g2 FIRE-RESISTING BUILDINGS. 



Strips of pine, covered both sides with ^s" asbestos boards, and 

 each side tinisiied with 3 1^,1 " of oak veneer. Fire at a tempera- 

 ture of 1,500° F. did not pass through in 60 minutes. 



1/3" sohd door, core of two thicknesses }i" pine, covered 

 both sides with 26 B W G tinned steel sheets. Flame appeared 

 outside in 12 minutes. 



2^" door, core three thicknesses of Js" pine, covered as 

 last. Flame appeared in 30 minutes. 



2 1,4" door, core two thicknesses of Ji" pine, covered both 

 sides, with Xs" asbestos boards, and 26 B W G tinned steel sheet- 

 ing. Flame appeared in 70 minutes. 



HoUozu Metallic Doors. — i ik " thick, with two ik " panels, 

 all of 20 B W G tinned steel |:)lates, with hollow between, fitted 

 with two Vs" thickness of sheet asbestos with layer of impreg- 

 nated felt between them as non-conductor. 



Fire at a temperature of 1,570° F. did not ]:)ass through in 

 120 minutes. 



Xoii-I'laminablc Wood Doors. — lyi^' solid deal. Fire at a 

 temperature of 1,680*" F. did not penetrate in 60 minutes. 



Solid Iron Door.—y^ thick plate all over with 3" X >4" 

 stiles, and three rails of 3" X li'' ii'on, screwed to the plate. 



Through Ijuckling, the fire passed through open si)aces at 

 the top and bottom in 19 minutes. 



Concrete Doors. — 2" tliick. with casing of 20 B W G steel 

 plates, stift'ened and reinforced by vertical steel bars, at 8"" 

 centres, with ^" cross bars to stiffen same. 



The space between casing filled with concrete composed of 

 innnice to pass I/2" ring, 48 })arts : sand 16 parts: and Port- 

 land cement 15 parts. 



Fire at a temperature of 1,800° F. did not pass through in 

 240 minutes. 



Shutter doors. — Rolling shutters, constructed with inter- 

 locking strips or slats of steel, have proved eft"ective checks to 

 fire, especially when placed on both sides of a wall. Being thin, 

 however, the one directly exposed soon gets red hot. If pro- 

 perly fitted, with properly protected gear boxes, they have with- 

 stood a 4 hours' exposure to a temperature of 1,800° F., and 

 even then the outer shutter could be raised and lowered. 



Jl'lndozcs require the most careful treatment, for if air can 

 be excluded from a room, fire is naturally extinguished. 

 If the glass of windows or skylights is broken by 

 heat or water-jet, a fire raging inside a building would 

 be intensified, and the flames would burst out and attack 

 other windows across courts or areas. Wired glass has 

 withstood severe tests, and can be considered a reliable 

 material for the passage of light and resistance to fire if pro- 

 perl v mounted, but the danger still remains in the frames or 

 sashes that hold the glazing. Electro-glazing, wherein bars of 

 metal and small squares of specially-prepared glass are electri- 

 callv fused into one homogenous slali, is the best known material,. 



