THE INDIA RUBBER WORLD 



[January 1, 1920. 



War Department Specifications for Mechanical Rubber Goods. 



General Specifications for Mechanical Rubber Goods. 



War Department Speoifloation No. 333-1-1— Juno 6. 1919. 



THESE SPECIFICAT10N.S covcr mechanical rubber goods used by 

 the War Department. The following arc details of such 

 specifications and tests as are common to the articles. For 

 specific information applying directly to particular articles, see 

 detailed specifications which shall take precedence whenever there 

 is any conflict. 



CONSTEUCTION. 



To be manufactured from the best material designated, free 

 from any and all imperfections and of dimensions as given in 

 the detailed 5pecifications or proposal submitted to manufacturer. 



(a) Hose. — Rubber hose shall consist of a rubber tube, cotton 

 reinforcements, and a rubber cover, and shall be of vi^rapped 

 construction unless otherwise specified in detailed specifications. 



Tube and cover of wrapped hose shall be smooth, free from 

 pitting and imperfections, and of uniform thickness. All cotton 

 canvas layers shall be applied on the bias, with edges lapped at 

 least ;4-inch (not sewed), and be well impregnated with a com- 

 position to comply with the detailed specifications. 



Plies of braided hose shall be evenly braided and imbedded 

 in a properly vulcanized rubber, compound best adapted to meet 

 (he requirements. 



(6) Couplings.— Each length of hose shall be properly fitted 

 with couplings and clamps without the use of tape or rubber 

 tissue if, and as required in the original proposal, they shall be 

 supplied by the War Department or as otherwise specified. The 

 female coupling shall be properly fitted with a rubber washer 

 supplied by the hose manufacturer, cut from a rubber lube of 

 the same composition as the hose tube, unless otherwise specified. 



(c) Belting. — Rubber and balata belting shall be made of 

 cotton duck, properly impregnated according to standard manu- 

 facturing practice, and be of the number of plies and width 

 specified. 



(d) Packing.— Rubber packing shall have comparatively 

 .smooth surfaces, be free from pitting, and of uniform thickness. 

 Al! rubber packing to be furnished in rolls weighing approxi- 

 mately 125 pounds. 



(f) Molded and Lathe-Cut Goods.— All molded goods shall 

 be of dimensions specified, free from surface imperfections, air 

 checks, and pits. 



BRANDING. 



All branding and stenciling shall contain the words "U. S. A., 



..._. " (blank to be filled in with such words as may be 



designated in the detailed specifications), manufacturer's name, 

 and date. 



(a) Hose. — All wrapped hose 25 feet or over in length shall 

 have red (unless otherwise specified) brands inlaid in the rubber 

 cover at two places on each length, appro.ximately four feet from 

 the ends, letters to be at least Krinch high; hose less than 25 

 feet in length shall have one inlaid brand approximately in the 

 center, unless otherwise specified. 



■(b) Belting — On the seam side of all belting over 4 inches 

 in width, brands shall be inlaid in red rubber at least every 30 

 feet in letters at least J^<|-inch high. For belting 4 inches and 

 under, the same words shall be stenciled in letters 1 inch high. 

 All balata belting shall be branded with stencil only. 



(c) Packing. — All packing shall be stenciled in letters at 

 least 1 inch high every fifteen feet for rolled packing and at least 

 once on each sheet of asbestos compressed packing. 



(rf) Molded and Lathe-Cut Goods. — Molded and lathe-cut 

 goods shall be branded as in detailed specifications. 



ICATERIALS. 



(a) Cotton Reinforcements : 



Wrapped Hose, Belting, and Packing. — The cotton fabric 

 layers shall be w^ell, evenly, and firmly woven from good cotton, 

 as free from unsightly defects, dirt, knots, lumps and irregularities 

 of twist as is consistent with the best manufacturing practice 

 and conform to requirements of detailed specifications. 



Braided Hose. — Cotton braided layers shall be of such nature 

 as to meet tests specified. 



(h) Ruhder: 



Rubber compounds shall in all cases be properly vulcanized 

 and meet the requirements as specified. 



When fine Para is specified it is understood to include only 

 such grades of plantation Hcvca rubber, as by virtue of their 

 physical and chemical characteristics, are practically equivalent 

 to fine para in its performance. 



Where sulphur limits are specified, mineral fillers may con- 

 tain barytes, but shall be practically free from sulphur in other 



forms and from any substances lending to have a deleterious 

 ettect on the finished product. The sulphur in barytes shall not 

 be nicluded ni the allowable sulphur content. 



All percentages shall be based upon the weight of total rubber 

 compound. 



INSPECTION AND REHEARING. 



Inspection and tests shall be made at place of manufacture 

 unless otherwise specified, manufacturer providing a place for 

 conducting test ; also necessary help, gages, equipment etc. In 

 case It IS not practicable to obtain suitable test specii^ens the 

 manufacturer shall furnish pieces M by V/. by 8 inches which 

 he guarantees to be of the same material and equivalent cure 

 as that used in article furnished. 



Inspector shall, after tests, mark the remainder of samples 

 with manufacturer s name, order, requisition, and item numbers 

 and forward them to the properly designated organization for 

 any further tests. Any lot which in any one or more tests 

 proves unsatisfactory shall be retested by taking two additional 

 samples which shall be at the expense of the contractor. Failure 

 of either in any respect shall be cause for rejection 



No rehearing may be had on any rejected material unless by 

 authority of the proper organization. 



(a) Hose.— Inspector may select three lengths at random 

 trorn each and every shipment of 5,000 feet or less. A 3-foot 

 section shall be cut from each length so selected for burst, after 

 which further physical tests shall be made on the same sample, 

 unless otherwise specified. Manufacturer shall refit couplings 

 to said lengths which shall be accepted as full lengths provided 



hey conform to specifications. When hose is furnished in 

 lengths under 10 feet, extra lengths shall be furnished for test 

 purposes at contractor's expense. 



(b) Belting.- Inspector may take a test sample 12 inches 

 long from any part of each roll of belting, 4 inches and under 

 in width ; 4 inches long from belting over 4 inches in width. 



, , A ■ PACKING.- Inspector may select at random one test sam- 

 ple 10 inches long, cut across the full width of roll or sheet from 

 every lot of approximately 250 pounds. 



(rf) Molded and Lathe-Cut Goods.— Inspector may select 

 at random one piece out of every 20O or less for tests. 



TESTS. 



All tests on material as a whole and on individual parts shall 

 be performed according to methods adopted by the National 

 Bureau of Standards as outlined in their circular No. 38, "Test- 

 ing of Rubber Goods," in effect at date of opening of proposal. 



Hydrostatic and tensile tests shall be in pounds per square 

 inch. All samples which are subjected to a steam, oil, or aging 

 test shall rest 24 hours before test specimens are cut. 



(n) Fabric— The tensile strength shall be obtained by cut- 

 ting strips from fabric 6 inches long, l;4 inches wide and un- 

 raveled from each side to a width of 1 inch. Jaws of testing 

 machine shall be more than 1 inch wide and 3 inches apart, sepa- 

 rating at the rale of 12 inches per minute. Results obtained by 

 taking the average of three tests each on both warp and filling 

 sha 1 be accepted as the tensile strength of the fabric. The tests 

 shall be made when practicable after conditioning the fabric in 

 an atmosphere having a relative humidity of 65 per cent and a 

 temperature of 70 degrees F. for two hours. When not prac- 

 ticable to test as above, the fabric may be tested under existing 

 humidity conditions and results corrected to a 6 per cent moisture 

 basis by multiplying by the following factor: 



100 



100 plus 7 X (per cent moisture — 6) 



Note.— The factor will be less than unity when the per cent 

 moisture is greater than six and vice versa. 



Moisture shall be determined bv weighing six samples together 

 before testing, and tensile strength immediately obtained in rapid 

 succession. The broken samples (entire) after rupture shall be 

 P'aced in a venlilated drying oven at 105 to 110 degrees C. (221 

 to 230 degrees F.) until weight is constant. Moisture present 

 shall be calculated on this basis of the bone dry sample. 



All fabric weights are given in ounces per square yard and 

 shall be calculated on a 6 per cent moisture basis. Tolerance 3 

 per cent plus or minus. 



(b) Hydrostatic Tests.— To insure proper attachment of 

 couplings when furnished with hose, pressure shall be held for 

 three minutes on each length of hose ; piece under test must not 

 leak, sweat nor rupture the cotton canvas layers. 



Bursting tests shall be made on samples 3 feet long, pressure 

 being raised at rate of 300 pounds per minute. 



