hwy Augusta GA, 30906 O-706-790-3473 C- 706-220-8821 F- 706-738-2119 gr...@keyfps.com<mailto:gr...@keyfps.com> _______________________________________________ Sprinklerforum mailing list Sprinklerforum@lists.firesprinkler.org<mailto:Sprinklerforum@lists.firesprinkler.org> http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org ________________________________ [http://static.avast.com/emails/avast-mail-stamp.png]<https://www.avast.com/antivirus> This email has been checked for viruses by Avast antivirus software. www.avast.com<https://www.avast.com/antivirus>
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