Hydroblasting & Water Jetting
Hydroblasting uses water at thousands to tens of thousands of pounds per square inch to clean heat exchangers, tanks, pipes and surfaces and to cut concrete. A jet at that pressure can cut through skin, muscle and bone. Injuries often look small, but water, bacteria and debris are forced deep into the body. Training, equipment controls and teamwork are essential.
- Industrial Cleaners
- Refinery & Plant Maintenance
- Concrete Removal Crews
- Contractors
- Supervisors
Pressure ranges
- Low pressure: up to about 5,000 psi (common pressure washers).
- High pressure: about 5,000 to 10,000 psi.
- Very high or ultra-high pressure: above 10,000 psi, up to 40,000 psi or more for cutting and surface removal.
- The Water Jet Technology Association (WJTA) publishes recommended practices for jetting operations. See also Pressure Washing at Home.
Main hazards
- Injection and laceration injuries: the jet can penetrate skin and inject water and contaminants into tissue. Amputations and deaths have occurred. Treat as a surgical emergency. See Puncture Wounds.
- Hose whip and burst: failed fittings, hoses and connections can lash and strike.
- Reaction force and loss of control of the gun or lance.
- Flying debris and rebound spray.
- Noise, slips on wet surfaces and electric shock near water. See Noise.
- Silica and hazardous residues when cutting concrete or cleaning process equipment. See Silica.
- Confined space hazards when blasting in tanks and vessels. See Tank Cleaning & Vessel Entry.
- Hot water and steam in some systems.
Equipment controls
- Use a dead-man foot pedal or trigger control with a dump valve so the jet stops the instant the operator releases it. Never tie down, bypass or modify controls.
- Use hoses, fittings and gun assemblies rated above the working pressure, and inspect them before every shift. Use whip checks or restraints at connections.
- Install a pressure relief valve and keep gauges working. Do not exceed the rating. Bleed pressure before disconnecting.
- Use nozzles and lances suited to the task and keep a firm grip. Use two-handed control and restraints where required.
- Keep equipment grounded and cords out of water.
Safe operation
- Operators must be trained and authorized, with refreshers. A team of at least two people is typical: an operator and a helper or standby who can stop the pump.
- Wear PPE built for jetting: a face shield and safety glasses, hard hat, hearing protection, a rain suit or jet-resistant suit, metatarsal boots and gloves. Standard rain gear does not stop a jet but protects against spray. See Eye & Face Protection.
- Never aim the jet at anyone, or at your own hands or feet. Don't hold the work with your free hand. Don't try to detect leaks with your hand.
- Barricade the area and post warning signs. Keep others back from the jet and the hose line.
- Use lockout on the pump before servicing. Depressurize before changing nozzles.
- Keep communication clear and have a stop signal. Plan emergency shutdown.
If someone is injured
- Shut down the pump immediately and call 911. Do not underestimate a small wound.
- Do not remove embedded debris. Control bleeding and keep the person still. Tell medical staff it is a high-pressure water injection injury. Surgery is often needed. See Bleeding Control.
Hydroblasting checklist
- The foot pedal or trigger dump valve works and is not bypassed
- Hoses and fittings are rated, inspected and restrained with whip checks
- Operators are trained and wear a face shield, rain suit and metatarsal boots
- The area is barricaded and a standby can stop the pump
- Anyone with a jet injury gets emergency surgical care
Standards & references
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