- Project plans
- Project activities
- Legislation and standards
- Industry context
Last edited 21 May 2020
Illuminance is ‘The level of light on a surface; measured in lux (lx). Previously called the illumination value. It can be used as a reference measurement of the performance of a lighting system as related to the activity.'
It is measured in lux (lx), the ‘...SI unit (the International System of Units) of illuminance or amount of light on a surface. One lux is equal to one lumen per square metre (lm/m^2)’ where a lumen (lm) is the ‘...SI unit of luminous flux, describing the quantity of light emitted by a lamp or received at a surface.’
Average illuminance is ‘The illuminance averaged over a specific area. In practice, this may be derived either from an average of the illuminances at a representative number fo points on the surface, or from the total luminous flux falling on the surface divided by the total area of the surface’
Maintained illuminance is ‘Illuminance at the time when maintenance is expected to take place. Most values of illuminance that are quoted as applicable to a store, eg 500-1000 lx, refer to this value. The time taken to reach the maintained illuminance level would depend on the lamp types and application’.
 Related articles on Designing Buildings Wiki
- Ballast or control gear.
- Colour appearance.
- Colour Rendering Index CRI.
- Commercial lighting.
- Daylight benefits in healthcare buildings.
- Daylight factor.
- Daylight lighting systems.
- Dichroic reflector.
- Discharge lamp.
- Extra-low voltage lamps.
- General lighting v task lighting.
- Lamp efficacy.
- Light pollution.
- Lighting designer.
- Lighting energy numeric indicator LENI.
- Lighting of construction sites.
- Luminaire efficacy.
- Rights to light.
- Uniformity of illuminance.
Featured articles and news
Love them or hate them, they are popping up everywhere.
The initiative to enhance the environment continues.
Could underused community spaces offer an alternative to working from home?
Keeping workers and workplaces safe in the United States.
A history lesson in geographic information systems.
A low tech, easy to use method of extinguishing small fires.
How can these valued spaces be reused?
Partnership avoids the need for listed building consent.
Connecting building design from inception to completion to operations.
Gregor Harvie predicts interoperability will be construction’s Uber moment.
Expert commentary and insight.
Guidance offered for stained glass window maintenance.
Define need before determining viability.