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 3
... metal frame of 34 - in ( 1.9 cm ) angle iron on which are mounted two microswitches 2.0 ft ( 61 cm ) apart . The actuating levers on the microswitches contain metal hooks , which are used to hold one end of 1 - in ( 2.5 cm ) paper ...
... metal frame of 34 - in ( 1.9 cm ) angle iron on which are mounted two microswitches 2.0 ft ( 61 cm ) apart . The actuating levers on the microswitches contain metal hooks , which are used to hold one end of 1 - in ( 2.5 cm ) paper ...
Page 5
... metal roofing were applied as directed by their suppliers to decks supported on 2 in x 4 in rafters , 2 ft ( 61 cm ) on centers . The built - up roofing specimens , 1 ft ( 30.5 cm ) square , were solidly mopped to 12 in ( 1.3 cm ) ...
... metal roofing were applied as directed by their suppliers to decks supported on 2 in x 4 in rafters , 2 ft ( 61 cm ) on centers . The built - up roofing specimens , 1 ft ( 30.5 cm ) square , were solidly mopped to 12 in ( 1.3 cm ) ...
Page 8
... evaluations were cracking for brittle roofings and objectionable indentations for metal roofing . Table 4 is a summary of the results of these tests . Diameter of smallest hailstone causing damage Description -in ( 0.3 8.
... evaluations were cracking for brittle roofings and objectionable indentations for metal roofing . Table 4 is a summary of the results of these tests . Diameter of smallest hailstone causing damage Description -in ( 0.3 8.
Page 9
... metal⚫ Edge Center Unsupported in em in ст in cm 11/2 ( 3.8 ) 14 ( 4.5 ) ( 4.5 ) 2 ( 5.1 ) 2 ( 5.1 ) 14 ( 4.5 ) 1/4 ... metal roofing was dented by all sizes of hailstones used . Deck cracking oc- curred when 22 - in ( 6.4 cm ) ...
... metal⚫ Edge Center Unsupported in em in ст in cm 11/2 ( 3.8 ) 14 ( 4.5 ) ( 4.5 ) 2 ( 5.1 ) 2 ( 5.1 ) 14 ( 4.5 ) 1/4 ... metal roofing was dented by all sizes of hailstones used . Deck cracking oc- curred when 22 - in ( 6.4 cm ) ...
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