322 



THE INDIA RUBBER WORLD 



tJUNE 1, 1911. 



Fire Hose — Criticism and Suggestion. 



FROM a report of the Committee on Fire Hose delivered 

 at the annual meeting of the National Fire Protection 

 Association at the Waldorf-Astoria (New York), May 23, 

 1911. Snhmitted by W. C. Robinson, chairman of Hose Com- 

 mittee. 



Fire hose is one of the most important factors entering into 

 the problem of protection against loss by fire. It fnrnisbes tlic 

 most common means by which water is utilized in fire extinguish- 

 ment by the trained men of our fire departments. The water 

 works system, the fire department and the lire liose must operate 

 together and each play its full part at time of fire, for the failure 

 of any one at a critical time will destroy the efficiency of the 

 others and a disastrous conflagration may result. 



Fire hose may be considered as the flcxilile end of the water 

 works system and this very quality necessitates that it be made 

 of materials less durable and less reliable than the materials 

 employed in the construction of the more permanent part of the 

 water supply system. 



Fire hose is subjected to a severe class of service, the great 

 importance of which makes it essential that the utmost care be 

 given to the quality of the materials and to the character of the 

 workmanship employed in its manufacture, and yet, this is rarely 

 the case, for fire hose is the one item regarding which but little 

 is known by those who should be thoroughly well informed. 



There has always been more or less of a mystery regarding the 

 make up of fire hose and this has been fostered by those engaged 

 in its manufacture. Very few buyers or users have had sutlicient 

 technical knowledge of the ingredients used or of their assemblc- 

 ment to enable them to prepare specifications sufficiently well 

 balanced to insure the receipt of fire hose of the quality desired. 

 Mimicipal authorities and fire departments have been obliged to 

 accept the statements of the manufacturers or their sales agents 

 and to purchase fire hose without any real information as to the 

 quality of the goods paid for. 



This has led to the establishment of tlie present almost universal 

 practice of selling fire hose under "trade names" or "brands" 

 which arc suposed to indicate, and in many cases undoubtedly 

 have indicated the quality of the materials supplied. In conse- 

 quence, where the better qualities of fire hose have in the past 

 been secured, a very strong inclination is found on the part of 

 fire departments to continue to buy the particular brand, which, 

 in their opinion, has given good service. This is natural, and 

 so long as the trade name represented the high quality of 

 materials which was responsible for its good reputation, no danger 

 existed, although the city is thus placing itself in a position where 

 competition is limited. 



Formerly the better grades of rubber were practically the only 

 grades employed in fire hose for which any real contention cover- 

 ing quality was made. In fact, the only raw rubber available 

 was of a high grade. Conditions arc now very materially changed 

 and crude rubbers of various grades have come into general use 

 and processes have been developed for reclaiming rubber and 

 admi.xing different grades for various purposes. This has re- 

 sulted in the substitution of inferior rubbers in fire hose which 

 has seriously affected its quality and reliability. 



Another important factor wdiich has undoubtedly influenced the 

 quality of fire hose is the greatly increased demand for the best 

 grades of rubber in other products, as, for instance, the inner 

 tubes of automobile tires. 



Under the present system of selling hose and with the pur- 

 chaser in ignorance of proper requirements or means to enforce 

 them, the temptation to use the cheaper and inferior raw gums 

 and shoddy is obvious. 



Tests of Hose From the Field. 



A careful investigation covering most of the better known 

 brands now being sold, furnishes undisputable evidence that the 

 quality of fire hose, even of brands enjoying the best reputation, 

 is inferior and the trend downward. 



•The results of extended tests and examinations of twenty- 

 eight different brands of cotton rubber lined fire hose, including 

 thirty-three different samples received from fire departments in 

 practically all sections of the country, show important deficiencies 

 in all, and clearly indicate that something should be done which 

 will enable municipalities to equip their fire departments with a 

 thoroughly reliable fire hose and afford owners and occupants of 

 private properties some sure means of securing hose of the 

 proper quality. 



Rubber Lining. 



The most eonnnon as well as the most important defect brought 

 out in the investigation relates to the rubber linings employed, 

 l^xtended analyses show that the percentage of gum used varies 

 from about twenty-six (26) to fifty-two per cent, and that low 

 grade gums are almost invariably used. In only a very few cases 

 could any claim for high grade rubber have been justified and 

 these did not meet rei|uirenients which woulil constitute a reason- 

 able niininium for rubber used in fire hose. Compmnids which 

 contain pure gum even of a liigh grade are often rendered in- 

 ferior by the admixture of reclaimed rubber or shoddy and min- 

 eral oils or by the use of too little gum in the mixture. 



The following summary of the results of the chemical and 

 physical analysis of a total of thirty-two samples will serve to in- 

 dicate the general quality of the rubber lining used in the hose 

 tested: 



Seventeen linings classify as very inferior grade. 

 Twelve linings classify as low grade. 

 One lining classifies as medium grade. 

 Two linings classify as fair grade. 

 One lining classifies as high grade. 



Average tensile strength, all samples 736.8 pounds 



Highest average tensile strength for any hose 1,368 pounds 



Lowest average tensile strength for any hose 199.5 pounds 



.Average elongation at breaking point for all samples 8.02 inches 

 Highest average elongation at the breaking point.. 11.9 inches 

 Lowest average elongation at the breaking point. ... 4.2 inches 



In only 12 cases could the samples be stretched to four and 

 one-half (Ayz) times their original length without rupture and 

 in only one of these was the recovery within the limits specified, 

 ten minutes after release, notwithstanding the moderate test con- 

 ditions. 



The averages for all hose given above were obtained from over 

 130 test samples and the averages for individual hose from four 

 samples, the test pieces being cut longitudinally from the tubes 

 in all cases. 



As rubber analysis is complicated and difficult the precaution 

 was taken to have the results verified by an independent rubber 

 chemist of standing. No important variations were found in the 

 analyses. 



High grade hose linings possessing the requisite aging qualities, 

 strength and elasticity require a fine grade of raw rubber, fairly 

 free from foreign matter, properly vulcanized with suitable mineral 

 filler. Compounds containing 40 per cent of fine Para rulilier 

 have been found to possess these qualifications. 



Pure fine Para gum remains today as in the past, the stand- 

 ard of quality. The fact that high grade compounds can be 

 made from it is beyond question. In order, therefore, to secure 

 a high grade hose lining of known quality and value, the safe 

 course is to see to it that this grade of rubber is used in its , 

 manufacture. It should be remembered that the quality of the 

 ruliber lining exerts the greatest influence on the life or lasting 

 property of fire hose. 



Cotton Fabric. 



The defects found in the cotton fabric used in the hose tested ' 

 while important in many instances were generally of secondary 

 importance compared with those relating to tlie rubber portion 

 of the hose. Wide variation was noted in the degree of excel- 

 lence in weaving as well as in the character of the finished prod- 

 uct. Very little, if any, staple cotton could be identified, that 

 most commonly employed being considerably less than one inch 

 in length. There was also evidence of material difference in the 

 grade of the cotton used. 



A difference amounting to nearly 80 per cent is noted between 

 the weights of the tinislied fabric of double-jacketed fire hose, 

 based on the difference between the weights of fifty feet of 

 finished hose without couplings and the weights of fifty feet of lin- 

 ing and backing, estimated from the weights of short sections. 



A wide variation was noted in the strength of the fabric as evi- 

 denced by the results obtained in the hydrostatic bursting tests of 

 three-foot sections lying straight, some of the lighter fabrics 

 showing an ultimate strength several hundred pounds higher 

 than others in which more material was used and which showed 

 no apparent defects. 



