Not exactly a radio topic, but I have one in my current workshop which in a previous use was a studio and has no windows and a solid door: For good reason.

The exit light was made 2012 and its battery pack April 2012. It has failed (So what). The shock horror is what they are. I cannot believe that in this time and knowing their behaviour that anyone would use NiCd batteries in it (LED type)

For those who are unaware: These are designed to stay on for a period of time in a power failure to allow people to see where the exit doors are to escape the building etc.

Why I have issues with NiCd cells is that they have a "Memory" phenomena. Eg. If you half flatten one, it will only charge to half and will not recognise the other half. So a 1000mAh battery suddenly becomes 500mAh. The only way to avoid this is to flatten it entirely.

With the exit light it is folly to consider that every time there is a power outage it is going to get fully discharged. In most cases It is totally impractical, without a battery rotation, (messy & expensive) to actually get an opportunity to flatten them & recharge.

The whole lot should be unconditionally recalled, or refitted with modules that have something like a Nickel Metal Hydride installed instead.

Apparently the charger is different? My homemade 12V no break has a Lead Acid battery, with a globe as a Barretter, acting as a current limiter if it goes dead flat. I have toyed with the idea of removing the mains & battery & hooking it to that no break.

Exit (and "running man") lights are usually completely replaced when they reach end of battery life.

At around $100 each plus labour, it's a nice little earner for those in the trade.

...it's a nice little earner for those in the trade.

And a nice bit of landfill for the rubbish tip too, like most of the crap that is manufactured these days and governments around the world do squat about it.

The memory effect that is associated with NiCad batteries rarely shows its head in exit lights and the less familiar 'Spitfire' fittings because they have to be discharged fully every six months during routine testing. In NSW emergency lighting has to run for at least 90 minutes after a loss of power though a fitting can generally run for much longer. I recently pulled a Famco exit light from service after 18 years and it took just over four hours to discharge and it still had its original battery.

New Stanilite exit lights are of the LED type now and the battery looks like three AA cells, so at least the batteries are getting smaller.

Around here in Vic I would doubt that it ever happens & does actually emphasise my point that if left un-tested and run flat, they have the chance of failing. If you do run them flat in a shopping mall it has to be when its closed (if ever) or broad daylight & hope for the best.

Anyone forgoten to switch the circuit back on?

Marc

In older installations, emergency lighting was just wired in with regular light circuits. Later down the track it was required that they be connected to their own circuits so they could be isolated from the power without disabling normal light fittings. In the last ten years or so it became mandatory that testing stations be installed on all new installs unless the emergency lighting was controlled by a central networked computerised monitoring system such as Nexus. In this central system the lights remain on at all times and when their legislated discharge time passes the LED module automatically becomes powered by the mains again.

...or broad daylight & hope for the best.

Every state has its own fire safety laws so I can only speak for the NSW situation. There are times when safety equipment can be removed from service for testing and maintenance and at these times it is known as an acceptable risk. This includes isolating automatic fire detection systems, emergency lighting systems and unusual things like chocking open fire-rated doors. As long as the risk is under management it is fine. I work in a large private hospital and one of my roles is Chief Fire Warden. When an alarm is triggered, it's humble electrician runs the whole hospital until the fire brigade makes an appearance. The down side to having all that power is that I go to gaol if something goes seriously pear-shaped but the aim is to make sure that doesn't happen. When some of the maintenance work gets carried out I have to manage contingency plans, given that there are people in the building that cannot move themselves in an emergency. Others can move themselves but are subject to earlier and more severe stages of panic because they are under the influence of anaesthetics and other legal drugs.

Before working there I worked at a large private school for just over seven years and was in a similar role there however disaster planning was very different. In the case of a hospital you need to manage crowds of people wanting to get out ASAP, no matter what. In the case of a school full of boys, the majority of people want to hang around, get closer and watch the disaster unfold and when you tell 1,600 people to shift their arses they don't want to do it because, to them, watching something explode or burn is fun and one of their foolish acts is sometimes the cause, so they require extra motivation such as weekend detentions for disobeying staff.

Two separate situations where the aims are the same but require different methods to control. By the way, for those who aren't aware, if there is a fire and a lot of associated smoke an exit light will be useless because dense smoke fills the top half of a room, even before it becomes superheated. Their main purpose is to provide a safe path out of a building before a fire takes hold. The reason they are green is because it is widely believed that green is the last colour a person with normal vision can see before they faint.

Actually green is the wavelength the eyes are most sensitive too.

I have actually been involved in a for real (no fire) evacuation in a chemical plant. The general consensus there, as to the steps to be taken in an emergency, was large ones "thataway", This one was fairly casual as we pretty much knew the cause: Electrician.

He was told that there appeared to be a fault in the charger circuit of a fire system battery after a storm: Of course we were Paper jockeys, Indians & Chemists not electricians. So after him doing naught, the battery went flat & the Mushroom valve in the deluge system which needed power 100% of the time, to hold it shut, opened......... Drama!

I saw a deluge system under test once. They do drop a lot of water when they are working well. It was at the now-defunct CSR plastics factory at the former industrial estate at Rhodes, pretty much next to Union Carbide and other similar outfits. For some now unknown reason I went there on an outing organised by the local Scout group I was a member of as a kid. A demo of the system was arranged for us toward the end of the day. We were all impressed at the volume of water it let go. I can imagine in your case the bloke copped it for his lack of attention, especially from wet colleagues.

The area is a housing estate these days and it took something like fifteen years to get the contaminants removed from the soil left by some of the former factories.

The area was actually Class 1 Zone 1 with pressure reactors, so water could not get into them, or the electrics. But as the fire tank of around 100,000 litres was pumped dry by the 6" pumps (one electric & one diesel) in pretty quick time, there was no fire fighting reserve, so we shut down until we reset it all. Naturally none of the drains could handle that amount of water, so the bund around the area looked like a dam.

Mess was limited as one keeps a minimum of anything and nothing flammable in that sort of area unless loading and even then its either in lines from bulk, or only one pallet of drums.

Marc

College dorms would get false alarms annoyingly often. Some idiot would pull the alarm. Some alarms have a coating that sticks to the idiot's fingers so the angry firefighters can identify the idiot. Though someone with a pencil or such could use it to trigger the alarm without their fingers ever touching it, though someone smart enough to figure that out would be smart enough to not trigger the alarm. When the alarm does go off, everyone assumes it's another false alarm and will hide in closets rather than go out of the building in the cold winter night.

A dorm manager at my college got smart and found that a metal and glass cage around the alarm cuts the false alarms way down. You then have to break the glass with the attached hammer and then pull the handle. Seems having to do all that makes idiots find some other prank to do... Like dropping copper pennies in the stairway upwards pointing wall sconce light fixtures with the light bulb missing. The penny would often short the Edison base, tripping the breaker and making the stairway go dark...

I suppose you could keep spare exit signs and other such on hand, so you could swap out a bad sign and immediately install a replacement, and take the bad one to your shop to see if it can be fixed.

I rather think that seeing this looks like a bit of a racket, that the answer would be a more appropriate battery type & holder that could still be modular serviced without pulling it to bits or even having to open it up & took batteries that you could (in an ideal world) buy of the shelf at a grocery store or any one that sells electrical & electronic stuff.

Modular service like it being like an electric kettle is not that silly. But do we have anyone left that can design it, be willing to market it, or be able to fix it?

A dorm manager at my college got smart and found that a metal and glass cage around the alarm cuts the false alarms way down.

Break glass devices have been standard here for decades: http://www.hkcby.com/upLoad/product/month_1210/201210262349249541.jpg

this looks like a bit of a racket

Sure is. In my experience, the NSW fire service industry is operated by cowboys.