FAQs - Emergency Lighting

Emergency lighting systems used energy stored in lead acid batteries when the mains power supply fails. The batteries are typically valve regulated lead acid (VRLA) batteries and will be monitored by the system itself for low charge. The batteries can also be tested using a hand-held battery tester and the store results compared after each visit to track batteries that may be approaching their end-of-life and require replacement.

In accordance with BS EN 50172:2004 / BS 5266-8:2004 emergency lighting should be tested both monthly and annually. The monthly test can be a partial discharge to test system functionality. The annual test should be a timed discharge to ensure that the battery set can provide at least 3 hours of backup time. All results should be recorded in a log book and the annual test carried out by a suitably qualified lighting specialist and/or electrical contractor and a certificate issued. The certificate may also be required for insurance purposes.

Emergency lighting should provide at least 10% of the normal lighting level according to BS5266 Part 1: 1999 and a minimum of 15 Lux. The Lux rating is commonly referred to as ‘illuminance’ or ‘illumination’ and is a standardised unit of measurement where 1 lux is equal to the illumination of a one metre square surface that is one metre away from a single candle.