Testing Hose.

Testing Hose.

In dealing with the hose question, in these days when competition in that particular article runs so high, great stress is laid by manufacturers and purchasers upon the amount of pressure which any given sample of hose will resist. Some manufacturers will claim that their hose will resist a pressure of from four to seven hundred pounds. In a previous article we showed that such pressure is never applied, and consequently such resisting capacity not required. It is seldom that a pressure exceeding 100 pounds is applied to hose in actual service, and if it is made to resist 200 pounds it will do all that ordinary service will require. In the principal Fire Departments an engineer is not permitted to carry more than 100 pounds pressure without the special order of the Chief. Instead of such great resisting power at the outset,what is wanted is greater durability and lightness. Hose is frequently subjected to too much pressure in testing it, whereby its future usefulness is impaired. When hose is tested to its full capacity every fibre in it is subjected to a severe strain, and it never recovers its elasticity. It is claimed that a severe test ol this kind destroys onehalf the life of the hose, and it not unfrequently happens that hose so treated gives out very soon when put into actual service, notwithstanding it has resisted the heavy pressure of the testing operation. The fact that hose when new and fresh trom the manufacturers’ hands will resist 400 or 500 pounds, is no proof that it is durable and will stand hard service. The severe test to which it has been subjected may have been the very means of destroying its usefulness. A horse may be speeded to a 2.40 gait in a moment of excitement, but the strain thus put upon him may ruin him forever. We all know that a boot or shoe is weakened by being stretched on a last—the stretching may relieve a favorite corn, but the leather suffers in consequence.

In buying hose it is well to stretch it in line, and subject it to a pressure of say 150 pounds. Careful scrutiny will betray any evidences of weakness that may exist, and if any sections show a bulging out or a leak, then subject these to the maximum pressure, and burst them if possible. If hose withstand 150 pounds pressure without betraying any weakness it may be safely accepted as good serviceable hose. The large Departments, where hose is in almost constant service, and subjected to very hard usage, require it to withstand a test pressure of 200 pounds, and occasionally such pressure is needed in actual service. But this test is seldom applied, the guarantee of the manufacturer being accepted as sufficient after a few selections have been tested. It is not deemed prudent to strain the hose and rob it of its elasticity and its life by a test applied to gratify curiosity and which is unnecessary. Let us have good, serviceable hose, combining lightness with durability, and dispense with this useless talk about its resisting extravagant and unnecessary pressure.