Thermal performance of windows, doors and shutters - Calculation of thermal transmittance - Part 1: General
|Publication Date:||1 May 2020|
|ICS Code (Thermal insulation of buildings):||91.120.10|
|ICS Code (Doors and windows):||91.060.50|
This document specifies methods for the calculation of the thermal transmittance of windows and pedestrian doors consisting of glazed and/or opaque panels fitted in a frame, with and without shutters.
This document allows for
- different types of glazing (glass or plastic; single or multiple glazing; with or without low emissivity coatings, and with spaces filled with air or other gases),
- opaque panels within the window or door,
- various types of frames (wood, plastic, metallic with and without thermal barrier, metallic with pinpoint metallic connections or any combination of materials), and
- where appropriate, the additional thermal resistance introduced by different types of closed shutter or external blind, depending on their air permeability.
The thermal transmittance of roof windows and other projecting windows can be calculated according to this document, provided that the thermal transmittance of their frame sections is determined by measurement or by numerical calculation.
Default values for glazing, frames and shutters are given in the annexes. Thermal bridge effects at the rebate or joint between the window or door frame and the rest of the building envelope are excluded from the calculation.
The calculation does not include
- effects of solar radiation (see standards under M2-8),
- heat transfer caused by air leakage (see standards under M2-6),
- calculation of condensation,
- ventilation of air spaces in double and coupled windows, and
- surrounding parts of an oriel window.
The document is not applicable to
- curtain walls and other structural glazing (see other standards under M2-5), and
- industrial, commercial and garage doors.
NOTE Table 1 in the Introduction shows the relative position of this document within the set of EPB standards in the context of the modular structure as set out in ISO 52000-1.