Dennis:

ASME tanks are to be periodically inspected and re-qualified.  It's been so long, I cannot recall the intervals - and they likely have change - but I did confirm that - in this country anyway - they are to be inspected.

On 06-Oct-2015, at 18:46, Dennis Haynes wrote:

> Once the tank is filed with any amount of "liquid" propane the pressure is
> dependent on temperature. On a hot day with road heat sinking into the tank
> you can get 200 psi in there. 
> 
> http://docs.engineeringtoolbox.com/documents/1020/propane_C3H8_vapour_pressu
> re.pdf
> 
> The tank is an AME rated tank, not DOT. The inspections/testing for the DOT
> tanks are not required. 
> 
> Dennis
>