scope:

1. NECB Part 3 addresses the transfer of heat and air through the building envelope and establishes the minimum acceptable measures for the adequate thermal performance of the building envelope materials, components and assemblies. The NECB defines the building envelope as the collection of components that separate conditioned space (including semi-heated spaces) from unconditioned space, the exterior air or the ground, or that separate interior spaces intended to be conditioned to temperatures differing by more than 10°C at design conditions. The building envelope, which includes the walls, roofs, floors, fenestration and doors of a building, plays an important role in determining the amount of energy required to accommodate the occupancy of a building. The transfer of heat and air through the building envelope is an important consideration for energy efficiency.

2. The Part 3 requirements apply to all new buildings and additions that are equipped with space-conditioning systems or have provisions for the future installation of such systems, and to buildings that have a heating and/or cooling system output capacity that is equal to or greater than 10 W/m2. The requirements do not apply to unconditioned spaces or to farm buildings.