Best Practice Penetration Prevention

Guarding of holes and openings

Holes, penetrations and openings in roofs and other structures need to be made safe immediately after they are formed.

Holes or openings in concrete floors need to be, where reasonably practicable, guarded with embedded wire mesh and covered with material that is strong enough to prevent objects or people falling through.

Holes or openings in any other type of (non-concrete) floor need to be covered with material that is strong enough to prevent objects or people falling through and need to be securely fixed to the floor.

Holes or openings covered with wire mesh should not be used as a work platform. When installing services, only the part of the wire mesh that allows access for installation needs to be removed, and the cover needs to be modified to fit around the installed service.

All covers need to be securely fixed and marked clearly with the words ‘Danger - Hole Beneath’.

Commercially available penetration guarding

This type of guarding can provide an effective and economical solution against falls through unguarded penetrations and ground openings in construction work, Confined space work and civil works applications.

These guarding systems can be a locked safety device that serves as an access cover in the closed position and a four sided guard rail in the open position.

This equipment is an improved fall protection safety barrier and, in particular, a collapsible and portable barrier for use in multi-storey building construction sites for safeguarding workers against falls through penetrations and down holes.

Administrative controls

In cases where a person could fall a distance greater than two metres, and physical fall prevention is not able to be used because it is not reasonably practicable, employers need to ensure that the corresponding safe-work method statement records contain a description of the administrative control to be used, and a description of the task to which that administrative control relates.

Guardrailing

Guardrailing may be used as fall prevention around the edge of a penetration as a proprietary designed system or through incorporation into scaffolding. Guardrails may be used to provide effective fall prevention at:

• the edges of roofs and roof framing;
• the edges of scaffolds;
• the edges of work platforms, suspended slabs, formwork and falsework;
• walkways, stairways, ramps and landings;
• the perimeters of buildings and other structures the perimeters of skylights and other fragile roof material; and,
• the edges of shafts, pits and other excavations.

Before a guardrail system is adopted, the employer needs to ensure it will be adequate for the potential loads. The required load resistance will depend on the momentum of a falling person. For example, the momentum of a person falling from a pitched roof will increase as the pitch (or angle) of the roof increases.

Proprietary systems need to be configured, installed, used and dismantled by a competent person in accordance with the manufacturer’s instructions.

The use of safety harness and fall-arrest systems

Safety harness systems can be used to arrest falls where workers are required to carry out their work near a penetration or hole. However, they can only be used as the primary means of risk control if it is not reasonably practicable to use measures higher in the control hierarchy.

Safety harnesses and lanyards can also be used as travel-restraint systems to prevent workers moving from safe to unsafe areas on roofs.

Full body fall-arrest harnesses need to be worn if you are required to work close to a penetration or hole where there is a potential to fall. Waist-type belts should not be used as severe injuries  can result when the wearer’s fall is arrested. The harness connection point to the fall-arrest line needs to be made at the top dorsal position. An alternative attachment position is when a line and rope-grab device is used and the user needs to manually operate the device by having the device in front. In these circumstances, the user can make the connection on to a front connection point, as recommended by the manufacturer.

Restraint lines

If a Restraint line is used, there needs to be a minimum of slack in the fall-arrest line between the user and the attachment. The anchorage point should be as high as the equipment permits. Never work above the anchor point, as this will increase the free fall distance in the event of a fall, resulting in higher forces on the body and greater likelihood of the arrest line snagging on obstructions.

Self-retracting lanyards and inertia reels

When using self-retracting lanyards or inertia reels, bear in mind that they might not be effective in certain situations. For example, if a worker falls down the inclined surface of a steeply pitched roof, the inertia reel line may keep extending from the reel - it may not lock.

Inertia reels should not be used as working supports by locking the system and allowing it to support the user during normal work. They are not designed for continuous support.

Vertical and self-retracting anchorage lines can be used as a risk-control measure in connection with work performed from boatswains’ chairs and ladders. Where such lines are used, no more than one person should be attached to any one line.

Compatible components

Fall-arrest systems and safety harnesses should only be used with the individual manufacturer’s components that are known to be compatible. The use of non- compatible components may lead to ‘roll-out’ with some hook/karabiner configurations, and could result in a user being injured or killed. The hazard cannot always be avoided by using components produced by the same manufacturer under the one brand name. If you are unsure about the components of a fall-arrest system are compatible, contact the manufacturer for further information.

Snap hooks need to be of the double action type, requiring at least two consecutive deliberate actions to open. Snap hooks should not be connected to each other as this could prevent the safe operation of the snap hook (e.g. roll-out may occur). Some double action hooks are susceptible to roll-out. Screw gate karabiners or hex nut connectors may sometimes be appropriate. For further guidance, see AS/NZS 1891.4 Industrial fall-arrest systems and devices - Selection, use and maintenance.

Rescue in event of a fall

It is imperative that the rescue of a worker who is suspended in a full body harness occurs promptly. Suspension trauma is a condition where a person suspended in a harness in a substantially upright position may experience blood pooling in the legs. Depending on the susceptibility of the individual, this may lead to loss of consciousness, renal failure and death.

To enable workers to be removed from the suspended position as quickly as possible, employers need to consider having a pre-rigged retrieval system in place and ensure that workers using safety harnesses do not work alone.

Employers must provide adequate training and ensure that any worker required to use a safety harness fall-arrest system is properly trained in its use.

Common fall hazards

The following is a list of some of the more common issues that need to be taken into consideration when identifying fall hazards in the workplace.

Surfaces:

• The stability, fragility or brittleness.
• The ability to slip (eg where surfaces are wet, polished, glazed or oily in the case of new steelwork).
• The safe movement of workers where surfaces change.
• The strength or capacity to support loads.
• The slope of work surfaces.

Levels: Where levels change and workers may be exposed to a fall from one level to another.

Structures: The stability of temporary or permanent structures.

Penetrations, openings and holes: Guard railing requirements to protect workers (similarly unguarded shafts and excavations).

Guard railing safety considerations

The safety requirements for guard railing include:

• Every open penetration, edge of a stair, landing, platform or shaft needs to be protected to prevent a person falling.
• The guardrail system needs to be constructed to withstand a force of 0.55kN (approximately equivalent to 55 kilograms) applied at any point.
• Top-rails need to be between 900 millimetres and 1100 millimetres above the working surface.
• Mid-rails and toe boards need to be provided. However, wire mesh infill panels incorporating a toe board may be used instead of the mid-rail.
• A bottom rail above the toe board needs to be provided for more severe roof slopes. Both a mid-rail and infill mesh panel will assist in preventing people and objects from falling through.
• Guard railing needs to comply with AS 1657 Fixed platforms, walkways, stairways and ladders - Design, construction and installation, AS/NZS 4576 Guidelines for scaffolding, or AS/NZS 4994 Temporary roof edge protection for housing and residential buildings.
• If access points are required for equipment (eg a hoist), they need to be protected with gates, safety chains or other means to prevent a person from falling through.
• Where guardrail systems are intended to be used in conjunction with steel structures or tilt-up construction, designers and builders need to plan for the guardrails and fixings to be attached to the panels prior to the structures being raised from the ground.

Skylights that are not protected with safety mesh and penetrations left for the installation of air-conditioning can be a danger to roof workers. Securely cover them or fix temporary guard railing around them.