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. 

euringharris said:

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. 

Seriously! It is decades since it was almost impossible to see from one end of a ward to another because of the patients' smoke generated by the very same people whose smoking had caused their heart attacks, strokes, and respiratory problems. In any event, that would be a Group 1 location.

I don't think that clinicians would be involved in risk assessment - they would not know where to start.

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.

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.... )

mapj1 said:

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.

Hi Mike and Chris

It wasn't meant to be a guessing game but I suppose that the term you used might be a generic term but it is very specific groups in mental health.

I did not say the number of hospital fires that are started like this. However lighting alcohol gel by a L-N arc is something that does occur in a specific patient group but is often dealt with by staff without incident as is done with many other incidents. This particular issue can be dealt with by providing E cigarettes but again it can end up with a trading commodity.  

This is not a requirement based on mental health accommodation alone. I simply fell intro the trap of giving one example which has  been over-examined as being the sole reason for the latter part of Regulation 710.421.1.7. 

As someone has already pointed out on this thread Group 0 locations are typically as per the general rules as Group 0 have limited special requirements under 710. Therefore, in order to more align with the general requirements (accepting there are differences such as observation, dedicated maintenance teams etc) the facility for a designer to add AFDDs into a design subject to a risk assessment was included.

The risk assessment needs to cover issues regarding the impact of loss of supply, flexibility of use amongst many other points. (I am aware of the Group 0 definition - regarding loss of supply).

Paul

Moving away from AFDDs - i noted that there was the comment about 24/7 supervision - this is outside the area of expertise of this forum- i will put forward my understanding of this. If needed 24/7 monitoring can be covered by special observations where a patient can be watched 24/7 to protect them from harming themselves or others. This is very intrusive as someone has to watch someone whilst they eat sleep shower etc. I believe it is incredibly tiresome for the observer and not comfortable for the patient - it is also very expensive but is in some instances very necessary.

Mike see my answer to you both on Chris' response- i have given you one example - not the reason for the regulation