Medium to Large Explosions

Submitted: Tuesday, Oct 14, 2014 at 11:56
ThreadID: 109807 Views:2324 Replies:6 FollowUps:7
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With storing petrol are the metal 20 litre jerry cans safer than the plastic ones?

My concern is that maybe with the metal cans there could be a spark as I open the metal cap. With plastic it is expansion in hot weather or breakage during a crash.

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Reply By: Les PK Ranger - Tuesday, Oct 14, 2014 at 12:11

Tuesday, Oct 14, 2014 at 12:11
I feel the plastic type now is quite up to the strength etc, although I have only carried diesel in my 20lt size drums . . . strength wise they would be on par with metal too I think (roto moulded one piece, tough), but less prone to long term rust, dents, etc.

The spout storage dilemma is one to consider.
Mine are stored inside, and especially with diesel they are a little messier to use when emptying, but travel externally a lot cleaner from dust / rain etc.

The external type are exposed to the elements, but can be stored inside the vehicle to ensure they are clean for use, and would air off quickly with petrol residue.

Metal ones have the pour spots separate, and I think sold separately ?
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Follow Up By: Les PK Ranger - Tuesday, Oct 14, 2014 at 12:12

Tuesday, Oct 14, 2014 at 12:12
Meant to type . . . ', but travel a lot cleaner from dust / rain etc.
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Follow Up By: Bob Y. - Qld - Tuesday, Oct 14, 2014 at 12:32

Tuesday, Oct 14, 2014 at 12:32
I'm with Les here, Mick.

We used to use Rheem 20L black jerrycans in the back of Landcruiser utes, to carry fuel for motorbikes, while mustering. Would swell up in the heat, never leaked and were often subjected to gross neglect. The steel ones seem to get leaks along the seam with heavy work, and if the operator doesn't close the lid correctly, it becomes deformed and will leak forever after.

Doesn't take much care to prevent explosions. Once as an 18 yr old, camped by myself about 30 clicks from the station, I was having trouble getting a fire going. With little thought, I gave the fire a splash out of a 4 gallon(20L) drum, and suddenly had a flame coming out of the drum. Did 2 circuits of the fire, like a chook with its head cut off, then returned to the drum, and quickly put the lid back on. Seem to recall throwing a couple of handfuls of black soil onto the drum which may have extinguished the flame.

I reckon petrol is a lot safer than many people believe. Otherwise there'd be vehicle fires, everywhere, everyday.


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Follow Up By: Ron N - Tuesday, Oct 14, 2014 at 14:53

Tuesday, Oct 14, 2014 at 14:53
I've got a couple of steel jerrycans and several of the Rheem black poly jerrycans, and I consider the poly ones superior in a number of ways to the steel jerrycans.

Steel jerrycans can be dented and the dent never comes out, reducing their capacity. Yes, you generally have to be a little careless to dent them - but accidents happen.
Steel can split along the seams and leak. This is more of a problem with Chinese-made steel jerrycans, where QC and metal thickness and strength is not always up to scratch.
Yes, I know they have to meet Australian Standards, but the cheap ones barely meet them.
Steel jerrycans can also abrade with movement and get pinholes worn in them. Yes, I know, it is essential to properly secure them - but abrasive movement can still occur occasionally.

Poly is a little more forgiving of being dropped or abused - and even though they swell in very high temperatures and look bloated, I've never had one fail.
They've never split, and I believe they are more abrasion-resistant than steel, as steel is generally pretty thin and it doesn't take long to wear through with any movement.

I've never had a static electricity problem or fire problem with either poly or steel jerrycans - but I'm very "fuel vapour aware".

When I was very much younger and still short on experience and knowledge and wisdom, I used to love cleaning parts and components with petrol.
I would alway carry around the workshop, and on job sites, a cut-open 1 gallon tin with a few cupfuls of petrol in it, whenever parts or oil-covered items needed to be cleaned down.

I was cured of this foolish habit when I went to wash some excessive grease off battery terminals one day - and the tin slipped from my grip - and landed right on the battery terminals!
The petrol exploded in my face - and to make it worse - the batteries were inside a small Cat loader cabin, and under the seat.

I went straight out the door backwards, and fortunately, landed on a pile of yellow sand. I was extremely lucky, I didn't catch fire, but I now had a fire inside the loader cab that I had to put out!
I was extremely fortunate, that despite suffering burns to my face and hands, that they were not severe burns - I would guess because most of the flame heat was above my head right after the petrol caught fire, as the flame is always hotter near its extremity.

I suffered a lot of skin and hair loss off my face and hands, and it took nearly 3 weeks to heal.
I was very lucky, I suffered no long-term scarring - but it was a very hard way to learn about the dangers of petrol, petrol vapours, and ignition sources.
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Reply By: olcoolone - Tuesday, Oct 14, 2014 at 12:51

Tuesday, Oct 14, 2014 at 12:51
Plastic are a lot more stronger and safer then the old metal types.

Look at how many fuel tanks are plastic these days including the big capacity ones earthmoving contractors use in the back of their utes and in boats.

I understand what you concerns are for the two but in the real world having the issues you said is extremely rare and nearly non existent.
AnswerID: 540323

Follow Up By: Sand Man (SA) - Tuesday, Oct 14, 2014 at 19:05

Tuesday, Oct 14, 2014 at 19:05
Not by my observation olcoolone.

Some friends took a couple of dirt bikes on a trip to Milparinka last year.
The spare fuel for the bikes were stored in certified plastic jerrycans and sat in an open rack behind the wheels/mudguard of the trailer.

We pulled up at the Packsaddle roadhouse on the way back and I noticed a small pool of liquid on one side of his trailer.
A corner of one of the jerrycans had shattered where it had been hit by a rock or stone. He lost the full 20 liters of fuel within. The trickle I saw was the last little bit of fuel remaining.
A steel jerrycan may have dented but would have been unlikely to have been punctured.

The big capacity ones earthmovers may use would be much thicker I think and with a higher certification level.

I have had my 4 steel jerrycans for about ten years, first carrying petrol and now diesel. No sign of rust and just the replacement of the rubber cap seals required.

So I believe it would depend largely on how you were carrying the Jerrycans and whether they where subject to a potential impact situation.

As for the original poster's prime question regarding expansion issues, both types are suitable. They are designed to allow expansion in hot weather without leaking. at least good quality ones are.
It is just the potential impact situations where I believe steel jerrycans are superior to plastic, where exposure to "missile impact" may be a risk.
If the plastic jerrycans are carried appropriately, with physical protection from impact situations, they are as safe as the steel ones.

I do have a plastic fuel tank for my outboard motor and the wall thickness is considerable. Plastic in this situation is probably superior as salt water would have an adverse effect on the steel Jerrys. That is why Outboard fuel tanks are made of plastic.
However, impact from stones/rocks is less of an issue where I carry this fuel tank on the camper and once in the tinny is of little "impact" risk" at all.

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Reply By: Ron N - Tuesday, Oct 14, 2014 at 13:11

Tuesday, Oct 14, 2014 at 13:11
We probably need to discuss what actually causes an explosion? It's not full jerrycans.

Explosions are caused by vapour in a confined space. Therefore an empty volatile fuel container is the most dangerous thing around - as many an explosion victim has found when he attacked an empty drum with a gas axe or angle grinder.
I have personally known two of those victims. One was killed, the other was seriously maimed.

If you open a jerry can, regardless of the type, you are exposing vapours to the air.
These vapours are where the real danger lies - not so much, the liquid fuel.

These vapours will NOT explode, unless they are confined in a container.
Vapours in open air will burn - they will go WHOOOOMPH!! - as they light up.
Thus, people believe this is an explosion - but it's not. It's just a rapid advance of vapour ignition, of burning.

From vapours lighting up, you then have a fire you have to put out (I've been there and done that, and it isn't fun, believe me - particularly when the vapours have lit up in your face).

Thus, the greatest threats you face when opening any petrol container are:

1. Fuel sloshing out under pressure and spilling on you, or the ground around you.
2. A source of ignition that is not readily recognised, or immediately understood.

The sources of ignition for fuel vapours are many and subtle.
By far the most dangerous, believe it or not, is synthetic clothing or synthetic upholstery.
Friction on synthetic clothing or upholstery creates static electricity.
A buildup of static electricity releases frequently in a sharp spark - as we've nearly all experienced as we get "zapped" quite often, as we open a car door and get out, after a drive.

The next sources of ignition to be aware of are things such as gas fridge pilot lights.
Vapours travel on the wind like you wouldn't believe. They travel to sources of ignition and then the vapours light up at the source of ignition and travel back to the vapour source - the fuel.
Then the fuel lights up and commences to burn. At that point you automatically, as reflex action, throw the fuel container away, and the fuel spreads and makes the fire spread. It can get very nasty.

The best thing to do with a fuel fire is not throw the container away, but place it quickly, upright on the ground.
Use a dry powder extinguisher if its available, or smother the flames with a blanket or towel or tarp or some other heavy covering if one is ready to hand.
If nothing is ready to hand, move everything and everyone away and let it burn out. It won't explode if the container is open.

It doesn't matter in the least whether you have poly or metal fuel containers.
The level of risk of fuel ignition upon opening is generally low - but it still pays to take extreme care when opening, and take steps to ensure that sources of ignition are minimised and preferably eliminated.

Thus, you keep well away from, and upwind, of any open flames such as pilot lights, and campfires, candles, or anything similar.
You eliminate, as much as possible, other potential ignition sources - such as mobile phones, any other radio-frequency emitting devices, or potential sources of sparks.
You eliminate, as much as possible, the potential of a static electricity spark - by touching earthed metal objects before opening fuel containers, and by placing the container on the ground before opening.
You must be aware of the potential for fuel splash upon opening, so always tilt the container back away from the cap when opening - and crack the cap or lid slowly to release pressure.

Don't hold a fuel container between your legs when opening. My leading mechanic opened a jerry can of petrol this way, the fuel sloshed out and over his feet and legs - and it immediately ignited from an ignition source they never found - and he was badly burnt.

If you don't believe that fuel can ignite from a static electricity spark from buildup on synthetic clothing, you need to watch this actual CCTV footage from a service station fire.

Cheers, Ron.

AnswerID: 540327

Follow Up By: Ron N - Tuesday, Oct 14, 2014 at 13:41

Tuesday, Oct 14, 2014 at 13:41
Sorry, my error - darn the lack of editing here - my brain was out of gear - I meant to put, DOWNWIND, of any source of ignition.

That means any vapours are travelling AWAY from potential sources of ignition when you open any container.
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Follow Up By: Allan B (Member, SunCoast) - Tuesday, Oct 14, 2014 at 14:15

Tuesday, Oct 14, 2014 at 14:15
Absolutely agree with all you say Ron, and the video clip was a very clear illustration of the perils of static electric discharge spark.
Must say that the young lady reacted cooly and with sense.

But no-one has answered Mick's original question....... "are the metal 20 litre jerry cans safer than the plastic ones?"
In terms of ignition by static electricity there would be virtually no difference Mick. If anything, metal would be perhaps safer than plastic, although I understand that plastic fuel containers manufactured to Australian specifications are formulated to have an electrical conductivity to avoid any static build-up. So use either, but observe safety precautions as per Ron's answer above.

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Reply By: The Bantam - Tuesday, Oct 14, 2014 at 23:20

Tuesday, Oct 14, 2014 at 23:20
I think that how you handle, store and carry fule and fuel containers is far more significant that the difference between plastic and metal

every single point that people raise favouring one over the other points to a failing in the handling storage or carrying of the container......and maybee the selection on the base of quality.....not that it is plastic or metal.

AnswerID: 540374

Follow Up By: Ron N - Wednesday, Oct 15, 2014 at 16:03

Wednesday, Oct 15, 2014 at 16:03
Yes, good point taken. When you're carrying jerrycans, you can have a potentially very dangerous situation develop if one is holed in any manner, and it releases liquid - which then promptly turns to vapour at even temperatures as low as 0 deg C.

Thus, it's imperative that you ensure that any jerry can is properly secured and protected from flying stones, from movement, and from being impacted by other loose items in the cargo.

Even as little as half a litre of petrol leaking from a jerry can, into a confined area such as a vehicle or camper cabin, can be a disaster just waiting to be set off.

Witness the number of petrol-powered boats with inboard tanks that explode every year as soon as the owner hits the starter.
The cause is generally a small fuel leak, or fumes from spilt fuel when refuelling.

I can well remember the bloke with car and caravan who burnt the Mobil fuel depot to the ground in Norseman in 1975.
He refuelled his car, still hooked to his caravan, at the bowser inside the fuel depot.
He splashed some petrol on the ground as he topped up the tank - the fumes drifted straight into the 'van - whereupon they were promptly ignited by the fridge pilot light - the fuel on the ground lit up, followed by the car and then the 'van - and by the time the firies got there, the entire depot was well alight.

It took about 2 hrs for them to put the fire out - and the most amazing thing was watching the firies playing water on the three 5,000 gallon overhead petrol tanks that were burning like roman candles from the pressure vents - until the tanks cooled, and the vents snapped shut, and the fire went out!
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Reply By: get outmore - Wednesday, Oct 15, 2014 at 13:16

Wednesday, Oct 15, 2014 at 13:16
make sure you wear a helmet while walking just in case the sky falls.....
ive used both with no issues.
ive kept plastic ones in the vehicle for many years with no spontaneous combustion
AnswerID: 540391

Reply By: Mick T3 - Monday, Oct 20, 2014 at 11:39

Monday, Oct 20, 2014 at 11:39
Thanks everyone for your advice. It seems that quality plastic is the way to go and watch the pilot lights, static and leaks in the cans.

AnswerID: 540583

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