In architecture, Light Reflectance Values (LRV), are a measure of the percentage of visible and usable light that is reflected from a surface when illuminated by a light source.
Why are Light Reflectance Values important?
The British Legislation (Equality Act 2010) requires that all new and refurbished public buildings and work places comply with current regulations via their ‘Access Statement’, ensuring safe entry, exit and safe passage throughout the building. The regulations mean that people, regardless of disability, age or gender, must be able to gain equal access to public buildings. For visually impaired people this means amongst other things that there must be a good visual contrast between various elements of the building, including doorways, fixtures and fittings. Therefore the contrast between, for example, floors and walls must achieve a certain level – measured by something called Light Reflectance Value (LRV).
Why do we need Contrast?
Most registered blind people will still have some vision in colour. Only a small percentage (less than 5%) can see nothing at all, and even people within this group will generally have some sensitivity to light and shade. So therefore ensuring that a minimum of 30 points of LRV difference is specified for adjacent surfaces will in the majority of cases help to ensure that visually impaired people are not discriminated against.
The reflection curve of a carpet is taken with a Perkin Elmer Lambda 900 spectrometer, equipped with an ‘integrating sphere’ between 400 and 700 nm with interval of 5 nm.
The colour coordinates CIE Y10, x10, y10 are determined and the LRV is calculated.