Over the past seven years, the water blast industry has witnessed significant positive progress in many areas of operation, most notably the area of safety. In September 2011, WJTA established a color coding scheme using system operating pressures through its Recommended Practices for the Use of High-Pressure Water Jetting Equipment. Manufactures throughout the water blast industry responded to meet this recommendation, with UHP hose manufacturers moving away from their traditional hose jacket colors to ones that complied with the recommended color scheme.
OEM pump manufacturers ensured each component from the UHP pump to the “shotgun” was compliant with WJTA recommendations. Since then, OEM’s have also made tremendous advancements in the process of heat exchanger cleaning. Automated equipment now allows the operator to work at safer distances from high- pressure lines while improving productivity and reducing worker fatigue.
To learn more, download our white paper Why Safety Concerns Are Changing the Water Blast Hose Market.
Major water blast contractors also embraced increased safety for operators by examining every area of their operation and looking for ways to eliminate risk while raising productivity and lowering operational costs. Overcoming these challenges, in many cases, required taking a second look at some of the most traditional water blast practices. For example, one tradition has been the use of a PVC cover on UHP hose assemblies. The objective was to lower operational costs by protecting the UHP hose from abrasion. The PVC cover served its purpose by protecting the underlying UHP hose and reducing the occurrences of abrasion damage. The lengthened service life of PVC covered assemblies justified the modest cost increase for the PVC and became an accepted practice in the water blast market.
While the PVC cover solution has remained unchallenged for decades, the increased focus on safety has exposed the weaknesses of this approach. With the proper inspection of every component of the assembly being paramount to safety, foremost, is the inability to thoroughly inspect the entire assembly before use:
The PVC cover obscures the underlying high-pressure hose.
Over time, as the PVC begins to discolor from exposure to UV rays, the ability to visibly inspect a PVC covered assembly decreases further.
As dirt and debris from the application find their way into the PVC cover, it becomes nearly impossible to inspect the UHP hose inside.
Secondly, a PVC cover adds weight to the assembly, increasing the amount of effort or force required to drag the assembly across a surface. A common issue with PVC cover is that water builds up between it and the hose, further adding to the weight. The heavier load requires more effort during the cleaning operation, moving hoses as the work progresses, and loading assemblies back on to service trucks upon job completion. This increased effort contributes to operator fatigue and muscle strains possibly leading to other injuries and job- related mistakes.
In many cases, weight is also the destructive force causing the PVC cover to detach from the retaining collar, commonly referred to as PVC cover pull out. Even without additional weight, PVC pull-out can occur by merely dragging the assemblies while holding the cover. The other alternative is pulling the assembly by the PVC collar. By applying the load to the collar, the force transfers into the fitting. While crimped fittings can sustain some level of external force, experts do not recommend it. The fact is, there is no good way to drag a covered hose.
Another potential hazard associated with a PVC covered hose assembly is operator confusion regarding the true purpose of the cover. It is not uncommon for operators to mistake the PVC cover for a burst containment shield. This misunderstanding could result in an operator using a PVC covered assembly when the application requires a safety shroud or burst shield, thus increasing the chance of injury for the operator and bystanders.
With the realization that PVC covers protect from abrasion but at the cost of operator safety, the challenge is to provide an abrasion resistant hose that:
• solves the problems of the inability to inspect the underlying hose;
• prevents water ingression and reduces weight to eliminate fatigue;
• eliminates PVC pull out; and,
• stops confusion regarding the burst shield.
Safety is important at Parker. Our hose engineers have developed a solution to these challenges by extruding a highly abrasion resistant secondary jacket directly onto the primary UHP hose. The extrusion of a secondary jacket on water blast hoses, referred to as TOUGHJACKET™, addresses every area in which a PVC cover falls short while adding a few more benefits.
“Abrasion testing of the TOUGHJACKET material to ISO 6945 showed the proprietary polyurethane jacket achieves abrasion levels at least 100 times greater than PVC.”
— George Molinar, senior engineer Parker Hannifin
The TOUGHJACKET hoses also have a WJTA compliant outer jacket color, with the underlying primary hose having a contrasting color. This contrast in the hose jacket colors serves as an early warning indicator of an abrasion problem to the operator and safety inspector, prompting the operator to correct the abrasion issue or potentially remove the assembly from service. And since the secondary jacket is extruded on to the UHP hose, it is impossible for water to ingress into the assembly, eliminating all weight gain caused by trapped liquids. Ultimately, it allows operators to fully inspect all components of the hose assembly.
To learn more about how safety concerns are changing the water blast market, download our white paper Why Safety Concerns Are Changing the Water Blast Hose Market.
Article contributed by Paul Walker, business development manager for Ultra-High Pressure Thermoplastic Hose at Parflex, Parker Hannifin.
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