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Transferring Petrol vs Diesel:
Why Petrol Needs Different Equipment
Diesel equipment is not petrol equipment. The difference is flashpoint, and it changes the pump, the nozzle and the earthing.
- The Naming Trap
- Flashpoint
- Nozzles
- What to Use
Petrol and diesel are not interchangeable in transfer equipment. Diesel will not produce an ignitable vapour at normal Australian temperatures, and petrol always will, so a pump motor, a switch or a static spark that is harmless around diesel becomes an ignition source around petrol. In practice that means the electric diesel pumps, kits and bowsers in the FuelGear range are for diesel only. Petrol is handled with hand operated rotary pumps rated for it and with unleaded nozzles. And the category called Diesel and Petrol Driven Transfer Pumps refers to the engine that drives the pump, not the fuel it moves.
Almost every week someone asks for a petrol version of a diesel transfer pump, expecting it to be the same unit with a different label. It is not, and the reason has nothing to do with how the two fuels flow. It is about what is happening in the air above them.
This article covers the one property that separates the two fuels, the category name that causes more confusion than anything else on the site, what changes component by component, and which parts of the range are genuinely rated for petrol.
Flashpoint The single property that separates the two fuels
Petrol driven Describes the engine, not the fuel being pumped
Hand pumps The pumps in the range that are rated to move petrol
Vapour Heavier than air, so it collects in pits, bunds and low corners
The Trap
"Petrol driven" does not mean it pumps petrol
Start here, because this one costs people the most time.
The category Diesel and Petrol Driven Transfer Pumps describes how the pump is powered. These are pumps with a small petrol or diesel engine bolted to them, for sites with no mains power and no vehicle battery to run from. A petrol driven unit has a petrol engine in the same way a generator does. The fluid going through the pump head is still diesel.
Read the product names and it becomes obvious: a "petrol powered diesel transfer pump" is exactly what it says. Petrol in the engine, diesel through the hose.
If you searched for a petrol transfer pump
You are almost certainly not looking for that category. Skip to what is actually rated for petrol further down, which is the hand operated range and the unleaded nozzles.
The Difference
One property does all the work
Flashpoint is the lowest temperature at which a liquid gives off enough vapour to form an ignitable mixture in air. It is not the temperature at which the liquid burns. It is the temperature at which the air above the liquid becomes dangerous.
Diesel sits above 61°C. On a hot day in an open yard, diesel in a tank is still nowhere near producing an ignitable vapour, which is why you can pour it, pump it and spill a little of it without creating an explosive atmosphere. Petrol sits around minus 43°C. There is no ambient temperature anywhere in Australia at which petrol is not giving off ignitable vapour.
That is the whole difference. Everything below follows from it.
| Behaviour |
Diesel |
Petrol |
| Flashpoint |
Above 61°C |
Around minus 43°C |
| Vapour at ambient |
Negligible in normal handling |
Continuous, and heavier than air |
| Australian classification |
Combustible liquid |
Flammable liquid |
| Static discharge risk |
Low in normal transfer |
A routine, designed-for hazard |
| Powered pumps in the FuelGear range |
The full electric, engine driven and bowser range |
None. Hand operated only |
Vapour sinks
Petrol vapour is heavier than air, so it runs downhill and collects in pits, bunds, trenches and the low corner of a shed. It can reach an ignition source well away from where the fuel is being handled, which is why ventilation matters as much as the equipment does.
Components
What actually changes
The pump
A motor is an ignition source
A standard electric pump has brushes, a switch and a motor housing that were never designed to contain a spark. Around diesel that is fine. In a petrol vapour atmosphere it is the ignition source. Rating a powered pump for petrol means rating the whole enclosure, and that is a different class of equipment.
The nozzle
Unleaded and diesel are separate ranges
Nozzles are built and sold per fuel, because the seals, the internal materials and the auto shut-off mechanism are specified for one or the other. FuelGear lists matched unleaded and diesel versions of the same nozzle for exactly this reason.
Earthing
Fuel moving through a hose builds charge
Flowing fuel generates static. With diesel the charge usually dissipates harmlessly. With petrol it has an ignitable vapour sitting right at the fill point, so bonding the container to the source before the fuel moves stops being good practice and starts being the control that matters.
What to Use
What in the range is rated for petrol
Two parts of the catalogue, and it is worth being precise about them.
Hand operated rotary pumps. The hand operated fuel transfer pumps are rated for petrol as well as diesel and kerosene. There is no motor, no switch and no electrical supply anywhere near the fuel, which is precisely why they remain the straightforward answer for moving petrol out of a drum. The ULTRAFLO Hi-Flow Rotary Drum Pump and the same pump with a filter both state petrol compatibility, as does the heavy duty rotary barrel pump supplied with hose and nozzle.
Unleaded nozzles. The fuel nozzle range carries unleaded versions alongside the diesel ones. If you are dispensing petrol, the nozzle is the component where getting the right part is easy and getting the wrong one is careless.
| Job |
What suits it |
Note |
| Petrol out of a 205L drum |
Rotary drum pump |
No power at the fuel. Add the filter version if the drum has been standing |
| Petrol with a nozzle on the end |
Rotary barrel pump with hose and nozzle |
Supplied as a complete hand unit |
| Dispensing unleaded, gravity fed |
Manual unleaded nozzle |
Rated to 100 LPM and suitable for gravity feed |
| Dispensing unleaded, pumped |
Auto unleaded nozzle |
Up to 60 LPM. Not suitable for gravity feed |
| Anything powered, on petrol |
A conversation, not a catalogue page |
See the section below |
Automatic nozzles and gravity feed
This catches people on both fuels. An automatic shut-off nozzle needs pumped flow to work its sensing mechanism, so it will not perform on a gravity fed tank. If the tank feeds by gravity, the manual nozzle is the correct part rather than the cheaper one. The same rule applies on the diesel side.
Powered Petrol
Why powered petrol transfer is a conversation
If you need to move petrol in volume, with a motor rather than a handle, the equipment exists but it is specified rather than picked off a shelf.
The reason is that the specification does not begin with the pump. It begins with the area around it: how much petrol, in what container, in what kind of space, with what ventilation, and how far the vapour could travel before it reaches anything electrical. That assessment determines what rating the equipment needs, and it is site specific. Two customers moving identical volumes can need different equipment because one is in an open yard and the other is in a shed with a pit in the floor.
This is also why you will not find a petrol bowser in the bowser range. Every bowser listed is a diesel unit. A petrol dispensing installation is a different piece of work with different obligations attached to it, and it starts with a phone call rather than an add to cart.
Do not adapt diesel equipment
Fitting an unleaded nozzle to a 12V diesel pump does not make it a petrol pump. The nozzle was never the problem. The motor is, and no change at the outlet end alters what is happening at the motor.
Mistakes
What goes wrong
- Buying from the petrol driven category expecting a petrol pump. The most common one, and entirely down to the category name. Check whether the word describes the engine or the fluid.
- Running petrol through an electric diesel pump. It will move the fuel. That is not the same as it being safe, and the pump seals are not specified for it either.
- Fitting an auto nozzle to a gravity fed tank. It will trip constantly or not latch at all, and the nozzle gets blamed for doing exactly what it was built to do.
- Sharing equipment between fuels. A hand pump moved from diesel to petrol carries diesel residue into the petrol. It is a contamination problem rather than a safety one, but it is still a problem.
- Filling a container on a ute tray. A plastic liner or a rubber mat insulates the container, so the static charge has nowhere to go. Containers go on the ground to be filled.
- Assuming the yard is open enough. Vapour sinks. An open yard with a service pit in it is not an open yard as far as the vapour is concerned.
Summary
Ask what the fuel does at ambient temperature
Diesel is a liquid you are moving. Petrol is a liquid and a vapour, and the vapour is the part the equipment has to be designed around. If the transfer is petrol and the equipment has a motor in it, stop and check. If it has a handle, you are almost certainly fine. Everything else in the specification, the hose, the nozzle, the filter and the meter, follows from the same question.
FAQ
Frequently asked questions
Can I use a diesel transfer pump for petrol?
No. An electric diesel pump has a motor, brushes and a switch that are not rated to sit in a petrol vapour atmosphere, and petrol produces that vapour at any ambient temperature. The seals are also specified for diesel. For petrol, use a hand operated rotary pump that is rated for it.
What does "petrol driven transfer pump" actually mean?
It means the pump is driven by a small petrol engine, for use where there is no mains power or vehicle battery. The fuel being transferred through the pump is still diesel. The words describe the engine, not the fluid.
Why is petrol treated so differently to diesel?
Flashpoint. Diesel is above 61 degrees Celsius, so at normal temperatures it does not give off an ignitable vapour. Petrol is around minus 43 degrees Celsius, so it always does. Diesel is classified as a combustible liquid and petrol as a flammable liquid for that reason.
Which pumps in the FuelGear range can handle petrol?
The hand operated rotary pumps. The ULTRAFLO Hi-Flow Rotary Drum Pump, the version with a filter, and the heavy duty rotary barrel pump supplied with hose and nozzle all state petrol compatibility. The electric pumps, engine driven pumps and bowsers are diesel units.
Is there a difference between an unleaded nozzle and a diesel nozzle?
Yes. They are separate products with materials and shut-off mechanisms specified for one fuel or the other, which is why the range lists matched unleaded and diesel versions of the same nozzle. Use the one that matches the fuel.
Why will my automatic nozzle not work on a gravity fed tank?
An automatic shut-off nozzle needs pumped flow to operate its sensing mechanism, so gravity feed does not give it enough to work with. Use a manual nozzle on a gravity fed tank. This applies to both unleaded and diesel.
Does FuelGear supply petrol bowsers?
The bowsers listed are diesel units. A petrol dispensing installation depends on the volume, the location and the ventilation around it, so it is specified case by case rather than ordered from a category page. Call and describe the site.
Why does earthing matter more with petrol?
Fuel flowing through a hose generates a static charge on both fuels. The difference is that petrol has an ignitable vapour sitting at the fill point ready to be lit by it. Bonding the container to the source before fuel moves, and filling containers on the ground rather than on a ute tray, are the two controls that matter most.
Tell us the fuel, then the job
For petrol, the range is the hand operated rotary pumps and the unleaded options in the fuel nozzle range. For diesel, the full electric pump and kit range is open to you. If the job is powered petrol transfer, describe the site and we will work out what it needs with you rather than sell you the wrong thing.