Your views please. Do you consider it necessary to link an electronic lock, on a final exit door, to the fire alarm system if its fitted with a green break glass box. Some varying views here at my neck of the woods.
Wow! This has got technical....
Returning to the original question, I think AnthonyB and Marty, early on, gave the ideal answer. But I've been in buildings that are huge (from Cathedrals to big sheds (and I mean big)) and to link every electronically secured door back to the alarm panel would mean literally miles of very expensive cabling. In such cases, is it not agreed that a reliable one of these
is satisfactory as the sole means for ensuring that the door is always available for escape.....provided it also has one of these
Stu
Stu, You can't have understood my answer. I apologise that it isn't clearer.
There is no question that the equipment shown in your pictures is what might be required for a system. However, It is how you wire them up that is the important part! You could install the equipment shown in your pictures in a manner that would mean that the system didn't fail-safe if affected by a fault. BS7273-4 provides recommendations to reduce the liklihood of faults causing the door(s) to remain locked in an emergency.
BS isn't interested in the difficulties you might have in complying with it because of cost and/or effort in doing so just because your site is a cathedral or a big shed.
Your post seems to be more in-line with the original question (not FSO's off-shoot) and it would be interesting to find out why exactly 'it is now commonplace to find an interface between the fire alarm system and electrical release mechanisms', when these 'mechanisms' are doors.
My last answer was given in response FSO to a diiferent question from the original. It was answering the question as to why you can't rely on just a RTE switch and fire alarm link. i.e without any EDR.
You also have to understand two things; One, that there is often much more than first meets the eye. Just seeing a RTE switch and EDR switch installed doesn't mean that the system is fail-safe. Two, that on this forum you get both personal opinions of what someone thinks is sufficient, and also details of what the authorative standards and guidance recommend. It is your own choice to decide which you follow.
However, some people also want to understand the reasons behind what the recommendations are asking for or why it is common practice to do somethin. I considered FSO's question to be this sort. I therefore answered FSO's question in as much depth as my knowledge and experience extended to. I apologise if it was too technical but I hope I covered every angle for FSO
Most importantly please note that the original question posted has not yet been answered by anyone. In other words ,the question asked was, ' If an EDR (green box) is installed (lets assume it is installed properly to BS7273-4) then why does the release system need to be linked to the fire alarm? The underlying question being that, fire condition or not, anyone needing to exit that door in an emergency could always use the EDR. Seems a good question to me.
I subsequently asked if anyone knew of any
authorative document that recommended the linking of door release mechanisms to the fire alarm system. There has been no answer.