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The safety chain debate explained

The safety chain debate explained

A number of serious mishaps involving failed trailer coupling eyes has recently caused industry to conduct a clarity check on the requirements for safe mechanical connections between trucks and trailers.

A recent safety alert issued by the National Heavy Vehicle Regulator (NHVR) advised industry to consider improved inspection systems with respect to towing equipment and the voluntary fitment of safety chains to heavy trailer drawbars – proving that the discussion on the importance of spec’ing the correct safety equipment has never been more fervent.

“For fleet operators, the matrix of operating rules and obligations can be complex, perhaps even daunting,” says Allan Bartlett (pictured below), Managing Director of Bartlett Equipment, an Australian-owned company that has pioneered safe and cost effective truck and trailer connection technology for more than 70 years.

Allan points out that the Bartlett suite of safety chain systems, designed to retain trailers behind trucks in the event of accidental decoupling, is a “proven answer” to the swelling debate as to the requirement of safety chains on dog trailers, which are currently exempted under the relevant Australian Design Rule (ADR) 62.

Allan says a recent in-field test program of Bartlett safety chain systems was conducted under varying operating conditions with the aim to assess truck and dog trailer behaviour, as well as equipment performance before, during and after a coupling separation. 

“Using a controlled coupling separation technique, examiners were able to observe the controlled behaviour of the truck and dog combination whilst connected only by an ADR-compliant safety chain system supplied by Bartlett,” he explains.

“The testing completely dispelled any concerns operators may have had regarding vehicle combination control when safety chains are engaged.”

According to Allan, such concerns regarding the applicability of safety chains to dog trailers may be rooted in the sheer size of the ‘do it yourself’ fabrication methods for safety chain systems that were popular in the 1990s, after the Queensland Main Roads authority published an endorsed design for public reference.

“Those early designs can only be described as costly, cumbersome and overly large, plus they required the use of expensive chain connectors to connect the chains with the larger diameter pins,” he says. “Despite being widely adopted on rigid drawbar trailers, they were inefficient and impractical.”

Allan says Bartlett safety chain systems feature weldable high-strength cast alloy steel attachments that are optimised for chain interconnectivity – effectively making heavy-duty chain connectors unnecessary to connect the high tensile chain to the truck and trailer.

“Eliminating risk is the responsibility of every road transport operator, so it makes perfect sense to insist on the use of safety chains on dog trailers.

“Our safety chain systems are the most cost effective way to achieve an ADR-compliant safety chain connection. In the event of coupling separation, we expect the driver to sense the chains taking the load and provide a controlled opportunity to react and find a safe place to stop.”

According to Allan, the National Code of Practice VSB6 “strongly recommends” the use of safety chains on all trailers, but in practice the take up on dog trailers has been poor.

“What we do know is that unrestrained dog trailers can run away and this is an unacceptable risk that has resulted in numerous fatalities, serious injuries and property damage. Specifying and fitting a Bartlett safety chain system will ensure you stay connected.”

He adds, “Bartlett safety chain systems are ADR-compliant and carry a component registration number (CRN) for use by Approved Vehicle Examiners to validate compliance. Chains should be kept as short as practicable, ensuring that the length allows free drawbar articulation in all directions.

"Always cross chains to encourage good control and a cradle for the drawbar. Finally, regular visual inspections of the trailer coupling, safety chains, air hoses and electrical wiring should be made in between scheduled maintenance works.”

According to Allan, the rules regarding fitment of safety chains are contained in ADR 62, but he says the rules may still require clarification. To give industry an overview, he has therefore developed a chart including different safety chain applications (see breakout box above).

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