[CZroe]

Originally Posted by Yasko

TIPS ON PUMPING GAS

When you're filling up do not squeeze the trigger of the nozzle to a fast mode If you look you will see that the trigger has three (3) stages: low, middle, and high. You should be pumping on low mode, thereby minimizing the vapors that are created while you are pumping. All hoses at the pump have a vapor return. If you are pumping on the fast rate, some of the liquid that goes to your tank becomes vapor. Those vapors are being sucked up and back into the underground storage tank so you're getting less worth for your money.

I would expect more to evaporate (become vapor) by spending more time with your fuel door open and exposed to the air.

Originally Posted by Yasko

One of the most important tips is to fill up when your gas tank is HALF FULL. The reason for this is the more gas you have in your tank the less air occupying its empty space. Gasoline evaporates faster than you can imagine. Gasoline storage tanks have an internal floating roof. This roof serves as zero clearance between the gas and the atmosphere, so it minimizes the evaporation.

Filling up twice as often means releasing the vapors twice as often and carrying around more weight for lower fuel efficiency. It can only evaporate until it reaches the maximum concentration the air can handle for a given temperature (dew point). When you fill up early, you release it all and make room for more evaporation, which runs counter to the reasoning for refueling early.

Ever wonder why the defrost in your car, which blows warm air on the windshield's water condensation, also kicks on the A/C light? I mean, you want HOT air, right? The reason why is because the the A/C removes water from the air and the dry air works like a sponge for absorbing humidity, which is obvious when you see an immediate improvement even before it has the chance to warm up. If fuel behaves the same way, why would you keep letting the vapors out and "dry" air in?

Originally Posted by Yasko

Another reminder, if there is a gasoline truck pumping into the storage tanks when you stop to buy gas, DO NOT fill up; most likely the gasoline is being stirred up as the gas is being delivered, and you might pick up some of the dirt that normally settles on the bottom.

I'm sure the pumps generally have some pretty good filtration systems. Besides, more people are equally concerned with what floats on the top of a tank and I'm been to many gas stations that have run dry a few times in recent years (they don't get too much time to build up floatsam).