In Ontario there are 2 different regulations, under 2 different Acts that cover propane handling, storage, sale and use.
The Ontario a Energy Act has been around for decades, then, as a result of the Sunrise Propane explosion they brought in more detailed regulations under the Technical Safety Standards Act. This second regulation however only covers the 'front end of it, the storage, handling, distribution and sale, but NOT the end use. The requirements in this regulation include recertification of tanker trucks only.
Under the Energy Act the regulation (514 / 96) covers amongst other things, propane-fuelled vehicles and portable cylinders. It is this regulation that propane filling stations are confused over and the reason they're quoting the 10 year rule. This also the regulation BTW that makes CSA Z240 compliance mandatory, but most filling stations (and owners for that matter) don't understand that either.
Section 4 of that regulation says;
"4. (1) No distributor shall supply propane to a container that is connected to an appliance or work unless the distributor,
(a) has inspected the appliance or work at least once within the previous 10 years; and,
(b) is satisfied that the installation and use of the appliance or work complies with the Act and with this Regulation or a predecessor of it as it read when the appliance or work was installed.".
However if you keep reading down to Subsection 3 it says;
"(3) This section does not apply to propane vehicles, industrial vehicles or to appliances on highway vehicles or recreational vehicles.".
This last part is what exempts ASME tanks from the 10 year rule.
Propane-fuelled vehicles are covered by another regulation under the Technical Safety Standards Act, Regulation 211 / 01.
Ted 'n' Laurie, plus Jackson (aka Deputy Dog, the Parson Russell Terrier 'fur kid') and, Rylie (who crossed the Rainbow Bridge June 14, 2012).