36 BULLETIN 246, U. S. DEPARTMENT OF AGRICULTURE. 



17. The initial collective weight of the 10 brick composing the charge and 

 their collective weight after rattling. 



18. The loss calculated in per cents of the initial weight ; and the calculation 

 itself. 



19. The number of broken brick and remarks upon the portions which were 

 included in the final weighing. 



20. General remarks upon the test and any irregularities occurring in its 

 execution. 



21. The date upon which the test was made. 



22. The location of the rattler and name of the owner. 



23. The certificate of the operator that the test was made under the specifica- 

 tions of the American Society for Testing Materials and that the record is a 

 true record. 



24. The signature of the operator or person responsible for the test. 



25. 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 brick shall not be judged 

 for acceptance or rejection by the results of individual tests, but by the average 

 of not less than five tests. Where a lot of brick fails to meet the required 

 average it shall be optional with the buyer whether the brick 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 brick 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 represented 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: 



( leneral 



average 



loss. 



Maximum 



permissible 

 loss. 



For brick suitable for heavy traffic. . . 

 For brick suitable for medium traffic. 

 For brick suitable for light traffic 



Per cent. 

 22 

 24 

 26 



Percent. 



24 

 26 

 28 



