Any propane experts on here?
When filling my 20# bottles, I have been told that filling above 80% is now prohibited by law.
I've done a little looking around on the web, and it appears that the DOT and NFPA folks have conspired somewhat to require all new bottles in the consumer range to be fitted with overflow protection devices, or OPDs. These are used to prevent "overfilling".
However, I can not find any code requirement or description of what "overfilling" means.
Can anybody point to a document on the web that defines what overfilling might be, or is this just a nebulous concept? Who defines what overfilling is?
The tanks have always been over filled if filled beyond the 80% amount. The tanks have always had a "bleeder" valve that IF used vents liquid propane when the level hits 80%. There is a dip tube that extends down to the 80% level. If the valve is closed it is possible for the supply pump to overfill the tank. Some dealers would. That's why the OPD valve was invented; to prevent dealers from going over 80%. It's limited to 80% to keep the over pressure valve from discharging when a cylider gets heated on a hoy summer day.
At least that is my understanding.
I'm guessing that the tanks turn into a "wet leg" if overfilled?
The reason that I am asking is that I was told that ACE Hardware has a habit of filling the tanks more completely... almost to 100% of capacity (before the OPD devices).
I was trying to find something on the web that indicates what these levels are, and why it is "code" to not fill completely.
Liquid propane expands much more with temperature change than water. Seventeen percent more. That's why it's important to leave space. The 80% is based on 60 F. The metered pumps have a temperature / volume compensation device built into them.
I learned a ton about propane today
http://countryplans.com/smf/Smileys/default/biggrin.gif
This also makes me a little suspicious of the place that I purchase propane.... Ortega's on 2nd street. I am going to watch them much more closely when they fill.