Guide to Non-Destructive Digging (NDD)
Compliance in Australia
No Dig Equipment -Australian Standards Complient Vacuum Excavators
Under Australian Standard AS 5488-2022 (Classification of Subsurface Utility Information), non-destructive digging (NDD) via hydro vacuum excavation is the only physical method recognized to achieve Quality Level A (QL-A) asset verification.
Utilizing high-pressure water and vacuum suction exposes buried services without mechanical blade contact, satisfying Dial Before You Dig (DBYD) protocols and Safe Work Method Statements (SWMS) on Australian civil sites.
AS 5488 Subsurface Utility Information Quality Levels
| Quality Level | Verification Method | Spatial Accuracy | Utility Risk Level | Role of NDD / Vacuum Excavation |
| QL-D | Desktop research & DBYD utility plans | No spatial tolerance | Highest risk | Planning phase research |
| QL-C | Surface feature correlation (pits, valves) | Visual location only | High risk | Identifies surface infrastructure |
| QL-B | Surface geophysics (GPR & EMI sweeps) | Horizontal: ±300mm | Moderate risk | Designates relative positioning |
| QL-A | Physical exposure via Vacuum Excavation | ±50mm Horizontal & Vertical | Lowest risk (Confirmed) | Mandatory physical verification |
Key AS 5488 Asset Marking Colour Standards
Orange: Electrical cables and power utilities.
Yellow: Gas, oil, steam, and flammable services.
White: Telecommunications, NBN, security, and traffic signals.
Blue: Potable drinking water pipes.
Cream: Sewerage and wastewater infrastructure.
Green: Stormwater and environmental drainage lines.
Steps to Achieve QL-A Compliance on Work Sites
Desktop & Geophysical Survey (QL-D to QL-B): Obtain DBYD records and execute Ground Penetrating Radar (GPR) or Electromagnetic Induction (EMI) sweeps to designate approximate utility paths.
Positive NDD Asset Exposure (QL-A): Deploy a hydro vacuum unit to pothole through topsoil, safely exposing the underground pipe, cable, or duct.
Survey & Data Logging: Measure and record exact subsurface coordinates, pipe size, depth, and material composition within the required ±50mm spatial tolerance.
Equipment Integration & Compliance
Executing QL-A verification in congested urban zones or tight access sites requires towable NDD equipment.
Vacuum Excavators from no Dig Equipment have the additianal compliance ratings:
- Vacuum Tank Hazard Level to AS4340 – Level “E” No design verification or inspection Required for Australian Standard compliance.
- High Pressure Water Hazard Level to AS4233 – Class A , Pressure: 241 BAR, Flow Rate: 15 L/min < 5600 BAR L/min
