Opting for a curtainsider body with XL rating does not automatically excuse operators from using an internal load restraint system. Failure to do so can still land a haulier in trouble no matter what the bodywork rating. That's the latest warning from trailer and body builders, as well as trade associations, following a change in attitude at DVSA (Driver and Vehicle Standards Agency) towards the European EN 12642-XL standard.
In light of alterations to draft European guidelines, the agency now accepts that curtainsider bodies meeting this non-mandatory standard can withstand a sideways force equivalent to 50% of the vehicle's maximum payload without additional restraint. The previous maximum was 40%. However, DVSA's stance is a qualified one, reflecting the fact that EN 12642-XL is a containment, rather than a restraint, standard.
"To meet DVSA guidance, the load has to be a positive fit," states Ray Engley, head of technical services at the RHA (Road Haulage Association). "That means it must go all the way up to the headboard and up to the back doors, with no gaps in between – any gaps must be filled – and be no more than 80mm from the curtains."
That may be fine if the operator is despatching a full load to a single location. But what happens if the driver has two or three deliveries to make and the load diminishes during the journey? "If the load is still up against the headboard, it will have to be strapped across the back," answers Cartwright technical director Lionel Curtis. "Bear in mind that even if you load a 13.7m 12642-XL trailer with a full consignment of 26 pallets, you still have a gap at the rear," adds Don-Bur marketing manager Richard Owens. "So it is likely that you will have to restrain the cargo at the back with straps or a net."
If pallets are being dropped off piecemeal, the cargo may of course have to be re-assembled and moved back from the headboard to avoid the axle over-loading problems associated with diminishing loads. I so, it will have to be restrained as completely as it would if it were housed in a body not built to XL standards – which may involve strapping it rave-to-rave.
FTA (Freight Transport Association) head of engineering Andy Mair takes the view that XL bodies, which can cost several hundred pounds more than non-XL, are best confined to full-load work. "If you know your load is going to diminish during a trip, then they don't bring any real benefit," he contends.
Nevertheless, Owens believes that XL could still become the new industry yardstick. And while Mair disagrees, he too expects increasing numbers of curtainsiders to be constructed in line with its requirements.
Certainly, the extra cost may prove worthwhile for some fleets: companies in the chemical and paper industries are already insisting that trailers used to transport their goods be tested to the standard. Furthermore, SDC contends that businesses in certain countries in mainland Europe may refuse to load trailers that do not meet it. Other trailer manufacturers claim that curtainsiders not displaying the distinctive label may be at greater risk of being pulled over by enforcement officials on the other side of the Channel.
Either way, if a body is built to XL standards, operators should still check its certificate so they can be sure it is loaded in line with specifications, advises FTA's Mair. "It may even make sense to provide the driver with a copy of the certificate in case there is any dispute, so it can be produced at the roadside," he suggests.
Owens is also concerned that some less scrupulous hauliers may attempt to hoodwink DVSA and avoid any requirement for strapping by equipping existing bodies with curtains intended for XL bodies. "I've seen evidence that this is happening," he says, adding that alternatively they may slap shiny yellow XL stickers onto non-compliant bodies and hope that will do the trick so far as the enforcement authorities are concerned.
Both practices are to be deplored. "An XL body does not just have extra strength in the curtains, but comes with a stronger roof, bulkhead and rear frame too," says Owens. "You cannot retrofit XL curtains to an unsuitable body that in some cases may be falling apart... We've been asked to do so by one or two operators. We've said a very firm 'no' and that will continue to be our policy."
Tried and tested
Don-Bur has tested trailers in line with the requirements of EN 12642-XL using static and dynamic rigs. "The static test involves putting very large airbags in the trailer, then blowing them up to see how far the curtains billow out," explains marketing manager Richard Owens. Anchored to heavy-duty steel frames, they apply a load to the front and the rear of the trailer, too.
"The dynamic test includes an acceleration test, a deceleration test and taking the laden trailer through 'S' bends and around roundabouts under controlled conditions," he adds.
Cartwright, SDC and Lawrence David are among other UK manufacturers that have tested trailers to EN 12642-XL, with Lawrence David stating that it was the first to have a pillar-less curtainsider accredited. Cartwright also has XL curtainsiders available on its rental fleet.
Operators are often keen to minimise load restraints, because removing and replacing restraints takes time. They may also fear that certain types of cargo may suffer damage if they are strapped across the top. So what's the solution?
"Rave-to-rave strapping is the best approach and there are wide straps available that can spread the load," answers FTA head of engineering Andy Mair.
Meanwhile, Cartwright has developed a suspended rave-to-rave strapping system with straps or nets suspended on a bungee assembly in the roof of the trailer. The number of straps and nets, and their design, can be varied to suit the type of load, and they can be brought down in any position to accommodate cargoes of varying height. Loads can be secured to the front and rear as well as rave-to-rave.
In light of the positive-fit requirement for EN 12642-XL, it is worth noting Don-Bur's recent launched of a load capacity calculator dubbed SCUASH (Solving Cube Utilisation Applying Simulation Heuristics).
The calculator enables operators to determine the maximum capacity and fill percentage of any uniform payload within specified trailer or rigid bodywork dimensions. It can handle various cargoes, including pallets, roll cages and totes, and allows users to calculate potential stack height and clearance between the underside of the roof or second deck.