On 10/3/2012 7:09 PM, Robert Mac Dowell wrote:
> Let me put it this way. I had all the valves and bungs out of my tank
> when I painted it. All this purging bull is just that,bull.

Which is, of course, why the National Propane Gas Association, which
doesn't know as much as you do about propane, publishes a bulletin
covering the proper procedure for purging, Bulletin #133-89 (a).

And, the idiots over at Rego, an international manufacturer of propane
equipment, who not as wise as yourself, say things like (
http://www.regoproducts.com/PDFs/LP-Gas_Servicemans_Manual.pdf ):

"The Importance of Purging
A very important step which must not be overlooked by LP-Gas
distributors is the importance of properly purging new LP-Gas
containers. Attention to this important procedure will promote
customer satisfaction and greatly reduce service calls on new
installations. Consider the following:
� Both ASME and DOT specifications require hydrostatic
testing of vessels after fabrication. This is usually done
with water.
� Before charging with propane, the vessel will contain the
normal amount of air.
...
Both water and air are contaminants
They seriously interfere with proper operation of the system and
the connected appliances. If not removed, they will result in costly
service calls and needless expense far exceeding the nominal cost
of proper purging.
...
If the natural volume of atmosphere in the vessel is not
removed before the first fill, these problems will result:
� Installations made in spring and summer will experience
excessive and false container pressures. This will cause
the safety relief valve to open, blowing off the excess
pressure.
� The air mixture present in the vapor space will be carried
to the appliances. This may result in as many as 5 or more
service calls from pilot light extinguishment.
� If a vapor return equalizing hose is not used, the contained
air will be compressed above the liquid level, resulting in
slow filling.
� If a vapor equalizing hose is used, the air, and any moisture
it contains, will be transferred from the storage tank to the
transport."