NCCER Hydroblasting key terms

The pressure, usually stated in psi or bar, at which a hydroblasting pump or tool normally operates during a job. It is the reference value used to select hose, fittings, and nozzles.

The pressure at which a hose, fitting, or component fails and ruptures. It is always far above working pressure, and the margin between the two is the safety factor.

Damage to skin, tissue, or eyes caused by a high-pressure stream, including pinhole injection through gloves or boots. Such injuries look minor at first but can be deep and limb-threatening.

The forcing of water or a water-abrasive mix through the skin at a tiny, nearly invisible point, usually from a pinhole leak or a jet striking close to the body. It requires immediate medical care.

The thrust that pushes back on a nozzle, lance, or hose when water leaves it at high pressure. It can knock a worker off balance, so the tool must be braced and controlled.

A second worker who stands clear of the jet path and helps control the hose or lance, watches the operator, and can shut down or signal for help if something goes wrong.

A trigger, lever, or valve that stops the flow as soon as the operator releases it. It prevents the jet from continuing if the operator loses grip or falls.

A valve that diverts or releases water when the trigger or control is released, letting the pump keep running while the jet stops. It reduces pressure spikes and sudden hose movement.

A pressure-regulating valve that bypasses water back to the supply or tank when the set pressure is reached. It protects the pump and hoses from overpressure and helps hold a steady working pressure.

A dial or digital instrument that shows the pressure in the system at a given point. Operators watch it to confirm the set pressure and to spot spikes, drops, or a clogged nozzle.

The replaceable tip at the end of a lance or hose that shapes the water stream and sets flow and pressure. Its size, angle, and pattern determine cleaning power and control.

The small opening in a nozzle through which water passes. Its size, often marked as a number, controls flow rate at a given pressure and must match the pump and job.

A flat, spread-out water stream produced by a fan nozzle. The angle of the fan is chosen for the width of cleaning and the standoff distance from the surface.

A nozzle assembly that spins a jet or jets to cover a wider area and add mechanical action. It is common in pipe and tube cleaning and needs guards and controlled entry.

A rigid tube, often with a handle and trigger, that carries water to a nozzle and lets the operator direct the jet from a distance. It must be kept pointed away from people.

A safety cable or restraint fitted across hose couplings so that, if a connection fails, the hose ends cannot fly apart and strike workers. It is checked before every job.

The routine checking of high-pressure hose for cuts, bulges, abrasion, exposed wire, and damaged fittings before and during use. Defective hose is removed from service at once.

The machine that raises water to high pressure and moves it to the hose and nozzle. Positive-displacement pumps are common because they deliver steady flow at high pressure.

The volume of water delivered per unit time, usually in gallons or liters per minute. Flow and pressure together determine cleaning energy, and both must match the nozzle.

The gap between the nozzle tip and the surface being cleaned. Too close can damage the surface or throw debris back; too far wastes energy and leaves soil behind.

The roughness pattern left on a surface after cleaning or preparation, which affects how well a coating will bond. Hydroblasting can produce a profile when abrasive or high energy is used.

Cleaning or surface preparation using a high-pressure water stream, sometimes with abrasives or heat. It removes scale, rust, coatings, and process soil without the dust of dry blasting.

A physical barrier, tape, or tagged boundary set up to keep people out of the jet path and debris zone. Only authorized workers wearing the required protection may enter.

The area around a hydroblasting job where only the crew may be present because of jet, debris, and noise hazards. Its size depends on pressure, nozzle type, and surroundings.

The gear worn to reduce injury risk, such as a face shield, safety glasses, hearing protection, gloves, boots, and rain gear. It supplements, but never replaces, safe procedures and guards.

A clear guard worn over safety glasses to protect the face from flying debris and water spray. It must be rated for the job and kept clean enough to see through.

A space with limited entry and exit that is not meant for continuous occupancy. Hydroblasting inside tanks or vessels requires entry permits, atmospheric testing, and an attendant.

Checking the air in a work area for oxygen level, flammable gas, and toxic gas before entry and during the job. Results decide whether entry is allowed and what respiratory protection is needed.

A worker stationed outside a confined space who monitors entrants, keeps communication, and summons help. The attendant does not enter the space to perform rescue alone.

The procedure for isolating energy sources, such as pumps, valves, and electrical feeds, and applying locks and tags before work. It prevents unexpected startup or release of stored pressure.

The condition in which all energy sources are isolated, stored pressure is bled off, and the equipment cannot move or flow. Work begins only after this is verified.

Energy held in pressurized lines, accumulators, or trapped fluid after the pump stops. It must be released and verified before anyone opens or works on the system.

Using a rotating or forward jet to remove scale, sludge, and blockages from the inside of pipes and tubes. The nozzle is fed in carefully and withdrawn under control.

A blockage in the nozzle opening that raises pressure, changes the spray, and can cause a sudden surge or hose failure. The pump is shut down and pressure released before clearing it.

The forming and collapsing of vapor bubbles in the pump when inlet flow is restricted or air is drawn in. It causes noise, vibration, and damage, and lowers cleaning performance.

The supply of water to the pump and the screens or filters that keep grit and debris out. Clean, adequate supply protects the pump and keeps pressure steady.

A pre-job review that lists each task step, its hazards, and the controls to be used. For hydroblasting it covers jet exposure, pressure, debris, noise, and confined space entry.

A physical check of the work area before starting, looking at access, lighting, drainage, other workers, and equipment condition. It confirms the plan matches actual site conditions.