93
3220.052
Small, A.R.
Retardant Report No. 1555
Paper
Underwriters' Laboratories, Inc. with ACI, Concrete Products Assn, and PCA
1924
May
1-100
N
Two principal objectives were considered in planning the investigation herein described, namely:a. To ascertain the effects of predetermined variables in composition, form and methods of manufacture upon the performance of hollow concrete units or assemblies of such units when subjected to fire exposure conditions; and
b. To determine the Fire Retardant Classification assignable to hollow concrete units or assemblies of such units under the procedure of the Standard Specifications for Fire Tests of Building Materials and Construction. (ASTM C-19-18, See Appendix III.)
Data obtained in fire exposure and other tests, as later described, is readily analyzed for either or both of these objectives without the necessity for tests foreign to either appearing. Consequently the following Plan of Investigation was adopted.
Panels one block thick and approximately 10 ft. wide by 11 ft. high were built into the brick lined structural steel frames provided for use with Underwriters’ Laboratories’ Furnace No. 2. (See Appendix II.) These panels were then subjected singly to standard fire exposure conditions in the manner prescribed in the Fire Test Specifications for non-load-bearing wall or partition assemblies. As mounted in the frames the panels were restrained on all four sides. The several panels were assembled of hollow concrete block or tile of known history, composition and form.
The temperatures of the furnace combustion chamber were controlled to agree with the Standard Time Temperature Curve. Representative specimens were taken from each lot of block as made (including also the materials used) and from many lots of block removed from panels after fire exposure. These specimens were subjected to various physical and other tests by the Structural Materials Laboratory of Lewis Institute.
The results of the several fire exposure tests and of the Hose Stream and Impact Tests on full size panels and of the physical and chemical tests were then analyzed and compared, leading to the conclusions hereinafter recorded.
It was concluded that coarse aggregates of other than crushed limestone, crushed slag, crushed cinders or calcareous gravel shall not be used until their performance in fire endurance and strength tests has been determined.