How Shingle Roofs Are Tested
Better home protection through fire-proof roofs is the purpose of special tests of roofing materials now being carried on by the Commerce Department’s Bureau of Standards, according to Dr. George K. Burgess, Director.
Much loss of property and even life, according to Director Burgess, results from brands from burning buildings falling upon nearby structures.
Dr. Burgess hopes to help eliminate this danger through the construction of fire-proof roofs and in addition it is hoped that the study will develop facts of interest regarding the tendency of the burning roofing materials to produce flaming brands. In his opinion a good material combines a reasonable fire rcsistence with only a slight tendency to produce sparks after the material is ignited.
According to the Bureau of Standards the work has made necessary the designing of some interesting equipment, as shown in sketch herewith. In the spread tests of section of the roof about 3 feet wide by 12 feet long is built up in the usual way, and is mounted on a sloping frame work giving the test “deck,” as it is called the position it would occupy on an ordinary house. The lower end of the deck is in front of an air duct which communicates with an electrically driven blower. Wind speeds of anv desired velocity can he produced. Equipment is also provided for raising the temperature of the air as high as 300 degrees F. to stimulate the conditions existing near a burning
building’ or area in a conflagration. This heated air is blown over the deck for a certain length of time, after which the roofing material is ignited at the lower end. The progress of the tire up the sloping deck is then recorded and close watch is kept on the number, size, and condition of the brands produced.