There is already a requirement (in NSW) for all refillable LPG cylinders to be tested before sale, at 10 year intervals thereafter, and for the date when the most recent test was undertaken to be engraved on the cylinder.
If the date shown on any cylinder is older than 10 years, then it cannot be refilled; only exchanged or replaced with/by a newer one.
I’m inclined to the view that 10 years between testing operations is a little long, but then minds greater than mine have decreed that interval as adequate.
As all of the above is legislated via the NSW Gas Supply (Consumer Safety) Regulation (2012) there’s nothing to be gained by an Owners Corporation (O/C) attempting to impose further or different requirements upon its Residents by way of the suggested Special By-Law, because as a “superior law” all provisions of the legislation (above) would take precedence and thereby nullify any initiatives by an O/C.