Hi there, I work at university and just making sure that our signs are legal. Around half our Fire exit signs are illuminated and many are not, it woud appear to be that they have not been maintained. Please see examples of attached images. I'm no expert but keen to learn little more around all aspects of fire safety. Are these lights classed as Sustained? And what's the difference to non sustained if I'm using the right terminology..

 

Many thanks

Kevin

Exit boxes are usually either "Maintained" which are permanently lit by the mains feed and by the internal batteries upon power failure; or   "Non Maintained" which are not normally lit by the mains feed and only illuminate via the internal batteries upon power failure.

Maintained fittings are usually required in places of assembly (pubs, clubs,cinemas,conference and exhibition areas,halls, etc) as these can sometimes have low light levels under normal operating conditions - Non maintained fittings are usually OK everywhere else as  under normal conditions there is suitable artificial (or natural) lighting to illuminate the sign.

It's not uncommon for random mixes of types in a building. Your unlit signs could be non maintained,or maintained with a blown bulb!

The enclosures are usually marked on the side or base with their type (either in full or abbreviated NM or M as part of the luminaire type code) 

Your fire risk assessment should determine the requirements across your estate.