Illuminance
According to BRE’s The essential guide to retail lighting:
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’.
[edit] 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.
- Lamps.
- Lamp efficacy.
- Light pollution.
- Lighting.
- Lighting designer.
- Lighting energy numeric indicator LENI.
- Lighting of construction sites.
- Luminaire efficacy.
- Lux.
- Rights to light.
- Uniformity of illuminance.
Featured articles and news
STEM ambassadors needed for ICE CityZen award.
Digital gaming competition for UK students aged 16 to 18.
Heritage protection in England vs Australia.
Fire doors and the Fire Door Inspection Scheme.
Three-quarters of fire doors fail inspections
UN International Day for Biological Diversity, May 22.
The role of geoparks, biospheres and world heritage sites.
BSRIA conference 2022, June 23.
Just one month to go ! Find out more here.
Restoring Broadbent’s Bath House
A new gallery for the University of Huddersfield.
Corruption in the construction industry.
What will it take to stop it ?
To celebrate world bee day 2022 !
Just one month until the changes to part L come into effect.
Not forgetting part F and the new part overheating part O.
Heat Pump demand rises by one quarter.
As energy prices jump up in cost.
With people in the UK from Ukraine.
Industry leader Steve Murray takes on role.
An abundant and versatile building material.
How overheating complicates ending gas in the UK.
600,000 heat pump installations targeted per year by 2028.
Cost planning, control and related articles on DB.
Helping prevent those unwanted outcomes.
ICE debate Public transport - post pandemic.
How has transport changed due to Covid-19 ?
Cross-ventilation in buildings. Do you have it ?
Will you need it ? after June 15 and the new Part O ?
Share your knowledge with the industry.
Create an account and write the first of many articles.
The green jobs delivery group.
CIAT commentary after the first meeting.
Liverpool's world heritage site status
Who is to blame?
Research recommends focussing on portfolio success rather than project success.