Fuel & Safe Refuelling in Detail


Safe handling and storage of petrol (gasoline)

Petrol deserves respect – and not just because it’s running out. Last month we went over the awesome destructive power the stuff. There are regulations about how you must store petrol, but it remains easy to catalyze disaster using perfectly legal quantities of petrol. (It’s why they’re suddenly so twitchy about passengers carrying liquids onto international aircraft.)

Click here for the full story on static electricity as a fuel fire hazard.

Here’s how not to dice with death using petrol.

Every time you refuel even the trusty lawnmower, or un-cork a portable 'Jerry' can, you really should take a moment (pause, breathe, think) to consider how supremely inconvenient and unpleasant a helicopter ride to the burns unit, and the subsequent skin grafts – or worse – really would be. This pause for reflection is certainly worthwhile, considering what could happen.

Petrol evaporates and forms an explosive vapour mix in air at temperatures above minus 40 degrees C (this is the so-called ‘flashpoint’ of petrol). This is why you must never handle petrol in an enclosed space. It must only ever be de-canted outdoors, with air movement preventing an explosive vapour mix from forming. So, no topping off the mower or emptying a Jerry into a vehicle inside the garage – ever.

If you store petrol, minimize the amount, and then only ever in approved containers. Don’t over-fill them. All approved jerry cans have a ‘full’ mark, which allows room for thermal expansion. In other words, when filled to the 'full' mark, there remains a void of gas above the liquid. If the container heats up and the liquid expands, the gas inside will compress. If you fill the container literally to the brim, and it heats up, there is the chance that the expanding liquid (which unlike gas is incompressible) will over-stress the container (result: leak) or work its way past the cap (ditto). If the leak happens in an enclosed space, it will evaporate into an explosive mix in air ... which is almost all you need to blow yourself up.

Here's what you do if the container develops a leak: Never attempt it. Get a newie.

Vapour mix is half of the ‘Molotov’ equation. The other half is ignition, which could be a lit cigarette (off the scale on the idiotometer), or a pilot light, workshop equipment (especially welders, grinders and power tools – look at the commutator in a running drill/saw/router/etc and check the sparks), or any other electrical equipment – battery or mains powered. Don’t store or de-cant fuel near any of those – and don’t re-fuel a hot engine (chainsaw, mower, etc.) because the heat alone could be enough to ignite the vapour (The auto-ignition temperature for petrol is 246 degrees C. The chainsaw’s exhaust gets hotter than that.)

Fuel containers with only a dribble in the bottom are more dangerous than full ones, because they’re full of explosive vapour. This is why less really is more in the best Molotov cocktails – the vapour explodes, spraying burning petrol and glass everywhere. It’s also why you should never leave a fuel container shut in a vehicle, with the windows up. Leak, vapour, door opens, dome light sparks – join the dots on the rest of the cascade of unpleasantness culminating in: paramedics, morphine, helicopter... Leave the windows open if there’s a portable fuel container in a vehicle. And strap it down. The last thing you need flying around the passenger space in a crash is a fuel container.

Jerrys pose a problem on the home front, too, when you return from a big trip with a couple of full Jerrys. You can only store the fuel for about 60 days before it starts going off – the varnishes and gums suspended in the fuel are unstable, and they start glomming up and will clog all your vehicle’s fuel filters if you tip old petrol into the vehicle three months down the track. Tip your spare fuel into the vehicle at the earliest opportunity after you return. Then put the open, empty Jerrys outside, away from ignition sources, for several hours on a nice, dry, sunny day. Evaporate off all the residual fuel using the sun’s heat, then store the Jerrys somewhere cool and dry until the next trip.

If you use Jerry cans, service the vehicle’s fuel filters more regularly, because you never know what gunge is lurking in some dubious Jerry. Use a funnel or (better) a clip-on pourer with a mesh filter.

Last vapour problem involves degreasing in the home workshop. Petrol is not a safe degreaser – even though it’s an effective one. It’s pumping explosive vapour into the air the whole time, close to you – which is so far from ideal it’s not funny. Use a commercial degreaser, which is designed not to explode at the drop of a spark.

Another easy way to blow yourself up involves pool chlorine. Granular pool chlorine plus petrol equals explosion. Never store the two chemicals close together. The most effective hazard control measure is to remove the hazard, so store the two chemicals under different roofs.

Petrol is not only officially a dangerous good (fire/explosion risk); it’s also a hazardous substance (health risk). It’s carcinogenic – don’t get it on your skin. Chemical-resistant gloves (not latex or dishwashing gloves, or leather rigger’s gloves) are required if you’re dumb enough to handle it, or required to service a carby, etc.

I know some of you think I just got into my dress and makeup here. I got plenty of petrol on my hands as a young bloke. We all did. And if back then someone from the World Health Organization told me it could give you cancer, then I probably would not have. Unfortunately I only found out later…

Petrol fumes are hazardous to breathe, as anyone who’s met even a short-term recreational petrol sniffer would know. Another good advertisement for minimizing your contact with the stuff, and for maximizing ventilation.

You should also never - ever - siphon it by sucking. Breathe in at the wrong moment, suck a couple of drops into your lungs, and you could easily wake up dead. So, on one hand you’ve got an unscheduled date with the Grim Reaper, and on the other you’ve got a $10 hand-squeezie siphon thingy from Repco. I know which option I’d choose.