Choosing colours for office blinds

27th Jun 2018

The #1 reason why your office blinds are not controlling glare...and how to fix it.

When working with office fit-out projects, we see a lot of specifications which specify the blind system and fabric range, but the fabric colour is left as TBC. The colour choice is sometimes regarded as a minor detail to be thrashed out between the interior designers and the client. Whilst it's true that the colour choice has an effect on ambience, and interior designers will need to have input... it is frequently overlooked that the colour choice has a massive impact on the physical performance of the blind.

Take Decor Arctic screen fabric for roller blinds for example - a typical office blind fabric. It's available in a range of colours from white through to black. If you look at the Light Transmittance (Tv) figures for the 3% openness range on the data sheet, you will see they range from 25% for White down to 6% for Black (Charcoal).

In simple terms this means that the White blind fabric will let more than 4 times the amount of light through than Black blind fabric. Consider that indirect daylight can be up to 20,000 lux - if you are filtering 25% of that with white blinds, it's still up to 5000 lux, or 10x the CIBSE recommended lux levels for offices. Whereas with the charcoal colour, filtering 6% of 20,000 lux is only 1200 lux. Although this is a very simplistic view and actual performance is influenced by many other factors, it gives an idea of the impact the window blind colour choice has on usability of office space.

How can we get it right? By paying close attention to the Visual Transmittance (Tv) figure for the blind fabrics selected. As a guide, the BRE quote a figure of 5% Visual transmittance as a maximum for fully glazed facades and 9% for half-glazed facades to avoid glare issues.

There's another big factor in blind fabric colour choice: Thermal Performance. White fabrics reflect significantly more heat than Black fabrics, so the thermal modelling engineers will always head for the white or light colours. However, it's no good having a building full of blinds which meet the spec for heat gain and thermal modelling but don't provide sufficient glare control. This is where specifiers resort to a metallised blind fabric like Decor Verve. With a metallised blind fabric, you can effectively have your cake and eat it. The metallised layer gives a high thermal reflectance rate and excellent Visual Transmittance across all colours.

In summary there are 3 simple rules to follow to achieve best outcomes:

  1. Be aware of the 3 factors that influence colour choice: Visual glare control, Thermal performance and interior look and feel.
  2. Engage with a shading specialist as early as possible to select a fabric range and colour which covers all 3 requirements. Include required Thermal and Visual performance data in the specification.
  3. Make sure the consultant provides budget costings for the selected ranges, to ensure that they fit within the overall project budget, and don't get subsequently swapped out for inadequate alternatives during the tender process.