Clean fuel could cause plant owners problems

'Virtually sulphur-free' fuel will become mandatory for off-road machinery from the start of 2011 and could spell problems for older diesel engines, infrequently used plant and those bunkering fuel.

New regulations cut the allowable sulphur level in red diesel from 1,000 parts per million (a recent reduction from 2,000ppm), to 10ppm to accommodate the low emission systems Stage 3B engines will require. Depending on output, new engines over 37kW have to meet Stage 3B regulations between 2011 and 2013 and are expected to use diesel particulate filters, which can be clogged by unburnt sulphur.

Andy Mair, head of engineering policy at the Freight Transport Association, said the introduction of low-sulphur fuels for on-highway trucks caused problems with the injection equipment, including reports of rapid wear because of the cleaner fuel's lower lubricating quality. More widespread were copious fuel leaks as the sulphur (or more precisely the aromatics) in the old fuel caused the seals in the injection system to swell, but on switching to low sulphur diesel, the seals shrank causing leakages.

Plant owners fear the same could happen with specialist, long-lived and infrequently used items such as graders, some cranes and dozers, which can even date back to the 70s and 80s, and for which spares and seal-sets can be difficult to source.

Hugh Tucker, technical director with the UK Petroleum Industry Association, said such problems are known about and the fuel specification had yet to be finalised.

Of wider concern is that the new fuels will contain up to 7% biodiesel, which can oxidise over time creating difficulties with the filtration system of infrequently used machines and contamination in storage tanks.

Colin Wood, chief executive of the Construction Plant-hire Association, said some of his members were concerned at the possible outcome of the switch and has pledged to raise the matter with the Department for Transport.