VITRIFIED BRICK AS MATERIAL FOR COUNTRY ROADS. 33 
17. The time of the beginning and ending of each test, and the number of revolutions 
made by the barrel during the test as shown by the indicator, 
18. Certificate of the operator as to number of stops and starts made in each test. 
19. The initial collective weight of the ten bricks composing the charge and their 
collective weight after rattling. 
20. The loss calculated in percents of the initial weight ; and the calculation itself. 
21. The number of broken bricks and remarks upon the portions which were included 
in the final weighing. 
22. General remarks upon the test and any irregularities occurring in its execution . 
23. The date upon which th? test was made. 
24. The location of the rattler and name of the owner. 
25. The certificate of the operator that the test was made under the specifications of 
the American Society for Testing Materials and that the record is a true record. 
26 . The signature of the operator or person responsible for the test . 
27. The serial number of the test. 
In event of more than one copy of the record of any test being required, they may be 
furnished on separate sheets, and marked duplicates, but The original record shall 
always be preserved intact and complete. 
ACCEPTANCE AND REJECTION" OF MATERIAL. 
Item 15. Basis of acceptance or rejection. — Paving bricks shall not be judged for 
acceptance or rejection by the results of individual tests, but by the average of no less 
than five tests. Where a lot of bricks fail to meet the required average, it shall be 
optional with the buyer whether the bricks shall be definitely rejected or whether 
they may be regraded and a portion selected for further test as provided in Item 16. 
Item 16. Range of fluctuation. — -Some fluctuation in the results of the rattler test, 
both on account of variation in the bricks and in the machine used in testing, are 
unavoidable and a reasonable allowance for such fluctuations should be made, wherever 
the standard may be fixed. 
In any lot of paving brick, if the loss on a test computed upon its initial weight 
exceeds the standard loss by more than 2 per cent, then the portion of the lot repre- 
sented by that test shall at once be resampled and three more tests executed upon it. 
and if any of these three tests shall again exceed by more than 2 per cent the required 
standard, then that portion of the lot shall be rejected. 
If in any lot of brick two or more tests exceed the permissible maximum, then the 
buyer may at his option reject the entire lot. even though the average of all the tests 
executed may be within the required limits. 
Item 17. Fixing of standards— The percentage of loss which may be taken as the 
standard will not be fixed in these regulations, and shall remain within the province 
of the contracting parties. For the information of the public, the following scale 
of average losses is given, representing what may be expected of tests executed under 
the foregoing specifications. 
General 
average 
loss. 
Maximum 
permissible 
loss. 
] Percent. 
For bricks suitable for heavy Traffic 22 
For bricks suitable for medium traffic 24 
For bricks suitable for light Traffic i 16 
Per cent. 
24 
26 
2S 
Which of these grades should be specified in any given district and for any given 
purpose is a matter wholly within the province of the buyer, and should be governed 
by the kind and amount of traffic to be earned, and the quality of paving bricks 
available. 
