Transport operators should carry out regular checks of the control valve for trailer spring brakes, ATA Industry Technical Council says
Transport operators should carry out regular checks of the control valve for trailer spring brakes, following an incident where the spring brake did not operate, the Australian Trucking Association (ATA) Industry Technical Council says.
Trevor Martyn, chairman of the ATA, says the technical group held its first meeting of 2009 recently, and discussed the control valve failure, which was caused by foreign matter entering the valve when the air lines were disconnected.
“As a safety feature, trailer spring brakes are designed to come on when the trailer is disconnected from its air supply or the air supply fails,” Martyn says.
“In this case, the operator disconnected the trailer but the spring brakes did not work, even though they are designed to fail in the on position.”
The unnamed foreign matter entered the air line and was pushed through to the control valve, where it lodged and jammed the valve in the ‘off’ position.
“Some tipper dog trailers would be more vulnerable to this sort of brake failure, because their air supply lines are disconnected and reconnected frequently. The risk could also be higher in extremely dusty conditions.
“Brake valve suppliers typically recommend that companies should test the operation of their spring brake control valves on a regular basis.”
Although unusual, Martyn says the technical council is taking the failure seriously, with parent body the ATA asking suppliers if more detailed recommendations about checking, servicing and replacing spring brake control valves can be supplied.
“In the meantime, operators should regularly check the functionality of their spring brake control valves. They should also consider installing filters in their trailer air supply lines to stop contamination reaching the valves. Some new trailers are already fitted with in-line filters.”