I heartily agree with this post as below. I have seen damage from a
propane explosion. It happened this way...
A manufactured home was purchased and set on the lot. The furnace
was a LP (Liquefied Propane) furnace. The owner had the local farm
co-op come out and set a tank. The line was buried from the tank to
the house there was a flare union made approximately 25 feet away
from the house in the high pressure line before the house regulator.
The house regulator came shipped installed under the house behind the
skirting. The piping ran right up from where it was buried to the
regulator. The union leaked and the LP gas followed the line under
the ground and up under the house to the regulator. When the owner
got impatient and tried to light his furnace the gas leak blew the
closet door off of the casing and burned the owner. It wasn't too
serious but bad enough.
Several things could have prevented this: The union wasn't leak
tested before burying it. Or it leak as a result of damage while
being buried. The line should have exited the ground outside of the
house and been looped before going back in the ground at a different
spot and into the house. This would have allowed the gas to vent
naturally outside. Propane (LP) has the property of being heavier
than air and will pool and collect in a low spot this is one thing
that makes it more dangerous than Natural Gas. I Do Not recommend it
for any area that is below grade such as a basement. Small cylinders
such as a 1 lb have much less potential for damage than 20 LB
containers. Good ventilation is a safety measure helping to prevent
the concentration of gas.
One of the safety measures on large burners (1 million BTU etc. ) is
a piping arrangement called double block and bleed. There are 2
electric valves which are powered open, failing closed. Between them
is a vent line tee'd off with an electric valve that fails open and
is powered off. This vents the gas line between the gas valves when
off and keeps the system relatively safe even if one or both of the
main valves leak by. LP is safe if safe practices are used with
wisdom and common sense.
Put the 20 lb barbeque tanks outside in the open. Connect to hard
piping with a braided high flex tube and put at least an electric
solenoid gas valve in the line outside. Then you can shut it off from
inside, when you are done. Low voltage valves are available that will
need just a basic cover from rain or snow. An electric indicator
light can be used inside to show the system is on or off.