Shotcrete Application — Safe Work Method Statement
Safe Work Method Statement for spraying wet-mix shotcrete or dry-mix sprayed concrete onto pools, retaining walls, soil-nail walls, basement walls and slopes, covering set-up, accelerator handling, spraying, blockage clearing and washout.
Download this template
Shotcrete is concrete sprayed at high velocity through a hose and nozzle, either as wet-mix pumped concrete with air added at the nozzle, or as dry-mix where dry material is blown through the hose and water is added at the nozzle. It is used for pool shells, retaining and soil-nail walls, basement shoring walls, slope stabilisation and concrete repair. Shotcrete work is High Risk Construction Work where it is done in an area with powered mobile plant (pumps, agitators, excavators), or where the nozzle operator works from a scaffold, EWP or excavation edge with a fall of more than 2 metres. A SWMS is required before spraying starts. Underground tunnel shotcrete has its own specific risks and is not covered by this template.
The hazards specific to shotcrete come from the pressure in the line and the material leaving the nozzle. Hose whip and blowouts at blockages can kill, so the line must be depressurised before any coupling is opened or blockage cleared. Rebound, which is aggregate bouncing off the surface, can injure eyes and skin, and the hose reaction makes the nozzle operator's job physically hard, which leads to fatigue and loss of control. Compressed air hoses need whip checks at every coupling. Set-accelerators can be strongly alkaline or corrosive and cause serious eye and skin burns. Dry-mix spraying generates cement and silica dust at the nozzle and the gun.
When spraying freshly excavated faces on soil-nail or shoring walls, workers are standing at the base of an unsupported face. Spray only the height and length of face the engineer allows for each stage, and keep the excavator and spoil back from the crest. Overspray can drift onto neighbouring property and vehicles.
There is no specific licence for nozzle operators, but they must be trained and experienced, and the pump operator must be competent with the concrete placing equipment to AS 2550.15 and the manufacturer's manual. Pumps and boom pumps may require plant registration, so check with your state or territory regulator. Everyone on the spray crew must understand the hand signals or radio protocol between nozzle operator and pump operator.
Customise this template with: the structure being sprayed and spray thickness; wet-mix or dry-mix method; the pump, compressor and hose configuration; the engineer's staging limits for excavated faces; the accelerator product and SDS; the exclusion zone and how it is marked; the communication method between nozzle and pump; the working platform for high walls; and the washout and waste concrete disposal arrangements.
Personal Protective Equipment
High Risk Construction Work Types
- •Risk of a person falling more than 2 metres
- •Work in an area with movement of powered mobile plant
Risk Assessment
1.Pre-start planning and face inspection
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Collapse of a freshly excavated soil face onto the spray crew | Catastrophic | Confirm the engineer's maximum excavated height and length for each stage before spraying. A competent person inspects the face before each shift and after rain. Do not work under overhangs or loose material. Keep plant, spoil and stockpiles back from the crest as specified by the engineer. Stop and get advice if the face shows cracking, seepage or slumping. | Moderate | Supervisor / Geotechnical Engineer |
| Other workers or the public in the spray zone | High | Mark an exclusion zone around the nozzle and pump line with barriers and signs. Only the spray crew enters it during spraying. Protect or move neighbouring vehicles and cover adjacent surfaces. Stop spraying if anyone enters the zone. | Low | Supervisor / Nozzle Operator |
2.Pump, compressor and hose set-up
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Coupling failure or hose whip under pressure | Catastrophic | Inspect all hoses, pipes, clamps and gaskets before set-up and remove worn or damaged items. Fit safety pins or clips to every concrete line clamp. Fit whip checks to every compressed air hose coupling. Run hoses in straight lines with large-radius bends and keep them out of traffic routes. Keep people clear of the line during priming. | Low | Pump Operator |
| Pump or truck instability, or boom contact with powerlines | Catastrophic | Set the pump on firm ground with outrigger pads as the manufacturer specifies. Check for voids, pits and excavation edges under outriggers. Identify overhead powerlines and keep the boom clear of them, with a spotter if the boom works near a line. | Moderate | Pump Operator |
3.Handling set-accelerators and admixtures
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Eye and skin burns from accelerator splashes or mist | High | Read the SDS before use. Decant accelerators with a pump or tap, never by pouring from drums. Wear goggles, chemical-resistant gloves and waterproof clothing when handling. Keep an eyewash station within reach of the dosing unit and the nozzle. Store accelerator in bunded containers away from drains. | Low | Pump Operator / Nozzle Operator |
4.Spraying
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Eye and skin injuries from rebound and overspray | High | Hold the nozzle at the correct distance and at right angles to the surface to minimise rebound. Nozzle operator and helper wear sealed goggles or a face shield and waterproof clothing. Nobody stands in the rebound zone in front of the face. Clear rebound from the base regularly so it isn't sprayed over. | Low | Nozzle Operator |
| Loss of nozzle control from hose reaction and fatigue | High | Use a nozzle helper to manage the hose behind the operator. Use a manipulator or boom for large volumes where practicable. Rotate nozzle operators on long pours and take regular breaks. Agree stop signals with the pump operator and test them before spraying starts. The pump operator stops the pump immediately on a stop signal or loss of contact. | Moderate | Nozzle Operator / Pump Operator |
| Falling from a scaffold or EWP while spraying high walls | Catastrophic | Spray high walls from a scaffold with full guardrails or from an EWP. Workers in a boom-type EWP wear a harness attached to the basket anchor. Keep scaffold decks clear of rebound build-up. Check the EWP basket load including the hose and the person. | Moderate | Nozzle Operator / Supervisor |
| Silica and cement dust from dry-mix spraying | High | Pre-dampen dry-mix material where the process allows. Adjust water at the nozzle to minimise dust. Nozzle operator, gun operator and helpers wear fit-tested P2 respirators. Position the gun and material supply where dust does not drift over other workers. | Moderate | Nozzle Operator |
5.Clearing blockages
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Blowout or projectile when opening a pressurised line | Catastrophic | Stop the pump and air supply, then relieve line pressure by reversing the pump as the manual describes, before opening any coupling. Never strike, kink or shake a pressurised line, and never open a coupling with anyone in line with it. Clear all non-essential people at least 5 metres from the line. Point the opened end into a skip or the ground. | Low | Pump Operator |
6.Finishing and cutting back
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Strain from trimming and finishing on vertical surfaces | Moderate | Use trimming rods and long-handled tools to keep work between knee and shoulder height. Work from a platform rather than reaching. Rotate finishers and take regular breaks. | Low | Finisher |
7.Washout and clean-up
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Projectiles during line washout and concrete washwater entering drains | High | Discharge the washout ball or sponge into a skip or catcher with nobody in line with the outlet. Wash out only into a lined washout bay or skip, never onto the ground or into stormwater. Let slurry set and dispose of it as solid waste. Remove rebound and waste concrete from the site. | Low | Pump Operator |
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.