It's also defined, well sort of in the Annex, in '13 A8.6.5.2.1.4. ... If an obstruction is so close to a sprinkler that water cannot spray on both sides, it is effectively a continuous obstruction as far as the sprinkler is concerned and the Beam Rule should be applied....this has been around for many editions. I'd also point out the section 8.6.5.2 applies to both continuous and non-continuous obstructions thus why the point in the annex becomes relevant. I have seen folks use the 3 times rule to argue there are allowable shadow areas and translate that to whatever situation they are dealing with. IOW when is a head so close to a sprinkler that water cannot spray on both sides, well when it affects more than the allowable floor area already allowed by the 3 times rule.
And it is different than the new definition 3.3.18.1 Continuous Obstruction. An obstruction located at or below the level of sprinkler deflectors that affect the discharge pattern of two or more adjacent sprinklers. Is effectively continuous the same continuous? So, it is an obstruction that affects at least two sprinklers or at least one sprinkler. Seems rather clear to me, lol. Chris Cahill, PE* Senior Fire Protection Engineer Burns & McDonnell 8201 Norman Center Drive Bloomington, MN 55437 Phone: 952.656.3652 Fax: 952.229.2923 [email protected] www.burnsmcd.com Proud to be one of FORTUNE's 100 Best Companies to Work For *Registered in: MN -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Tuesday, October 01, 2013 3:05 PM To: [email protected] Subject: Re: Continuous Obstruction It is defined. See 3.3 18. in the 2013 edition. John Hoffman P.E. | Fire Protection Engineer | Facility Engineering Services, KCP, LLC - Burns & McDonnell Engineering | National Nuclear Security Administration's Kansas City Plant | Operated by Honeywell FM&T | 2000 E. 95th St | Kansas City, MO 64131 | ph 816-997-7213 | [email protected] From: "G. Tim Stone" <[email protected]> To: <[email protected]> Date: 10/01/2013 02:58 PM Subject: Continuous Obstruction Sent by: [email protected] Can someone please provide me a definition for the term "Continuous Obstruction" as referenced in NFPA 13, 13D or 13R. I wonder why this is not defined in NFPA 13, Chapter 3. Are round semispherical surface mounted light fixtures (found in residential dwelling units) considered such? Thank you in advance. Regards, G. Tim Stone G. Tim Stone Consulting, LLC NICET Level III Engineering Technician Fire Protection Sprinkler Design and Consulting Services 117 Old Stage Rd. - Essex Jct., VT. 05452 CELL: (802) 373-0638 TEL: (802) 434-2968 Fax: (802) 434-4343 <mailto:[email protected]> [email protected] _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
