Concrete Sawing and Core Drilling Safe Work Method Statement

Wet cutting is the preferred and most effective method for controlling crystalline silica dust during concrete cutting operations, reducing airborne dust by 85-95% compared to dry cutting. Safe Work Australia's Code of Practice on Managing Crystalline Silica Exposure recommends wet cutting as the primary control method. Dry cutting should only be used in specific circumstances where wet cutting is impractical due to electrical safety concerns, freezing conditions, or water contamination risks. When dry cutting is necessary, on-tool dust extraction using industrial HEPA-filtered vacuum systems is mandatory, combined with respiratory protection (P2/P3 respirators), atmospheric monitoring to verify dust levels remain below exposure standards, work area isolation to prevent exposure to other workers, and limitation of cutting duration to reduce individual exposure. Even with optimal dust extraction, dry cutting typically cannot achieve the same low airborne dust concentrations as wet cutting. Many jurisdictions and project specifications specifically prohibit dry cutting due to extreme silica exposure risks. The combination of wet cutting plus on-tool extraction provides maximum dust suppression for high-risk operations including extended cutting in confined spaces. Employers must conduct documented risk assessment before permitting any dry cutting operations, demonstrating wet cutting is impractical and that additional controls will maintain exposures below workplace exposure standards.

Minimum respiratory protection for concrete cutting and drilling is a P2 particulate respirator certified to AS/NZS 1716, providing 95% filtration efficiency for crystalline silica particles. P3 respirators with 99% filtration efficiency provide superior protection for extended operations. Critical requirements include individual fit-testing to ensure effective seal against each worker's face, with testing documented and repeated annually or when facial characteristics change. Disposable P2/P3 filtering facepiece respirators are suitable for short-duration cutting operations but must be replaced when damp from breath moisture or visibly loaded with dust. For regular or extended cutting work, half-face reusable respirators with replaceable P2 or P3 filter cartridges provide better comfort, seal, and cost-effectiveness. Powered air-purifying respirators (PAPRs) with P3 filters are recommended for full-shift cutting operations, providing positive-pressure filtered air that reduces breathing resistance and maintains protection even if seal is temporarily compromised. PAPRs are essential for workers who cannot achieve effective seal with negative-pressure respirators due to facial hair or facial structure. Facial hair including beards and heavy stubble prevents effective seal for negative-pressure respirators and requires either clean-shaven faces or supplied-air respirators. All workers must be trained in correct respirator donning, user seal checking, and recognising when replacement is required. Respiratory protection is essential even when wet cutting is used, as wet methods do not completely eliminate airborne silica dust. Respiratory protection serves as final control layer protecting against residual exposure not eliminated by engineering controls.

Selecting appropriate diamond cutting blades requires matching blade specifications to concrete properties, equipment characteristics, and cutting application. Key selection criteria include blade diameter and arbor size matching saw equipment, maximum blade operating speed (RPM) meeting or exceeding tool speed, blade type designed for concrete, masonry, or specific materials being cut, segment bond hardness matched to concrete hardness (hard bond for soft concrete, soft bond for hard concrete), wet or dry use designation matching cutting method, and specialised blades for reinforced concrete or materials containing metal. Verify blade speed rating prominently displayed on blade body never allows use of slow-speed blades on high-speed grinders, as this causes immediate catastrophic failure. General purpose concrete blades work for standard concrete, but hard aggregates including granite or quartz require harder diamond concentrations and specialized segment designs. Cutting asphalt requires specific asphalt blades as standard concrete blades wear rapidly. For concrete containing significant rebar, blades designated for reinforced concrete include segments designed to cut both concrete and steel without premature wear. Green concrete (newly placed, not fully cured) requires specialised early-age cutting blades. Diamond blade quality varies substantially - premium blades from reputable manufacturers provide longer life, faster cutting, and reduced failure risk compared to cheap alternatives. Before each use, inspect blades for cracks, missing segments, warping, and wear, rejecting any damaged blades. During cutting, monitor blade performance - unusual vibration, wobbling, or difficulty cutting indicates blade damage requiring immediate replacement. Replace blades when segment height wears to manufacturer minimum specifications, before complete loss that could cause core breakage. Store blades properly hung or laid flat to prevent warping, and never drop blades as impact can cause invisible cracks that propagate rapidly during use.

Silicosis is an irreversible lung disease caused by inhaling crystalline silica dust, with symptoms developing gradually over months to years depending on exposure intensity. Early silicosis often produces no symptoms, with disease detected only through health surveillance including chest X-rays. As disease progresses, symptoms include shortness of breath initially only during exercise but progressively occurring at rest, persistent dry cough, chest tightness or pain, fatigue and reduced exercise tolerance, weight loss and loss of appetite, and susceptibility to respiratory infections including tuberculosis. Acute silicosis can develop within months in workers exposed to very high silica concentrations from extensive dry cutting without protection, causing rapid onset severe breathlessness, cough, fever, and weight loss that can be fatal within one to two years. Chronic silicosis develops over 10-30 years of lower-level exposure, with progressive breathlessness and cough. Accelerated silicosis occurs with 5-10 years of higher exposure. Once established, silicosis is irreversible and progressive, continuing to worsen even after silica exposure ceases. There is no cure, with treatment limited to managing symptoms, preventing complications including tuberculosis infection, and in advanced cases, lung transplantation. Detection requires health surveillance program including pre-employment baseline chest X-ray, respiratory health questionnaire, and spirometry (lung function testing), with follow-up X-rays every two years for workers with regular silica exposure. Any worker experiencing progressive breathlessness, persistent cough, or other respiratory symptoms should seek medical assessment immediately, informing doctor of occupational silica exposure history. Early detection allows cessation of further exposure and appropriate medical monitoring, though cannot reverse existing damage.

Concrete cutting generates substantial quantities of silica-contaminated waste including concrete slurry from wet cutting, dust collected in HEPA vacuum systems, cut concrete sections, and water used for dust suppression. This waste requires proper handling and disposal to prevent silica exposure during cleanup and disposal. Wet cutting slurry containing concrete particles, water, and silica dust should be collected in containment systems including sumps or vacuum collection tanks, allowed to settle, with water decanted and recycled or disposed through approved environmental channels, and settled solids collected and disposed as solid waste. Never discharge concrete slurry directly to stormwater systems as this causes environmental contamination. Dust collected in HEPA vacuum extraction systems must be wetted with water spray before emptying vacuum bags or tanks to suppress dust generation during transfer. Transfer wetted dust to sealed plastic disposal bags or containers clearly labeled as containing silica dust. Dispose of silica-contaminated waste as hazardous waste through licensed waste contractors, or at approved landfill sites accepting construction waste if local regulations permit. Never empty dust collection bags by shaking, compressed air blowing, or other dry methods that create extreme airborne dust exposures. Workers handling silica waste must wear appropriate respiratory protection (P2/P3 respirators), protective gloves, and protective clothing. Cut concrete sections can be disposed as construction rubble but should be wetted to suppress dust during handling, loading, and transport. Equipment cleaning should use wet methods including hosing or damp cloth wiping, with cleaning water containing concrete residue collected and disposed appropriately rather than washing to stormwater. Implement documented procedures for waste handling and disposal, train workers on procedures, and maintain records demonstrating proper disposal. Environmental regulations in your jurisdiction may impose additional requirements for concrete waste disposal, particularly regarding alkaline water discharge and sediment control.

Hand-arm vibration exposure limits are established to prevent Hand-Arm Vibration Syndrome (HAVS), with exposure calculated based on vibration magnitude (measured in metres per second squared, m/s²) and exposure duration. Safe Work Australia guidance references international standards including European Union Directive 2002/44/EC establishing exposure action value of 2.5 m/s² (8-hour time-weighted average) and exposure limit value of 5 m/s². Handheld concrete cutting equipment including angle grinders, handheld saws, and jackhammers typically produce vibration levels of 5-15 m/s² depending on equipment design, maintenance, and cutting conditions. Using published vibration data or measuring actual equipment, calculate daily exposure using formula that accounts for vibration magnitude and exposure time. For example, equipment producing 8 m/s² vibration reaches exposure action value after approximately 1 hour of continuous use, and exposure limit value after 4 hours. Higher vibration equipment requires proportionally shorter exposure times. Practical controls include selecting modern anti-vibration equipment designed with vibration damping, maintaining equipment properly as worn components increase vibration, limiting continuous tool operation periods to 30 minutes with breaks allowing blood circulation to recover, using correct cutting techniques without excessive grip force or pressure that increases vibration transmission, keeping hands warm with gloves and breaks in heated areas (cold amplifies vibration effects), and implementing job rotation so individual workers do not exceed safe daily exposure levels. Employers must assess vibration exposure for equipment used, comparing against action and limit values, and implementing controls ensuring exposures remain below limits. Workers should report early symptoms including finger tingling, numbness, or blanching, as early intervention by reducing exposure can prevent progression to irreversible HAVS. Once established, HAVS is permanent and progressive, making prevention through exposure control essential.