Concrete Scanning SWMS

Concrete scanning uses ground-penetrating radar (GPR), electromagnetic locators and sometimes X-ray imaging to map embedded reinforcement, post-tensioned cables, conduits and services within slabs, walls and columns before any cutting, coring or anchoring work begins. This activity is performed across commercial construction, civil infrastructure, fit-out and refurbishment projects, frequently in occupied buildings, basement carparks and live operational environments. Under WHS Regulation 2025, scanning is treated as a precursor to high-risk construction work because the integrity of the scan directly governs whether subsequent core drilling, chasing or fixing will strike live electrical conductors, pressurised hydraulic lines, gas mains or post-tensioned tendons. A documented SWMS is mandatory whenever scanning informs penetrations into structural elements that contain or may contain energised services, because the work falls within high risk construction work under section 291 categories and engages PCBU duties under sections 19 and 38 of the WHS Act. The SWMS captures scanner calibration, exclusion zones, interpretation limits, sign-off authority and the explicit link between the scan report and the permit to drill.

Hazards identified

7 hazards covered, sorted by priority.

Control measures

Hierarchy-of-controls order: elimination → substitution → isolation → engineering → administrative → PPE.

1. 1Elimination — Where possible, eliminate the penetration entirely by relocating fixings, services or anchors to verified clear zones identified from as-built drawings and BIM models.
2. 2Elimination — Remove all non-essential personnel from the scanning zone and adjacent floor levels during radiographic (X-ray) scanning operations to remove exposure pathway.
3. 3Substitution — Substitute X-ray radiography with dual-frequency GPR (1.6GHz and 2.7GHz antenna) wherever target depth and resolution permit, eliminating ionising radiation hazard.
4. 4Substitution — Replace single-pass scans with orthogonal grid scanning (0.5m x 0.5m) and 3D tomographic processing to reduce interpretation error on congested rebar.
5. 5Engineering — Use calibrated GPR units (e.g. Hilti PS300, Proceq GP8000) with current calibration certificate, depth-corrected against known reference targets before each shift.
6. 6Engineering — Install physical exclusion barriers, radiation warning signage and interlocked controlled-area lighting for any radiographic scanning per AS/NZS 2243.4.
7. 7Administrative — Implement a scan-to-core permit system requiring technician sign-off, supervisor counter-sign and 24-hour validity before any coring proceeds on scanned penetration.
8. 8Administrative — Conduct daily pre-start briefings using this SWMS, confirm scanner operator AS 5104 competency, and record toolbox attendance with worker consultation per s47.
9. 9PPE — Wear AS/NZS 1337.1 safety eyewear, AS/NZS 1801 hard hat, AS/NZS 2210.3 safety footwear, hi-vis AS/NZS 4602.1 and cut-resistant gloves during scanning setup.
10. 10PPE — For radiographic scanning, issue calibrated personal dosimeters (TLD badges) to all operators within the controlled area as required by ARPANSA RPS C-1.

Applicable Codes of Practice

High-Risk Construction Work triggered

Worked example

On a Tuesday morning at a 14-storey CBD office refurbishment, a scanning technician arrives at Level 8 to locate clear penetration zones for new hydraulic risers passing through a post-tensioned slab. At the 6:45am pre-start, the supervisor opens this SWMS on a tablet and walks the two-person crew through each hazard line, focusing the discussion on the post-tensioned tendon strike risk because the structural drawings flag this slab as PT. The technician confirms the Hilti PS300 calibration certificate is current and the orthogonal grid control is being applied rather than a single-pass scan. All three workers sign on electronically. During scanning, the technician identifies a tendon profile only 45mm below the proposed core location — shallower than the as-built indicated. Following the SWMS administrative control, the technician halts, marks the area with red paint, and escalates to the structural engineer rather than approving the core. The supervisor amends the scan-to-core permit, relocates the penetration 300mm east into a verified clear zone, and re-briefs the coring crew using the same SWMS before they mobilise after lunch. The amended scan report, the original SWMS, the sign-on sheet and the engineer's email are attached to the project safety file that afternoon, demonstrating the live, working role of the SWMS in field decision-making.

Related legislation

• WHS Act 2011 (model)
• WHS Regulation 2025
• AS 3600 — Concrete structures

Frequently asked questions