Jump to content

emergency lighting


Recommended Posts

A little more info may be useful; are they self contained units? is it the lamps that go or another fault? are they fixed or do they get moved around a lot? do they spend a lot of time in use (ie running off batteries)?
Link to comment
Share on other sites

  • 2 weeks later...

Sorry for the delay in replying, I've had a few days off.

Our Emergency lighting system comprises essentially a UPS with an external bank of batteries, (essentially maintenance-free car style batteries) with an output of 240v AC, via a static inverter in the UPS unit, which also provides a trickle charge for the batteries. The system has been installed for 30 months, by Emergilite, who provided a BPC UPS unit. This system has failed recently, twice in as many months. In both cases a resistor went short circuit in the Static Switch Board. The lighting load - mainly fluorescent - in mains failure mode is about 40% of capacity of system. The emergency lighting system is a fixed installation and is fed from the mains except when tested and when the mains fail. So the question is - does anybody out there have a similar system? Have they experience a similar problem or is their system reliable?

Link to comment
Share on other sites

As a general comment on UPS (and generator) systems, I have usually found that they fail at the most critical moment ie when the power fails. I was until recently responsible for 24/7 engineering for a TV transmission facility. We had a number of UPS and generators to keep it all running. To keep it all running we went to failure major lengths in terms of servicing and regular checks.


Some observations based on my experiences...


1/. Cheap UPSes are not worth it, always buy a good brand and get references for any kit you do not know. Some systems are not made by the manufacturer whose name is on the box but are re-branded units made elsewhere. Do not trust the recommendation of the installer, they will usually sell you what their wholesaler stocks.


2/. Test your batteries regularly. The only problems we had with UPSes were batteries going high resistance (once we got rid of bad UPSs). To test them needs a proper meter which can measure their internal impedance whilst they are on load. If all your batteries in a series string are not the same impedance, when they come to supply load they will not share the voltage equally which will result in your killing off some cells. We used to have a service contract which measured the batteries on a 2-monthly basis.


3/. Never buy a system where the batteries are in parallel, it's just wrong.


4/. Test any generators you have regularly. We started them ourselves every week and had a service visit every month. On top of that we did a full load test and a 120% load test every year using dummy loads (a 1MW dummy load is an impressive sight running, especially when it has been snowing).


5/. The best battery lighting system I have used are those that run 12v DC to the emergency lamps. Yes the cabling is slightly more expensive, yes the lights are slightly more expensive but I know of one system which is over 30 years old and has never failed. The beauty is that you have reduced the number of components which can kill the whole system to about 2, a battery and a relay. Any failures are then moved into individual lights which is much less drastic when it goes wrong.



It's interesting that in a couple of months, two members have reported major problems with UPS emergency light systems (Guy and Ben P). Our members don't cover that many venues so I would guess that the percentage failure of UPS systems must be quite high.

Link to comment
Share on other sites

Guest lightnix

Good advice from Brian there, especially the bits about spending enough money and regular testing. I was in a building recently where the power failed, along with 80% of the emergency lighting. Luckily I had a torch :angry:


At the risk of drifting slightly OT, I heard a story that during the recent New York blackout, it emerged that there is no legal requirement in the city for buildings to have emergency lighting systems, which got me thinking...


Surely LEDs would be an ideal solution for emergency lighting, given their longevity and reliability. Their low power consumption means that you could have brighter emergency lighting and could maybe leave the system running in a "glow" mode at all times, to help identify any problems as they occurred. Multicoloured LEDs could possibly be used to create a "smart" emergency lighting system, linked into fire and smoke detectors, which could indicate which exit routes were hazardous and which were safest. "Serious" LED lighting runs on 12 volts, so there should be no need for extensive re-cabling.


I've been starting to surf around recently for info on solar and wind powered / charged systems and am pleasantly surprised at the amount of stuff that is out there. If I was building an emergency system from scratch I would seriously consider using solar/wind to charge the emergency lighting. Let's face it: there's usually one or the other in the UK and the forces of nature are surely more reliable than any electricity company.


The initial costs would be higher and the need for regular testing would still remain (the batteries still being the weak link in the system), but the long term benefits would outweigh these factors.


©2003 Nick 'lightnix' Cooke



Link to comment
Share on other sites


This topic is now archived and is closed to further replies.

  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.