Consulting-Specifying Engineer - November 2007 - (Page 12)

M/E Roundtable due to smoke stratification. A hot-air layer frequently forms under the ceiling of an atrium. This hot-air layer may be hotter than the smoke rising from the fire below, which prevents the smoke from reaching the detectors. Beam smoke detectors often are used to detect the developing smoke layer. To determine the most advantageous location and spacing of beam detectors, the designer calculates the expected plume diameter and locates the detectors to accommodate the plume dynamics. GOLDHAMMER: For high heat release rates, standard smoke detection can be effective. For lower heat release rates, where stratification is a concern, use of beam detection, air sampling technology, and even video detection may be appropriate. Ultraviolet infrared detection also may be appropriate for deluge-type sprinkler system applications. CSE : There are many technological advances in fire protection for high-bay racking systems. What t ypes of systems are the most popular nowadays: in-rack, earlysuppression fast-response (ESFR), large orifice sprinklers? GOLDHAMMER: My experience with clients is to avoid rack sprinkler protection when possible. In many applications, the use of ESFR technology does not require rack sprinklers. This especially is true with the larger orifice/ k-factor heads. Full-scale fire testing has demonstrated superior suppression capability of ESFR technology. However, ESFR technology is limited to certain storage and ceiling heights. Using ESFR outside of the testing criteria may lead to rack sprinklers or even barrier sprinkler protection schemes. ALLEN: For warehouses, ESFR sprinklers provide the best solution, because numerous storage arrangements and commodity types are protected without using in-rack sprinklers. Eliminating the need for in-rack sprinklers provides more flexibility in changing rack arrangements and the potential for damage to in-rack sprinkler piping. Because ESFR sprinklers can be used for many different types of storages, they provide a sprinkler design that is used in warehouses where tenants or storage arrangements change. CSE: Beyond the types of suppression systems mentioned above, w h at o t h e r n ew t e c h n olo gic al innovations have there been for these sprinkler systems? GOLDHAMMER: Some of the latest technological innovations are based on the use of full-scale fire testing. Examples include using different k-factors (orifice sizes) and operating end head pressures to achieve adequate protection solutions to the high bay environment. Fire testing also has shown that adequate protection can be achieved using the declining density method, which uses higher end head pressures during initial sprinkler head operation. ALLEN: In aircraft hangars, foam-water sprinkler systems and low-level underwing AFFF systems are used. CSE : What are some of the most common design errors in systems for high-bay? ALLEN: The installation rules in NFPA 13 are specific for ESFR sprinklers, including the maximum pitch of ceilings and clearance from obstructions. Without attention to detail in the design and installation, ESFR sprinklers may not be installed in accordance with the requirements. The suppression principle of ESFR sprinklers is for sprinklers to operate in the early stages of a fire by using a more (Continued on page 16) SEE TOUCH COMPARE At The World’s Largest HVAC&R Marketplace January 22-24, 2008 Tuesday, Wednesday, Thursday Javits Convention Center, New York, New York For FREE Registration: Over 1,800 Exhibitors www.ahrexpo.com Co-sponsors: Honorary sponsor: tel: (203) 221-9232 e-mail: info@ahrexpo.com Produced and managed by: Input #208 at csemag.com/quickResponse 12 Consulting-Specifying Engineer • NOVEMBER 2007 http://www.ahrexpo.com http://www.ahrexpo.com http://csemag.com/quickResponse

Table of Contents Feed for the Digital Edition of Consulting-Specifying Engineer - November 2007

Consulting-Specifying Engineer Contents Editor's Viewpoint Letters In The News M/E Roundtable Emergency Power for Healthcare 2007 Products of the Year Industrial-strength Lighting Hazardous HVAC Codes and Standards Management Report Jobs/Classifieds Specifier's Notebook On-Peak Performance Contents Best Battery Selector in Engine Starting Applications NEC 708: Practical Impact on Backup Power Systems Protecting Power: Specifying Outdoor Generator Enclosures Investing in Backup Power Systems Coes, Consultants, Manufacturers, and Standby Power Systems

Consulting-Specifying Engineer - November 2007

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