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
... . It was conceded , following Laurie , that ( 1 ) ordinary impact tests were not satis- 1 Figures in brackets indicate the literature references at the end of this paper . perature much below the freezing point of water , the 1.
... . It was conceded , following Laurie , that ( 1 ) ordinary impact tests were not satis- 1 Figures in brackets indicate the literature references at the end of this paper . perature much below the freezing point of water , the 1.
Page 2
... FIGURE 1. Hail storm distribution map . 7. Hailstone mold . 8. Triggering mechanism . FIGURE 2. perature much below the freezing point of water , the ice that forms does so rapidly and traps air in the process . This forms a milky layer ...
... FIGURE 1. Hail storm distribution map . 7. Hailstone mold . 8. Triggering mechanism . FIGURE 2. perature much below the freezing point of water , the ice that forms does so rapidly and traps air in the process . This forms a milky layer ...
Page 3
... Figure 1 is a map of the central United States showing the distribution of storms during the years 1960-1966 in which at least $ 5000 worth of building damage was done by hail in each storm . The orographic storms form an imper- fect ...
... Figure 1 is a map of the central United States showing the distribution of storms during the years 1960-1966 in which at least $ 5000 worth of building damage was done by hail in each storm . The orographic storms form an imper- fect ...
Page 4
... FIGURE 2. Hail resistance apparatus . 5 MOD 360 A 1. Test specimen . 2. Timing section . 3. Compressed gas gun . 4. Gas cylinder . 5. Timer . 6. Hailstone carriers - one in gun and one in open to show cavity . nally ( Item 6 fig . 2 ) ...
... FIGURE 2. Hail resistance apparatus . 5 MOD 360 A 1. Test specimen . 2. Timing section . 3. Compressed gas gun . 4. Gas cylinder . 5. Timer . 6. Hailstone carriers - one in gun and one in open to show cavity . nally ( Item 6 fig . 2 ) ...
Page 5
... figure 2 with large C clamps . The 1 - in ( 2.5 cm ) paper computer tapes were hooked to the microswitches and fastened to the top of the timing frame with masking tape . They were held under tension , just insufficient to close the ...
... figure 2 with large C clamps . The 1 - in ( 2.5 cm ) paper computer tapes were hooked to the microswitches and fastened to the top of the timing frame with masking tape . They were held under tension , just insufficient to close the ...
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