Kindly share your comments and experience on the application of AFDD on electrical distribution system.
Is it proven on enhancing electrical safety and is it worthwhile on the additional cost involved ?
Kindly share your comments and experience on the application of AFDD on electrical distribution system.
Is it proven on enhancing electrical safety and is it worthwhile on the additional cost involved ?
Is it proven on enhancing electrical safety and is it worthwhile on the additional cost involved ?
To the best of my knowledge, the UK does not record fire safety statistics for electrical installations to an appropriately granular level to assess this properly.
Apologies for any confusion Graham, that was supposed to be a reply to Albert's main request for supporting evidence, not to you in particular - that is just a mixture of my fumble fingers and a counterintuitive software feature. My slightly odd turn of phrase is because I had already seen a copy of that article some time ago, as a private communication, but only now realised it was now on the web, and so I felt I could therefore mention it.
But there is a second serious point.
I am reminded that back when RCDs first came into common use and long before they first got snuck into the regs and then only for sockets that might be used to supply equipment outdoors, there were a whole rash of newspaper and tragic That's Life style reports to encourage us to use them of the form ' boy saved from cut lawnmower lead by new safety device'; 'disaster averted', 'life could have been saved' ' tragedy in the sun' Sun says 'whew what a scorcher' etc.
Far more recently, prior to the changes about cables remaining supported in fires driving the installation of metal clips and so on, there were several reported cases of folk becoming entangled in fallen wiring during fires and rescue attempts, and nasty injuries or deaths occurring that could have been fewer or maybe even avoided altogether as supporting evidence that the changes were proportionate.
Comparatively any equivalent reporting has been very quiet on the AFDD front, even in North America where the things originated, and the UK regulatory requirements rather appear to have preceded the body of evidence.
Mike.
It seems to me that an engineer can demonstrate in the lab that an AFDD does what it is intended to do during product development, but that is very different from demonstrating that they can save lives or property.
Along similar lines, a statin can be shown to reduce harmful lipids in the blood, but evidence of added quality adjusted life years could only emerge after they had been in extensive use for a number of years.
This is a moderately serious regulatory intervention, directly changing wiring practices with direct financial costs being imposed on the end-consumer.
It's definitely not a 'regulatory intervention' ... that would require legislation!
To state the obvious, there must be some evidence base, a safety incident analysis, a cost-benefit calculation to justify the imposition of this requirement.
Presumably the committee responsible for deciding to add that requirement into the BS 7671 must have that evidence and analysis, does anyone know where that is recorded?
All I can say to that, is that it's been through public consultation (multiple times) and rigorous debate ... I've added something to a subsequent reply that might be of interest, that is in the public domain.
I am reminded that back when RCDs first came into common use and long before they first got snuck into the regs and then only for sockets that might be used to supply equipment outdoors, there were a whole rash of newspaper and tragic That's Life style reports to encourage us to use them of the form ' boy saved from cut lawnmower lead by new safety device'; 'disaster averted', 'life could have been saved' ' tragedy in the sun' Sun says 'whew what a scorcher' etc.
Don't forget that there has also been expert evidence given in court on a few occasions, that in certain cases, presence of an RCD (for additional protection) might have saved a lives.
To state the obvious, there must be some evidence base, a safety incident analysis, a cost-benefit calculation to justify the imposition of this requirement.
It's definitely the case that the expert evidence given in the Grenfell Enquiry pointed to the most likely cause of the fire (on the balance of probabilities) being an arc fault in a fridge-freezer.
It's definitely the case that the expert evidence given in the Grenfell Enquiry pointed to the most likely cause of the fire (on the balance of probabilities) being an arc fault in a fridge-freezer.
Did the Enquiry come to the conclusion that an AFDD would (on the balance of probabilities) have prevented the fire please?
The report you need to read is that relating to the expert witness Dr John Glover.
In summary he opined that wiring he has inspected showed that the FF175BP fridge-freezer in Flat 16 has what appeared to be a "poor crimp connection" - suggesting a weakly compressed wire in the connecter barrel.
https://humanfactors101.com/wp-content/uploads/2023/10/Grenfell-Tower-Inquiry-Phase-1-Report-Volume-4.pdf pages 505 (the first page of actual text, page 4 of the PDF) to about 520.
The MCB and RCD did both trip, and the occupant turned off the power at the CU before they left the flat. Sadly by then the spread of fire was already irreversible.
Mike.
Did the Enquiry come to the conclusion that an AFDD would (on the balance of probabilities) have prevented the fire please?
Dr GLover's complete report is here: webarchive.nationalarchives.gov.uk/.../dr-j-duncan-glovers-expert-report
To state the obvious, there must be some evidence base, a safety incident analysis, a cost-benefit calculation
I tend to disagree with the "MUST" aspect.
We shouldn't need to kill people first, so as to gather evidence to allow our selves to be safer. We do have to match that tendency to being scared of our own shadow, to decide about ALARP (as low as reasonably possible), or other 'value of a life' etc. financial measures of safety.
It is a 'gamble'. We are happy to pump prime commercial industries for gain (the early funding for wind power, solar power, etc), where that investment creates rapid learning with scale benefits, so we should be able to do the same with safety systems.
Did the Enquiry come to the conclusion that an AFDD would (on the balance of probabilities) have prevented the fire please?
Another thought on this ... if the statistics are not there at present to support such a conclusion, would Dr Glover have been confident making that judgement?
I tend to disagree with the "MUST" aspect.
We shouldn't need to kill people first, so as to gather evidence to allow our selves to be safer. We do have to match that tendency to being scared of our own shadow, to decide about ALARP (as low as reasonably possible), or other 'value of a life' etc. financial measures of safety.
The difference between making a decision about a provision of a standard, vs coming to a conclusion without sufficient supporting evidence as an expert witness.
I tend to disagree with the "MUST" aspect.
We shouldn't need to kill people first, so as to gather evidence to allow our selves to be safer. We do have to match that tendency to being scared of our own shadow, to decide about ALARP (as low as reasonably possible), or other 'value of a life' etc. financial measures of safety.
To make something safer, requires that there must be some level of unsafety, some risk, some hazard or danger to begin with, and further it requires that whatever action we propose to take will somehow reduce that risk or danger.
Evidence does not require us to wait until people are killed or injured, the Accident Triangle principle of identifying near-hits, low level events that point to the risk of more severe events occurring in future, is still good evidence toward justifying action.
If we're then going to make some intervention, then to know it actually improves safety requires some evidence that it is effective, that it does indeed reduce the danger or risk, otherwise we could pursue ineffective and ultimately pointless activities, when our efforts and expenditure would have been better spent on other more effective measures. Again, that does not require us to wait for severe events, deaths injuries, the evidence could come from testing, trials, sampling or other methods.
But to go back to your key point "to allow our selves to be safer" well if we have no evidence of there being a hazard, a risk and we have no evidence that what we propose to do will effectively reduce that hazard or risk, then have we really made anything safer? Arguably we may have been better searching out and focusing on other safety hazards.
It is a 'gamble'. We are happy to pump prime commercial industries for gain (the early funding for wind power, solar power, etc), where that investment creates rapid learning with scale benefits, so we should be able to do the same with safety systems.
Today, we already have a number of highly effective safety measures which are not universally used, for example smoke alarms, probably one of the most powerful and effective measures to prevent deaths by fires. A quick check, shows Government statistics indicate 20% of all electrical fires occur in houses without a working smoke alarm, greatly increasing the risk of injury and death.
So if our goal is to improve public safety, wouldn't you start by amending the Wiring Regulations to stipulate that in every domestic property at least one hard-wired smoke alarm shall be installed, connected into the fixed wiring, either a lighting circuit, or a dedicated smoke alarm circuit where available to provide protection against electrical fires, and all fires in general.
That is likely to be a far more effective safety measure, and provide a far better cost-benefit outcome than AFDDs.
I tend to disagree with the "MUST" aspect.
We shouldn't need to kill people first, so as to gather evidence to allow our selves to be safer. We do have to match that tendency to being scared of our own shadow, to decide about ALARP (as low as reasonably possible), or other 'value of a life' etc. financial measures of safety.
To make something safer, requires that there must be some level of unsafety, some risk, some hazard or danger to begin with, and further it requires that whatever action we propose to take will somehow reduce that risk or danger.
Evidence does not require us to wait until people are killed or injured, the Accident Triangle principle of identifying near-hits, low level events that point to the risk of more severe events occurring in future, is still good evidence toward justifying action.
If we're then going to make some intervention, then to know it actually improves safety requires some evidence that it is effective, that it does indeed reduce the danger or risk, otherwise we could pursue ineffective and ultimately pointless activities, when our efforts and expenditure would have been better spent on other more effective measures. Again, that does not require us to wait for severe events, deaths injuries, the evidence could come from testing, trials, sampling or other methods.
But to go back to your key point "to allow our selves to be safer" well if we have no evidence of there being a hazard, a risk and we have no evidence that what we propose to do will effectively reduce that hazard or risk, then have we really made anything safer? Arguably we may have been better searching out and focusing on other safety hazards.
It is a 'gamble'. We are happy to pump prime commercial industries for gain (the early funding for wind power, solar power, etc), where that investment creates rapid learning with scale benefits, so we should be able to do the same with safety systems.
Today, we already have a number of highly effective safety measures which are not universally used, for example smoke alarms, probably one of the most powerful and effective measures to prevent deaths by fires. A quick check, shows Government statistics indicate 20% of all electrical fires occur in houses without a working smoke alarm, greatly increasing the risk of injury and death.
So if our goal is to improve public safety, wouldn't you start by amending the Wiring Regulations to stipulate that in every domestic property at least one hard-wired smoke alarm shall be installed, connected into the fixed wiring, either a lighting circuit, or a dedicated smoke alarm circuit where available to provide protection against electrical fires, and all fires in general.
That is likely to be a far more effective safety measure, and provide a far better cost-benefit outcome than AFDDs.
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