A series of seven large-scale rack storage f i e tests was conducted, using four ESFR sprinkler models, to determine the required sprinkler spray characteristics for achieving effective protection of rack storages of the FM standard plastic commodity up to 10.8 in high in a 12.2 m high warehouse. AU four models have a nominal K factor of 0.34 ~/s/(k~a)", and the sprinkler discharge pressure was maintained at 517 kPa. The sprinkler spacing was 3.05 m x 3.05 m. The test variables include storage heightlceiling clearance, ignition location and sprmkler models. The sprays of the sprinkler models used in the fire tests were characterized by their drop size distribution, center-core thrust force, and water distribution under no-fire condition. For ESFR sprinkler protection, the effect of drop size distribution was demonstrated to be unimportant through the fire tests. For the case with ignition directly over a sprinkler, the spray center-core thrust force and the water flux under no-fue condition over the top surface of a two pallet-load by two pallet-load fuel array directly underneath the sprinkler have been shown to be critical for achieving f i e suppression. A minimum centercore thrust force of 101.3 ~/ m ' measured at 1.77 beneath the sprinkler deflector, and a minimum water flux of 0.614 l/s/m2 measured over a 2.15 m x 2.15 m area 4.42 m beneath the ceiling directly under the sprinkler have been found to be necessary for achieving fire suppression. For the case with ignition centered below two sprinklers and with 10.8 m storage height / 1.77 m ceiling clearance, only the water flux under no-fire condition over the fuel array top was shown to be critical. A measured water flux of 0.667 0/s/m2 over a 2.15 m x 2.15 m area, centered below the two sprinklers, 1.77 beneath the ceiling, was found to be sufficient for achieving fire suppression.
A series of seven rack storage fire tests was conducted, using four pendent fast-response prototype sprinklers to determine the sprinkler discharge characteristics necessary for suppressing four-tier array rack storage fires under a 9.14-m high ceiling. The sprinklers had a nominal K-factor of either 11 or 14, and the sprinkler discharge pressure was maintained at 345 kPa. The commodities used as fuel consisted of polystyrene cups packaged in compartmented cartons. The commodities were arranged in double-row steel racks, two pallet-loads wide, two palletloads deep and four tiers high. Three different ignition locations with respect to sprinklers were employed. Sprinkler water distribution under a no-fire condition and spray center-core thrust force were identified as key parameters of sprinkler discharge characteristics pertaining to sprinkler fire-suppression ability. The relationships among the fire sizq at first sprinkler actuation, plume momentum flux, Required Delivered Density, sprinkler water distribution and spray center-core thrust force, with regard to suppression of the rack storage fires, were explored.For fire tests with ignition directly under a sprinkler, it was highly desirable for the sprinkler spray to overpower the fire plume to achieve efficient delivery of sprinkler water to the fire source. In the fire tests when the spray center-core thrust force was greater than the plume momentum flux and the average water flux over the top surface of the fuel array under a no-fire condition was greater than the Required Delivered Density, fire suppression was achieved.For fire tests with ignition centered below either two or four sprinklers, the fire plume was largely confined to the center flue of the fuel array, and most of the sprinkler water projected toward the top surface of the fuel array reached the top surface without passing through the fire plume. Therefore, the measured water flux over the top surface under a no-fire condition was expected to be close to that delivered during a fire. Fire suppression in these tests resulted from contributions of both the sprinkler water reaching the top surface and the side exposed surfaces of the fuel array. When the average water flux over the top surface under a no-fire condition was greater than the Required Delivered Density, fire suppression was achieved. INTRODUCTI ONSprinkler protection against rack storage fires has been a major concern of the fire protection community for the past 20 years. Rack
Twelve large-scale fire tests were conducted to compare the fire protection performances of selected European conventional style and U.S. spray sprinklers. Two different fire test scenarios were investigated. The assessment of sprinkler effectiveness was based upon total numbers of sprinkler operations and resulting fire damage to the fuel arrays. Using these criteria, both European conventional-style sprinklers and U.S. spray sprinklers provided control of fires for the scenarios in which they were evaluated. However, there were differences in the levels of protection provided. In general, the spray sprinklers provided better fire protection than European conventional-style sprinklers under identical test conditions. In tests involving highchallenge plastic commodityfires, the spray sprinklers provided significantly better fire protection. For moderate-to-high challenge commodity fires involving a simulated noncombustible product in cardboard cartons, the relative performance of the two types of sprinklers depended upon the ignition location relative to overhead sprinklers. I NTRODUCTIONThe automatic sprinklers used in the United States from 1878 until the early 1950s were designed to project approximately half of the water upward toward the ceiling and the remaining half downward. These sprinklers could be installed in either upright or pendent position and provided protection against roof involvement during fires.Attempts to reduce fire protection costs resulted in the development of the spray sprinkler, which was introduced in 1952. This sprinkler was designed to project all of the discharging water downward and outward, creating a parabolic (umbrella) spray pattern with the deflector at the vertex of the pattern. The rationale was to effect early fire control by directing all of the available water to the likeliest fire source locations, i.e., at the floor level. Gaining early fire control would therefore obviate the need to protect the ceiling against fire involvement. The newly developed sprinklers would also provide fine water droplets, or spray, which would cool the ceiling gases and prevent roof involvement during a fire.In 1958, after several years of successful application, the spray sprinkler was designated as the standard sprinkler in the United States, and the early generation sprinklers were classified as &dquo;old-style&dquo; sprinklers. The old-style sprinklers were gradually phased out of use in the United States.However, old-style sprinklers, with their ceiling protection philosophy, continued to find application in Europe, where they were referred to as &dquo;conventional style&dquo; sprinklers. The conventional style sprinkler is still preferred over the spray sprinkler in Europe. Recently, questions have been raised regarding the relative merits of the two types of sprinklers in providing effective fire protection. The objective of this paper is to compare the fire protection performance of U.S. spray sprinklers and European conventional style sprinklers in selected large-scale rack storage...
Fire testing was performed to determine if Early Suppression-Fast Response (ESFR) sprinklers could be used to protect warehouses containing flammable liquids in small metal relieving-style containers.A total of seven large-scale fire tests was performed using heptane in 3.8 L (1 gallon) or 18.9 L (5 gallon) relieving-style metal containers stored 6.1 m (20 ft) and 7.6 m (25 ft) high under a 9.1 m (30 ft) high ceiling. Three of these tests evaluated sprinkler protection for 6.1 m (20 ft) and 7.6 m (25 ft) high double row rack storage arrangements of 3.8 L (1 gallon) containers packaged in corrugated paper cartons. The remaining four fire tests were performed using uncartoned 18.9 L (5 gallon) metal containers in a 7.6 m (25 ft) high double row rack arrangement (three tests) and in a 3.7 m (12 ft) high palletized storage arrangement (one test) under a 9.1 m (30 ft) high ceiling.Sprinkler protection consisted of either ESFR sprinklers installed at the ceiling only, or a combination of ESFR ceiling sprinklers and in-rack sprinklers installed within the longitudinal flue space of the double row rack storage arrangements.The results of the tests indicated that flammable liquid in relieving-style metal containers packaged in corrugated paper cartons were more easily protected than when the containers were stored uncartoned. The tests also showed that the most effective protection for both cartoned and uncartoned containers consisted of the combination of ESFR ceiling sprinklers and quick-response, large-orifice in-rack sprinklers installed within the longitudinal flue space of the rack storage arrangements. Ceiling-only ESFR sprinklers proved to be adequate protection for palletized storage configurations.
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