SWMS template · Excavation & Earthworks

Non-Destructive Vacuum Excavation (NDD) — Safe Work Method Statement

Safe Work Method Statement for non-destructive digging using hydro (water) or air vacuum excavation trucks to expose underground services, dig potholes and excavate around assets.

Last reviewed

Category
Excavation & Earthworks
HRCW
5 categories
Job steps
7
Hazards rated
15
PPE items
8

Non-destructive digging (NDD) with a vacuum excavation truck is the accepted way to expose underground services before mechanical excavation or boring. It removes much of the strike risk, but it does not remove it: a high-pressure water lance can still cut through cable sheathing or PE gas pipe if it is held still on an asset, and the work happens next to services that are live. NDD is usually High Risk Construction Work because it involves powered mobile plant, is often done on or beside a road in use, and is carried out on or adjacent to energised electrical services and pressurised gas mains. Holes deeper than 1.5 metres also trigger the trench HRCW category.

The hazards specific to this task are the high-pressure water lance (injection injuries, flying debris and service damage), the vacuum hose (suction can grab hands, clothing and loose objects), reversing a heavy truck in a tight road corridor, noise from the vacuum blower, and the open hole left behind. Air vacuum excavation adds dust from the air lance, which can include respirable crystalline silica in some soils. Decanting the spoil tank creates its own hazards and must happen only at an authorised disposal site.

Every job starts with a Before You Dig Australia (BYDA) enquiry and the asset owners' plans, and the operator must follow each asset owner's conditions for pressure, nozzle type and clearances. Operators must be trained and competent on the specific truck and lance, and the truck driver must hold the licence class for the vehicle. Traffic controllers need the accreditation required by your state or territory.

The SWMS should set the maximum lance pressure and nozzle type for working near services, the exclusion zone around the lance, how the operator and vacuum hose handler communicate, and how holes are made safe when left open.

Customise this template with the BYDA reference and asset owner conditions, the truck model and type (hydro or air), the lance pressure limits used near services, the traffic guidance scheme reference, the number and depth of holes, and the spoil disposal facility.

High Risk Construction Work Types

  • Work in or near a shaft or trench deeper than 1.5 metres, or a tunnel
  • Work on or near pressurised gas distribution mains or piping
  • Work on or near energised electrical installations or services
  • Work on, in or adjacent to a road, railway or other traffic corridor in use by traffic
  • Work in an area with movement of powered mobile plant

Personal Protective Equipment

  • Hard hat
  • Face shield over safety glasses (lance operator)
  • Waterproof jacket and trousers (hydro excavation)
  • Waterproof steel-capped safety boots or gumboots
  • Hearing protection (earplugs and earmuffs where the blower is loud)
  • High-visibility clothing (day/night compliant for road work)
  • Gloves
  • P2 respirator for air excavation in dusty soils

Risk Assessment

RatingsCatastrophicHighModerateLow

Step 1Pre-start planning and service plans

Hazard / RiskInitial RiskControl MeasuresResidual RiskResponsibility
Excavating without knowing what services are presentHighObtain BYDA plans and asset owner conditions before mobilising. Locator marks services on the ground. Operator reads all asset owner conditions, including pressure limits and whether a standby officer is required.LowSupervisor / Operator
Truck or equipment defectsModerateDaily pre-start on truck, boom, hoses, lance, dead-man trigger, tank door seals and emergency stops. Defective items tagged out until repaired.LowOperator

Step 2Truck positioning and traffic control

Hazard / RiskInitial RiskControl MeasuresResidual RiskResponsibility
Workers or public struck by reversing truckHighSpotter guides all reversing. Reversing camera and alarm working. Truck positioned so the crew works away from live traffic.LowDriver / Spotter
Workers struck by road trafficCatastrophicTraffic control set up to approved traffic guidance scheme before work. Work zone delineated and kept clear of pedestrians. Accredited traffic controllers where required.ModerateSupervisor / Traffic Controller
Boom contacts overhead power linesCatastrophicCheck for overhead lines before raising the boom. Keep the boom outside the approach distance set by the network operator or your state regulator. Use a spotter when working near lines.LowOperator / Spotter

Step 3Hydro or air excavation around services

Hazard / RiskInitial RiskControl MeasuresResidual RiskResponsibility
Water jet injection injury to hands, feet or legsHighLance fitted with a working dead-man trigger. Operator never points the lance at a person or their own feet. Nobody else within 2 m of the lance tip while it is pressurised. Any water injection injury treated as a medical emergency even if the wound looks small.LowLance Operator
Lance damages cable sheathing, PE gas pipe or fibreHighUse the pressure and nozzle type allowed by the asset owner near their services; use a rotating or fan nozzle, not a zero-degree tip. Keep the lance moving and work in from the side, never directly at the asset. Stop and notify the asset owner immediately if any damage occurs, even a scratch.ModerateLance Operator
Gas leak after a strike on a gas serviceCatastrophicIf gas is smelt or heard: stop, shut down the truck engine, move everyone upwind, eliminate ignition sources and call the gas distributor's emergency number and emergency services. Do not attempt to repair.ModerateOperator / Supervisor
Flying debris and dust (air excavation)ModerateFace shield and safety glasses for lance operator. Keep vacuum tube close to the air lance to capture debris. P2 respirator where soils are dry or likely to contain silica.LowLance Operator

Step 4Vacuum hose handling

Hazard / RiskInitial RiskControl MeasuresResidual RiskResponsibility
Hand, limb or clothing sucked into the vacuum tubeHighNever put hands near the open end of the vacuum tube. Keep loose clothing, rags and gloves away from the inlet. Use the boom or a tube handle rather than holding the end. Operator and hose handler agree a stop signal before starting.LowHose Handler / Operator
Blockage cleared under vacuumModerateShut off vacuum before clearing any blockage. Clear with tools, not hands.LowHose Handler

Step 5Noise exposure

Hazard / RiskInitial RiskControl MeasuresResidual RiskResponsibility
Hearing loss from vacuum blower and lanceHighHearing protection worn by all crew within the work zone while the vacuum runs. Use the truck's lowest blower setting that does the job. Rotate tasks on long shifts.LowAll Crew

Step 6Leaving holes open and backfilling

Hazard / RiskInitial RiskControl MeasuresResidual RiskResponsibility
Falls into open holesModerateHoles left open are covered with plates rated for the expected traffic or barricaded with mesh barriers and lit at night. Exposed services protected from damage.LowSupervisor
Damage to exposed services during backfillModerateBackfill around services with sand or approved material by hand or hydro; do not compact directly on the asset. Reinstate marker tape where removed.LowCrew

Step 7Decanting the spoil tank

Hazard / RiskInitial RiskControl MeasuresResidual RiskResponsibility
Struck by tank door or slurry surge during tippingHighDecant only at an authorised facility. Nobody behind the tank or under the door when tipping. Raise tank on level ground; follow manufacturer's tipping sequence.LowDriver

Relevant Codes of Practice

Worker Acknowledgement

By signing below, I confirm that I have read, understood and agree to comply with this Safe Work Method Statement.

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