Demolition projects generate some of the highest respirable dust and silica concentrations of any construction activity. Concrete breaking, masonry removal, floor sawing, and site preparation all create intense dust plumes. Effective dust monitoring must begin before work starts and continue through completion—a three-phase approach that protects workers, manages liability, and ensures project compliance.
This guide walks through pre-demolition planning, during-works monitoring, and post-demolition clearance protocols.
Why Three-Phase Monitoring Matters
Demolition is not a static activity. Dust generation varies dramatically depending on:
- Which materials are being removed (concrete, masonry, plaster, asbestos-containing materials)
- What tools and methods are being used (breakers, saws, excavators, hand labour)
- Environmental conditions (wind, humidity, temperature)
- Control measures in place (water suppression, enclosures, ventilation)
- Time of day and work intensity
A single monitoring snapshot captures only one moment. Three-phase monitoring—before, during, and after—builds a complete picture and demonstrates due diligence.
Phase 1: Pre-Demolition Monitoring and Assessment
Hazardous Materials Survey
Before any dust monitoring design, you must conduct a hazardous materials assessment:
- Asbestos survey: Identify all asbestos-containing materials (ACM). Asbestos fibres and silica dust are distinct hazards but often co-occur (asbestos cement products contain silica). The presence of ACM affects work methods and monitoring strategy
- Silica content assessment: Determine which building materials contain crystalline silica. Concrete, masonry, stone finishes, and floor screed all contain silica. Some buildings have specific high-silica materials (granite cladding, limestone, terrazzo) that elevate risk
- Building survey documentation: Review architectural and structural plans to identify material types and locations
This information is essential because it guides where to place monitors and which workers to sample.
Dust Risk Assessment
Conduct a formal dust risk assessment for the demolition scope:
- Identify high-dust tasks: Concrete cutting and breaking, floor removal, masonry demolition, excavator work, vehicle movement and unloading
- Estimate exposure potential: Which tasks generate the most dust? Who will be exposed? For how long?
- Assess baseline conditions: Is the site in an urban area with sensitive receivers nearby? Is it a warehouse or enclosed structure? These factors affect monitoring strategy
- Review planned control measures: What dust suppression and enclosure is the demolition contractor planning? Are controls realistic and effective?
- Identify monitoring requirements: Based on tasks and controls, determine what personal and area monitoring is needed
Monitoring Design
Based on the risk assessment, design a monitoring plan:
Personal Sampling Targets:
– Concrete breaker/jack hammer operator
– Concrete saw operator (floor sawing)
– Excavator operator (if not in enclosed cab with filtration)
– Site labourer involved in manual removal or material handling
– Site supervisor or spotter (may be exposed to background dust)
Number of samples: Typically 3–5 personal samples per monitoring event, targeting highest-exposure roles
Area/Static Monitors:
– Site boundary monitors: Typically downwind and at the property line, to confirm dust isn’t migrating beyond the site and exposing the public
– Site interior monitors: If there’s an enclosed structure being demolished, place monitors inside to document air quality in the active work zone
Baseline Monitoring Timing: Schedule baseline monitoring for the first 1–2 weeks of active demolition work, capturing initial high-risk tasks under typical conditions.
Phase 2: During-Demolition Monitoring
Personal Air Sampling
Conduct personal sampling on a regular schedule:
High-intensity demolition phase (concrete breaking, heavy machinery work):
– Frequency: Weekly or every 2 weeks if daily work intensity is high and controls are new/untested
– Workers sampled: The highest-exposure roles (breaker operator, excavator operator, site labourer most exposed)
– Sampling duration: Full shift (typically 8 hours) during a day when high-dust work is planned
– Rationale: High-dust phases carry the greatest risk; weekly sampling allows rapid response if exceedances occur
Lower-intensity phases (selective demolition, final cleanout, finishing):
– Frequency: Every 2–3 weeks or at shift-change if different crews rotate in
– Rationale: Lower dust intensity but still hazardous; less frequent monitoring is acceptable
Static/Area Monitoring
Run continuous or multiple static monitors throughout the demolition:
Site boundary monitoring:
– Place monitors downwind of the active work area (confirm with site supervisor or wind monitoring)
– Run for 4–8 hours during high-dust work periods
– Purpose: Confirm dust is not exceeding background levels beyond the site boundary; documents community exposure (important for liability management)
Site interior monitoring (if demolishing enclosed structures):
– Place monitors in active work zones, break areas, and exit routes
– Use real-time monitors for immediate feedback on dust levels and control effectiveness
– Allows on-site decision-making: if real-time levels spike, trigger additional water suppression or work pause
Real-Time Process Control Monitoring
Deploy a real-time dust monitor (optical particle counter or equivalent) in high-risk work zones:
Benefits:
– Immediate feedback to site supervisor and work team
– Enables rapid response if dust exceeds trigger levels
– Identifies which tasks or conditions generate the most dust
– Allows optimisation of controls in real-time
How it works:
– Place monitor in the breathing zone or near the highest-dust activity
– Set an alarm threshold (e.g., 0.5 mg/m³ or site-specific level)
– When the alarm triggers: pause work, increase water suppression, activate additional ventilation, or implement other controls
– Document all triggers and responses
Trigger-Action Response Protocol: Develop a simple written protocol:
– “If real-time monitor reads above X mg/m³, immediately increase water suppression on the active task”
– “If reading exceeds Y mg/m³, pause that task and review controls”
– “If readings remain high after control upgrade, cease work and consult the occupational hygienist”
Exceedance Response
If any personal sample result exceeds the WorkExposure Standard (0.05 mg/m³ RCS):
- Notify affected workers within 24–48 hours; provide a copy of the result
- Analyse what went wrong: Which task, which day, what conditions? (Discuss with site supervisor and occupational hygienist)
- Upgrade controls immediately: Increase water suppression intensity, improve ventilation, modify work method, or restrict the high-risk task
- Re-sample within 2–3 weeks to confirm controls are effective
- Document all actions and decisions in the monitoring report
Phase 3: Post-Demolition Monitoring and Clearance
Confirmation Monitoring
Once demolition work is complete, conduct confirmation monitoring before releasing the site to subsequent trades:
Purpose: Verify that dust has settled and the site is safe for other trades (builders, electricians, plumbers, etc.) to enter
Timing:
– Immediately after the final dust-generating work ceases (may be hours or 1–2 days depending on site ventilation)
– Before other trades are allowed on site
– Before the site is handed to the next contractor
Sampling strategy:
– Run static monitors in the main work areas and common areas (passageways, break areas, entries)
– Sample for 4–6 hours to capture baseline air quality after dust has settled
– Compare results to background levels (from pre-demolition baseline)
– If results are elevated above background, allow more settling time and re-sample, or conduct final cleaning (wet mop, HEPA vacuum) to remove residual dust
Final Documentation and Clearance Report
Compile a demolition monitoring summary report that includes:
- Scope: What was demolished, where, over what time period
- Baseline findings: Pre-demolition air quality and hazardous materials identified
- During-works data: All personal and static monitoring results, with key findings and any exceedances
- Control measures: Description of dust suppression and containment used; any upgrades or changes made during the project
- Post-works confirmation: Final air quality testing and clearance decision
- Health monitoring: Records of any workers exposed above the WES; recommendations for occupational health follow-up
- Data tables and graphs: All raw monitoring data, clearly presented
Clearance sign-off: The occupational hygienist and site supervisor should jointly sign off that the site is safe for entry by other trades.
The Role of the Competent Person
Demolition regulations require a competent person to oversee dust monitoring and control:
- Responsibilities: Reviewing monitoring plans, ensuring sampling is executed correctly, interpreting results, and making decisions about work changes
- Qualifications: Typically an occupational hygienist (AIOH member preferred) or other qualified WHS professional with specific demolition experience
- On-site presence: For large demolition projects, the competent person should visit regularly (weekly during high-dust phases) to verify controls and review real-time data
- Reporting: Provide written updates to the principal contractor and client
Frequently Asked Questions
Q: How much does demolition monitoring cost?
Typical cost: $3,000–$7,000 per monitoring event (including personal and area sampling, real-time monitoring setup, and initial report). Full project cost depends on demolition duration: a 4-week project with weekly monitoring and post-works confirmation may cost $15,000–$25,000. This is usually split between the principal contractor and client. Budget it as part of project cost, not an optional extra.
Q: Can I use a general construction site monitoring contractor, or do I need a specialist in demolition?
Specialisation matters. Demolition dust monitoring requires understanding of high-intensity dust generation, rapid control changes, and the specific hazard profile. Whilst many construction monitoring providers can do it, experienced demolition-specific providers (like Anitech) bring valuable expertise in high-risk task identification and trigger-action protocols.
Q: What if the site is very large and spread over multiple locations?
For large demolition projects, design a tiered monitoring approach: intensive sampling in the primary high-dust areas during active demolition, lighter sampling in lower-risk zones. Use static/area monitors for broad coverage and personal samples for focused high-exposure assessment. Discuss sampling strategy with your occupational hygienist to balance coverage and budget.
Q: Do I need enclosures or water suppression for all demolition work?
Best practice is to use water suppression on all concrete cutting and concrete breaking. Enclosures are valuable for fine control (floor sawing, internal work) and for containing asbestos removal (if applicable). Not every task requires both, but high-dust tasks should have at least one primary control in place, supplemented by good site housekeeping and RPE where necessary.
Q: What if weather conditions (high wind, rain) disrupt monitoring?
Document weather conditions on monitoring days (wind speed, humidity, temperature). These factors affect dust levels and should be noted alongside results. Rain can temporarily suppress dust but does not eliminate the need for active controls. If conditions are severely adverse (extreme wind, heavy rain), reschedule sampling to a more representative day.
Q: Can I do demolition monitoring if I don’t have baseline pre-demolition data?
Ideally, yes you should have baseline data to compare post-work results against. However, if baseline wasn’t collected, you can still conduct during-works and post-works monitoring using regulatory standards (WES 0.05 mg/m³) and industry reference levels as comparison points. Going forward, ensure baseline is captured at the start of future projects.
Supporting Major Demolition and Construction Projects Nationally
Demolition monitoring is fast-paced and high-stakes. Results inform real-time control decisions and protect workers from acute exposure incidents. Anitech Group provides end-to-end demolition monitoring services: hazard assessment, monitoring design, weekly sampling, real-time process control, and post-works clearance.
Whether you’re managing a small demolition or a major CBD redevelopment, request a project-specific monitoring program design and quote.
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- FEATURE: 1200x630px. Demolition site in action: excavator breaking concrete; visible dust cloud with water suppression spray system in operation; real-time dust monitor on tripod in the foreground; site boundary marker visible in background; professional documentation of three-phase monitoring in progress.
- BODY_1: 800x450px. Close-up of a personal air sampling cassette being attached to a concrete breaker operator’s lapel and clothing (hard hat, high-visibility vest visible); occupational hygienist or site monitor fitting the equipment; professional setup documentation; represents “Phase 2: Personal Sampling” section.
