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FIRE TESTS OF SOME NEW YORK BUILDING STONES 



To determine the durability and desirability of the various 

 building stones they are subjected to a number of artificial tests. 

 The agents at work tending to destroy the building stone are 

 the crushing and shearing forces caused by its position in a struc- 

 ture, the chemical action of gases and moisture in the atmosphere, 

 and the physical agencies due to changes of temperature. The 

 determinations sought in the laboratory of the effects of these 

 various agencies are by tests for: crushing and transverse strength, 

 permanence of color, specific gravity and weight per cubic foot, 

 porosity and percentage of absorption, effect of alternate freezing 

 and thawing, effect of the action of gases, as CO2 and SO3, effect 

 of alternate expansion and contraction and effect of extreme heat. 



It is our purpose to discuss the relative effect of extreme heat on 

 a series of typical New York building stones. This phase of 

 testing building stones has been heretofore more or less over- 

 looked, yet its importance is evident so long as building construc- 

 tion in centers of population is largely dependent on these mater- 

 ials. A knowledge of the relative effect of extreme heat on the 

 various stones employed for building purposes is of value in deter- 

 mining the kind of stone to be used in constructions and locations 

 exposed to the chance of conflagration. 



PREVIOUS INVESTIGATIONS OF THE REFRACTORINESS OF BUILDING STONES 



The first investigator to carry on any series of tests to ascertain 

 the relative capacity of the various building stones to resist the 

 action of extreme heat was Cutting, who performed some experi- 

 ments for the Weekly Underwriter in order that insurance rates 

 might be more properly adjusted. He estimated the relative 

 rank of different stones in their capacity to withstand the action 

 of extreme heat as, from highest to lowest, marble, limestone, 

 sandstone, granite and conglomerate. 



Cutting! states: 



As to granites ... a heat sufficient to melt lead is suffi- 

 cient to injure granite walls beyond the capability of repair, other- 

 wise than by taking down, and it is almost, if not quite, impossible 

 to burn out a granite building of small size, even, without injuring 

 the walls. 



Sandstones stand fire much better than granite. They stand 

 uninjured a degree of heat that would destroy granite. 



1 Weekly Underwriter. 1880. 23:42. 



