The European association of abnormal road transport and mobile cranes (ESTA) has reiterated its concerns regarding the use of diesel exhaust fluid (DEF), also known as AdBlue, urging for the introduction of a time-limited override system to help prevent dangerous safety incidents.

Research carried out by ESTA last year exposed deep concerns in the heavy transport and lifting sectors about engine malfunctions thought to be caused by AdBlue additives, including problems with mobile and crawler cranes, trucks and SPMTs.

According to its research, the most common type of incident was a public road breakdown, with almost half of the respondents saying that safety had been compromised as a result. A small number reported dangerous interruptions to wind turbine and SPMT load-out work.

Those concerns have now been amplified by similar research carried out in Canada by the Canadian Crane Rental Association (CCRA). Taken together, the ESTA and CCRA research shows that 48 percent of cranes and 40 percent of transport equipment faced DEF/AdBlue-related issues. Of those, 80 percent resulted from component error or failure and 73 percent compromised safety.

AdBlue is a mixture of water and urea used in diesel engines to minimise the production of nitrogen oxide (NOx) emissions. It reacts with NOx in the catalytic converter, breaking it down into nitrogen and water vapour in a process known as selective catalytic reduction (SCR).

Particular concern is focussed on the current system of derating when the engine control unit intentionally reduces engine power or speed to ensure compliance with emissions requirements – specifically, to ensure that the DEF/AdBlue system is functioning and being used correctly.

This system was requested by regulators to ensure that cranes, trucks and heavy-duty diesels cannot emit excess NOx for extended periods, and cannot operate indefinitely without DEF.

However, ESTA said there is a growing body of evidence of trucks and mobile cranes losing power in dangerous situations on public roads or part-way through an operation.

Earlier this year, ESTA’s European Regulations Working Group – which includes members from the crane manufacturers and the European Materials Handling Federation (FEM) – produced a new technical bulletin to help companies reduce the risks. Now, ESTA is taking its concerns a step further and requesting a temporary override or derate reset so a vehicle can be moved to a service location, or safely finish its current operation.

Speaking to ESTA members at its Autumn meeting in Copenhagen, Mammoet’s Hermen Kamp said: “The outcome of the survey is shocking. The AdBlue systems won’t go away, and with the proper use of the engines, quality fuel, alternative (better) AdBlue products problems can be reduced.

“But ultimately what we as ESTA (and CCRA) would like to achieve is a functional system, and in the case of an emergency have an override function available for a set period of time to get the transport completed, the load out safely on the barge, or the lift completed, and then to solve the problems at a safe location.”

ESTA policy officer Miguel Florez de la Colina added: “This is an issue of huge concern to both crane and heavy transport companies and has resulted in a number of safety incidents. We will keep campaigning and hope that together we can make progress on this important issue.”

The impact of DEF/AdBlue is also causing concern in the USA. In August, the country’s Environment Protection Agency (EPA) issued new guidance to manufacturers regarding SCR/DEF systems to reduce abrupt performance derates or shutdowns.