Tyre Changing Heavy Vehicles Safe Work Method Statement

Split rims (also called multi-piece rims or lock ring rims) are wheel rim assemblies consisting of multiple separate components including rim base, side rings, and lock rings that mechanically interlock to create complete rim assembly holding tyre in position. Unlike single-piece rims used on most passenger vehicles which are manufactured as single continuous units, split rims can be disassembled by removing lock rings allowing tyre mounting and dismounting without specialized tyre machine equipment. This design was developed for large tyres used on trucks, earthmoving equipment, and agricultural machinery where tyre sizes and weights make conventional tyre mounting impractical. Split rim assemblies are inherently more dangerous than single-piece rims because their multi-component construction creates explosion hazards during inflation and dismounting operations. Lock rings that secure rim components together are held in rim grooves by mechanical interference and internal air pressure—if lock rings are not fully seated in grooves during inflation, increasing pressure can cause sudden violent separation where lock rings are launched as projectiles at extreme velocities (documented at 50-150 metres per second in incident investigations). Similarly, if workers attempt rim disassembly before tyres are completely deflated, residual air pressure causes explosive separation when lock rings are removed releasing stored pressure energy. The heavy mass of rim components (typically 10-100 kilograms for rings and 50-300 kilograms for rim bases) creates enormous kinetic energy when accelerated by explosive separation—equivalent to explosive fragmentation injuries documented in military ordnance incidents. Australian Standard AS 4457.1:2007 recognises split rim explosion hazards specifying mandatory safety cage use for all split rim tyre inflation operations, yet fatal incidents continue occurring when workers bypass safety cage use or fail to verify complete deflation before disassembly. Single-piece rims eliminate mechanical separation hazards as rim is continuous structure without removable components, and explosion risks are limited to tyre bead blowoff scenarios which are less severe than split rim component projection incidents. Workers must be able to identify split rim assemblies versus single-piece rims—split rims feature visible lock ring groove around rim circumference and separate side ring components, while single-piece rims have continuous rim flanges without separation joints. When in doubt about rim construction, treat all heavy vehicle and earthmoving equipment rims as split rims implementing safety cage use and complete deflation verification before any service operations.

Complete tyre deflation verification requires multiple redundant checks providing high confidence that zero residual pressure remains before commencing rim disassembly operations. Single verification method is inadequate as tyres can appear deflated while retaining hazardous pressure levels—comprehensive verification addresses multiple indicators and uses time delays allowing all trapped air to release. Start verification by removing valve core completely from valve stem using valve core removal tool rather than merely pressing valve pin, as complete core removal provides largest flow path enabling full deflation and visual confirmation of valve interior. Observe air release from valve stem for sustained flow—initial strong flow lasting several minutes is normal for large tyres, but flow should gradually diminish to nothing as deflation completes. Continue deflation until absolutely no air movement is detectable at valve stem by holding hand adjacent or placing tissue paper near valve observing for movement. After audible deflation ceases, wait minimum 10 minutes before proceeding as this delay allows air trapped in tyre void spaces, between tyre plies, or in damaged tyre structures to migrate to valve release path. This waiting period is non-negotiable time control preventing workers from rushing into disassembly before complete pressure equalisation. After waiting period, conduct physical sidewall depression test by applying leverage with tyre iron or pry bar against tyre sidewall—properly deflated tyre should visibly collapse under applied force with no springback resistance. Attempt to insert tyre wedge or similar blunt tool between tyre bead and rim—insertion should meet zero resistance if internal pressure is absent, while residual pressure creates resistance preventing insertion. Next perform bead breaking operations using hydraulic bead breaker or mechanical leverage tools forcefully separating both tyre beads from rim sealing surfaces around complete tyre circumference—this physical separation releases any remaining trapped air pockets and provides definitive confirmation no pressure remains. Bead breaking should occur easily without excessive force if tyre is truly deflated. For dual wheel configurations where two tyres share common hub, deflate both tyres independently using same verification procedures for each. Do not assume deflation of one tyre ensures second is also deflated—pressure can migrate between tyres through valve connections or through wheel hub cavities connecting wheel spaces. Some equipment features central tyre inflation systems (CTIS) connecting all tyres through manifolds—on CTIS-equipped equipment, verify inflation system is depressurised and disconnected before commencing service. If tyre will not deflate through normal valve stem procedures suggesting valve core blockage or seized valve mechanism, implement alternative deflation including drilling small hole in tyre sidewall well away from rim and working area (minimum 200mm from rim) allowing controlled pressure release. Mark the drill location and patch during tyre repair. Document deflation completion on work orders recording method used, verification checks performed, and workers' confirmation deflation is complete. This documentation provides accountability and prevents one worker assuming another has completed deflation when responsibility is ambiguous. Train all tyre service personnel that assumption tyres are deflated based on visual appearance or single check is fatal error—complete verification using multiple methods and time delays is only acceptable approach preventing explosive rim separation incidents during disassembly.

Australian Standard AS 4457.1:2007 specifies mandatory safety cage use for all heavy vehicle and earthmoving equipment tyre inflation operations without exception, and no alternatives to engineered safety cages are acceptable for ongoing operational use. The standard's absolute cage requirement reflects the severity and preventability of rim explosion incidents—safety cages engineered to contain explosive rim separation provide only reliable protection preventing fatalities, and any inflation approach without cage protection exposes workers to unacceptable fatal injury risks that are readily preventable through proper equipment use. Sites lacking safety cages must immediately procure or construct cages before any tyre inflation operations continue. In interim period before cage acquisition (maximum 2-3 days for emergency procurement of commercial cages), absolutely no tyre inflation work should occur other than emergency temporary inflation using extreme distance procedures detailed below. Long-term absence of safety cages represents serious WHS compliance failure and regulatory enforcement action including prohibition notices and prosecution would be expected outcomes of safety regulator inspection. For emergency temporary inflation in absolute emergency situations where operational necessity requires immediate tyre service before permanent cage installation (breakdown requiring urgent repairs to enable equipment operation), implement extreme distance inflation procedures: Position tyre assembly minimum 50 metres from any workers, buildings, or equipment using remote inflation lines long enough to reach from worker position to tyre. Use regulated air supply with pressure relief valve preventing overpressure beyond target inflation. Establish exclusion zone with physical barriers and warning signage preventing anyone approaching within 50 metres during inflation. Operator positioned behind substantial barrier (earth berm, heavy equipment, concrete structure) uses remote controls to inflate tyre while observing through binoculars or camera system from protected position. Inflate to maximum 170 kPa, then approach tyre to verify bead seating only after 30 minute waiting period allowing energy dissipation if delayed rim separation occurs. If bead seating is satisfactory, retreat to protected position and continue inflation to working pressure. This extreme distance method provides inferior protection compared to safety cages and should only be used once or twice in genuine emergencies before proper safety cage is procured—using extreme distance methods as standard practice is unacceptable risk management. For permanent solution, sites must procure commercial engineered safety cages meeting AS 4457.1:2007 requirements, available from industrial safety equipment suppliers with costs ranging $5,000-15,000 depending on capacity and features. Alternatively, sites can fabricate custom safety cages designed by qualified structural engineers and load-tested to verify containment capability—site-fabricated cages must demonstrate equivalent protection to commercial cages including strength to contain 200 kilogram mass at 10 metres per second impact velocity, structural design using minimum 10mm steel plate or equivalent, three-sided enclosure with rear opening for tyre insertion, and operational features including inflation controls positioned outside cage and pressure monitoring systems. Safety cage investment is small fraction of cost of single fatal rim explosion incident considering workers' compensation, business interruption, equipment damage, regulatory penalties, and reputational consequences. Budget constraints do not justify continued inflation without safety cage—work must cease until proper equipment is provided. Sites conducting frequent heavy vehicle or earthmoving equipment operations should install safety cages as standard workshop equipment providing reliable safe inflation capability for decades of service. Regular safety cage maintenance including structural integrity inspection, door operation verification, and inflation system checks ensures ongoing protection throughout service life.

Workers conducting heavy vehicle and earthmoving equipment tyre changing must demonstrate competency in recognising and managing specific hazards including split rim explosion risks, stored energy from pressurised tyres, manual handling of heavy components, and vehicle stabilisation procedures. Competency can be demonstrated through formal qualifications, structured workplace training, or combination approaches providing equivalent knowledge and skills. National competency unit AURKTJ011 'Remove, inspect and fit earthmoving and off-the-road tyres' defines comprehensive competency requirements including identifying tyre service requirements, safely deflating tyres and removing wheels, inspecting tyres and wheels for serviceability, mounting tyres using correct procedures, inflating tyres using safety cages, and fitting wheels to equipment using correct torque. This competency is delivered through registered training organisations offering Certificate II or III in Automotive qualifications with heavy vehicle or off-road tyre service specialisations. Training duration ranges from several days for experienced workers seeking formal recognition through recognition of prior learning, to several weeks for workers new to heavy vehicle tyre service requiring supervised practical experience developing competency. Workplace-based training programs can provide equivalent competency through structured approach combining theoretical instruction, supervised practical experience, and competency assessment. Theoretical training must cover Australian Standards requirements (AS 4457.1 and AS 4457.2), split rim construction and explosion hazards, complete deflation verification procedures, rim component inspection and rejection criteria, safety cage operation and inflation procedures, mechanical handling techniques for heavy components, vehicle stabilisation and support procedures, and emergency response for rim explosions or equipment collapse. Duration of theoretical training should be minimum 8-16 hours depending on worker experience. Practical training requires supervised hands-on experience conducting all tyre service operations under observation of competent supervisor or mentor, progressively building from basic tasks (deflation, wheel removal) through complex operations (rim disassembly, component inspection, reassembly, and inflation). Competency assessment verifies workers can independently conduct tyre service operations safely including demonstrating complete deflation verification procedures, correctly identifying damaged rim components requiring rejection, properly assembling multi-piece rim components with correct lock ring seating, operating safety cage and inflation equipment, and responding appropriately to abnormal conditions indicating problems. Assessment should include both written knowledge testing and practical observation of work performance in realistic service scenarios. Refresher training should occur annually or following procedural changes, covering incident case studies demonstrating consequences of procedural shortcuts, updates to Australian Standards or workplace procedures, and reemphasis on absolute requirements including safety cage use and deflation verification. Some organisations implement tiered competency levels distinguishing between workers authorised only for basic tyre service under direct supervision, intermediate workers authorised for routine services with general supervision, and fully qualified workers authorised for complex services including split rim assemblies and field service operations. Documentation of competency including training records, competency assessment outcomes, and authorisation to conduct tyre service independently provides evidence meeting WHS obligations. Maintain individual training files for all tyre service personnel including initial qualification documentation, workplace familiarisation records, competency assessments, and refresher training completion. Verify competency of all tyre service contractors before permitting site access, requesting evidence of formal qualifications or equivalent workplace competency assessment. Competency verification is PCBU responsibility and cannot be delegated—assumptions that workers 'must be competent because they've been doing it for years' are inadequate and have resulted in fatal incidents when workers with long experience lacked understanding of specific hazards and elected dangerous shortcuts under production pressure.

Systematic rim component inspection identifies damage requiring component replacement before reassembly preventing structural failures during subsequent inflation and service. Inspection addresses all rim components including rim base, side rings, lock rings, valve stems, and wheel mounting bolts examining for multiple degradation modes including cracks, corrosion, deformation, and wear. Start inspection with thorough cleaning removing all corrosion scale, accumulated dirt, grease, and debris using wire brushes and solvent cleaning, exposing actual metal surfaces beneath contamination enabling assessment of true component condition. Visual inspection conducted in good lighting conditions using magnifying glass for detailed examination identifies surface cracks appearing as fine lines or opened gaps in metal, corrosion pitting showing as pockmarks or craters in metal surfaces particularly in areas exposed to moisture accumulation, severe rust with substantial metal loss creating rough textured surfaces or through-thickness perforations, deformation from impacts appearing as dents or bent flanges distorting circular rim form, and lock ring grooves showing wear indicated by widening or depth reduction compared to original specifications. Cracks commonly initiate at stress concentration points including wheel bolt holes where cyclic loading creates fatigue damage, rim base to rim flange transition areas with sharp geometry changes, areas with previous mechanical damage including impact marks or welded repairs, and lock ring ends subject to bending stress during installation and removal. Critical crack inspection focuses on these high-stress areas using inspection techniques including visual examination with magnifying glass (minimum 4x magnification) identifying cracks as fine dark lines contrasting with cleaned metal surfaces, and dye penetrant or magnetic particle non-destructive testing for subsurface cracks not visible during visual inspection. Corrosion assessment evaluates pitting depth using depth gauges, measuring deepest pit dimensions comparing to 2mm rejection threshold, and evaluates overall corrosion extent determining whether localized corrosion in non-critical areas versus widespread deterioration affecting structural integrity. Severe corrosion particularly in lock ring grooves preventing proper component seating requires rejection even if measured pit depth remains below threshold. Deformation assessment using straight edges, radius gauges, or dimensional templates compares rim circular form to ideal geometry, measuring deviations at multiple circumferential positions. Deformation exceeding 5mm from true circular form requires rejection as distorted rims create uneven stresses during inflation and prevent proper tyre bead seating. Lock ring groove inspection includes dimensional measurement verifying groove depth and width remain within manufacturer specifications, as worn grooves may not adequately retain lock rings allowing dislodgement during service. Some organisations implement ultrasonic thickness testing measuring remaining metal thickness in corroded areas, particularly useful when external corrosion appearance suggests severe damage but extent of through-thickness metal loss is uncertain. Valve stem inspection verifies valve core moves freely without binding or excessive play, valve stem bodies show no cracks or deformation, rubber mounting grommets remain pliable without cracking or hardening, and valve stem length is adequate for rim depth enabling proper valve cap installation. Rejection criteria established in workplace procedures must provide clear unambiguous determination for component disposition including any visible crack regardless of length requiring immediate rejection—cracks propagate under cyclic loading and no crack is acceptable, corrosion pitting depth exceeding 2mm requires rejection—deeper pitting significantly reduces remaining metal strength, deformation exceeding 5mm from true circular form requires rejection—distorted rims create dangerous uneven stresses, lock ring groove wear reducing groove depth below minimum specification requires rejection—worn grooves cannot reliably retain lock rings, and any lock ring showing cracks at ring ends requires rejection—these high-stress areas commonly fail during service. Age-based rejection criteria supplement condition inspection, with some organisations implementing maximum service life limits (10-15 years for rim bases, 5-7 years for lock rings) recognising that metal fatigue develops even in absence of visible damage. Rejected components must be physically destroyed by cutting or crushing preventing inadvertent reuse by workers under production pressure who might consider 'using it one more time' despite known defects. Paint or permanently mark rejected components 'REJECTED FOR SAFETY - DO NOT USE' during period between rejection and destruction. Document rim inspection outcomes on inspection forms recording component identification, inspection date, inspector name, defects identified, and disposition decision (approved for service or rejected for replacement), maintaining records demonstrating systematic inspection and prompt rejection of unserviceable components. When inspection identifies questionable areas where rejection determination is uncertain, adopt conservative approach rejecting components rather than taking risk—component replacement cost is tiny fraction of consequences if questionable component fails explosively during subsequent inflation.

Rim explosion incidents during tyre service require immediate emergency response prioritising injured worker first aid, scene security preventing additional casualties, and emergency service notification ensuring rapid professional medical intervention. If rim explosion occurs despite safety cage use and procedures designed to prevent such incidents, immediate actions focus on worker safety and emergency medical response. First, immediately stop all inflation operations and ensure no additional personnel approach safety cage or surrounding area until situation is assessed and controlled. If explosion occurred outside safety cage contrary to procedures creating debris field and injury risks, establish initial exclusion perimeter minimum 20 metres radius around incident location preventing additional workers from entering hazard zone potentially containing projected rim components, damaged equipment creating ongoing hazards, or injured workers requiring immediate but cautious approach. Assess casualties from protected position observing from distance whether any workers are visible and their condition—do not rush into incident area without first assessing ongoing hazards including unstable equipment, pressurised air hoses whipping under residual pressure, or secondary explosion risks from remaining pressurised tyres. If casualties are observed and immediate life-threatening conditions are apparent (unconsciousness, significant bleeding, entrapped beneath equipment), designate one worker to immediately call emergency services (000) reporting tyre service incident with explosion injuries, providing specific location, number of casualties, and nature of injuries known. Second responder approaches casualty cautiously watching for ongoing hazards, providing immediate first aid focusing on life threats including controlling severe bleeding with direct pressure using available cloth materials, maintaining airway and breathing for unconscious casualties using recovery position or rescue breathing, preventing shock by keeping casualty warm and reassured, and stabilising suspected spinal injuries preventing movement until paramedics arrive. Do not attempt to move casualties unless immediate danger (fire, additional explosion risk, unstable equipment collapse threat) requires evacuation to safer location, in which case move using spinal precautions if possible. Third responder secures incident scene deploying physical barriers or assigning personnel to prevent unauthorized entry, accounting for all personnel verifying no missing workers may be in hazard area, gathering witness statements from personnel observing incident for subsequent investigation, and preserving evidence photographing equipment position, rim component locations, and incident scene condition before disturbance. If casualties are entrapped beneath equipment or heavy rim components, do not attempt rescue without adequate equipment and personnel—improper rescue attempts create additional casualties when equipment collapses or shifts during rescue. Request specialized rescue resources including heavy rescue trucks with airbags and cribbing capable of safely lifting heavy equipment from casualties, with fire service heavy rescue teams typically providing these capabilities. For conscious casualties with significant injuries, provide reassurance and comfort while awaiting professional medical response, monitoring vital signs and consciousness level, and recording any changes in condition communicated to incoming paramedics. After casualties are evacuated and emergency medical phase concludes, implement incident investigation retaining all equipment and components in as-found condition for examination, interviewing all witnesses documenting incident sequence and causal factors, examining rim components for defects or assembly errors contributing to explosion, and reviewing procedures to identify prevention opportunities for similar future incidents. Notify regulatory authorities as required for serious injuries including WorkSafe or equivalent state WHS regulator for injuries requiring hospitalization or resulting in fatalities, preserving incident scene until regulator inspection if serious outcome incident. Conduct comprehensive investigation identifying root causes which commonly include inflation without safety cage use, inadequate deflation verification before rim disassembly, improper rim component assembly with unseated lock rings, use of damaged deteriorated rim components, or overpressure from unregulated inflation equipment. Implement corrective actions preventing recurrence including immediate procedural reinforcement, equipment upgrades, enhanced training, or operations suspension until satisfactory controls are established. Provide psychological support for workers involved in or witnessing incident, recognising traumatic nature of serious injury incidents and offering employee assistance program counselling to affected personnel. Review incident outcomes with all tyre service personnel ensuring lessons learned are understood and reinforcing absolute importance of following safety procedures including safety cage use and deflation verification. Fatal and serious injury tyre service incidents are preventable through consistent application of established controls—incidents represent system failures where procedures were not followed, equipment was inadequate, or supervision was insufficient, requiring organizational learning and improvement rather than attributing solely to individual worker error.