What should the lighting levels in a workplace be?

By: Yasser El-rahimUpdated: April 07, 2021


Site Statistics

  • Questions
  • Answers
  • Categories
  • Last Updated
    June 26, 2022
It is recommended that the task area (e.g. desk area worked in) should be between 300 to 500 lux and 1200 to 1600 mm above floor level should be lit to 150 lux.

Just so, what is ugr19?

UGR19 stands for Unified Glare Rating of 19 or less, which is a parameter of how bright a luminaire is in a sample room layout, and is particularly important in office spaces where workers have to spend many hours a day and would be using display terminals for a large proportion of that time.

What is the minimum lux level?

200 lux – Entrance areas and lobbies require this level of light, and it is also the minimum for a restaurant dining area. 500 lux – Retail spaces should have this as a minimum light level, as should general office spaces. This level should be suitable for prolonged work on computers, machinery and reading.

What is average to minimum uniformity ratio?

A ratio of 3:1 for average to minimum roughly corresponds to a ratio of 10:1 for maximum to minimum. Compared to systems meeting criteria of 6:1 and 20:1, systems meeting 3.5:1 and 10:1 ratios as criteria will have increases in lighting system costs and energy use of 30% or more.

What is the recommended lux level for an office?

Area Recommended Lighting Level
General 500 lux
Computer work stations 300 – 500 lux
Filing rooms 300 lux


Can office lights be too bright?

Poor lighting (which includes light being too bright or creating glare) can cause us to lose our ability to focus through eyestrain, fatigue and headaches. This can result in lower productivity; absenteeism and a recent study by the HSE has shown it also has an adverse effect on our daily moods.

Should an office have natural light?

Numerous studies have shown that natural light in office spaces improves worker satisfaction and productivity. That's because natural light helps regulate the body's natural circadian rhythms (sleep-wake schedules). Better sleep also leads to greater employee productivity and satisfaction.

What is poor lighting?

Poor lighting can cause several problems such as: Insufficient light – not enough (too little) light for the need. Glare – too much light for the need. Improper contrast. Poorly distributed light.

What are the key safety issues with lighting?

Common health effects associated with poor lighting include:
  • Headache and eyestrain.
  • Neck, back, and shoulder strain (when straining to see items because of poor lighting)
  • Falling, tripping, slipping.
  • Dropping materials or tools.
  • Depression (in the case of insufficient or gloomy lighting)

How is Ugr calculated?

The equation that is used to calculate the UGR is:
  1. L= The luminance value of the luminaire.
  2. Lb= The value of the background luminance.
  3. ω= The solid angle of the luminaire that is seen by the viewer.
  4. p= The Guth Index.
  5. Σ= Shows that the equation (shown above) includes all the fittings located within the area.

What is limiting glare index?

Glare index. A value for predicting the presence of glare as a result of daylight entering an area. The glare index is affected by the size and relative position of fenestration, orientation to the sun, sky luminance, and interior luminance.

What is glare rating?

UGR stands for Unified Glare Rating. The UGR rating helps to determine how likely a luminaire and its operation in a room are to cause discomfort to those around it, taking account of the eye level and direction of view of the user. The lower the value, the less discomfort the user will experience from the lighting.

What is Ugr in lighting?

UGR (Unified Glare Rating) is a method of calculating glare from luminaires, light through windows and bright light sources. The UGR rating helps to determine how likely a luminaire is to cause discomfort to those around it. This classification ranges from 5 to 40, with low numbers indicating low glare.

How do you read an UGR table?

Follow these steps to determine the UGR value:
  1. Determine room size.
  2. Determine reflectances of the room surfaces/cavities*.
  3. Determine viewing direction: crosswise or endwise relative to the luminaire dimensions (if not symmetrical) (see graphic image below).
  4. Read the UGR value from the table.

How do you measure glare?

Measurement. Glare is typically measured with luminance meters or luminance cameras, both of which are able to determine the luminance of objects within small solid angles. The glare of a scene i.e. visual field of view, is then calculated from the luminance data of that scene.

How is Ugr calculated in dialux Evo?

UGR Print. According to EN 12464-1 the level of direct glare from luminaires of a lighting system has to be determined by the table of the CIE – Unified Glare Rating – method (UGR). This means: Lb Background luminance in cd/m², calculated from Eind/π with Eind as vertical indirect illumination at the observer's eye.

How many Lux is too bright?

150 lux – Restrooms and plant rooms require this level of light. Again this is not particularly bright but good enough for simple tasks. 200 lux – Entrance areas and lobbies require this level of light, and it is also the minimum for a restaurant dining area.