Jet Wash Safety Training

OBR Construction — Mandatory Health & Safety Module

~25 minDuration

10Questions

75%Pass Mark

12 MonthsCertificate Validity

Your Full Name

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! Why This Training Matters

High-pressure water jets — commonly known as jet washers or pressure washers — are widely used on construction sites for cleaning plant, equipment, vehicles, and surfaces. Despite appearing straightforward, they can cause serious and potentially fatal injuries if misused.

Jet wash injuries are frequently underestimated. High-pressure water can penetrate skin and inject water, bacteria, and contaminants deep into tissue — an injury that looks minor on the surface can require surgery or cause permanent damage.

⚠️ Pressure washers used on construction sites are covered by PUWER 1998 — they must be suitable for purpose, maintained, and only operated by trained persons. This course satisfies the awareness training requirement.

1 Hazards of High-Pressure Water Jetting

A typical site pressure washer operates at pressures between 100 and 300 bar — enough to cut through skin, soft tissue, and even bone. Understanding the hazards is essential before operating any jet wash equipment.

💉 Injection Injuries

The most serious jet wash injury. High-pressure water penetrates the skin with little pain but injects water, dirt, bacteria, and chemicals deep into tissue. Symptoms appear minor initially but can lead to serious infection, tissue death, and amputation. Requires immediate emergency treatment.

🌊 Impact and Lacerations

Direct contact with the jet stream can cause deep lacerations, bruising, and blunt force injuries. Eye contact with the jet can cause permanent vision loss. Even at distance, fine spray can cause eye and skin irritation.

⚡ Electrical Hazards

Water and electricity are a lethal combination. Spraying near electrical installations, cables, junction boxes, or electrical plant can cause electrocution. Always check for electrical hazards before starting.

🧪 Chemical Hazards

Cleaning chemicals used with jet washers can cause chemical burns. High-pressure spray can aerosolise chemicals and contaminated water, which can be inhaled or cause skin and eye contact at distance.

🌊 Slips and Falls

Wet surfaces created during jet washing significantly increase the risk of slips and falls. The reaction force of the jet can also cause the operator to lose balance, particularly on ladders or elevated platforms.

🔇 Noise

Pressure washers typically generate 80–100dB during operation. Prolonged use without hearing protection can cause permanent hearing damage. Hearing protection is required for extended use.

2 Pre-Use Checks & Risk Assessment

Before operating a pressure washer, you must carry out a risk assessment and equipment checks. Never assume the equipment is ready to use — check it every time.

Risk assessment — check the work area for:

Overhead or underground electrical cables and installations
Other workers in the area — establish an exclusion zone
Drains and watercourses — contaminated water must not enter surface water drains
Fragile surfaces that could be damaged by high-pressure water
Asbestos-containing materials — never jet wash suspected ACMs
Flammable or hazardous substances that could be disturbed or aerosolised
Public access — protect or exclude members of the public

Equipment checks:

Inspect hoses for cracks, bulges, or damage — replace any damaged hose
Check all connections and fittings are secure
Check the trigger gun lock is functioning — gun must lock off when not in use
Check the lance and nozzle are correct for the task
Ensure the pressure relief valve is working
Check the power cable is undamaged and RCD protected

❌ Never jet wash suspected asbestos-containing materials. High-pressure water will release asbestos fibres into the air and surrounding environment. If in doubt, stop and report.

3 Safe Operation

Correct operating technique significantly reduces the risk of injury. Follow these principles every time you use a pressure washer.

Establish an exclusion zone — keep all other persons at least 3 metres away. Use barriers or signs if needed
Never point the lance at a person — even briefly, even as a joke. A momentary burst can cause a serious injection injury
Start at low pressure — begin with the lance further from the surface and work closer if needed
Use both hands — maintain a firm grip on the lance at all times to control the reaction force
Maintain a stable stance — feet shoulder-width apart, never use from a ladder unless specifically assessed
Keep the lance moving — do not hold the jet in one place on sensitive surfaces
Lock off the trigger when not jetting — use the trigger lock whenever you stop, even briefly
Never modify the nozzle or bypass the pressure relief valve
Be aware of the jet's direction at all times — including where overspray and runoff is going

⚠️ Reaction force: High-pressure lances produce a significant reaction force. Never use a pressure washer from a ladder — the recoil can cause you to lose balance. Use appropriate access equipment if elevated work is required.

4 PPE Requirements & Environmental Considerations

Correct PPE must be worn at all times when operating a pressure washer. The minimum requirements for construction site jet washing are:

⛑️ Mandatory PPE

Full face shield or safety goggles
Waterproof gloves (chemical-resistant if using detergents)
Waterproof clothing / coveralls
Steel toe-capped waterproof boots
Hearing protection for extended use
Respiratory protection if chemicals are being used

🌍 Environmental Controls

Contaminated wash water must not enter surface water drains or watercourses
Use drain covers or bunded areas to collect runoff
Dispose of chemical waste water correctly — not to foul drain without treatment
Check Environment Agency requirements if near a watercourse

🌊 Water Discharge: Discharging contaminated water (including wash water containing oil, fuel, cement, or chemicals) to surface water drains or watercourses is an offence under the Environmental Protection Act 1990 and the Water Resources Act 1991. Always contain and dispose of wash water correctly.

After use:

Lock off and disconnect the machine from the power supply
Release residual pressure by triggering the gun with the machine off
Rinse through with clean water if detergents have been used
Coil hoses correctly and store safely — do not leave under tension
Report any defects found during use to your supervisor

5 Injection Injuries — Emergency Response

Injection injuries from high-pressure water are a medical emergency. The wound may appear small — perhaps just a pinprick — but the damage beneath the skin can be severe and life-threatening.

⚠️ Signs of an injection injury:

Small entry wound, often on the hand or fingers
Initially little or no pain — do not be reassured by this
Swelling, discolouration, or numbness around the entry point
Symptoms may worsen significantly over the following hours

Immediate action if an injection injury occurs:

Call 999 immediately — this is a medical emergency requiring urgent hospital treatment
Tell the emergency services it is a high-pressure injection injury — this affects the treatment needed
Do not squeeze or attempt to clean the wound
Apply a clean, dry dressing to the wound
Keep the person calm and still while awaiting emergency services
Inform the treating hospital that the injury is a high-pressure water injection

📋 OBR Protocol: Any injection injury must be reported to your site manager immediately and recorded in the site accident book. An investigation must be carried out and the incident reported under RIDDOR if the person requires hospital treatment beyond first aid.

6 Key Summary — What You Must Remember

✅ DO

Carry out a risk assessment before use
Check equipment before every use
Establish a 3 metre exclusion zone
Wear full PPE including face shield
Lock off the trigger when not jetting
Contain and dispose of wash water correctly
Call 999 immediately for any injection injury
Report defects and near misses

❌ DON'T

Point the lance at any person
Use from a ladder
Jet wash suspected asbestos materials
Spray near electrical installations
Discharge contaminated water to drains
Use damaged hoses or fittings
Modify nozzles or bypass safety valves
Underestimate a small injection wound

🔁 Certificate Validity: This Jet Wash Safety certificate is valid for 12 months from the date of issue. Annual refresher training is required.

? Knowledge Assessment

Answer all 10 questions. You must score 75% or above (8/10) to pass and receive your certificate.

Question 1 of 10

What makes a high-pressure injection injury particularly dangerous?

The wound is always very large and painful The entry wound may appear minor but water, bacteria, and contaminants are injected deep into tissue, causing serious internal damage It always causes immediate severe pain It only occurs at very high pressures above 500 bar

Question 2 of 10

What is the minimum exclusion zone that should be established around jet washing operations?

1 metre 2 metres 3 metres No exclusion zone is needed

Question 3 of 10

You suspect a surface you are about to jet wash may contain asbestos. What should you do?

Jet wash at low pressure to minimise risk Wear a dust mask and proceed carefully Stop and report to your supervisor — never jet wash suspected ACMs Wet the surface first then jet wash

Question 4 of 10

A colleague suffers a small puncture wound to their hand from a jet wash lance. They say it doesn't hurt much. What should you do?

Apply a plaster and monitor — seek medical attention if it gets worse Call 999 immediately — this is a medical emergency regardless of how minor it appears Clean the wound thoroughly and apply antiseptic Squeeze the wound to remove any injected water

Question 5 of 10

Why should a pressure washer never be used from a ladder?

The water could damage the ladder The reaction force of the jet can cause the operator to lose balance and fall The pressure is reduced when used at height It is only prohibited in wet weather

Question 6 of 10

Discharging contaminated wash water into a surface water drain is:

Acceptable if the volume is small An offence under environmental legislation and must be avoided Only prohibited when chemicals have been used Acceptable if it's raining heavily

Question 7 of 10

Which of the following must always be checked before using a pressure washer near buildings or plant?

The colour of the equipment The presence of overhead or underground electrical installations The wind direction only Whether the surface is painted

Question 8 of 10

The trigger gun on a pressure washer must be locked off:

Only when the machine is switched off Whenever you stop jetting, even briefly Only when changing the nozzle The trigger lock is optional

Question 9 of 10

What minimum eye protection must be worn when operating a pressure washer?

No eye protection is required Standard safety glasses Full face shield or safety goggles A hard hat with brim is sufficient

Question 10 of 10

After finishing jet washing, what should you do before disconnecting hoses?

Leave the machine running to keep the pump primed Switch off the machine and release residual pressure by triggering the gun before disconnecting Immediately disconnect all hoses while the machine is still running Pour cold water over the machine to cool it down

Certificate of Completion

Jet Wash Safety

This is to certify that

Jet Wash Safety Awareness Training

Has successfully completed the OBR Construction Jet Wash Safety online training module in accordance with the Provision and Use of Work Equipment Regulations 1998 (PUWER) and HSE guidance on the safe use of high-pressure water jetting equipment in construction.

Score Achieved

Date of Issue

Valid Until

Trainer

Martin Jones

Reference

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