Hoses are one of the most essential components in industrial settings and a hose failure costs time and money.
The top reasons for hose failures are obvious to industry personnel, but other causes can sneak up if you're not careful. When a hose fails, it is most often because of human error: improper usage, misapplication or improper maintenance. Additionally, hose failures are also often a result of natural causes such as age or climatic conditions. The following are some of the most common hose failures.
Outer cover abrasion. The outer cover could become damaged due to tearing and corrosion or rubbing against an external object. Excessive rubbing can weaken the outer surface. A surface can weaken when the hose is lying on a sharp bracket or against other hoses. To prevent this, you can install protective hose guards or re-route the hose assembly. You can also use clamps to avoid contact with other objects.
Inner tube erosion. Erosion of the inner tubing is often caused by concentrated fluid, usually with contaminated media. The contaminated media transferred through the hose rubs against the inner tubing, eroding it over time and weakening the inner walls. The rubbing can cause a leak to develop. Bending the hose at an extreme angle or using the wrong size tube for the type of fluid can also cause the inner walls to weaken. The hose you choose must be compatible with the fluid passing through. Always ensure you have the proper hose size and fittings.
Failure near or at the fitting. Bending the hose too close to the seal of the crimp can create a weak point. Bend restrictors can prevent somebody from bending the hose too close to the fitting. Incorrect crimp dimensions also cause this type of failure. The solution to this problem is to lengthen the assembly. When under pressure, the hose assembly could shorten, which is why you should never try to stretch the hose to fit.
Before you bend the hose, it should be routed straight for at least double the length of the inside radius of the hose. Routing the hose correctly will prevent over-bending and causing kinks to form in the wall. Improper insertion of the fitting could also cause failure near the fitting. The entire fitting, including all grips, needs to be inserted properly. If the fitting is crimped too much or too little, this can cause the fitting to blow off. The only solution is to replace the hose assembly.
Temperature stress. Temperature plays a huge role in the longevity of the hose. The inner tube or outer cover might have cracks in frigid temperatures but be soft and pliable at room temperature. Similarly, exposing a hose to higher than recommended temperatures will cause the outer cover to be hard and brittle at room temperature. The inner tube can also oxidize from high temperatures, causing it to harden. The combination of oxygen and heat accelerates the rate at which the hose hardens. Rising temperatures also correlate to a decrease in pressure ratings, which should be considered during use. The solution for a temperature hose failure is to use a properly rated hose for the temperature situation. If possible, raise or lower the temperature to meet the hose requirements.
Age. The shelf life of a hose can be anywhere from one to 20 years, depending on the environment, application, velocity and proper usage. Hoses frequently exposed to UV rays will age faster, just as a lawn chair left in your yard weakens over time. In addition, older hoses are prone to burst at low temperatures and become brittle.
The life of a hose could vary greatly, even in the same plant, due to the temperature of fluids, the velocity of the fluid transfer and operating cycles. With proper knowledge, training and maintenance, you can extend the life of your hose and possibly prevent hose failures from happening during application. You should use the STAMPED Method when choosing a hose. STAMPED stands for: size, temperature, application, media, pressure, end fittings, delivery. This helps ensure your hose fits the requirements of the job. Correctly assembled hoses have a longer shelf life, which is why it's crucial to choose a hose distributor with strict hose assembly guidelines in place.
For more information, visit www.gopherindustrial.com or call (800) 997-3177.
