Hail Resistance of Roofing ProductsBuilding Research Division, U.S. Institute for Applied Technology, 1969 - 9 pages A test was developed for evaluating the hail resistance of roofings, in which synthetic hailstones (ice spheres) of various sizes were shot at roof assemblies at their free-fall terminal v * elocities.Indentations, granule loss and roofing fracture were observed.The principal conclusion is that:All roofing materials have some resistance to hail damage, but as the size of the hail increases, a level of impact energy is reached at which damage occurs.This level lies in the range of 1 1/2 to 2 inch (3.8-5.1 cm) hailstones for most prepared roofings.(Author). |
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Page 1
... sizes were shot at roof assemblies at their free - fall terminal velocities . Indentations , granule loss and ... size of the hail increases , a level of impact energy is reached at which damage occurs . This level lies in the range of ...
... sizes were shot at roof assemblies at their free - fall terminal velocities . Indentations , granule loss and ... size of the hail increases , a level of impact energy is reached at which damage occurs . This level lies in the range of ...
Page 3
... size of the charge in the blank cartridges used in the launcher . Because of the difficulties in controlling the ... sizes , cast the " hailstones " to approximate spheres more closely and explore areas of different vulnerability on ...
... size of the charge in the blank cartridges used in the launcher . Because of the difficulties in controlling the ... sizes , cast the " hailstones " to approximate spheres more closely and explore areas of different vulnerability on ...
Page 4
... sizes of hemispheres centered 214 in ( 5.7 cm ) from its other end . Thus , when the two hemicylinders were reas- sembled , they formed carriers for the several sizes of hailstones and permitted one size barrel to be used for all of the ...
... sizes of hemispheres centered 214 in ( 5.7 cm ) from its other end . Thus , when the two hemicylinders were reas- sembled , they formed carriers for the several sizes of hailstones and permitted one size barrel to be used for all of the ...
Page 5
... size was taken from the freezer , cleaned of any burrs or projecting pieces of ice ( from the gate in the mold ) ... sizes used : TABLE 1. Terminal velocities and energies of hailstonesa Terminal velocity Approximate impact energy ...
... size was taken from the freezer , cleaned of any burrs or projecting pieces of ice ( from the gate in the mold ) ... sizes used : TABLE 1. Terminal velocities and energies of hailstonesa Terminal velocity Approximate impact energy ...
Page 6
... size traveling at velocities within 10 percent of the terminal velocities reported in table 1 for hailstones of that size . The results are reported under the types of roofing studied . 4.1 . Asphalt Shingles When applied according to ...
... size traveling at velocities within 10 percent of the terminal velocities reported in table 1 for hailstones of that size . The results are reported under the types of roofing studied . 4.1 . Asphalt Shingles When applied according to ...
Common terms and phrases
15 cents air gun apparatus Applied Technology areas of different Asbestos cement asphalt flood coat Asphalt Roofing asphalt shingles automatic data processing building damage Building Research Building Science Series Built-up roofs Bureau of Standards Cement and Concrete Center Class C shingle Coal tar Concrete Properties cracking cylinder dense decks dents DEPARTMENT OF COMMERCE diameter different vulnerability felt damage Fiberboard on 1-in Foamboard free-fall terminal velocity freezing ft 61 cm Gas cylinder Glass fiber insulation hail damage hail resistance hailstone carrier Hailstone Molds Hailstorms ice spheres indentation Institute for Applied interply asphalt Interrelations Between Cement Joules kg/m² kg/m³ large hailstones launcher lb/sq Meteorol microswitches National Bureau Nonbituminous Roofing organic felt polyethylene Portland Cement prepared roofings reported Resistance of Roofing resistant to hail shingles showed Sidney H sizes of hailstones slag solidly supported areas specimen steel decking substrates tested Type 235 shingles U.S. DEPARTMENT U.S. Government Printing velocity 9 ст