Show BlOCKS WITHSTAND TEST Walls Stand Despite Intense Heat and Water CHICAGO Jan 27 The 27 The correct composition composition com corn position of ot cement blocks to give the highest fire resistant qualities is being studied at the fire tire underwriters' underwriters laboratories laboratories laboratories lab lab- oratories here at the request of or cement manufacturers Tests which have been under way I for tor some time cover many different mixtures t r of cement sand gravel and l h other materials In the t tests teste walls composed of ot several kinds of blocks have been built up In front of ot gas furnaces furnaces furnaces fur fur- naces and subjected to five hours fur of Intense heat reaching 2075 2015 degrees at the end of the period Through electrical heat recorders ce cemented cemented ce- ce with the blocks themselves and thermometers and measuring devices devices de de- de- de vices on the outside the engineers have tr traced ced the effect of ot heat changes on the various materials The walls usually usual usual- ly buckle somewhat the heat the center curving curving- in toward the fire due to the expansion of the Inner side In some of the tests after five hours of baking the red hot wall has been subjected to five minutes cooling under undera a I two-Inch two fire tire hose The sudden coolIng coolIng cooling cool- cool Ing splits the tiny gravel ravel In the outer surface of the block bushels of fine tine particles flying flying- through the air and leaving the S surface e pitted as though ls lse under J J'S a sand d blast J Despite e this treatment treatment treat treat- ment the walls have still stood The blocks withstood tood heat so Intense that the surface of the bricks surrounding the test walls turned liquid and flowed lowed down the frame work |