What is your take on the last sentence? Does it mean if AFDDs are used their operation might introduce a danger and therefore should be risk assessed or does it mean that AFDDs must be used on the proviso that a RA permits?
What is your take on the last sentence? Does it mean if AFDDs are used their operation might introduce a danger and therefore should be risk assessed or does it mean that AFDDs must be used on the proviso that a RA permits?
The intent of the last sentence is to give the designer and installer opprtunity to use an AFDD in a Group 0 location where they may consider an AFDD is of benefit to the building occupiers.
An example of this could be where patients purposely intend to create arcs in order to create an ignition source for lighting of materials such as cigarettes etc. The type of location where this risk exists are typically Group 0 locations.
The intent of the last sentence is that ordinarily AFDDs are not required. However, in order to counteract a specific risk (normally identified by clinicians), AFDDS shall be provided where a risk assessment demonstrating the use of AFDDs will avoid of such a specific risk.
Chris
I dont know your experience in this part of healthcare design but I have given a specific example where clinicians would comment on this.
I think you are thinking about a general medical or surgical ward which is not the scenario i am discussing. Remember the regulations have to cover all areas.
Paul
I think anyone breaking into the mains wiring to create an arc to light a cigarette, deserves for the power to go off !!
A hand held rechargeable electric lighter should not be capable of tripping an AFD If it does the AFDD is not fit for purpose.
There are medical surgery machines that use similar arcs to cut and seal flesh - as an electric knife if you like, but their EMC performance is carefully controlled.
Mike.
Hi Mike
The example I quoted is a very specific instance and is not breaking into a wiring system - they create a fault L-N at the socket-outlet becaue they know an RCD will trip and it usually involves silver paper (or similar) in conjunction with alcohol gel. Yes - in this instance the desire is for it to trip!
I dont know about plug in devices tripping or not tripping.
Finally, in terms of medical equipment that should not be an issue because there inormally no galvanic connection between in and the output and as you point out EMC performance is controlled to align with the BSEN 60601 series of documents.
Paul
Hmm. There may be places where a reduced low voltage arrangement might be safer, or indeed no sockets at all, or supply dead until made active by the staff. But I can imagine prisons, some rougher secondary schools (*), and some other public places have a similar risk. And yet they are not singled out in the regs.
Mike
(*) Actually I went to a fairly well behaved state school, and teachers became wise to the penny behind the light bulb, compasses in the socket kind of stupidity that routinely kicked the power off. And no, it was not all just me ;-) Lighting cigarettes would have been no problem even in a power cut though , as matches and lighters were common. The 1970s is/was another time.
Hi Mike
Regulation 710.421.1.7 relates specifically to medical locations and modifies Regulation 421.1.7 which is part of Section 421 Protection against fire caused by electrical equipment. (Hence it cannot be applied to prisons or schools without specific consideration.) Furthemore, you tend not to have sleeping risk in the schools you refer to which brings into question whether you would install AFDDs anyway.
Removal of sockets is an unreasonable approach in most instances in hospitals even in special hospitals. Reduced low voltage is not really appropriate as this is not an electric shock issue and again would mean ordinary equipment cannot be used.
In the example i have raised ignition sources such as matches and lighters are not allowed on the wards. As you are not permitted to smoke on NHS premises any lighting of cigarettes or other materials is not permitted. This can mean that ignition sources are sought by illicit means one of which is the local socket-outlet.
The final sentence in 710.421.1 seeks to address that point and others where AFDDs may benefit the building occupiers.
Paul
I'm not trying to be a pain, but I find it hard to believe this is a main mechanism that starts fires in hospitals in the UK , even secure ones, and therefore deserves consideration with a regulation all of its own.
How often, really, does this happen ? Thousands of times a year, hundreds or just a few tens ? or maybe just the once that someone remembered ?
And if by some chance, it actually is as common as that, and is not manageable by better supervision, then it might be safer to provide lighters and safe places to smoke, so the situation was controlled, and again if it is a common technique, what is so special about hospitals, if folk do this anywhere the risks are broadly the same, so why do we not hear more about it ?
M.
(and if I wanted to ignite alcoholic gel I'd use potassium permanganate. (KMno4) like school.... )
Paul, I think that I know where you are coming from - a secure mental health service? So yes, clinicians would determine what individual patients could obtain, and the patients will undoubtedly fight the system.
It seems to me that Section 710 is not well-suited to mental health institutions.
penny behind the light bulb
Yes, but where's the sport nowadays? The soft click of an MCB/RCBO is insignificant compared with the bang of a fuse.
Evidently Mike and I were tryping at the same time.
I think that it is rather naïve to think that attempts at interfering with the electrics are rare. Leaving aside cigarettes and fires, perhaps you would want to disable cameras and locks? Perhaps you just want to annoy the nurses? Supervision cannot be 24/7.
It seems to me that Section 710 is not well-suited to mental health institutions.
As Paul hinted at earlier, it's just one of the seemingly-infinite number of things that need to be considered when putting a standard like BS 7671 together ... which is one of the reasons parts of it seem an "odd" approach, because of the diversity of real-world applications.
It seems to me that Section 710 is not well-suited to mental health institutions.
As Paul hinted at earlier, it's just one of the seemingly-infinite number of things that need to be considered when putting a standard like BS 7671 together ... which is one of the reasons parts of it seem an "odd" approach, because of the diversity of real-world applications.
We're about to take you to the IET registration website. Don't worry though, you'll be sent straight back to the community after completing the registration.
Continue to the IET registration site