FIRE-RESISTINC, l!UlLDlN(rS 93 



and is superior to wired glass, but very expensive. Wired 

 glass must be of the best material as the cheaper makes may 

 crack when exposed even to extreme sun. The cracks then 

 get dirt-laden, and admit damp to the wiring, which corrodes 

 and causes failure when an extreme test is applied. Electro- 

 glazing has the advantage of being entirely transparent, and 

 though it may crack w^hen exposed to extreme heat, the pieces 

 will be retained by the bars, and not fall out. The safest types 

 of sashes are those made of hollow metal, steel or hardwood, 

 according to circumstances, and the frames should be of the 

 same material, carefully stopped around their joints with the 

 walls, with incombustible and permanent material that will resist 

 displacement when exposed to fire or water. As a rule, it has 

 been found, when an actual conflagration occurs, that water 

 applied to hot glass causes a more dangerous disintegration of 

 the material than the fire itself, and that hard wood is less 

 afifected than metal framing. 



The results of tests upon several classes of windows have 

 been as follows : — 



Horizontal Sashes to Skylights. — >^" wired rolled glass to 

 concrete reveals sight sizes 2' o" X 2' o" withstood a maximum 

 temperature of 1,520° F. for 60 minutes. 



The same glass secured to teak frame of sight size 4' 7j^" 

 X 2' 6" withstood a maximum temperature of 1,475° F- for 30 

 minutes, but bulged 2" in the centre. 



Vertical Sashes. — 32 oz. sheet glass 3' o" X' 4' o" to teak 

 frame. Maximum temperature 1,050° F. failed in 6 minutes. 



Lead glazing in 4" squares. Maximum temperature 



1,500° F., collapsed in 7 minutes. 



J4" plate glass 3' o" X 4' o" to teak frame. Maximum 

 temperature 1,550° F., failed in 12 minutes. 



^4" wired rough-cast glass 2' 3" X -' 3" to teak, inni and 

 brick reveals maximum temperature 1,500° F., withstood for 45 

 minutes. 



%" wired rolled plate glass 4' o" X 2' 10" to teak frames 

 buckled, and let fire pass at maximum temperature of 1,600° F. 

 in 30 minutes, and at 1,715° F. the glass fused in 7 minutes. 



Electro-glazed sheets 4' X 3' with 4" X 4" prisms, teak 

 frames, at maximum temperature 900° F., bulged 2" in 12 

 minutes, and at maximum temperature 1.315° F., the glazing 

 sagged and left frames in 21 minutes. 



7 out of 324 prisms were fractured, and the teak frame 

 charred y/\ with maximum temperature of 1,520° F. in 30 

 minutes. 



Electro-glazed sheets 2' o" X 2' o" to steel frames at 

 maximum temperature 1,630° F., glass sintered, bulged J<^", 

 and solder melted, but fire did not pass in 90 minutes. 



The above tests proved that the larger sheets of glass are 

 less efifective than the smaller. It is to be hoped that tests wnll 



