78 BULLETIN 1216, U. S. DEPARTMENT OF AGRICULTURE. 
FLOAT TEST OF RESIDUE. 
17. The float test of the residue shall be made in accordance 
with the "Float test for bituminous road materials." 
METHODS OF SAMPLING AND TESTING DRAIN TILE 
AND CULVERT PIPE. 
METHODS FOR TEST OF DRAIN TILE, CLAY CULVERT 
PIPE, AND CEMENT-CONCRETE CULVERT PIPE, PLAIN 
OR REINFORCED. 
(Methods from A. S. T. M. standard specifications, serial designations C 
14-20 and C 4-21, slightly modified.) 
1. Tbe physical tests of tile and pipes shall include: ('rushing 
test, absorption test, and freezing and thawing tests, at option 
of tbe purchaser. 
2. The specimens to be tested shall be selected by the pur- 
cbaser or his representative at the point or points designated by 
him when placing the order. The manufacturer or seller shall 
furnish specimens for testing, without separate charge. 
3. Failure of the specimens to meet the requirements of any 
of the tests imposed shall result in rejection of all the pipe in 
the shipment or delivery corresponding to the sizes thus fail- 
ing to comply, except that in the event the specimens in any size 
fail to meet the requirements the manufacturer or seller may, 
with the consent of the consumer or purchaser, furnish for test- 
ing additional specimens from the same shipment without 
charge. 
4. The specimens of pipes shall be sound, full-sized pipe. They 
shall first be freed from all visible moisture. When dry each 
specimen shall be weighed, measured, and inspected. The results 
of these observations shall be recorded and preserved. 
5. Specimens which, when placed in a vertical position, do not 
give a metallic ring when struck with a hammer, or are observed 
to have cracks or other defects in form or dimensions in excess of 
the limits permitted in the specifications, shall be discarded and 
replaced with additional specimens from the shipment. 
(A ) Crushing Test. 
Crushing test. 6. ( a ) Any prime mover or hand power which will apply the 
load at a uniform rate of about 2.000 pounds per minute, or 
in increments of not more than 100 pounds at iiie same rate, may 
be used in making the test. 
(h) The pipe shall noi be allowed to stand under load longer 
than is required to apply the load and to observe and record it. 
(c) The testing machine shall be substantial and rigid through- 
out, so that the distribution of the load will not be affected ap- 
preciably by the deformation or yielding of any part. 
(d) The bearings and the specimen shall be accurately cen- 
tered so as to secure a symmetrical distribution of the loading 
on each side of the center of the pipe in every direction. 
(e) The load shall be applied until the pipe yields by cracks 
passing through the shell. 
7. Except as otherwise hereinafter specified, the pipe to be 
tested shall be supported by a metallic knife bearing 1 inch wide 
and extending from a point just back of the socket to the spigot 
end of the pipe. Before the pipe is placed, a fillet of plaster of 
Paris and sand 1 inch wide, and thick enough to compensate 
for all the inequalities of the pipe barrel, shall be cast on the sur- 
face of the knife bearing. The pipe shall be placed upon the 
fillet while the plaster of Paris is still somewhat plastic. The 
load shall be applied through an upper knife bearing of tbe 
same size and length as the lower bearing. A plaster of Paris 
fillet 1 inch wide shall be cast along the length of the crown of 
