User:EnvironmentalSafety/sandbox

Diesel Refueling Safety
Subject: Addressing the potential for mobile equipment (trucks, dozers, shovels, drill rigs, excavators, etc.) to spill fuel, leak fuel, and catch fire, as well as the risk of occupational hazards associated with re-fuelling.

Summary of hazard

Since the 1980’s fast filling for heavy and large equipment has become the standard in the industry. Fast filling can deliver filling speeds of well above 1,000 litres per minute. Fast filling significantly increased efficiencies and productivity while also aiming at reducing fuel spills due to a clean-break system, it has also had some adverse effects. •	Pressurising Fuel Tanks •	Increased volumes of spills when the system is overridden •	Operator Diesel baths due to back pressure •	Fuel loss and spillages while operating

Pressurising Fuel Tanks

Manufacturers design their fuel tanks to be pressurised at 4-8PSI. Fast Fill systems are designed to shut off at 13-14PSI tank pressure. The cyclic over-pressurisation of tanks leads to tank failures through ballooning (over pressurisation and deformation) and rupture. While tanks are designed to last for 15+ years, the cycle of tank fatigue is accelerated and will often start at as little as three years into operation.

Increased volumes of spills

The dry-break system was designed to reduce spills from fuel contained in the fuel line of a traditional splash fill system once filling completed. When the tank is full and the couplings are removed, Diesel will be contained within the fuelling system. Common practice when re-fuelling is that the operator will re-activate the fuel filling gun (after initial automatic shut off) to ‘top off’ the tank. This creates two more issues:

•	The tank pressure now will be equal to the pressure delivered by the fuelling pump, which can be up to and beyond 80PSI •	The operator holds down then gun until fuel spills from the breather at the top of the tank. At 600 litres per minute, this equates to 10 litres every second, which would be the maximum expected reaction and shut-off time for the system

In some cases, operators have from the beginning of the re-fuelling process tied the gun down, to disable automatic shut-off. If the operator is not near the gun, the amount of fuel spilled will be considerably more.

Diesel Baths

As the Diesel is now disbursed through the breathing vent, it can create to what is referred to as a “Diesel bath” for the operator re-filling the equipment. At this volume, there is a high risk of Diesel entering the operator’s eyes. Best case scenario the worker will be off for the rest of his/her shift, however if Diesel has entered the eyes, this will most likely mean about three days in hospital. While diesel baths are not known to be common, they have occurred and are considered severe, high risk injury.

Spillages while operating

Now that the tank is filled to the top, and as the heavy machinery moves back into production, Diesel will spill through the fuel vent creating further issues;

•	Risk of Fire •	Environmental Pollution •	Economic loss

The risk of fire due to Diesel spilling and coming in contact with engines, radiators or tyres is real and has over the years occurred many times.

While spills at the filling stations are often catered for by bunding arrangements, this is not the case once the equipment is on the move. This part of the pollution often goes unnoticed.

Contributory factors

•	Mobile Equipment is often used on uneven ground •	Operators are not trained properly •	The applicable Australian standards do not take alternative solutions into account •	Knowledge about the risk of pressurising tanks is limited •	Fear of fines mean that minor spills are not reported

Recommendations

•	A more rigorous approach when training operators •	Mechanical Non-Pressurised Refuelling Systems to be fitted to all existing mobile equipment as best practise •	OEM’s and suppliers to integrate Non-Pressurised Refuelling Systems to be fitted to all mobile equipment as standard •	Fuel Vents to have fuel surge protection •	Fuel Vents to have roll-over protection •	A change in Australian Standards to acknowledge non-pressurised solutions should be the norm •	A pro-active maintenance program to establish tank issues early •	An audit of risks with current mobile equipment pertaining to fuel spill and tank damage.