70 DEPARTMENT BULLETIN 1216, IT. S. DEPT. OF AGRICULTURE 
48. METHOD OF TEST FOR FLASH AND FIRE POINTS BY 
MEANS OF OPEN CUP 
(A. S. T. M. standard method <)), serial designation D 92-24. except as indicated. 
See p. 1) 
1. The open cup flash and fire test on all products except fuel oils and those 
having an open cup flash below [175° F.] 158° F. shall be determined in the 
Cleveland open cup, or by method 2 (b). 
(b) The method used shall be stated in the report of the test. 
APPARATUS 
2. The cup shall be supported by a metal plate one-fourth inch (0.635 centi- 
meter) in thickness and 6 inches (15.24 centimeters) in width. The plate shall 
F- 
(Asbestos Disk 
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1 
Plate--' 
Fig. 26.— Heatim 
plat. 
be of brass, cast iron, wrought iron, or steel. In the center of the plate there 
shall be a plane depression one-thirty-second inch (0.079 centimeter) in depth. 
and of just sufficient diameter to fit the cup. There shall be a circular opening 2-h 
inches (5.50 centimeters) in diameter, cut through the plate, centering with the 
center of the above-mentioned depression. The plate shall be covered with a 
sheet of hard asbestos board one-fourth inch in thickness, and of the same 
shape as the metal plate. There shall be cut in the center of the asbestos board 
a circular hole just fitting the cup. Heat may be supplied from any convenient 
source. The use of a gas burner, electric heater, or alcohol lamp is permitted 
but under no circumstances are products of combustion or free flame allowed to 
come up around the cup. The source of heat shall be centered under the open- 
ing in the plate and shall be of a type that will not produce local superheating. 
If a flame heater is used, it may be protected from drafts or excessive radiation 
by any suitable type of shield that does not project above the level of the upper 
surface of the asbestos board. 
