Thanks Rick...that explains things more than I expected.
It looks like you gave such a detailed answer that you forgot about my question about [is my gas still good in my tank from speedweek and how soon soon should we get it in a sealed container]?
JL222
JOHN:
Sorry, I did overlook that question.
The best practice is to never leave fuel sitting in any kind of open container for any time at all. A vented fuel cell or tank is an open container. Plug off your fuel vent(s) during the event when you're not racing (
always remembering to unplug the vent before you run) and, immediately upon conclusion of racing, empty the tank/cell and put the fuel in a well sealed metal container (D.O.T.) 5G, 16G, or 55G drum.
The above is best practice but rarely followed. Note that any fuel sitting in a vented tank for more than a couple of days has probably volatalized at least some of the low carbon number/light hydrocarbons out via the tank vent. This lowers gross volatility and negatively alters the distillation curve of the fuel. What this means in a practical sense is that the fuel formula after a couple of days has actually changed from what you initially poured in the tank. i.e. Now the tank contains fuel with a larger proportion of heavy, less lightable, chemicals, which also have a lower hydrogen to carbon ratio; a ratio very important for net heat production. Everything you do for fuel storage should be to minimize this light end "boil off" phenomena and also to minimize the exposure of the liquid fuel to UV light which can have adverse effects on fuel dye and on T.E.L.
Plastic Superjugs are handy and are OK for short term (a couple of days) fuel storage. However, they do admit UV light and they usually don't seal well creating the light end "boil off" described above. So use Superjugs when you must. But after the event seal up the fuel tightly in a metal D.O.T. drum with "O" Ring sealed bungs.
When storing the fuel in a garage or shed, keep the fuel elevated off the ground or concrete on a pair of wood 2X4's. This will minimize temperature changes on the fuel and will also let you see if there is any leakage out the bottom of your storage container. Often the bottom chine of the drum will leak slightly or "weep". If the drum is right on the floor the seepage can be hidden under the bottom of the drum.
If you store the fuel outside, make sure no standing water accumulates on the drum head. A small, cheap tarp with the flaps secured by a bungy cord will prevent this.
Never store fuel in any area where there is open flame (water heaters, furnaces, etc); even if the drum is sealed tightly. Drums can and do begin to seep in storage sometimes. If they begin to emit significant vapors near an ignition source obviously bad things can happen.
Best regards.
Rick Gold
ERC Fuels-owner
