When it comes to your emergency lighting design it is imperative that you consider the levels of glare from each light fitting. When emergency lighting is activated it is essential that people are not dazed from disability glare or are at any risk from any objects that may potentially obstruct an escape route due to dazing or reflection.
Current standards for permitted glare are as follows:
- Mounting height (h) Escape route/Open area Max lux (cd) High risk max lux (cd)
- h 2.5 < 3.0 900 1800
- 3 < 3.5 1600 3200
- 3.5 < 4 2500 5000
- 4 < 4.5 3500 7000
- 4.5 < 5000 1000
Certain rules need to be taken into consideration when using emergency lighting design software.
- Room reflectants must be set to zero
- Set reference plane to floor level
- Obtain emergency lighting design lumens
- Ensure that when calculating the average illuminance select the lower of F5, F60 and Fend. (K)
- Value for luminous flux is ELDL x K
- The highest value of K should be used when considering glare
- For illuminance, use ELDL value and multiply it by K. Use this value for the emergency lighting scheme calculations
For horizontal routes the glare calculation takes into account the number of luminaires that can be seen and glare contribution from each of these fittings — any glare above 60 degrees can contribute to disability glare values — glare values should not be exceeded at any angle so ensure all levels have the appropriate changes
