Could be wrong, but Im thinking the maglock is powered all the time, so if power fails, it opens.

What if the output on the panel fails in the powered state, or there is a short so power is applied to the maglock, or the relay sticks...

Even without a fault, surely there may come a time when a situation arises where a *emergency* exit is needed for its purpose, ie to exit in an emergency and the panel has not alarmed, or some other reason that means the door remains locked when its needed urgently (the time taken for a staff member to manually be altered to a problem, and manually overide /set a panel, or even cut the power if faulty could be time where people are trapped inside in a major emergency.)

The reason is simply curiosity, fire exits are quite often blocked or locked on purpose when they should be available and there have been many, many deaths over the years, when I read online that its practice to have a door locked until a panel decides to unlock it, then I was pretty shocked.

Unless of course it is impossible for a system to have a failure, and it is 100 percent guarenteed to be available whatever the emergency, but to be honest, Im not sure technology exists that is that reliable, or does it?

I can understand the need for supermarkets to want to stop theft, but could they not just alarm the exit, and stick a camera on it to get a nice clear exit shot if someone left that way, rather than locking it and possibly putting lives at risk in the (albeit slim risks, but when the **** hits the fan, you need to know there is no chance a faulty 30p component is not going to be responsible for trapping you in a emergency..)

The risks may be low, but if they exist then it seems odd to me that it is allowed.

granted a relay may stick as you say etc, but the local breakglass is highly unlikly to. Plus these things are tested regulaly (or are supposed to be) by the client. Also a lock 'can' fail and it could stick, also a door 'can' stick etc.

Agreed there are risks, but a lot of people lock fire doors with padlocks, dead locks. Seen a few welded up.

But you would need to asses those risks. Only thing that wouldnt jam, fail or stick is a permanent hole.

The fun starts when you have automated openers on doors for the disabled.

but when the power is off, dont they operate the same as a door closer? The units we use do. Plus they are battery backed.

but when the power is off, dont they operate the same as a door closer? The units we use do. Plus they are battery backed.

fire doors must be fail safe.

But auto openers require power to operate - contrary to all the fire door rules. Hence the battery. 40mins coverage iirc. But by definition, this introduces some risk.

so slightly off topic.

Can a fire door have a door closer?

so slightly off topic.

Can a fire door have a door closer?

Fire door as in fire restricting door. Or, Fire door as in escape route??

fire door as in escape route. ie our front door at work, has a closer, and id assume its an escape door.

I know fire containing doors must have a closer, but from what i read your saying, fire escapes cannot.

fire door as in escape route. ie our front door at work, has a closer, and id assume its an escape door.

I know fire containing doors must have a closer, but from what i read your saying, fire escapes cannot.

They can have them. The DDA saw to that. There are certain requirements you must comply with regarding the door - such as 90N max force to push it open (in direction of escape) and of course, sufficient back up power to allow door to operate automatically for 40 mins (i think). PSU would need to be close to these doors to ensure continuity of supply.

i see. The backup batts are usually in the operators.