1. Introduction
Shotcrete operations involve multiple high-risk elements operating simultaneously.
These include:
• High-pressure concrete pumping
• Compressed air systems
• Chemical accelerators
• Unstable ground conditions
• Fresh structural support material
For this reason, shotcrete safety must be approached as a system rather than a set of isolated precautions.
EFNARC recognises safety as a primary objective of sprayed concrete execution and requires that all operations be conducted within defined exclusion and control procedures.
2. Unique hazards associated with shotcrete
Shotcrete presents hazards not encountered in conventional concrete work.
These include:
• Stored energy within hoses
• Sudden release of pressurised material
• Chemical exposure at the nozzle
• Falling fresh material
• Incomplete early-age strength
Each hazard requires specific control measures.
3. High-pressure pumping hazards
Concrete pumping systems operate under significant pressure.
Failure of hoses, clamps, or fittings can result in violent discharge of material.
This risk increases during:
• Blockage events
• Pump reversal
• Improper clamp installation
Personnel must never stand in line with pressurised hoses.
Pressure must always be relieved before disconnection.
4. Compressed air hazards
Compressed air increases projection velocity but also introduces risk.
Air hose failure can cause:
• Whipping of hoses
• Loss of control at the nozzle
• Sudden depressurisation
Safety devices and secure couplings are mandatory.
Air must be isolated during maintenance or blockage removal.
5. Chemical exposure risks
Accelerators are chemically active substances.
Exposure risks include:
• Skin irritation
• Eye injury
• Respiratory effects
Direct contact must be avoided.
Handling procedures must include appropriate PPE and emergency washing facilities.
EFNARC requires that chemical safety data and training be provided to all personnel involved in sprayed concrete operations.
6. Fresh shotcrete hazards
Freshly sprayed shotcrete has limited early strength.
Until sufficient strength develops, it cannot support loads or protect against falling rock.
Entering areas beneath fresh shotcrete prematurely exposes personnel to collapse or delamination risks.
Exclusion zones must be enforced until safe strength is confirmed.
7. Exclusion zone principles
Exclusion zones are controlled areas where access is restricted during and after spraying.
Zones must consider:
• Potential fall-out
• Hose movement
• Equipment swing radius
• Early-age lining stability
Only essential personnel may enter exclusion zones during spraying.
8. Working under unsupported ground
No personnel should enter unsupported ground during shotcrete operations.
Spraying should proceed from areas of established support toward unsupported zones, never the reverse.
This principle ensures personnel remain protected at all times.
9. Sequencing of underground activities
Shotcrete must be integrated into the excavation sequence.
Correct sequencing includes:
• Scaling
• Mapping
• Initial support installation
• Shotcrete application
• Secondary reinforcement
Poor sequencing increases exposure to ground instability.
10. PPE requirements
Personal protective equipment forms the final barrier against residual risk.
Typical PPE includes:
• Hard hat
• Eye protection
• Hearing protection
• Respiratory protection
• Gloves
• Protective clothing
• Safety footwear
PPE must be selected based on task-specific risk assessment.
11. Nozzle operator safety considerations
The nozzle operator is exposed to the highest risk.
Key safety considerations include:
• Stable footing
• Clear visibility
• Controlled hose handling
• Continuous communication with the pump operator
Loss of balance or visibility can result in serious injury.
12. Assistant and support crew positioning
Assistants must position themselves outside direct spray zones.
They must avoid standing beneath fresh material or in line with pressurised hoses.
Clear communication between team members is essential.
13. Blockage response safety
Blockages represent one of the highest-risk events in shotcrete operations.
During blockage response:
• Pump must be stopped
• Air supply isolated
• Pressure relieved
• Area cleared
Under no circumstances should material be forced through a blockage.
Stored pressure must be assumed until proven otherwise.
14. Equipment movement hazards
Shotcrete machines often operate on uneven ground.
Movement hazards include:
• Boom swing
• Machine repositioning
• Restricted visibility
Spotters should be used where visibility is limited.
15. Ventilation requirements
Spraying introduces dust, fumes, and chemical vapours.
Adequate ventilation is required to:
• Maintain air quality
• Remove accelerator mist
• Control temperature
Ventilation failure increases health risk and reduces visibility.
16. Human factors and fatigue
Shotcrete work is physically and mentally demanding.
Fatigue reduces:
• Reaction time
• Situational awareness
• Technique consistency
Fatigue management is therefore a safety control measure.
17. Training as a safety system
Competent personnel make safer decisions.
Training ensures understanding of:
• Equipment behaviour
• Hazard recognition
• Emergency procedures
EFNARC places strong emphasis on trained operators and structured competence development.
18. Emergency preparedness
Emergency procedures must be clearly defined and rehearsed.
This includes:
• Chemical exposure response
• Hose rupture response
• Injury management
• Evacuation routes
Preparedness reduces reaction time and severity of incidents.
19. Safety culture and leadership
Safety performance reflects leadership commitment.
Clear expectations, consistent enforcement, and visible supervision are required.
Shortcuts rapidly degrade safety margins.
20. Safety as part of performance
Safe shotcrete operations and high-quality lining performance are inseparable.
Unsafe practices inevitably lead to poor execution and structural risk.
EFNARC guidance integrates safety into execution rather than treating it as a separate discipline