Working safely around voids and penetrations

Falling through unguarded voids is a contributing factor to a number of serious injuries and deaths in the construction industry¹.

Construction workers risk serious injury or even death when working at heights. Falling from heights between 2 to 4 metres can lead to devastating injuries and are often fatal. Even falling a short distance can also be serious or fatal if a worker sustains a head injury.

 

Risks of voids and penetrations
The risks of falls are greatest when there are open voids where workers can fall through. Voids in construction exist as openings for stairwells, live edge in partially completed floors, holes for window or skylights as well as entry/exit points in a structure high above ground. Workers can also fall at ground level into holes such as pier holes, trenches or service pits.

The main reasons workers fall through voids and penetrations are because they:
• Are uncovered
• Have unsuitable covers in place or,
• Have no guardrails.

 

Managing the risks of penetrations and voids

The hierarchy of controls must be applied when managing the risks of voids and penetration.

 

Elimination of the hazard
Elimination of the hazard is the most effective way to manage the risks. Make sure that work is planned to prevent the creation of voids and penetrations in the first place. For example, use cast-in safety mesh when pouring concrete to eliminate the creation of voids and penetration in the formwork. The safety mesh should be 50mm x 50mm or smaller mesh size and made of material capable of withstanding potential loads. The safety mesh can then be removed later when the void is filled in (such as when a window or skylight is installed etc).

Other ways of eliminating the risks of falls for workers include prefabrication of roofs, wall frames and trusses at ground level as well as using tilt-up concrete to construct walls.

 

Substitute or engineer the hazards
When it is not practical to eliminate the hazard, risks can be minimised by substituting (replacing) the hazard with something safer, or engineering (changing the design).
For example if a ladder is used to access another level, consider substituting temporary stairs instead, such as erecting a scaffold with stairs. This will minimise the danger of having a live edge in the work area.

       

Substitution – instead of using a ladder consider erecting a scaffold with stairs

 

Isolate the hazard
The risk of falls can also be minimised by isolating voids and penetrations through the use of physical barriers to protect workers. This might include:
• Installing guard railings around live edges. Ideally guard railings should have a top-rail at least 900mm above the working surface, a mid-rail and a toe board.
• Installing a physical barrier to prevent access to incomplete decks or voids.
• Ensuring that all voids and openings have fit-for-purpose covers that can withstand the load of workers and materials.

 

Installing void and penetration covers
If you have voids or penetrations on your worksite make sure:
• Work is planned so that fixed covers and edge protections are installed as soon as the void or penetration is created.
• All voids and penetrations have a cover that is secured, fit for purpose and strong enough for people, materials and likely impacts.
• The area is clearly identified so they are not mistaken for construction material. For example marked with a sign, a different coloured cover or spray painted.
• Make sure all workers are aware of the void or penetration – Explain your void protection to everyone on site, including your workers, sub-contractors and other visitors to site. Make sure they know what to do when changes are needed.

 

Inadequate penetration and void covers

The following are examples of real incidents where workers have fallen through voids when the penetration cover has either not been installed, has collapsed, or been pushed out of the way (source SafeWork NSW²).

11 February 2021 – A worker suffered serious back injuries after falling feet first approximately six metres into an unprotected pier hole. The hole was uncovered at the time of the incident, and was not visible due to the shadowing from the cab of the truck.

A pier hole covering should be fixed securely in place as soon as the void is created

12 August 2021 – A worker was seriously injured when he fell approximately 5 metres through a void on a bridge under construction. The worker stepped onto a steel panel void cover which dislodged.

A void cover should be fixed in place and strong enough for people, materials and impacts

May 2023 – A young worker was fatally injured after falling through a penetration that was inadequately covered.

 

Safety management is important
The risks when working at heights are foreseeable and sadly many incidents are entirely preventable. Prioritising safety might appear to be a major inconvenience, but no one should get injured or killed just for doing their job. By planning ahead and using the proper equipment, your workers can all return home safely to their loved ones at the end of the day.

 

 

 

 

References
1. WorkSafe ACT, Working at Heights, accessed 25th February 2025, <https://www.worksafe.act.gov.au/health-and-safety-portal/safety-by-industry/building-and-construction/working-at-heights>
2. SafeWork NSW, 6th June 2024, Incident Information Releases, media release, accessed 24th February 2025, <https://www.safework.nsw.gov.au/compliance-and-prosecutions/incident-information-releases/industries/construction>