The transport and insurance industries are being guarded in their response to the recent spate of truck fires, a number of them in curtainsider trailers.
There are concerns about the potential ramifications of the fires, such as increased insurance premiums for companies running the kind of units involved….possibly even legal action.
The fires have occurred often enough since spring 2018 that at least one major insurer confirms that it is now investigating the incidents.
The well-publicised fires included loads not considered a high fire risk. The fire in a curtainsider on the Canterbury Plains, for instance, in which the driver continued on to find a place to stop where it wouldn't set off a grass fire, was reportedly in a load of milk powder.
One insurance industry heavy vehicle assessor points out that fires in curtainsiders are not a new phenomenon – but agrees that the incidence appears to be increasing….even allowing for the fact that there are more curtainsiders on the road now than there were five years ago.
In the past, he adds, fires have often been put down to overheating brakes or wheel bearings – the exact cause difficult to determine due to the often severe fire damage.
Factors now being discussed as possible causes of fires include curtainsider trailer design changes and an increased use of mezzanine floors – some with adjustable floor heights – to optimise freight space.
The assessor doesn't believe the fires are a major issue – and certainly haven't reached epidemic proportions.
His company is awaiting reports from investigators on fires involving clients' trucks, to try to pinpoint any particular problems.
The boss of one major freight transport and logistics company confirms that it has experienced fires in a couple of its curtainsider units. He believes they were most likely caused by metal friction involving the mezzanine floors. 
The company is installing fire blankets under the floors and Teflon hooks to reduce the chances of heat friction buildup resulting in ignition.
Apart from the obvious safety issues for the driver and other road users, he points out that it's not a good look marketing-wise to have a truck catch fire out on the highway. It could lead to increased insurance premiums, which is the last thing the industry needs, he adds. 
He believes that while the curtain material may be quite flammable, the heat to spark and initiate a fire is probably generated elsewhere.
He raises the question of whether the use of different metals in the construction of mezzanine floors may be more prone to generating heat friction buildup by movement between adjacent parts of the floor, compared to materials used previously.
Other possibilities include a change in the design of the mezzanine floors in recent years, or the way they are installed.

It's understood that the fires have occurred in vehicles built by a number of different manufacturers.