Prince Edward Island
As a starting point consult the Prince Edward Island Boiler and Pressure Vessels Act R.S.N.W.T 1988, c.B-2 for useful information on pressure equipment exemptions and requirements. Always consult the chief inspector of a jurisdiction.
Prince Edward Island Canadian Registration Numbers for fittings are issued by ACI Central who is the designated regulatory authority for seven provinces and territories that include: Newfoundland, Nunavut, Prince Edward Island, New Brunswick, Nova Scotia, North West Territories, Yukon. This small agency located on Prince Edward Island vastly simplifies what could be a terribly long and bureaucratic process of dealing with seven entities.
For boiler and pressure vessel registrations and piping system registration applications, you may also directly contact the Prince Edward Island Government, Communities, Land & Environment section, Installation / Alternation Permit for Boiler & Pressure Vessels page provides further information.