52 
BULLETIN 1216, V. S. DEPARTMENT OF AGRICULTURE. 
Flash cup. 
Thermometer. 
TEST FOR FLASH AND FIRE POINTS BY MEANS OF 
OPEN CUP. 
(A. S. T. M. tentative method, serial designation D 92-21 T, slightly 
modified. 
1. (a) The open-cup flash shall he determined in the Clove- 
land open cup, or by method 2 (6). 
(&) The method used shall be stated In the report of the test. 
APPARATUS. 
2. (a) The flash cup proper shall be made of brass and shall 
have the following dimensions: 
Dimensions. 
Tolerances. 
Dimensions. 
Tolerances. 
Inches. 
2H 
2H 
1* 
k 
Inches. 
±A 
±A 
±A 
±h 
Centimt/i r». 
6.350 
6. 826 
3.334 
.318 
.9.53 
Centimeter*. 
±0.079 
± .079 
± .079 
± .040 
± .040 
Thickness of bottom 
Depth of filling mark be- 
low top of cup 
The cup shall he heated by contact with a metal plate one- 
quarter inch (0.635 centimeter) thick and 6 inches (15.24 centi- 
meter) wide. (The plate may be of any suitable metal and may 
be either circular or square.) In the center of the plate there 
shall be a plane depression one-thirty-second inch (0.079 centi- 
meter) deep and of diameter just sufficient to fit the cup. The 
plate shall be covered with a sheet of hard asbestos board one- 
quarter inch (0.635 centimeter) thick 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. The metal plate may 
be heated in any convenient manner. The use of a gas burner, 
electric heater, or alcohol lamp is permitted. If a flame heater 
is u*ed, 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. 
(b) The cup proper shall be a 3-ounce gill type can 55 milli- 
meters in diameter and 35 millimeters in depth. The can shall 
be heated in a sand bath of a diameter approximately twice that 
of the can. The sand shall be about one-quarter inch deep beneath 
the can and an additional amount of sand shall be spread around 
the can, so as to surround it to a depth of* one-half inch. 
3. The thermometer shall conform to the following specifica- 
tions: 
Type : Etched-stem glass. 
Total length: 305 millimeters. 
Stem: Plain front, enamel back, suitable thermometer tubing. 
Diameter, 6 to 7 millimeters. 
Bulb: Corning Normal, Jena 16 III, or equally suitable thermo- 
metric glass. Length, 13 millimeters maximum. Diameter, nol 
greater than stem. 
Actuating liquid : Mercury. 
Range: 2<>° to 760° F. 
Immersion: 1 inch. The words "1 in. immersion" shall be 
etched on the stem and also a line around the stem to indicate 
the depth of immersion. 
Distance to no line from bottom of bull) : 40 to 50 millimeters. 
Distance to Too line from top of stem: 30 to 45 millimeters. 
Filled : Nitrogen gas. 
Top finish: Red glass ring. 
Graduation: All lines, figures, and letters clear-cut and dis- 
tinct. Scale graduated in 5° divisions. Scale numbered every 20°, 
the first and each succeeding 10° F. line to be longer than the 
others. 
