72 DEPARTMENT BULLETIN 1216, TJ. S. DEPT. OF AGRICULTURE 
surface of the oil shall be free from bubbles. There shall be no oil above the 
filling line or on the outside of the apparatus. 
(c) The test flame shall be approximately five thirty-seconds inch (0.397 
centimeter) in diameter. 
Note. — For purposes of comparison it is recommended that a bead of suitable light 
colored material be mounted in a convenient position so that the size of the test flame 
can be determined. The device for applying the flame may be of any suitable type but it 
is suggested that the tip be approximately one-sixteenth inch (0.159 centimeter) in 
diameter at the end and that the orifice be one thirty-second inch (0.79 centimeter) in 
diameter. If the device lor operating the test flame be mounted in such a manner as to 
permit automatic duplication of the sweep of the test flame the radius of swing shall be 
not less than 6 inches. 
id) The test flame shall be applied as the temperature read on the thermome- 
ter reaches each successive 5° F. mark. The flame shall pass in a straight line 
(or on the circumference of a circle having a radius of at least 6 inches) across 
the center of the cup and at right angles to the diameter passing through the 
thermometer. The test flame shall, while passing across the surface of the oil, 
be in the plane of the upper edge of the cup. The time for the passage of the 
test flame across the cup shall be approximately one second. 
(e) The oil shall be heated at a rate not exceeding 30° F. per minute tem- 
perature rise, till a point is reached approximately 100° F. below the probable 
flash point of the oil. Thereafter the rate of heating shall be decreased and 
for at least the last 50° F. before the flash point is reached, the rate shall be not 
less than 9° nor more than 11° F. per minute. 
5. The flash point shall be taken as the temperature read on the thermometer 
when a flash appears at any point on the surface of the oil. The true flash 
must not be confused with a bluish halo that sometimes surrounds the test flame. 
6. After determining the flash point, the heating shall be continued at the 
specified rate of 9° to 11° F. per minute, and application of the test flame shall 
be made at the specified intervals until the oil ignites and continues to burn for 
a period of at least five seconds. The method of application of the flame shall 
be the same as for flash point. The temperature read at the time of the flame 
application which causes burning for a period of five seconds or more shall be 
recorded as the fire point. 
7. The flash point and fire point tests shall be made in a room or compart- 
ment free from air drafts. The operator shall avoid breathing over the surface 
of the oil. It is desirable that the room or compartment be darkened sufficiently 
so that the flash may be readily discernible. 
49. METHOD OF TEST FOR PENETRATION OF BITU- 
MINOUS MATERIALS 
(A. S. T. M. standard method U), serial designation D 5-25, except as indicated. See 
P- 1) 
1. Penetration is defined as the consistency of a bituminous material, ex- 
pressed as the distance that a standard needle vertically penetrates a sample 
of the material under known conditions of loading, time, and temperature. 
Where the conditions of test are not specifically mentioned, the load, time, and 
temperature are understood to be 100 grams, 5 seconds, 25° C. (77° F.). respec- 
tively, and the units of penertation to indicate hundredths of a centimeter. 
APPARATUS 
2. The container for holding the material to be tested shall be a flat-bottom, 
cylindrical dish. 55 millimeters (2& inches) in diameter and 35 millimeters 
(1% inches) deep. 43 
3. The needle (fig. 27) for this test shall be made from a cylindrical 
steel rod approximately 50.8 millimeters (2 inches) long, and having a 
diameter of 1 to 1.02 millimeters. This shall be symmetrically tapered at one 
end to a cone approximately 6.35 millimeters (one-fourth inch) in height and 
whose angle shall be within the range of 8° 40' and 9° 40'. After tapering, the 
point shall be " blunted " by grinding off to a truncated cone, the smaller base 
41 This requirement is fulfilled by the American Can Co.'s Gill-syle ointment box, deep 
pattern, 3-ounce capacity. 
