As a starting point consult the Nova Scotia Boiler and Pressure Equipment Regulations made under Section 49 of the Technical Safety Act S.N.S. 2008, c. 10 O.I.C. 2011-27 (January 18, 2011, effective April 1, 2011), N.S. Reg. 10/2011 for useful information on pressure equipment exemptions and requirements. Always consult the chief inspector of a jurisdiction.
Nova Scotia (NS) 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 boilers, pressure vessels and piping system design registration applications, you may also directly contact the Nova Scotia (NS) government Labour and Advance Education, Boiler and Pressure Vessels site provides further information.