Roof Edge Protection Safe Work Method Statement

Australian Standard AS/NZS 4994.1 specifies that top rails on edge protection systems must be installed at a minimum height of 900mm and maximum height of 1100mm above the floor, roof, or working surface being protected. This range is critical for effectiveness—rails below 900mm allow workers to topple over the barrier when falling against it, whilst rails above 1100mm may encourage workers to duck under rather than use designated access points. The top rail provides the primary fall prevention barrier, intercepting workers who lose balance or step backwards toward edges. Measurements should be taken from the actual working surface to the top of the rail, accounting for any surface irregularities, overlays, or floor build-ups. Where roof surfaces are sloped, measurements should be taken perpendicular to the slope. Installation plans should specify exact top rail heights within the compliant range, with heights typically set at 1000mm providing mid-range compliance. During installation and ongoing inspections, actual installed heights must be measured and documented at multiple locations along each edge protection run, as height can vary due to uneven surfaces or installation errors. Any sections found to be outside the 900-1100mm range must be adjusted immediately.

AS/NZS 4994.1 specifies maximum post spacing of 2.0 metres centre-to-centre for edge protection systems. This spacing limit ensures that horizontal rails can resist specified loads without excessive deflection between supports. Wider spacing allows rails to deflect more when horizontal loads are applied, potentially creating gaps between rails that workers can slip through, or allowing total rail deflection that reduces protection effectiveness. The 2-metre maximum applies to standard edge protection configurations—some proprietary systems with engineered rail sections may permit different spacing if supported by engineering calculations and certification. However, using spacing wider than 2 metres without specific engineering approval constitutes non-compliance and creates heightened fall risks. Installers should mark post positions at intervals not exceeding 2 metres before commencing installation, accounting for corners, gate locations, and interfaces with other structures. Actual installed spacing must be measured during post-installation inspection to verify compliance. On sites where edge protection must interface with existing structures, building columns, or other obstructions, post positions may need adjustment from regular spacing, but must never exceed the 2-metre limit. Where irregular spacing is unavoidable, additional engineering review should confirm that load capacity and deflection limits are maintained.

Acceptable fixing methods for roof edge protection depend on the structural conditions at the edge being protected and must be selected to ensure fixings can resist specified horizontal loads of 0.35kN per metre on top rails plus vertical loads. Pin-fixed systems insert vertical posts into pre-formed or drilled holes in concrete slabs, with pins extending sufficient depth to develop adequate pull-out resistance, typically 100-150mm minimum depth depending on concrete strength and hole diameter. Clamp-mounted systems use mechanical clamps attached to slab edges, structural steel members, or formwork, with clamp jaw engagement verified and bolts tightened to specified torque. Weighted freestanding systems use counterweighted bases that resist overturning through gravitational forces, with counterweight mass calculated based on post height, rail spans, and roof slopes to ensure adequate stability factors. Each fixing method has appropriate applications—pin-fixed systems are ideal for concrete construction with accessible slab edges, clamp systems suit structural steel or formed slab edges, whilst freestanding systems are necessary where roof membrane penetration must be avoided. Inappropriate fixing methods include screws into thin sheeting materials, tie-off to services or conduit, attachment to incomplete formwork, or under-weighted freestanding systems. All fixing methods must be verified through post-installation load testing and inspection. On complex buildings with varying edge conditions, multiple fixing methods may be used in different locations, with appropriate systems selected for each condition.

WHS regulations in most Australian jurisdictions require edge protection to be inspected at least weekly throughout the period it remains installed, with additional inspections required following any event that may affect structural integrity. Weekly inspection frequency recognises that construction sites are dynamic environments where edge protection can be damaged, displaced, or deteriorated through normal construction activities, weather exposure, and interaction with trades. Inspections must be documented on checklists recording findings, deficiencies identified, rectification actions taken, and inspector identity and date. Beyond weekly schedules, additional inspections are required after severe weather events including high winds or storms that may have displaced components, after any impact from mobile plant or materials handling that strikes edge protection, following scaffold alterations adjacent to edge protection systems, and after any reports of damage or concerns from workers. Daily visual checks by supervisors and leading hands supplement formal weekly inspections, providing continuous monitoring of obvious deficiencies. Post-installation certification inspection by competent persons should occur immediately following installation before the system is released for general construction use. All inspection findings must be acted upon immediately, with work stopped in areas where edge protection deficiencies create fall hazards until rectification is completed. Records of inspections form critical evidence of ongoing compliance and due diligence, and must be retained throughout the project and for specified periods post-completion.

Workers installing edge protection systems face the paradox that they must work at unprotected edges to install the barriers that will protect others. This creates mandatory requirements for personal fall arrest protection during installation operations. All installers must wear full body harnesses compliant with AS/NZS 1891.1 with current inspection tags, connected via shock-absorbing lanyards to secure anchor points rated to 15kN minimum throughout all work within 2 metres of unprotected edges. Anchor points must be pre-existing certified anchorage, or temporary anchor systems installed by competent persons before edge protection work commences. Horizontal lifeline systems can provide continuous anchorage allowing installers to move along edges whilst maintaining connection. Installation procedures should be designed to minimise time spent at unprotected edges by pre-assembling components in safe areas, using mechanical aids to position heavy items, and working progressively from protected areas toward edges. Two-person installation teams provide mutual monitoring and assistance. Rescue procedures and equipment must be in place before installation work at height commences, as fall arrest only prevents workers hitting the ground—rescue from suspended position must be implemented within minutes. Installers must be trained and competent in both edge protection installation and fall arrest equipment use. Site-specific risk assessments should identify high-risk installation areas requiring additional controls such as catch platforms, safety nets, or elevating work platforms that reduce reliance on personal fall arrest alone.

Temporary removal of edge protection to facilitate specific construction activities should be avoided wherever possible through careful work planning and use of alternative methods. However, when temporary removal is genuinely necessary and alternative methods are not reasonably practicable, strict permit-to-remove procedures must be implemented. These procedures require formal risk assessment identifying why removal is necessary and what alternative fall protection will be provided, typically personal fall arrest systems for all workers who may be exposed to edges during the removal period. Permits must document the specific section to be removed, exact duration of removal, personnel authorised to work in the affected area, alternative fall protection systems required, and specific responsibility for reinstallation with timeframe. Only competent authorised personnel should be permitted to remove edge protection components, and the affected area must be barricaded or controlled to prevent unauthorised access whilst protection is absent. The removed section must be reinstalled and inspected before the end of each work shift—overnight removal is prohibited. All workers potentially exposed must be briefed on the temporary removal and alternative protection requirements. Principal contractors must approve all permit-to-remove requests before removal occurs. Repeated or routine temporary removal indicates inadequate work planning and should trigger review of construction sequences to eliminate the need for removal. Documentation of all temporary removals must be maintained as part of site safety records.