This review of ASTM Test for Surface Burning Characteristics of Building Materials (E 84) is intended to provide a source document on the 25-ft tunnel test method as well as to provide a basis for its evaluation by ASTM Subcommittee E05.32 on Research. It covers the history of ASTM E 84 including its development and acceptance by the regulatory authorities. It describes the test method as it exists today and the current operational and calculational procedures. It discusses the work of the tunnel operator's task group in continually reviewing the method, conducting research, and proposing revisions for consideration for adoption by ASTM Committee E-5 on Fire Standards. The effect of air velocity, burner gas flow, and other variables on the results of the test and the reproducibility between testing laboratories is discussed. The correlation of the results of the tunnel tests with those of room and corner tests is presented. The present state of the analysis of the tunnel is described. The efforts to determine the total quantity of smoke produced during the test by improving the photometer system, eliminating stratification, and changing the calculational procedures are discussed. The oxygen consumption method for determining the total heat contribution is described. The benefit of reporting the rate of flame spread as well as the flame spread index (FSI) is pointed out. The advantages and disadvantages are discussed. A list of ASTM E 84 test facilities along with the person to contact is provided. A comprehensive bibliography of the tunnel is included.