Fire while refueling

[Bluey]

While refuelling the trike today, a fire started when a spark jumped from the tip of the nozzle on my fuel drum to my mr funnel. The fire was contained mostly within the funnel with a small fuel spillage around the funnel. The tip of the nozzle was also on fire and when I dropped the drum a few metres from the trike, it tipped spilling a small volume of fuel which also burnt. A fire extinguisher eventually put the flames out. A very scary experience. What saved me was that there wasn't much fuel in the drum thus preventing any significant splashing when the drum was dropped. Having said that though, we've all filled up in similar conditions in the past without a problem. In fact I spoke to a number of trike pilots who said they experienced no issues today.

 

The conditions today were ideal for static charge build up.

 

The drum was a plastic one and no earthing has ever been used at this airfield by trike pilots to date. Airborne doesn't think earthing is necessary. In fact, they aren't sure it increases safety. There have been only two other instances of a refuelling fire before my example and only one that airborne was aware of in the history of airborne trikes.

 

I think earthing is a must and I'll be taking this precaution from now on. Also, I'll be having a fire extinguisher at hand whenever one is available. I will consider getting one for the trike if possible and will definitely be carrying a fire blanket from now on.

 

Bluey.

 

 

[rankamateur]

Was your Mr Funnel the anti-static one?

 

http://www.aeroshop.com.au/BiziGen6a37.html?ownerID=AEROSHOP&docID=85 this site suggests earthing is required.

 

Please "earth" all vehicles before refueling, and if possible "earth" the Mr Funnel.

 

 

[Bluey]

Yes, it's the black one. I'll be earthing it and the trike body from now on. Does anyone know of other instances where this has occurred?

 

Bluey.

 

 

[Jabiru Phil]

Scary experience

 

Our airfield, council owned has extinguishes all over the place

 

After reading your post it reminds me of an Incident that actually happened.

 

A good lesson

 

I was at Swan Hill some years ago, minding my own business. A car at the service station opposite at the bowser erupted in flames. The driver got a blanket from the boot and covered the engine, all OK until the blanket caught fire.

 

Anyway, I went into the office to tell the operator that he had a fire at the bowser, he was on the phone to the fire brigade and told me he was busy ringing. I asked him where was the fire extinguisher? He hung up the phone and put the fire out!!!

 

I have since made myself aware of the location of safety gear

 

Phil.

 

 

[planedriver]

Happy your learning experience had a good outcome Bluey.

 

Many years ago I had a plastic jerry-can go up on me at a go-kart track.

 

I had just refuelled the cart and it was a bit wet around the top, and was sitting on dry grass.

 

Getting my racing gloves from the car, I slid across the front bench seat and obviously got a good static charge, and as I picked it up, it just went woof and burst in to flames before I threw it clear.

 

That was another lesson very quickly learned

 

 

[goflying]

Bluey, This was discussed at great length at one of our club meetings last year, a club member developed a gadget which some members are now using. Go to southernmicrolightclub.com.au click on newsletters, then click november 2012, article is on 2nd last page.

 

Frank

 

 

[Bluey]

Thanks, it's amazing how hard it is to find a fire extinguisher when you really need one. Our trike hangars are chock full and I couldn't find one today when under pressure. I was standing no more than 5 metre from one but it was behind something so I missed it. It's critical to not only know where they are but to make sure they are in obvious places and in plain site under normal circumstances. You should be able to easily see it every time you walk into the hangar. This one is out of the way. You don't realise how important this is until something like this happens.

 

 

[kaz3g]

[quote="Bluey, post: 316591, member: 706". ...What saved me was that there wasn't much fuel in the drum thus preventing any significant splashing when the drum was dropped....

 

Bluey.

 

Buy yourself a Tatts ticket because you were ever so lucky this time. Full tanks or containers are far less hazardous than those only partly full.

 

Full ones just burn. Part full ones can explode because of the volume of air inside to promote combustion and rapid gas expansion.

 

Kaz

 

 

[Bluey]

Are you sure about that Kaz? The drum had a nozzle on it and the trikes fuel tank was without lid. It seems to me that the vapours inside the tanks expelled much of the air needed for combustion in this case. It took as much as 90 seconds to extinguish the flames. Hard to say for sure how long it was as perception of time is really stretched in such stressful situations.

 

 

[Bluey]

I just remembered some work I did on this very subject many years ago and from memory the results showed that the correct fuel air mixture was reached when there was pretty much no fuel at all left in the tank. At anything more than this you just get burning of vapours at the mouth of the container. However, if the burning is allowed to continue unabated, you eventually get the magic ratio and then suddenly it goes bang!

 

 

[metalman]

I've been concerned about this with my refueling, with rental planes it was always AvGas at the bowser but since I've got my own plane I'm fuelling from jerry cans at the hangar, I've often thought about earthing but hadn't done anything about it, till now, I'll be setting something up before next time , I also use a mr funnel but it's touching the tank all the time and I try to not let the can lose contact with it , it easy to get complacent. You said conditions were right ,what did you mean ?

 

Matty

 

 

[Mark11]

I always use a metal jerry can and mr funnel

 

Trike always filled away from hangar

 

Never intentionally earthed the can - it's so heavy (25L), have to put it on the ground before lifting to fill

 

What other earthing is suggested? A tag line to the ground?

 

 

[Head in the clouds]

I always use a metal jerry can and mr funnelTrike always filled away from hangar

Never intentionally earthed the can - it's so heavy (25L), have to put it on the ground before lifting to fill

 

What other earthing is suggested? A tag line to the ground?

It's a bit like your car Mark, the airframe gets a static charge from moving through the air and some of the plastics and fabrics used on the structure can result in quite a high build up of the charge. That static charge (potential) remains different from the potential of the Earth because the airframe, like the car, is sitting on rubber tyres which keep it insulated. The 'right' conditions for large build-ups of static charge is when the humidity is very low Matty - dry days.

 

Unless you bring the airframe's potential down to the same as the Earth's potential there is no way to avoid sparks, or at least a very rapid electrical discharge, between your jerry can and the airframe because as you noted you have set the jerry-can's potential to the same as the Earth by 'Earthing' it when you put it on the ground, so the jerry has a low potential (for potential read voltage) and the airframe has a high potential. To prevent a fire you need the potentials of the jerry and the airframe to be the same so that sparks don't fly between them while refuelling. The favoured way is to earth the airframe - you've seen those leather straps that used to hang from car chassis perhaps - for an airframe you can have a steel or copper wire with an alligator clip on each end and clip it to the airframe near the fuel tank then drop the other end on the ground. That should earth the airframe but to be sure of it, you then pick up the 'earth' end again and clip it to the jerry can. Now you know that the airframe and jerry are at the same potential and only then should you open the fuel cap and the jerry can.

 

Always close the fuel cap and the jerry can before disconnecting the lead.

 

 

[Mark11]

Bluey, This was discussed at great length at one of our club meetings last year, a club member developed a gadget which some members are now using. Go to southernmicrolightclub.com.au click on newsletters, then click november 2012, article is on 2nd last page.Frank

Frank

 

Thanks for the link

 

After reading that article and the newsletter, ill be reading all the others too

 

Regards

 

Mark

 

 

[Mark11]

It's a bit like your car Mark, the airframe gets a static charge from moving through the air and some of the plastics and fabrics used on the structure can result in quite a high build up of the charge. That static charge (potential) remains different from the potential of the Earth because the airframe, like the car, is sitting on rubber tyres which keep it insulated. The 'right' conditions for large build-ups of static charge is when the humidity is very low Matty - dry days.There is no way to avoid sparks, or at least a very rapid electrical discharge, between your jerry can and the airframe because as you noted you have set the jerry-can's potential to the same as the Earth by 'Earthing' it when you put it on the ground, so the jerry has a low potential (for potential read voltage) and the airframe has a high potential. To prevent a fire you need the potentials of the jerry and the airframe to be the same so that sparks don't fly between them while refuelling. One way is to earth the airframe - you've seen those leather straps that used to hang from car chassis perhaps - for an airframe you can have a steel or copper wire with an alligator clip on each end and clip it to the airframe near the fuel tank then drop the other end on the ground. That should earth the airframe but to be sure of it, you then pick up the 'earth' end again and clip it to the jerry can. Now you know that the airframe and jerry are at the same potential and only then should you open the fuel cap and the jerry can.

 

Always close the fuel cap and the jerry can before disconnecting the lead.

Thanks HITC

 

Ill be doing this from now on and having my fire extinguisher on hand!

 

 

[skeptic36]

Does anyone know of other instances where this has occurred?Bluey.

One at Porepunkah. I don't have any details.

Eagle school had an earth peg in the ground which you connect to the airframe, and Mr Funnel had a metal gauze going inside the funnel connected to a metal strip which went down the outside of the funnel into the tank.

 

My method is to keep a hand on the funnel and the nozzle touching the funnel, it can be difficult to maintain the latter when the can is full.

 

Sounds like I better make up a wire with some alligator clips though.

 

Regards Bill

 

 

[goflying]

 

This is why we don't have the trigger locks anymore.

 

Frank

 

 

[Bluey]

I have to agree with what's been regarding earthing the aircraft and the can. There is no point earthing the aircraft without the can as sparks will always be generated from a charged object coming into contact with earth. The problem may be exacerbated by the plastic containers as they cannot be effectively earthed. The fuel itself is another problem as it will develop a charge when it flows. It cannot be effectively earthed as it is non conductive too. There is no way to eliminate the risk completely except to not fuel when humidity levels are very low. Yesterday's humid bottomed out at 27% which coincided with the time I was refuelling. My advice is to check humidity levels at your airfield via the BOM site and avoid refuelling from cans when humidity drops below 40% or so. If your not at an airfield with observations, pick the closest area to you with observations as humidity levels can be dramatically different over short distances. Alternatively, if you are detected static discharges on yourself or objects near you then you know it is a danger period for working with fuels.

 

After the decision is made a fire extinguisher at hand should be mandatory from now on.

 

 

[nomadpete]

Way back when we worked with electronic components, we used to go to great lengths to prevent static discharge from destroying integrated circuits. Simply walking across the room was enough to create thousands of volts of static.

 

Ideally one should bond all mobile metal parts to a common potential. Planet - Airframe - funnel - jerrycan and spout, prior to opening any caps.

 

Note that although your Mr Funnel is plastic, I believe that it is carbon impregnated to make it mildly conductive. So your crocodile clip (we don't have alligators in Australia) should successfully 'earth' it.

 

What worries me though, is whether those ever popular plastic jerry cans are conductive. Almost certainly the yellow plastic nozzle won't be conductive, and this could bring about the static spark problem.

 

Now I'll have to get the multimeter out and go looking for some facts. A resistance of some megohms is enough to discharge static.

 

 

[Head in the clouds]

I have to agree with what's been regarding earthing the aircraft and the can. There is no point earthing the aircraft without the can as sparks will always be generated from a charged object coming into contact with earth. The problem may be exacerbated by the plastic containers as they cannot be effectively earthed. The fuel itself is another problem as it will develop a charge when it flows. It cannot be effectively earthed as it is non conductive too. There is no way to eliminate the risk completely except to not fuel when humidity levels are very low. Yesterday's humid bottomed out at 27% which coincided with the time I was refuelling. My advice is to check humidity levels at your airfield via the BOM site and avoid refuelling from cans when humidity drops below 40% or so. If your not at an airfield with observations, pick the closest area to you with observations as humidity levels can be dramatically different over short distances. Alternatively, if you are detected static discharges on yourself or objects near you then you know it is a danger period for working with fuels.After the decision is made a fire extinguisher at hand should be mandatory from now on.

No, this is rather alarmist and factually incorrect. You can equalise the potential between any two items whether they are metal, plastic or whatever material just by following the procedure I outlined in post #13 above and make the refuelling process quite safe (as far as ignition caused by static discharge is concerned) in any state of humidity. Refuelling has been conducted in GA quite safely for decades because every bowser is provided with an earth lead ...

 

If you lived in inland Australia and only re-fuelled when humidity was above 40% you'd probably only fly every ten years or so, or become very proficient at night VFR

 

EDIT - I've tested plastic jerrycans for earthing with a wire and Crocodile clip, it works fine, just place a plastic jerrycan (sealed) on a car seat (to insulate it by means of the rubber tyres), rub it with a synthetic cloth, connect a wire and crocodile clip and hold the other end of the wire close to your hand or a fence-post, you'll get a spark which shows that it has discharged though the wire.

 

PS - glad your 'event' wasn't more serious Bluey! Bet it gave you a scare though.

 

 

[Guest Crezzi]

After the decision is made a fire extinguisher at hand should be mandatory from now on.

For RAAus members, adequate fire fighting equipment" is already required during refuelling ops - not sure if HGFA / ASRA etc have the same rule.

 

Coincidentally I was doing some research recently (for a different reason) and came across a useful article on static electricity here http://murraybridgegc.com/download-page.html

 

Cheers

 

John

 

 

[Louie]

Thanks HITC very informative and have also read the link supplied by Crezzi.

 

To clear things further if using the red type plastic gerry with the yellow spout and black Mr Funnel what would be the best procedure?

 

Is it ok to attach the clip to the gerry handle to earth?

 

Is the yellow spout a problem?

 

Should the MR Funnel also be earthed?

 

Is it better to use metal containers?

 

 

[horsefeathers]

Thanks HITC very informative and have also read the link supplied by Crezzi.To clear things further if using the red type plastic gerry with the yellow spout and black Mr Funnel what would be the best procedure?

 

Is it ok to attach the clip to the gerry handle to earth?

 

Is the yellow spout a problem?

 

Should the MR Funnel also be earthed?

 

Is it better to use metal containers?

and if you dont have a metal airframe, where is the best place to attach the earth strap to the airframe?

 

 

[turboplanner]

A few refuelling fires on You tube.

 

If you don't have an earth and work out of a medium to larger airfield, just refuel in the refuelling area, and use the earth provided, remembering as HITC said to earth first and disconnect earth last.

 

 

[Head in the clouds]

Thanks HITC very informative and have also read the link supplied by Crezzi.To clear things further if using the red type plastic gerry with the yellow spout and black Mr Funnel what would be the best procedure?

 

Is it ok to attach the clip to the gerry handle to earth?

 

Is the yellow spout a problem?

 

Should the MR Funnel also be earthed?

 

Is it better to use metal containers?

and if you dont have a metal airframe, where is the best place to attach the earth strap to the airframe?

The thing is you really just need to discharge everything to Earth, the earth 'strap' cable with crocodile clips is just to keep the potentials equalised. A composite airframe does usually have a grounding point and if not many people clip the grounding wire to the exhaust pipe because the engine has an Earth strap for cranking which connects to the battery Earth and the battery Earth is connected to the airframe to prevent radio interference (noise from static build-up), so you can be fairly sure that all components of the airframe are connected to the exhaust pipe.

 

If you don't have an earth strap handy and even if you are using plastic containers you can still safely ground everything with your body, you might get a few static shocks in the process but then at least you know you've grounded everything. Simply remove a shoe and stand on the ground with a bare foot and touch the airframe and the fuel container. That process won't discharge everything to quite the same potential but it will bring them close enough that they won't have enough power left to cause a spark, just as someone mentioned above by keeping their hand touching the jerry and the funnel at the same time.

 

The main thing to keep in mind is that you need to discharge the static before opening the fuel cap or the jerrycan. And if you want to use the body method it's no good doing it with rubber soled shoes on ...

 

On a slightly different note, Earthing yourself regularly can be very refreshing particularly on dry days, Reiki and many other alternative therapy practitioners recommend it strongly, taking your shoes off and standing on a patch of fresh grass works best.