Design Principles of window blinds for offices - #3 Light
Hugh McCreadie
Blinds and Curtains Consultant - helping property developers and their designers create market-leading spaces
The primary function of any window blind is to regulate daylight for the comfort of the building user.
Two key principles to consider are the positioning of the blinds and the fabric selection.
Fabric selection will also have an impact on thermal performance; so light and thermal factors should always be considered together.
BLIND POSITION
Blinds should coincide with vertical mullions, and overlap the mullions so there are no gaps which allow direct sunlight to penetrate.
Blinds should be sufficiently close to the window prevent direct sunlight penetrating at oblique angles.
FABRIC SELECTION - VIEW OUT
Fabric should be a semi-transparent screen type fabric, which still retains a view out even when the blinds are fully down.
Openness factor describes the closeness of the threads in woven screen fabrics. It has an impact on view out. Screen fabrics should have 3% openness factor for spaces containing workstations.
FABRIC SELECTION - GLARE CONTROL
Visual Light Transmittance (VLT or Tv) of the fabric should be between 2% and 6%. VLT greater than 6% is likely to result in unacceptable levels of glare.
Our preference is for metallised fabrics. Metallised fabrics offer consistent glare control and thermal performance regardless of colour.
For the fully illustrated 2019 design guide covering all 8 principles request your copy at [email protected]
