Shotcrete & Gunite Application SWMS

Shotcrete and gunite application is the pneumatic spraying of concrete onto surfaces for slope stabilisation, pools, tunnel and structural linings. It is high risk construction work under the WHS Regulation because it is carried out with powered mobile plant and high-pressure spray equipment, frequently on batters and slopes where the footing or cut exceeds 1.5 m, and often from height above 2 m (s291), so a SWMS is mandatory (s299). The central hazard is the high-pressure material stream: a hose can burst at full pressure, a nozzle can disconnect and whip the hose, and the spray and rebound strike the nozzleman and adjacent workers. The dry-mix process in particular generates substantial respirable crystalline silica, making P3 respiratory protection and fit-testing mandatory; wet-mix silica is lower but still significant. Alongside sit the working-at-height exposure on EWPs and scaffolds, the alkaline concrete burns (pH 12-13) and eye burns from spatter and overspray, and the powered plant in the work zone. The SWMS controls the pressure equipment, whip restraints and exclusion zone, silica extraction and RPE, fall protection and rebound management. It supports the engineered mix and structure to AS 3600 and AS 4458 and does not replace the engineer's design. It is supplied in eight jurisdiction editions, each citing its own Act, Regulation and regulator.

Hazards identified

8 hazards covered, sorted by priority.

Control measures

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

1. 1Elimination — Use cast or precast facing where the geometry allows so pneumatic spraying is eliminated
2. 2Substitution — Substitute the wet-mix process for dry-mix to substantially cut airborne silica, and remote/robotic nozzles for hand application at height
3. 3Engineering — Pressure equipment maintained and inspected to AS 4458 with a current certificate, hoses inspected pre-use, and whip-stop devices at all couplings
4. 4Engineering — Exclusion zone within the whip radius (3-5 m) and rebound-protected positions for adjacent workers
5. 5Engineering — On-nozzle or local dust suppression/extraction for silica, and EWP or scaffold with edge protection for work above 2 m
6. 6Administrative — Certified nozzleman (ACI CP-60 or equivalent) with annual assessment, and an engineer-approved trial panel before structural production
7. 7Administrative — Silica exposure monitoring and health monitoring for silica-exposed workers, with respirator fit-testing
8. 8Administrative — Batter/cut-face stability assessment before slope-stabilisation shotcrete, and a plant traffic-management plan
9. 9PPE — P3 respiratory protection (mandatory for dry-mix), fit-tested, plus eye/face protection against rebound
10. 10PPE — Alkali-resistant gloves, Type 1 hard hat, high-visibility clothing and non-slip footwear

Applicable Codes of Practice

High-Risk Construction Work triggered

Worked example

At 7:00 am a crew from Apex Shotcrete sets up to stabilise a rock batter. The nozzleman is CP-60 certified and the engineer has approved the trial panel. Before spraying, the hoses are inspected, whip-stops are fitted at every coupling, and a 4 m exclusion zone is marked so no one stands in the whip line. Because the batter is high, the crew work from an EWP with edge protection and are clipped on above 2 m, and the face has been checked for loose rock before anyone works beneath it. They are running the wet-mix process to keep silica down, and every worker is in a fit-tested P3 respirator with local suppression at the nozzle; the silica-exposed crew are on the health-monitoring program. When a hose coupling shows wear, spraying stops and it is replaced before pressure is restored. Rebound is directed away from the adjacent scaffold crew, who are behind a rebound screen. The crew work in alkali-resistant gloves and eye protection against overspray. The panel is completed and signed off against the trial standard.

Related legislation

• WHS Act 2011 (model)
• WHS Regulation 2025
• Working with Silica and Silica Containing Products Code of Practice
• AS 4458 Pressure equipment — Manufacture

Frequently asked questions