1. Introduction
Shotcrete is one of the few construction activities where final structural performance depends directly on human execution.
Unlike cast concrete, which is largely controlled through formwork and batching systems, sprayed concrete relies on operator judgement, timing, and coordination at the face.
For this reason, competence is not optional. It is structural.
EFNARC recognises training and competence as essential components of reliable sprayed concrete execution.
2. Shotcrete as a skill-based construction process
Shotcrete application cannot be fully automated.
Although modern equipment provides consistency in pumping and dosing, the following remain under human control:
• Nozzle angle
• Stand-off distance
• Spraying pattern
• Layer thickness development
• Reaction assessment
These variables change continuously during application and require real-time decision-making.
This makes shotcrete a skill-based trade rather than a purely mechanical process.
3. Role of the nozzle operator
The nozzle operator is the final controller of lining quality.
Their actions determine:
• Compaction efficiency
• Rebound generation
• Fibre embedment
• Thickness consistency
• Surface integrity
Two operators using the same equipment and mix can produce significantly different results.
This variability highlights the importance of structured competence development.
4. Knowledge required for competent operation
Competent nozzle operators must understand:
• Basic concrete behaviour
• Influence of air volume
• Effect of nozzle angle
• Accelerator response
• Signs of instability
Without this understanding, operators rely on habit rather than judgement.
Habits may work under stable conditions but fail when conditions change.
5. Understanding cause and effect
Expert operators do not simply follow procedures.
They understand cause and effect relationships such as:
• Increased rebound indicates angular deviation
• Sloughing indicates insufficient early stiffness
• Dry appearance indicates moisture loss
• Pulsation indicates pump instability
This understanding allows corrective action before defects develop.
6. Training beyond basic instruction
Basic instruction teaches what to do.
Professional training teaches why it must be done.
Training programs must therefore include:
• Material behaviour education
• Equipment mechanics
• Application physics
• Safety principles
Without theoretical understanding, practical skill plateaus quickly.
7. Structured training progression
Competence develops progressively.
Typical progression includes:
• Observation and assistance
• Controlled spraying under supervision
• Independent spraying with monitoring
• Advanced application under variable conditions
Skipping stages results in incomplete skill development.
8. Importance of supervised practice
Supervised practice allows immediate correction of technique.
Small deviations in nozzle angle or distance may go unnoticed without experienced supervision.
Early correction prevents poor habits from becoming ingrained.
9. Certification and competence recognition
Formal competence recognition provides:
• Objective verification of skill
• Standardised performance expectations
• Confidence for engineers and clients
EFNARC has established certification schemes recognising nozzle operator competence based on defined performance criteria.
10. Role of supervisors and engineers
Supervisors and engineers play a critical role in performance control.
They must:
• Monitor application behaviour
• Review quality control data
• Identify trends
• Intervene early
Effective supervision is proactive rather than reactive.
11. Performance monitoring systems
Performance must be measured.
Key indicators include:
• Rebound percentages
• Thickness compliance
• Flow consistency
• Energy absorption results
These metrics provide objective insight into execution quality.
12. Feedback loops and continuous improvement
Performance data must be fed back to operators.
Constructive feedback allows operators to understand how their actions influence results.
This creates continuous improvement rather than repetition of errors.
13. Relationship between training and safety
Competent operators work more safely.
They anticipate risks, recognise abnormal conditions, and respond appropriately.
Training therefore reduces both accidents and quality defects.
14. Fatigue management and human limits
Shotcrete work is physically demanding.
Fatigue affects:
• Balance
• Reaction time
• Concentration
• Technique consistency
Work schedules must consider human limits to maintain performance.
15. Team coordination and communication
Shotcrete is a team operation.
Effective communication between:
• Pump operator
• Nozzle operator
• Assistant
• Supervisor
ensures stable application and rapid response to issues.
Poor communication leads to delays and unsafe conditions.
16. Leadership influence on performance
Leadership establishes behavioural standards.
When quality and safety are visibly prioritised, operators follow suit.
When production is prioritised above execution discipline, performance deteriorates.
17. Training as an investment
Training reduces:
• Material waste
• Rework
• Equipment damage
• Safety incidents
Well-trained crews consistently outperform untrained teams.
18. Competence retention and refresher training
Skills degrade over time without reinforcement.
Periodic refresher training maintains standards and incorporates updated practices.
Competence must be maintained, not assumed.
19. Integration of training into project planning
Training must be planned, not reactive.
Projects should allocate time for:
• Initial training
• Site-specific familiarisation
• Ongoing monitoring
This ensures performance stability from commencement.
20. Engineering conclusion
Shotcrete performance is ultimately delivered by people.
Equipment, materials, and procedures support the process, but competence governs the outcome.
EFNARC guidance recognises training and competence as essential to achieving reliable, safe, and durable sprayed concrete linings