4.2 Collective Fall Protection: Guardrails, Floor Openings, Nets and Catch Platforms

Collective first

The CDM 2024 First Schedule gives collective protective measures priority over individual protective measures. DOSH's falls guideline (section 10.5) says the exposed edges of all floors and work platforms from which a fall of 2 metres is possible shall be fitted with guardrails, with toe-boards where objects could fall and endanger people below. Only where guardrails are impractical should other fall protection, such as nets or harnesses, be used. While guardrails are being erected, the erectors themselves use other fall protection, such as harnesses and lines.

Guardrails and toe-boards

DOSH falls guideline requirements

What the SSS checks

• Continuity: no gaps at corners, column positions, stair landings or lift shafts
• Fixing: stanchions into cast-in sockets, clamps or bolted bases as the system design requires, not wedged into rebar
• Removal control: sections removed for crane landings are replaced at once. Anyone working near the gap uses fall arrest (falls guideline section 10.2). Use a lifting-zone gate where loads land often.
• Brick guards or mesh where materials are stacked higher than the toe-board
• Damage after crane or material impacts; inspect after storms
• Guardrails are not anchors. DOSH's guideline says not to use guardrails as fall-arrest anchors, because they are not designed for arrest forces.

Floor openings, wall openings and shafts

CDM 2024 regulation 19(3) requires every floor opening that could cause a fall to be suitably and sufficiently guarded to prevent a fall from any height. DOSH's guideline adds detail:

Making covers fail-safe

• Fix them: cleats underneath that locate inside the opening, or bolts or clamps so the cover cannot slide.
• Make them strong enough: design for the heaviest load likely, including wheelbarrows and stacked materials, not just a person. Thin plywood offcuts are a common cause of falls through openings.
• Mark them: for example "AWAS: LUBANG / DANGER: HOLE – DO NOT REMOVE", with hazard striping.
• Control removal: only with the supervisor's permission, with edge protection or fall arrest in place, and with immediate replacement. Put this in the site rules.
• Lift shafts: full-height barriers or gates at every landing; protection inside the shaft for installers.

Safety nets

DOSH's falls guideline section 7 requires that:

• safety nets comply with BS 3913 or another acceptable industrial standard, and are of a type tested and approved by a testing body approved by the Director General
• nets are rigged by trained personnel
• nets are inspected daily for wear or damage and rejected if damaged
• nets are stored dry and shaded, and protected from combustibles, chemicals and welding slag

DOSH's public safety guideline (section 20.2) adds that:

• nets are anchored to supports outside and beyond the area of a possible fall, high enough that a falling person does not hit a surface or object below
• nets are big enough and strong enough for the area of possible fall
• broken nets are not installed
• a designated person inspects them before each installation, and nets and supports are inspected daily afterwards
• peripheral nets envelop scaffolds where falling objects could endanger pedestrians or traffic

BS 3913 has since been replaced in Britain by the European standard EN 1263. EN 1263-1 defines four net systems:

Under EN 1263-2, nets are rigged as close as practicable below the work surface, and the fall height into a horizontal net is limited to 6 m or less. Nets carry test meshes, which are removed and tested at intervals of no more than 12 months to check for UV and age degradation. Clear debris from nets at once: debris reduces the net's capacity to absorb a fall and can impale anyone who falls onto it.

Catch platforms and fans

Catch platforms and fans intercept falling materials before they reach workers or the public:

• DOSH's public safety guideline (section 20.3) recommends catch platforms along exterior walls to protect the public below, and gantries over pavements where materials could fall on pedestrians or traffic (section 11.4).
• For demolition of the exterior walls of structures originally more than 12.2 m high, the guideline (section 14.3, written under the former BOWEC regulation 43) says catch platforms should be designed by a Professional Engineer, kept no more than 6 m below the storey being demolished, and never used for storage or as a working platform or walkway.
• The former BOWEC regulation 44 specified catch platforms at least 1.5 m wide, inclined so the outer edge is 152 mm higher than the inner edge, with ends fenced to at least 0.9 m and designed for a live load of at least 735 kgf/m². These figures remain a useful design reference, but today the temporary works design under CDM regulation 21 decides.

Scenario: the Level 14 walkabout

The SSS finds:

1. A 2.0 x 2.5 m lift-shaft opening covered with unfixed 12 mm plywood that workers walk across
2. Perimeter guardrail at 0.85 m with no toe-board
3. Timber offcuts and a steel conduit lying in the Level 12 fan net

Actions:

1. Stop access across the lift-shaft opening at once. Fit a cover designed for the loads, fixed with cleats and marked, or a full barrier with a gate. Record the hazard as a near miss.
2. Raise the guardrail to the 0.9–1.1 m range, add a midrail and toe-board, and check the system's tested configuration.
3. Clear the net using a safe method, inspect it before reuse, and tell the trade above to stop dropping materials.
4. Add "opening cover removal" to the permit or site rules, and brief all trades at the next toolbox meeting.