Trigger Guns Dump Guns and Injection Injuries: Site Safety Brief

800 to 5,600 bar litres per minute: that is the output range WorkSafe Victoria gives for a Class A high-pressure water jetting system under AS/NZS 4233.1, with anything above 5,600 classed as Class B. Multiply pressure by flow and many commercial pressure washers land inside Class A. A machine running at 150 bar and 15 litres per minute, for example, works out at 2,250 bar litres per minute. That number is a reminder that the water leaving a lance is a tool capable of cutting skin.

What controls pressure washer injection injury risk on Australian sites?

Injection injury risk is controlled by a gun that stops the jet on release, hoses and fittings rated at or above the machine's pressure, eye and face protection, an exclusion zone, trained operators and a rule that the lance is never pointed at people or electrics. Any skin penetration goes straight to hospital.

This brief is for supervisors and buyers setting site rules. Freshway's commercial pressure washing safety checklist covers the wider pre-start routine; this article concentrates on the gun, the jet and what happens if it goes wrong.

Injection injury reality

WorkSafe Victoria's safety alert on high-pressure water jetting lists the main risks: the jet may pierce the skin, contaminated material may be injected into the body, flying debris may cause injuries including to the eyes, and a flailing hose, out-of-control nozzle or separated coupling may hit someone. It also lists noise, chemical and biological exposure, and electric shock.

The trouble with injection injuries is that they can look minor. A small entry wound tempts the operator to tape it up and keep working, while water, detergent or dirt has been driven under the skin. Site rules should remove that choice: any suspected penetration is an emergency.

Dump gun vs trigger discipline

Commercial pressure washers usually use a trigger gun that shuts off the jet when the trigger is released, while some jetting setups use dump-style controls that divert flow away from the nozzle when released. The trade-off is less about which type is fitted and more about whether the control works every time and whether operators respect it.

Control or habit	What it does	Risk it reduces	Check before each shift
Trigger gun that shuts off on release	Stops the jet when the hand lets go	Uncontrolled jet after a slip or fall	Trigger returns freely, no leaks, jet stops instantly
Dump-style control	Diverts flow away from the nozzle on release	Jet continuing after release	Release fully diverts flow; no partial jet
Trigger safety catch	Locks the trigger when not spraying	Accidental spray while moving or changing nozzles	Catch engages and holds
Gun and hose rated above machine pressure	Keeps components inside their limits	Burst fittings and flailing hoses	Ratings marked and matched to the machine
Never tie or wedge a trigger open	Keeps the operator in control	Jet with no hand on the gun	Supervisor spot checks

Ratings matter here. Freshway lists the Suttner trigger gun with swivel at a maximum of 4500 PSI, 40 litres per minute and 150 °C, with a 3/8 inch female BSP swivel inlet and 1/4 inch female BSP outlet. The Kranzle M2000 gun with extension is listed at 210 bar (3045 PSI), 30 litres per minute and 150 °C, with an M22 male inlet and D12 quick release, for the Kranzle models named on its page. Match the gun to the machine's maximum pressure and flow, and to its fittings, rather than to whatever is in the van.

PPE that matters

WorkSafe Victoria's summary of AS/NZS 4233.1 says eye protection should always be worn near jetting operations, and the person in direct control of the water flow should, at a minimum, wear safety glasses and a face shield. Head protection should be worn where needed, leg and body armour where there is a risk of injury from the jet, and hearing protection where noise cannot be controlled.

Freshway lists Bastion safety glasses as complying with AS/NZS 1337.1:2010 with a medium impact rating, and an anti-fog clear face shield with anti-fog treatment on both sides of the visor. Gloves and coveralls in the gloves and PPE range protect against splash and chemicals but are not armour against a direct jet, so they do not replace distance and gun discipline.

Noise is easy to underrate on long washes. SafeWork NSW's noise code of practice sets the exposure standard at 85 dB(A) averaged over eight hours and explains that every 3 dB increase halves the safe exposure time, so 88 dB(A) reaches the standard in four hours.

Exclusion zones

• Mark a zone around the operator with cones or barrier tape before starting.
• Keep other workers and the public out while the machine is pressurised.
• Allow for rebound, debris and the reach of the hose if a coupling separates.
• Stop work if anyone enters the zone.

Wet ground adds its own risk. SafeWork NSW's page on slips, trips and falls lists liquids, water and spills among common sources of slip risk; an operator who slips with a gun in hand is exactly the case a shut-off-on-release control is meant for.

Never point at people or electrical equipment

Treat the lance like a loaded tool. Never point it at a person, including your own feet or hand to "test" the jet, and never use a hand to clear a nozzle while the system is pressurised. Keep the jet off power points, lights, switchboards and cables; WorkSafe Victoria lists electric shock among jetting hazards. For plug-in machines, SafeWork NSW explains when residual current devices must be provided in higher-risk workplaces and that they must be tested regularly.

Training sign-off

WorkSafe Victoria says operators should be trained by a competent person, including why all parts, fittings and hoses must be the right size, compatible and rated equal to or more than the equipment's maximum operating pressure. Class B operators must be trained through a Registered Training Organisation, and competency or refresher training must be done and recorded at least every two years. A practical sign-off sheet covers:

1. Pre-start check of gun, hose, couplings and nozzle.
2. Correct use of the trigger and safety catch.
3. Depressurising before changing nozzles or lances.
4. PPE selection for the task.
5. Setting up and enforcing the exclusion zone.
6. What to do after any injury.

Spec safety accessories

Beyond the gun, a splash guard helps where rebound is a problem. Freshway lists the Kranzle 132600 splash guard, made of transparent impact-resistant polymer with a synthetic bristle skirt, for Kranzle straight cleaning lances. Replacement guns, lances and couplings are in the pressure washer accessories range, and machines in the commercial pressure washers collection. WorkSafe Victoria notes that only the equipment maker, their agent or competent persons should repair jetting equipment; Freshway's service and repairs team in Sydney works on pressure washers.

Emergency response mindset

A Queensland mines safety bulletin on managing high pressure fluids and gases sets out a protocol that transfers well to cleaning sites: treat all possible fluid injection injuries as extremely serious or life threatening, provide emergency transport to hospital, give the treating medical team the safety data sheet for the product involved, and document the time, date, circumstances and symptoms. Put those four steps on the first aid card in every van.

Frequently asked questions

Next steps with Freshway

Check every gun and hose against its machine's rating, issue glasses and face shields to operators, and add the emergency steps to your first aid kit. Freshway can help match guns, lances and accessories to your pressure washers; contact the team with the model and fittings you use.