31 replies to this topic

[Dangerous]

A well known car parts cleaning/stripping company in Adelaide steams fuel tanks prior to any work. It sounds cheap and nasty, but basically all they do is get a cheap kettle without a power cutoff, seal the kettle output to the tank filler, turn on the kettle, and let it steam through the tank for 5 to 10 minutes.

I don't think I'd try the exhaust gas through the fuel tank trick, even though I've heard of it many times, as most engines run rich at idle, leaving unburned fuel in the exhaust.

Pete, I think you've taken all the sensible precautions for the type of work that you're going to do. Whe you've fuinished your tank, can you do one for me??

[shanegtr]

The lower explosive limit of petrol fumes (LEL) is 1.4% by volume and the upper explosive limit (UEL) is 7.6%. This means that in a fuel tank, the percentage of petrol fumes need to be within those two %ages to cause an explosion

The LEL for diesel fuel is typically 3.5% by volume and the UEL is 6.9%; ie, a higher LEL and a smaller range than petrol

So both are quite limited when you really look at it

Are those % for normal air Shane? Does it depend on the temperture of the ignition source?
Maybe it looks a narrow range, but how often do those particular mixture ratios occur in a typically closed container that has still has small amounts of liquid petrol changing state?

Those % are for the normal air you and I breathe. The ignition temp makes bugger all diff. If you are below the LEL there is not enough vapour to ingite causing and explosion. If above the UEL then there is not enough oxygen so support the rapid compustion required for an explosion to take place.
Regardless of these % how many of you are carless with your oxy set. Acetylene has a LEL of 2.2% and a UEL of 82.5% which is farking huge. It pays not to think about it to much