9.7.3.2 — Heat Transfer Performance

(1) This Section applies to, (a) windows, doors and skylights separating conditioned space from unconditioned space or the exterior, and (b) main entrance doors. (2) For the purpose of this Section, the term “skylight” refers to unit skylights, roof windows and tubular daylighting devices. (3) For the purpose of this Section, the term “doors” includes glazing in doors and sidelights for doors.

(1) Except as permitted in Sentence (2), metal frames and sash of windows, doors and skylights shall incorporate a thermal break. (2) Windows and doors described in Sentence (1) do not require a thermal break where they are installed as, (a) vehicular access doors, (b) storm windows and doors, or (c) windows and doors that are required to have a fire-resistance rating. (3) Windows, doors and skylights, with or without storm doors or sash, that are installed in buildings where the intended use of the interior space will not result in high moisture generation shall have a maximum thermal transmittance (U-value) or minimum temperature index (I) in accordance with Table 9.7.3.3. (4) Windows, doors and skylights, with or without storm doors or sash, that are installed in portions of buildings where the intended use of the interior space will result in high moisture generation shall be designed in conformance with Subsection 5.3.