94
3220.053
Stoehr, E.K.
Retardant 3461-1-2-3, Application No. 51C2634v
Paper
Underwriters' Laboratories, Inc. and National Slag Association
1952
July 1
1-20 + fig,foto
N
The subject of this report is concrete masonry units (blocks) nominally 8 in. wide, 8 in. high, and 16 in. long made of portland cement and expanded slag aggregates as herein described.The concrete masonry units (blocks) are intended for use in exterior and interior bearing and nonbearing walls installed by methods commonly employed in erection of walls in which concrete blocks are used.
The masonry units (blocks), when conforming to 8- by 8- by 16-in. nominal size of the following equivalent thicknesses (approximate face shell thickness): 4.13 in. (1-14/ in.), 4.78 in. (1-1/2 in.), and 5.30 in. (1-3/4 in.) will afford 2-hour (D-2), 3-hour (C-3), and 4-hour (B-4) protection, respectively, against passage of flame and dangerous transmission of heat when made of expanded slag aggregate and cement aggregate proportions described in this report.
The fire retardant performance of the concrete masonry unit having variation in equivalent thickness and weight of slag, as summarized on Fig. 18, provides the basis for the classification. The test walls retarded transmission of heat to the degree that the critical temperatures, as defined by the Standard Fire Test Specifications, were not reached during the classification periods.