Selecting industrial hose

Selecting and installing industrial hose, whether for hydraulics, air, water, chemicals, acid or steam, is not a job for novices. Choosing the wrong hose for an application can spell disaster. So can improper crimping and coupling. Only properly trained technicians should inspect, test or service hose assemblies.

Double-check the manufacturer’s manuals for suitability of the hose for the intended application. There are millions of possible hose and assembly combinations so proper technician training and access to manufacturer application and assembly recommendations are the essential starting points for any task involving hose. Beyond this, some basic precautions to consider are:

1. Hose application and pressure
Use the correct hose (as designated by the manufacturer) for the job, especially in terms of pressure ratings. Exposing hose to higher than rated operating pressures or pressure surges will quickly lead to failure. Likewise, exposing hose to harsh chemical environments, corrosive liquids or gases for which it is not intended will also lead to swift failure.

Hose manufacturers establish reliable working pressure ranges for hose but as the user it is your responsibility to ensure you are using the correct hose for your systems. Utilize pressure gauges, and in applications where surges exist, electronic pressure monitoring systems as well

2. Assemblies
Be sure to choose the correct hose assemblies for the application. Pay particular attention to the respective pressure ratings and ranges of all components. Correct hose-to-assembly ID and OD is just one factor to be aware of. The likelihood of changes in operating pressure or periodic pressure surges is another critical factor. Test repeatedly before installation. Evaluation of a hose and coupling combination cannot be determined by a simple burst or pressure hold test.

3. Routing
Hose assembly routing must be as direct as possible so as to avoid either damage to the hose or potential injury to workers. This includes not exceeding minimum bend radii or stretching, twisting, kinking or crushing the hose.

4. Heat
Make sure application temperatures will not exceed the components’ safe operating range. High temperatures can degrade rubber very quickly and significantly reduce hose life.

5. Electrical conductivity and other hazardous operating conditions
No hose is 100 percent electrically inert. In highly abrasive applications, periodically rotate the hose 90 degrees to maximize service life.

6. Safety
Among other safety considerations, always wear safety glasses. Establish, maintain and document a predictive program of inspection, testing and replacement. How often the equipment runs, how hard it runs and how long hose assemblies have endured in the past are all benchmarks that can be considered.
WARNING: Fluid injection injuries can kill. The highly pressurized fluid in hydraulic and other closed systems can cause serious injuries or even death. Fluid jetting from a pinhole in pressurized hose or an assembly can be virtually invisible yet still pierce the skin into the body. Never touch a pressurized hydraulic assembly; stay out of range of assemblies being tested. If such an injury occurs, seek professional medical help immediately, regardless of whether the injury is painful or not.

A note on storage
Factors from hose components — types of rubber and other materials used to make the hose — to external atmospheric conditions, all impact hose life in storage.

A general rule of thumb is that with proper care and storage techniques, hose will last up to five years before significant degradation begins. But this is a very general rule and not to be taken as gospel.

Numerous variables can and do contribute to hose deterioration with time. Temperature is a major culprit. Store hose in a cool, dry area. Do not store hose where temperatures may either exceed 100 degrees F or fall below freezing. If hose has been exposed to freezing, it should be gradually warmed and then tested before use. Avoid storing hose near heaters or electrical equipment. Other factors impacting hose include exposure to direct sunlight or rain, excessive humidity, oil, solvents, chemicals and fumes, ozone and radioactivity, or critters – insects and mice will eat anything.

Whenever possible, store hose in its original container. This not only helps protect product but also makes it easier to identify later. You should also store hose in a first-in, first-out supermarket manner so the oldest product gets used first. Don’t stack too high; the weight of a large stack of hose can gradually crush the hose at the bottom. And remember, if it looks wrong, it probably is. Whenever there is any doubt, TEST!

Information for this article was supplied by JGB Enterprises, Inc. Contact John Snyder at 315-451-2770 x365; e-mail: jsnyder@jgbhose.com.

This article appeared in the June/July 2006 issue of MRO Today magazine. Copyright 2006.

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