High-pressure hose is a critical component of almost any high-pressure water-blasting application. In many if not most of these applications, the high-pressure hose is a component of the overall system that can receive significant abuse simply due to the nature of the application in which it is used. As a result, the safe care and use of high-pressure hose are essential to protecting property and, most importantly, the people who may be near it. From a technical standpoint, the information given here refers to high-pressure thermoplastic hose, sometimes referred to as ultra-high-pressure hose. However, most of the information can be applied to any type of hose used.
Many people assume the most common cause of high-pressure hose failure is fatigue. While fatigue can certainly be a factor in high-pressure hose failures, in most cases the hose assembly will become damaged, causing the hose to be removed from service or fail far sooner than it becomes "worn out" or fatigued. The most common causes for high-pressure hose failures are listed below and are generally noticeable by sight, enabling the hose to be removed from service prior to failure:
- Kinks: Kinks in the hose inner core can restrict flow as well as cause the inner core to crack, leading to failure. Any kink in the hose assembly should be an indicator that the hose should be removed from service.
- End-fitting stress: Excessive stress at the assembly end fittings is commonly caused by failure to properly support and protect the assembly in applications where the assembly is subjected to hanging or excessive movement.
- Outer cover damage/exposed wire: Hose with outer cover damage exposing the support wire can be problematic once the support wire is subjected to external elements, causing the wire to begin corroding and thereby limiting its ability to support the inner core.
The key factor in helping to prevent high-pressure hose failure is a pre-use inspection of the hose assembly. I am often asked by high-pressure hose users how often they should test their high-pressure hose to "weed out" the bad assemblies. While periodic testing can be beneficial, the result is only indicative of the condition of the hose assembly at the time of the test. The hose assembly may pass the test with no issue and then begin leaking or fail the next day due to a kink or some other factor. Pre-use inspections are critical to ensuring we are as diligent as possible in preventing hose failures. Kinks, corroded and damaged end fittings, damaged outer covers and corroded support wires are all key indicators that should be looked for during inspections.
Anything that looks out of the ordinary should be questioned. The supplier of the high-pressure hose you are using should be able to provide you with some form of a guideline on what to look for in regard to hose inspection. As an example, below is an outline that could be used:
- Visually inspect the hose assembly for any damage.
- Be certain that the working pressure rating of the hose assembly is known prior to use.
- Be certain that the assembly end-fitting type is known and that the type and working pressures of any related connecting components such as adapters are known, as well as proper installation methods.
- Confirm that any accessories included on the hose assembly are in safe working condition and properly installed.
Another key factor that can assist in prolonging the life of a high-pressure hose assembly and help prevent failures is the use of proper accessories. Accessories such as abrasion covers (installed to protect the hose's outer cover) or bend restrictors and support grips (to relieve end-fitting stress) are generally inexpensive additions to a hose assembly that can have a significant benefit in protecting the hose assembly and, in some cases, personnel and property.
For years, the use of high-pressure hose has proven an effective and efficient component in water-blasting applications. While there continue to be advancements in hose safety by hose manufacturers, equipment manufacturers and the end-users of the product, high-pressure hose safety must remain a focus for the protection of employees and customers, as well as the overall success of the high-pressure hose industry.
For more information, visit www.spirstar.com or call (800) 890-7827.
