386 HOSE, COUPLINGS, AND FITTINGS 



"4. The cover must be of the same quality of gum as the 

 tube, and must not be less than & in. thick. 



"5. Hose is to be furnished in 22-in. lengths. Variations ex- 

 ceeding i in. in length will not be permitted. Rubber caps not less 

 than f in. nor more than | in. must be vulcanized on each end. 



"6. The inside diameter of hose must not be less than If in. 

 nor more than liV in., nor must the outside diameter exceed 2| 

 in. Hose must be smooth and regular in size throughout its 

 entire length, except at a point 2j in. from either end, where the 

 inside calendar of rubber may be increased & in. for the dis- 

 tance of J in. toward either end and then tapering to the regular 

 diameter. 



"7. Each length of hose must have vulcanized to it a badge 

 of white or red rubber. On the top of the badge the name of the 

 purchaser; on the bottom the maker's name; on the left-hand 

 end the month and year of manufacture, and on the right-hand 

 end the serial number and the letters 'M. C. B. Std.' These 

 letters and figures must be clear and distinct, not less than ^ 

 in. in height, and stand in relief not less than ^ in. so that they 

 can be removed by cutting without endangering the cover. 

 Each lot of 200 or less must bear the manufacturer's serial 

 number, commencing at 1 on the first of the year, and continu- 

 ing consecutively until the end of the year. 



"For each lot of 200, one extra hose must be furnished free of 

 cost. 



"8. Test hose will be subject to the following tests: 

 TESTS TO WHICH SAMPLES WILL BE SUBJECTED 



"Bursting Test. All hose selected for test will have a section 

 5 in. long cut from one end and the remaining 17 in. will then be 

 subjected to a hydraulic bursting pressure of 400 Ib. per sq. in. 

 for 10 min. which it must stand without failure. At a pressure 

 of 100 Ib. per sq. in. it must not expand more than \ in. in 

 diameter or change in length more than J in., nor develop any 

 small leaks or defects. 



"Friction Test. A section 1 in. long will be taken from the 

 5-in. piece previously cut off, and the quality determined by 

 suspending a 20-lb. weight to the separated end, the force being 

 applied radially, and the time of unwinding must not exceed 

 8 in. in 10 min. 



