MECHANICAL CONTRACTING e Continued from p 56
warehouses with ceiling height up to 40 ft, since both the ESFR sprinklers and the new sprinkler were evaluated with the same fire scenarios. Based on the performance of the new sprinkler, FM Global has treated the sprinkler in the same fashion as the ESFR sprinklers, requiring a “12 head” design for the system water demand, identical hose stream demand and water supply duration. The same sprinkler installation rules with regard to physical obstructions and ceiling elements are applied to both the ESFR pendent sprinklers and the new sprinkler. However, because it does not use a fast-response link, the new sprinkler is being classified not as an ESFR sprinkler but as a CMSA sprinkler. This type of technology can offer a
58
significantly reduced end-head pressure as compared to traditional ESFR technology and is poised to replace ESFR as a design choice in storage applications. A benefit of the reduced end-head pressure of this new storage sprinkler is the opportunity to reduce pipe diameters in branch lines and cross
mains and, potentially, even to eliminate the need for a pump, if the public water supply is strong enough, affording significant cost savings in material and labor.
Moving forward The needs for adequate fire
protection continue to grow in the storage environment as these spaces grow taller and broader and as racks are built higher. A broader variety of materials with different levels of flammability are now being stored, requiring a wider range of fire protection solutions. Complex installation guidelines for each class of sprinklers further complicate the design landscape. In 2010, FM Global began an
update of its data sheets that specifies the rules for system design and installation for storage sprinkler systems. The goal is to simplify the variations in sprinkler classes and to base the system design rules on performance of the sprinkler, not on the traditional names of the sprinkler. Hence, greater consistency in system performance can be obtained.
The fire suppression or control
performance of sprinklers depends on the combined effects of the sprinkler attributes: sprinkler orientation (pendent or upright), sprinkler deflector design for generating the desirable spray pattern, volume median diameter of the spray, sprinkler sensitivity (RTI) and temperature rating. FM Global’s new data sheets base the system design rules on performance of the sprinkler rather than on the traditional name associated with the sprinkler. This sprinkler performance is predictable, based upon the parameters of the system. As storage space design continues
to evolve, new technologies continue to be introduced into the marketplace to meet increasing challenges. ;
Dr. H.C. Kung is the research director at
Victaulic and a Fellow of the Society of Fire Protection Engineers. His career spans more than 35 years with Factory Mutual and Un- derwriter’s Laboratory, where he drove de- velopment of residential, quick response, ESFR, Extra Large Orifice, ESFR upright and K17 large drop sprinkler technologies.
phc february 2011
www.phcnews.com
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68