ELECTRO-MAGNETIC RETAINERS (EMRs) have been around for some time now and were introduced to try and resolve the problem that is sometimes created by fire doors when they interrupt the free flow of the movement of people throughout a building. Also, they have the added feature of stopping these types of doors being illegally wedged open with all kinds of objects. Indeed, one of the ironies that of undertaking fire safety inspections is to find fire doors wedged open with fire extinguishers!

EMRs are designed to conform to BS5839 Part 3 and are 'hard wired' into the detection and alarm circuit. Simply put, when the alarm is sounded/activated, any EMRs fitted should disengage and the fire door that it is holding open is then free to close against the doorjamb by way of the self-dosing device that is fitted to the door. Because of this 'hard wired' element into the detection and alarm circuit, these types of devices have become familiar and accepted by fire engineers and fire brigades as part on an 'integrated' system that supposedly links a number of important elements of the fife safety detection and alarm systems together.

Worrying Trend

Up to the present it is assumed that both fire engineers and fire brigades have given their approval wholeheartedly and positively embraced such systems and have not, to our knowledge, voiced any concerns about the reliability, function or operation of EMRs. However, both of us have found what we believe is a trend which is worrying to us and, we would suggest, should also worry fire brigades, fire engineers and other enforcing authorities alike with these types of magnetic hold open devices.

We would therefore like to present the problem to all who are interested in fire safety. We have both found that on a number of occasions, when carrying out either fire safety risk assessments or evacuation training at establishments where EMRs are fitted, that there are three results that have occurred when they have been tested/operated in conjunction with the fire alarm/detection system:

1) The EMRs have worked correctly releasing the doors and they remain de-energised until the alarm has been cancelled and the system reset to normal mode

2) Some of the EMRs do not release at all

3) The EMRs have worked correctly but when the alarm is placed into 'silent mode (silenced)' at the annunciator panel, the fire doors fitted with EMRs can be pushed back into the open position and the EMR engages again holding the door open. In an emergency this can be accidentally done just by pushing the door open against the EMR and although we have also considered other hold open devices, it appears that they would have to be operated by someone making a thoughtful positive action rather than an accidental one.

Obviously, 2) and 3) are not a good result at all It is our experience that whilst failure of the door to release at all, as described in 2), is quite unusual (although it does happen from time to time but we could not state a formal level of significance for this type of event), the situation as described in 3) is much more common. Dare we say it happens more times than not, especially in residential care establishments where the silencing of the alarm may be part of the fire routine.

Voicing Concern

I think it is fair to say that this is not a scientific study or analysis of the problem we have encountered, but it is a report based on empirical as well as sound anecdotal evidence gained by ourselves whilst carrying out fire safety risk assessments and/or training independently of each other. It goes without saying that having encountered this type of failure we would be most interested to hear from others who have had similar experiences in the past, or, after reading this article, start to test the EMRs as described and find that they either do or do not engage the doors again (both types of results would be interesting to both of us so that we can try and identify any trend).

The point that we would like to make and hope that it will be taken 'on board' by the enforcing authorities as well as those people who write the standards for such products, is that quite clearly there is a worry about the function of such products. We are not electrical engineers or experts within that field but we might just hazard a guess that from what we both know and have experienced, the EMRs have been wired in to the sounder circuit only and not fully integrated into the alarm/detection system.

This would then explain what is happening within the electrical circuitry but it does not really explain how fire brigades who inspect premises where these devices are fitted have missed such a fundamental check during their inspections. It also does not explain why, when the standards were written and then revised, how this was overlooked or not considered in any way, or how the standards that apply omit any mention of this and do not contain any guidance or standard itself for ensuring that these types of failures cannot occur.

We hope that we have not only presented a problem that needs to be placed openly on record for all fire safety engineers to take heed of, but also we hope that those who make and determine the standards for this type of equipment will take action to include whatever is needed to ensure that this kind of failure does not occur in the future.

If you wish to send any test information regarding the above please email: bob@flamerisk.co.uk

Dr Bob Docherty is Managing Director of Flamerisk Safety Solutions Ltd and Andy Frankowski is an independent Fire Safety and Training Consultant