Do Your Designs Meet Safe Design Requirements?

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Monday, August 10th, 2015
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Back in 2013, a near tragedy unfolded after a crane carrying an 85-tonne load collapsed at a Karara mine site in Western Australia and narrowly missed workers as it plummeted five storeys to the ground.

According to media reports, the crane should have been designed to carry loads greater than 80 tonnes and was being tested at 110 per cent capacity when the structure folded in half.

According to a report in The West Australian, the incident was a legal first in that the crane’s designer, Wally Entschmann of Entschmann Engineering was fined $16,000 in the Perth Magistrate’s Court for failing to design the crane to the Australian standard.

In that case, the court was told the crane was not strong enough because of a design modification which had reduced the thickness of the plates which were designed to take the weight of the boom. Entschmann pleaded guilty to breaching the Mines Safety Inspection Regulations.

The case underscored the need for engineers and others to understand their responsibilities with regard to the safety of any buildings or structures of which they are involved in the design. Under recent changes to occupational health and safety legislation, those who conduct any form business that involves the design of buildings or structures which are expected to be used as workplaces (i.e. offices, hospitals, shopping centres, power plants, mines etc.) are required to ensure as far as practical that the structure in question does not pose a risk to health or safety.

The requirements apply to anyone whose business involves drawings, plans or material decisions relating to the design, including architects, engineers, building surveyors, interior designers, building service designers (such as mechanical engineers) and any contractors who carry out design work as their part of a contribution to projects in which they are involved. The structure must be safe for workers involved in all phases of the building’s life cycle. In other words, it must be able to be built, operated and used, maintained, and altered or demolished in a safe manner using existing techniques.

The new laws are in place in every state except for Victoria (which has existing rules upon which the new laws were modelled) and Western Australia, where the legislation to implement the new laws is currently before Parliament. While the above-mentioned case was in Western Australia, this related to a breach in Mines Safety Inspection Regulations rather than the new safety in design rules, though the case did relate strongly to the safety in design concept.

John Giles, owner of Sydney based HV engineering and safety in design training provider Appleseed Engineering, says responsibilities placed upon designers have become more onerous since the inception of the new legislation.

“They’ve got a hell of a lot of key responsibilities now – they’ve got to make sure all of the safety in design is there so that people aren’t injured throughout all of the life cycle of the product,” he said. “That’s the building, the operation, the maintaining and the demolition.”

While the responsibilities are many and varied, Safe Work Australia recommends a systems-based approach involving a number of steps throughout the various phases of the design process. During pre-design, significant areas of hazard should be identified along with relevant legislation and codes, while the project brief should reflect a shared understanding of expectations and requirements from a safety perspective. All major hazards as well as broad strategies to mitigate these should be considered during conceptual and schematic design, while detailed measures to mitigate all risks should be decided upon during detailed design and adopted solutions should be reviewed during later stages of the design process and evaluated after construction.

Elimination of relevant risks altogether is preferred – by, for instance, designing components that facilitate pre-fabrication on the ground and avoid the need to work at heights – but other measures will need to be considered where this is not possible. Examples of such measures could include:

  • Replacing a hazardous process or material with one which is less hazardous (substitution), such as using pre-cast panels as opposed to building a masonry wall.
  • Separating the hazard from people (isolation) by, for example, designing building layouts so that noisy machinery is isolated from work stations.
  • Using engineering control measures to minimise risk by, for example, designing and positioning permanent anchorage and hoisting points into buildings where maintenance needs to be undertaken at height.
  • Using warning signs or exclusion zones where a hazardous activity is carried out.
  • Using hard hats, respiratory protection, gloves, ear muffs etc. to protect workers from residual risk.

Giles says a challenge for engineers revolves around not so much the ability to deliver sound design but to understand how structures are going to be built, operated and maintained.

He says many are having to learn to talk with people about how they maintain, operate and demolish things in order to incorporate such considerations into their design.

In response to the Entschmann case, Western Australian Department of Mines and Petroleum director of mines safety Andrew Chaplyn said he hoped the case sent a strong message to designers working across the mining industry.

Indeed, architects, designers and engineers not only in mining but right across the building and construction sector are having to take note. The responsibility to design offices, warehouses, shopping centres, power plants mines and other structures which are safe to build, operate, use, maintain, alter and demolish has never been greater.

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