There are various measures of light. In another of our blogs, we talked about lumens which is our preferred measure but within the lighting industry there are also references to 'lux'. The two are relatable as one lux = one lumen per square metre. Lux enables us to measure the total amount of visible light present and the intensity of the illumination on a surface. If the light output is focused on a small area, we see this as very bright light. If the light output is spread in a wide beam over a greater area, we experience this as a weaker light, although it is actually the same 'amount' of light.
There is also a tendency to describe light in wattage, although a move to reduce this as a term of reference came into play as far back as 2007 when legislation came into force to direct manufacturers to label products primarily in lumen. Like the yards v metre measurement, we're guessing old habits will die hard and it'll take some time for people to think in lumens/lux.
Anyway, back to lux. We came across an interesting comparison of the understanding of lux through a table that showed 1 lux as a full moon and direct sunlight as going up to as much as 130,000 lux.
A well-lit office should be in the region of 400-500 lux, according to CIBSE (Chartered Institution of Building Engineers), so you can see how bright direct sunlight is. Consider the effects of lighting within an office where an average clear day may offer around 10,000 lux, with desks near the windows being well lit, using natural light. However as you move towards the centre of the room, it can fall dramatically meaning that additional lighting equipment is nearly always necessary to compensate for the low levels.
Talk to us about lighting levels in your workplace - it is something we work hard to ensure is optimum whilst also creating a comfortable and efficient work environment. No one likes a sick building!