Workplace Health and Safety Queensland has released a safety alert to highlight the risk of collapse of self-supporting signs, and to raise awareness of the need to properly design, maintain and inspect sign structures.
Just last month, a sign structure collapsed and fell on cars in a shopping centre park. The cause of the collapse is still being investigated, but it appears that severe corrosion of the main support column at its base was the primary cause. Water ingress and the inability for it to drain away are likely to have contributed to the corrosion.
Queensland’s safety regulator said all sign structures should be able to safely withstand all anticipated loads and should be designed with great durability considering the environment where they are located. Sign structures should also be corrosion-resistant and preferably should not have internal cavities where moisture can accumulate.
“If it is possible for water to enter the support structure, a system should be provided to ensure water can be drained to minimize the likelihood of internal corrosion. It should be noted that it is often possible for water to enter internal cavities by capillary action,” Workplace Health and Safety Queensland stated.
“Where practicable, the design should allow for access to carry out internal inspections (e.g. an inspection hatch) or an alternative method implemented that allows for corrosion monitoring (e.g. a non-destructive test method such as ultrasonic testing).
“Sign support posts should not be placed directly in the ground but should be attached to foundations that are corrosion resistant (e.g. post base plate bolted to a concrete pad above ground level).”
A competent person should regularly conduct an inspection of the signs and its support structure. If the inspection uncovers defects with the sign and/or its supporting structure, a written advice from a qualified Registered Professional Engineer of Queensland should be obtained.
More information about this safety alert is available on Workplace Health and Safety Queensland’s website.