Safe work at height rules update

The extra risks associated with roof anchors on single-storey buildings has again been highlighted in the revised workplace falls model code of practice.

Safe Work Australia published a revision of the model code of practice ‘Managing the Risk of Falls at Workplaces’ (“code”) in March. Chief among the changes to the code are fall distances for harness use.

Fall distance for harness use explained

A worker wearing a harness attaches it to a shock absorber and lanyard system. During a fall, the shock absorber deploys and extends.

This extended distance is added to the person’s height, lanyard length and a safety factor, which allows for harness stretch.

Under the revised code, a person who falls can be expected to travel 6.5 metres before their fall is arrested. Effectively, that eliminates single-storey buildings and typical warehouses. Those around 6 to 8 metres high do not provide enough fall clearance if there are obstacles below like trucks or canopies.

Buildings around 6 to 8 metres high do not provide enough fall clearance if there are obstacles below like trucks or canopies.

Using a technique of restraint, it is possible to use a harness-based system on a roof that is less than 6.5 metres from the ground safely but equally as easy to get it horribly wrong. Simply use the incorrect length lanyard on an anchor close to gutters, for example, and a system design intended to prevent any risk of fall can unravel in an instant — with fatal consequences.

Practical and commercial considerations and solutions

In fact, the code points out that harness-based systems should only be used if it is not practicable to provide a barrier such as a guardrail.

In many cases, a guardrail is the most practicable and commercial solution. Consider the lifetime costing of equipment and all of the administrative, inspection, maintenance and training requirements for anchor and static line based systems.

The code makes 34 references to rescuing people in harnesses and dedicates an entire section to suspension intolerance, highlighting the importance of having a second person on-site and trained to implement a site-specific rescue plan, equipped with the right equipment.

Also known as toxic shock and suspension trauma, the risk of death is real, explain Dr Bill Wheems and Dr Phillip Bishop of the University of Alabama in Will Your Safety Harness Kill You? “Harnesses can become deadly whenever a worker is suspended for durations over five minutes in an upright posture, with the legs relaxed straight beneath,” the paper said.

Using higher-order controls like platforms, catwalks and guardrailing satisfies the legally powerful hierarchy of controls. Importantly, such passive height safety equipment reaps cost savings with lower lifetime costs, reduced administration and ready access for maintenance without the need for specialised height safety skills.

How the code and standards fit together

The code offers practical guidance to reduce or eliminate the risk of falls. Workplaces that adopt the code methodology are deemed to have met their requirements under the regulations.

Australian Standards AS/NZS1891 (anchors and static lines) and AS1657 (Ladders, platforms, walkways, guardrailing) are referenced in the code. Deviating from them would need to be justified if an incident was examined in court. Document reasons for any deviation in a risk assessment, reviewing the likelihood and consequence of a fall, comparing the cost of safe and compliant control measures versus the cost of injury.

Standards are undated in codes of practice, ensuring that revisions to standards are always referenced. This is particularly relevant to AS1657, which was revised in 2013 and AS/NZS5532 (Anchors), which was published as an addition to AS/NZS1891 dealing with testing of anchorage points.

*Carl Sachs is managing director of Workplace Access & Safety and the Technical Chair of the Working at Height Association (WAHA). A member of the Standards Australia committee for AS/NZS1891 (Fall arrests systems and devices), AS/NZS5532 (Anchor points) and AS1657, Sachs was involved in the drafting of the recently released standards. Sachs’ business is independently accredited by NATA for the testing of AS1657 equipment and AS/NZS 5532 safety anchors.