Coal Tar Pitch Roofing Handbook - 1896 - Pages 42 and 43
THE fire retardant qualities of all the Barrett Specification Roofs as compared with slate, tin, iron or ready roofing are well known to practical fire underwriters.
In the roofing laid over boards it is simply a question of which will resist the action of heat the longest and thus retard fire.
Numerous comparative fire-resisting tests have been made between Tin and Standard Coal Tar Pitch, Felt, and Slag or Gravel Roofing, in the presence of representatives of boards of fire underwriters and municipal building authorities, the results always showing the boards under the slag and gravel unharmed when the same exposure to fire had ignited the wood under the tin.
- 42 -
The accompanying photographs show the result of a recent fire test between a Barrett Specification five-ply Gravel Roof and a Ready Roof
which is composed of one sheet of Tarred Felt and one sheet of burlap cemented together with a bituminous cement.
- 43 -