The roof of my commercial building is flat – do I need a height safety system?

FRP walkway installed on a metal roof.

Falls from heights are a major workplace hazard and require specific control measures in order to keep employees and contractors safe. Despite this, the risks associated with working at heights are often misunderstood and not mitigated properly. This can, in part, be put down to a lack of understanding of relevant legislation either due to unawareness or confusion regarding liability.

A common question we get asked here at HSE by building owners and facility managers is whether a height safety system needs to be installed if the building in question has a flat roof.

To answer this question, we first need to look at what a flat roof actually is. 

It is generally accepted across the roofing industry that a slope of up to 15° is considered to be flat, However, definitions vary across jurisdictions and the conditions of a roof need be judged individually. 

For example, a roof with a 10° slope may be considered “flat” but still actually pose a significant slipping risk due to moss forming on tiles or the presence of frost. Excess diesel exhaust is another condition that can make a roof extra slippery if a building is located next to a major highway or in a facility with significant truck movements. 

So while a roof may be deemed flat, there could still be fall risks present that require mitigation, such as through the installation of a height safety system. It’s also important to note that whenever people are working on a roof and there is a possibility of falling to a lower level, protection measures need to be put in place. 

As to what types of safety measures are required, it depends on where the work is being done on the roof. It is generally accepted that workers more than 2m away from a fall edge may not require a harness or other means of fall protection.

The other thing to consider when assessing the risk of a seemingly flat roof is how the roof is accessed. For example, if there is a hatch and ladder system to access the roof, it will need to be protected by guardrails to avoid a worker falling through the open accessway. When the hatch is open, it is a fall hazard, and the stepping-off point is the most dangerous. A system that enables the worker to connect to a fall protection system (usually a first-man up cable or anchor point) before stepping off the ladder would be appropriate in such a case.

Given the different types of roof and the range of different access needs, it’s not exactly easy to determine what sort of risk mitigation needs to be installed on a roof of any slope as there are so many different factors to take into consideration.

The Work, Health and Safety Act places the burden of responsibility of managing risks to health and safety associated with a fall on the key person conducting the business or undertaking (PCBU) at a workplace. 

For PCBUs who are unsure whether their commercial building requires a height safety system, it’s best to let a trained professional assess the risks and put forth a recommended safety plan, no matter how high or low a roof slope may be.

Need help understanding your responsibilities regarding height and safety? Or want to ensure you are meeting your workplace obligations? 

Height Safety Engineers are experts in the design, installation, and certification of height safety systems. We can design, fabricate, and install systems for fall arrest, fall restraint and fall prevention needs.

Our expert team can provide you with a safety system design specific for your location, using only the highest-quality components sourced from handpicked suppliers ensuring your safety system meets the highest standards.

With industry-leading and best practice design principles guiding our work, Height Safety Engineers can develop a height safety or roof access system that arrives on time, on budget and is fully compliant with Australian standards.

Height Safety Engineers have over a century of combined experience in designing and installing best practice height and roof safety solutions, made perfect.

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