Any takers to my previous post? Ryan Hinson Burns & McDonnell Direct: 952-656-6003 Ext 3662
From: Hinson, Ryan Sent: Wednesday, July 14, 2010 11:33 AM To: '[email protected]' Subject: Adjacent Hazards NFPA 13 (2010) section 11.1.2* and the newly added appendix section gives an example of how to determine the remote area size for adjacent hazards, what it does not include is quick response reduction in the portion of the hazard area that is OH2 or less. Is it appropriate to use Quick Response area reduction as allowed by other sections of the standard in a portion of a design area when the ceiling is less than 20 ft AFF over the entire floor in question? As a follow up, is it known why QR cannot be used in Extra Hazard occupancies per sections 8.4.1.2, 11.2.3.2.2.2, 11.2.3.2.3.1(2), and 12.6.6? 11.1.2* Adjacent Hazards or Design Methods. For buildings with two or more adjacent hazards or design methods, the following shall apply: (1) Where areas are not physically separated by a barrier or partition capable of delaying heat from a fire in one area from fusing sprinklers in the adjacent area, the required sprinkler protection for the more demanding design basis shall extend 15 ft (4.6 m) beyond its perimeter. (2) The requirements of 11.1.2(1) shall not apply where the areas are separated by a barrier partition that is capable of preventing heat from a fire in one area from fusing sprinklers in the adjacent area. A.11.1.2 The situation frequently arises where a small area of a higher hazard is surrounded by a lesser hazard. For example, consider a 600 ft2 (55.7m2) area consisting of 10 ft (3.05 m) high on-floor storage of cartoned unexpanded plastic commodities surrounded by a plastic extruding operation in a 15 ft (4.57 m) high building. In accordance with Chapter 12, the density required for the plastic storage must meet the requirements for extra hazard (Group 1) occupancies. The plastic extruding operation should be considered an ordinary hazard (Group 2) occupancy. In accordance with Chapter 11, the corresponding discharge densities should be 0.3 gpm/ft2 (12.2 mm/min) over 2500 ft2 (232m2) for the storage and 0.2 gpm/ft2 (8.1 mm/min) over 1500 ft2 (139 m2) for the remainder of the area. (Also see Chapter 11 for the required minimum areas of operation.) If the storage area is not separated from the surrounding area by a wall or partition (see 11.1.2), the size of the operating area is determined by the higher hazard storage. For example, the operating area is 2500 ft2 (232 m2). The system must be able to provide the 0.3 gpm/ft2 (12.2 mm/ min) density over the storage area and 15 ft (4.57 m) beyond. If part of the remote area is outside the 600 ft2 (55.7 m2) plus the 15 ft (4.57 m) overlap, only 0.2 gpm/ft2 (8.1 mm/min) is needed for that portion. If the storage is separated from the surrounding area by a floor-to-ceiling/roof partition that is capable of preventing heat from a fire on one side from fusing sprinklers on the other side, the size of the operating area is determined by the occupancy of the surrounding area. In this example, the design area is 1500 ft2 (139 m2). A 0.3 gpm/ft2 (12.2 mm/min) density is needed within the separated area with 0.2 gpm/ft2 (8.1 mm/min) in the remainder of the remote area. Thank you, Ryan L. Hinson, EIT, NICET III Fire Protection Engineer, Aviation & Facilities Group Burns & McDonnell Minneapolis-St. Paul Office 8201 Norman Center Drive, Suite 300 Bloomington, MN 55437 Direct: 952-656-6003 Ext 3662 Fax: 952-229-2923 [email protected] www.burnsmcd.com<BLOCKED::www.burnsmcd.com> Proud recipient of PSMJ's Premier Award for Client Satisfaction _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field)
