MASONRY 



305 



being discolored or disintegrated to such an extent as to require 

 repairs: 



Life of Stone 

 Name of Stone Years 



Coarse brownstone 5 to 15 



Compact brownstone 100 to 200 



Limestone 20 to 40 



Granite 75 to 200 



Marble. . . 40 to 200 



BRICK 



Size and Weight. The dimensions of bricks vary consider- 

 ably. The standard adopted by the National Brickmakers" 

 Association is, for common clay brick, 8i in.X4 in.X2J in., 

 and for face or pressed brick (clay) 8i in. X4| in. X2J in. The 

 weight of a common clay brick is about 4| lb.; that of a 

 pressed-clay, enameled brick, about 7 lb. Enameled and 

 glazed bricks are made in two sizes: English size, 9 in. X3 in. 

 X4 in.; American size, 8| in.X2J in.X4| in. The usual 

 dimensions for firebricks are 9 in. X4J in.X2j in.; various 

 sizes and forms are made to suit the required work. The 

 dimensions of the lime-sand bricks are 8| in.X4J in. X2| in. 

 The weight varies between 5 and 6 lb. 



WEIGHT AND STRENGTH OF BRICK 



The accompanying table gives the approximate weight and 

 resistance to crushing of brick. 



