Hello Sbush
1) The Alberta Boiler Safety Association (ABSA) is a non-profit organization recognized and authorized by the Alberta government to oversee boiler safety. It is not the same as the ASME, whose Canadian equivalent is the CSA (Canadian Standards Association) ABSA collects fees from boiler owners, designers, manufacturers and power engineers. The annual regular inspection is covered by the boiler owner's regular annual fee; additional or special circumstance inspections are charged for on an hourly rate and paid for by the boiler owner.
2) Yes, inspectors may challenge safety devices. If any major repairs to a boiler are made, especially if they involve pressure welding, an inspector must be present to verify the work. An inspector must be present at any hydrostatic test performed on any boiler, be it low or high pressure, hot water or steam, residential or industrial. The regular annual inspection is normally performed with the boiler drained and out of service, so that the tubes and surfaces can be closely inspected. If the inspector feels it necessary, the boiler can be inspected under performance.
3) According to ABSA, the most common cause of boiler failure in Alberta is the burner continuing to burn during a low-water condition. I'm still looking for a statistic describing the frequency of catastrophic boiler failure in Canada - I'm not having much luck. Maybe that says something in and of itself?
The ABSA website is a fun place to browse. Interesting to note, Dr. Lau personally supervises the exams of power engineers of all levels, across Alberta (yep, including mine.)
"Eat well, exercise regularly, die anyways."