can a diesel tank explode?

[cumbrian]

I have a rusty old auxiliary fuel tank in the lazarette that is too large to come out through the locker opening. Can I safely cut this in half with an angle grinder without something nasty happening?

 

[sarabande]

much better off with an air nibbler or shears, as sparks from the grinding wheel could go anywhere, not just the tank where there may be residual oil sludge despite draining and flushing. Grinding wheels can also throw bits of metal into the bilge where they play havoc with pumps and things.

Nibbler, Shears, compressor, all available from hire companies.

Air tools are much better, especially for visibility of the work area and noise.

 

[Stemar]

At your own risk, 'cos I'm no expert, here's what I'd do:

1. I know you said iwas a diesel tank, but... Have a good sniff.

1A If it held petrol: Pay a professional - life's short enough as it is
1B If it held diesel Goto 2

2.Drain it down - even if you "know" it's empty
3. Fill it with water
4. Slurp out the top few inches with a Pela pump or similar (This will get rid of any diesel that didn't come out when you drained it
5 Add a good quantity of washing up liquid and swill it round well
6 Drain it down
7. Hack away

 

[rivonia]

I have a rusty old auxiliary fuel tank in the lazarette that is too large to come out through the locker opening. Can I safely cut this in half with an angle grinder without something nasty happening?

In a nutshell YES it can explode.. Nuff said

Peter

 

[cumbrian]

In a nutshell YES it can explode.. Nuff said

ouch.

still, my original halfwit plan is benefitting from the addition of others' common sense...

so, if going via the flushing and airtools method - what additives will best flush out any remaining diesel to achieve a non-volatile condition?

 

[sarabande]

any detergent which does not have a hydrocarbon solvent base. e.g domestic washing up liquid. Agitate well and suction out. Repeat. Repeat till the sniff test works.

Best to stuff some absorbent stuff below the tank to deal with Sodde's law remnants. In any case, lots of ventilation, as even ordinary detergent has a hazard notice about being set on fire.

Fire and Explosion Hazard Data
===========================================================================
Flash Point: NOT APPLICABLE
Lower Explosive Limit: N/A
Upper Explosive Limit: N/A
Extinguishing Media: CO*2, WATER, OR DRY CHEMICAL.
Special Fire Fighting Proc: WEAR NIOSH/MSHA APPROVED SCBA AND FULL
PROTECTIVE EQUIPMENT (FP N).
Unusual Fire And Expl Hazrds: NONE.

 

[Ubergeekian]

I have a rusty old auxiliary fuel tank in the lazarette that is too large to come out through the locker opening. Can I safely cut this in half with an angle grinder without something nasty happening?

I had to remove an old central heating oil tank last year. Because of building work since it was installed in 1973 it had to come out in bits.

I started as Mr Nice guy and hired in a power nibbler. Far too slow, turned out to be damaged (by previous hirer) no replacement available. Jigsaw wouldn't touch it. 4.5" grinder wore out cutting disks at one every three inches.

So I ended up hiring an eight inch grinder and shredding the bugger with that. There was about 1/4" of diesel in there when I started, and I had a few small fires, but nothing to worry about, and I just let them burn themselves out.

So on that experience I wouldn't be too worried about explosion but I would be VERY careful about the fire risk. Flush the tank well first and have a good extinguisher or two to hand, just in case ...

 

[cumbrian]

boom!

thanks all

here's the plan - lots of lemon squeezy, loadsa water, flushing, sniff test, attempt with airtools, failing which, big grinder with linings to keep the bits out of the bilge

keith

 

[1955patric]

I have a rusty old auxiliary fuel tank in the lazarette that is too large to come out through the locker opening. Can I safely cut this in half with an angle grinder without something nasty happening?

Diesel can't explode - but a mix of diesel and air in the ullage space can and will if subjected to sufficient heat. I would suggest cold cutting with shears or nibblers as alredy suggested.

 

[vyv_cox]

I have a rusty old auxiliary fuel tank in the lazarette that is too large to come out through the locker opening. Can I safely cut this in half with an angle grinder without something nasty happening?

I have gas welded diesel tanks several times. Fill with water and some detergent, stir or shake, drain out. Very unlikely that any problem will occur at that stage, especially if only grinding.

 

[haydude]

In a nutshell YES it can explode.. Nuff said

Peter

Rubbish! Diesel does not explode if ignited with naked flames. It may catch fire, and I say may, but will only explode if under great pressure like that inside an engine cylinder compressed by a piston.

Try it yourself, poor a bit of diesel in an old pan and throw a lighted match in it.

That is why diesel is safe for boats and camper vans where fuel is kept close to living spaces.

 

[peterb]

Yes, diesel in a tank can explode. But first you must heat it above its flash point. From memory that's somewhere between 50 and 100 deg C. Below that the vapour pressure is below the lower explosive limit (LEL). If you heat the fuel until the vapour pressure exceeds the LEL then the tank can explode.

At normal temperatures petrol in a tank won't explode because the vapour pressure is too high. Cool it down sufficiently (about -40 should do it) and you can get an explosion. I've stood within 25 yards of a 100 ton tanker of 4 star petrol, watching it happily burn safely away. If it had been diesel you wouldn't have seen me for dust.

 

[230K]

Hi

I have welded a diesel tank of a 124 Estate with a mig, it was emptied as best i could but there was still some in there. No problems but i was a bit nervous. Keep the temp down as discussed.

If you throw a match into a tank of diesel the match will go out!!

230K

 

[1955patric]

Rubbish! Diesel does not explode if ignited with naked flames. It may catch fire, and I say may, but will only explode if under great pressure like that inside an engine cylinder compressed by a piston.

Try it yourself, poor a bit of diesel in an old pan and throw a lighted match in it.

That is why diesel is safe for boats and camper vans where fuel is kept close to living spaces.

As I mentioned earlier diesel will not explode, but diesel vapour mixed in the correct ratio with air IS explosive. This is what happens in the combustion chamber of your engine - finely atomised droplets of diesel in contact with air - the pressure is irrelevant except to produce sufficient heat to cause combustion. There have been numerous explosions of diesel tanks on ships caused by welding onto the tank walls above the level of the diesel. Welding significantly below the level of the diesel is considered safe as there is no air in contact with it. Safest is to ensure either no diesel vapour or no air in the tank. Grinding can easily produce enough heat to cause an explosion.

 

[JeffBoath]

A liquid will not burn, it must first change it's state to a vapour or true gas, the vapour pressure of all liquids is largely dependent on tempreture and pressure. If diesel is heated the vapour pressure increases,the vapour produced will chemically react with the oxygen in the air, if it falls to within it's flammable range and finds an ignition source (your angle grinder) it will combust, if it happens to find it's stoicemetric mix (ideal mix) it will react quite violently and whilst not technically an explosion (more of a deflagration) a significant risk exists. The use of nibblers would prove the safest however if you choose to go down the flushing route an engine degreaser left inside for an hour or so then flushed with plenty of water should emulsify any residual fuel left in there.

 

[TQA]

Rubbish! Diesel does not explode if ignited with naked flames. It may catch fire, and I say may, but will only explode if under great pressure like that inside an engine cylinder compressed by a piston.

Try it yourself, poor a bit of diesel in an old pan and throw a lighted match in it.

That is why diesel is safe for boats and camper vans where fuel is kept close to living spaces.

WARNING THE ABOVE IS WRONG.

Diesel fuel tanks can and do explode.

See http://www.cdc.gov/niosh/face/stateface/ca/07ca006.html this one killed the guy.

Yes conditions need to be exactly right but there are many well documented cases of tanks blowing up. Mostly when someone was trying to weld a tank.

The most dangerous state is an empty tank but uncleaned tank. The pro's steam clean the tank, allow it to cool but it can still blow if there is some residue. A couple of egg cups of diesel fuel will do it.

 

[Heckler]

ouch.

still, my original halfwit plan is benefitting from the addition of others' common sense...

so, if going via the flushing and airtools method - what additives will best flush out any remaining diesel to achieve a non-volatile condition?

Bit of a story to illustrate, some one pitched up outside the HM office in Pwllheli Harbour with one of those containers in a cage in a trailor behind his disco, they hold a 1000 litres I believe, full of red diesel.
He then brought his mobo alonside and started to siphon it in to the boat. I mentioned this to a H&S friend, bit dangerous innit, says I, traffic, crash etc v dangerous? illegal? Nah says he, the flash point of diesel is such that no special regs are in force regarding transportation.
So going back to your prob, no vapours as such to form an LEL. If you filled it with water and soap etc, there would be little left to turn in to "gas" with heat from the grinder.
Wouldnt worry about it myself, go for it!
Stu

 

[Frontier]

I replaced both of my tanks. Had to cut each onto 3 parts to get out of boat. I rinsed first with soapy water then drained them . We found a recprocating saw worked very well. Just eats through no sparks, not very hot.

Like this
http://www.screwfix.com/prods/23449...s/Titan-TTB132RSP-600W-Reciprocating-Saw-230V

One way to clear tanks if worried about explosions, is to feed exhaust gas through them, its inert. Sometimes not so easy to rig up though.

Good luck

 

[Csail]

Poor loads of chalk in then phone customs and report that after chartering your boat out you found this. They will soon get it out!!!

 

[Gordonmc]

I won't get into the debate about whether deisel tanks will explode but it probably would be a good idea to flush the tank with detergent and water.
The purpose of the post is to point out that the tank may well have baffle plates which makes cutting it in half a sod of a job. I did the job on a big tank mounted transversely under the cockpit of a boat and the only way I could deal with the baffles was to use a long cold chisel after cutting a big access hole.
Have fun.