Canal boats require a boat safety check every four years to obtain a general safety certificate (BSC). An important part of the check is a gas leakdown test. The lines are pressurised then gas turned off at bottle. There is a mandated connection point on the system that allows a check on gas pressure remaining in lines as a means of determining leaks.
Not sure if there have been changes recently but sea-going craft did not require such tests!
Agreed Richard, I always thought that was balmy, the number of checks for the 4yr inland test was quite exhaustive
