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). |
From inside the book
Results 1-3 of 3
Page 5
... dents will be reported , only the fractures of the coating , felt or other shingle material will be called failure in this report . For each material and roofing system , the thresholds of failure , or the smallest hail size producing ...
... dents will be reported , only the fractures of the coating , felt or other shingle material will be called failure in this report . For each material and roofing system , the thresholds of failure , or the smallest hail size producing ...
Page 6
... dents . In general , the smaller hailstones produced cir- cular indentations approximating one half their diameter and the larger hailstones , those above the felt - damage threshold , produced dents . greater in diameter than one ...
... dents . In general , the smaller hailstones produced cir- cular indentations approximating one half their diameter and the larger hailstones , those above the felt - damage threshold , produced dents . greater in diameter than one ...
Page 9
... dents with hailstones larger than 21⁄2 in ( 6.4 cm ) . Note tested . All roofings tested were vulnerable to hail ... dented by all sizes of hailstones used . Deck cracking oc- curred when 22 - in ( 6.4 cm ) hailstones were used . This ...
... dents with hailstones larger than 21⁄2 in ( 6.4 cm ) . Note tested . All roofings tested were vulnerable to hail ... dented by all sizes of hailstones used . Deck cracking oc- curred when 22 - in ( 6.4 cm ) hailstones were used . This ...
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