FIRE-RESISTING MATERIALS IN BUILDING 



CONSTRUCTION. 



By Arthur Henry Reid. F.RT.B.A., F.R.SanT., F.R.S.A. 



The increasing congestion of habitations in towns renders 

 the study of materials used in building construction one of vital 

 interest to the community. The following notes, though 

 gathered into a small compass, are the results of investigations 

 made during the past decade, and in this record I have en- 

 deavoured to combine some indication of underlying principles 

 with suggestions regarding problems that still await solution. 

 Further research may yet discover materials that are suitable for 

 the purposes of insulation and protection, which may combine 

 easy mani])ulation with moderation in cost. The knowdedge we 

 possess is not altogether satisfactory in many respects, and the 

 subject is one worthy of our widest and most careful considera- 

 tion. 



The author, in submitting this paper, wishes it to be under- 

 stood that its scope is confined to " Materials " only, and is not 

 intended to cover the constructional features of fire resisting 

 buildings. It may be fairly claimed that no construction is 

 absolutely fireproof, and that even iron and masonry, in their 

 crude form, could with propriety be designated as " slow burn- 

 ing." Steel has, in the process of manufacture, been smelted 

 in a furnace which produced little greater heat than would some 

 of our modern buildings with their contents when in a state 

 of full combustion. It is, therefore, necessary to cover and 

 protect steel units with non-combustible and non-conducting 

 material to prevent exposure to fire and consequent expansion 

 or distortion. 



It is proposed to review the leading classes of material that 

 are used in buildings, and to enumerate the peculiarities of each 

 as well as the precautions that experience has shown to be neces- 

 sary for their protection. 



Steel. — Wrought and cast-iron may be regarded as 

 practically obsolete for structural purposes, though both have 

 the advantage, under certain circumstances, of being less liable 

 to corrosion than steel. 



Mild steel, containing a proper percentage of carbon, is 

 produced by the Bessemer and other processes. In the former 

 molten " pig " iron is blown through, the carbon and other 

 elements Ijurnt out, and then the desired proportions of carbon 

 and manganese are added. Steel is about universally used for 

 the purpose of reinforcement in fire-resisting construction, and 

 ordinary " mild " steel is preferred of an ultimate tensile 

 strength of, say, 64.000 lbs. (30 tons) per square inch. Mild 

 steel that has been rolled possesses an ultimate strength of about 

 89,000 lbs. (40 tons) per square inch, but it has been found that 



