421.1.7 Arc fault detection devices ... shall be provided for ... Purpose-built student accommodation.

I suggest that, "shall" obviates a fire risk assessment.

BPG4 would support the view of the other contractors (page 20 of Issue 6 says C3), so they are following latest industry guidance on the matter.

 lyledunn , I just re-read my previous reply, and it's a little short ... I didn't mean to imply there was nothing to discuss, please accept my apologies.

To put things into context, blindly following guidance is not "competence" ... competence is knowing which guidance applies under what circumstances, and knowing the limitations of the guidance.

I wondered how the absence of AFDDs jumped to code 3 status in Best Practice Guide 4 issue 6 as the same issue only warranted an observation “worthy of note” in BPG 4 issue 5. Further investigation revealed a subtle change between the two issues in the use of the codes.

In BPG 4 issue 5, a code 3 should be used where a recommendation would result in a significant enhancement of the safety of the installation whereas in the more recent BPG 4 issue 6, a code 3 should be used where a recommendation would result in an enhancement of the safety of the installation.

Note the dropping of that all-important word “significant”.

This opens the gate for any recommendation, no matter how minor, to be considered an improvement.

So according to BPG 4 issue 6, where AFDDS are absent in locations such as the one mentioned by me in the OP, a code 3 should be given, as Graham correctly indicated (thank you for pointing this out).

Now whilst I think that I could use my knowledge and experience of fire safety to argue that the provision of AFDDs in this particular building would not bring significant enhancement to the safety of the installation, the case would be weak to contend that AFDDs would bring no enhancement at all.

Looking at the contributors to the compilation of Best Practice Guide 4 issue 6, I note many of the great and the good of our industry, including the IET. I assume, therefore that the re-worked wording of the concept of a code 3 comes with the blessing of the IET.

I have never been a slave to the plethora of guidance that emanates from other self-appointed doyens of the industry, but I have always done my best to stick as close as possible to that which originates from the IET, a body for which I have the utmost respect.  

Whilst I would whole heartedly agree with Grahams view that following guidance is not competence, I do feel that this Best Practice Guide diminishes the need for it.

I have an old suitcase in the loft which is full of dusty old electrical books from my college days, just the place to park the remnants of any engineering judgement I may once have had.   

lyledunn said:

In BPG 4 issue 5, a code 3 should be used where a recommendation would result in a significant enhancement of the safety of the installation whereas in the more recent BPG 4 issue 6, a code 3 should be used where a recommendation would result in an enhancement of the safety of the installation.

Neither of those definitions are given, nor used, in BS 7671.

In context, BPG4 is guidance on informative (guidance) text in BS 7671. However, I would agree that, in this particular context, we are talking abut the 4th dashed indent to Regulation 653.2. I think in this context, we are looking at the C3 being a non-conformity to a normative requirement

lyledunn said:

Whilst I would whole heartedly agree with Grahams view that following guidance is not competence, I do feel that this Best Practice Guide diminishes the need for it.

Perhaps ... then again perhaps not.

For example, it perhaps would not be correct to give a C3 to no AFDD on a socket-outlet circuit rated up to 32 A in an installation that is not in the four bullets in Regulation 421.1.7, as its installation is a recommendation not a [normative] requirement?

Chris Pearson said:

Purpose-built student accommodation.

An interesting concept.

I suggest that modern high-quality purpose-built student accommodation ought not to require AFDD: arc faults ought not to develop.

Then we have the medieval universities: do they not contain "purpose-built student accommodation"? On historical grounds alone, they need best quality fire precautions.

By contrast, the ancient university colleges have bought buildings and converted them into student accommodation. Clearly they were not "purpose built" so they do not fall under 421.1.7. Surely they require AFDD, especially if they are timber-framed.

I am bound to conclude that the prescriptive nature of 421.1.7 is unhelpful.

That is a good point and one I suspect most readers will have missed - the most dangerous accommodation buildings  can be the 'change of use' kind rather than the 'purpose built' as the adaptions are quite often necessarily something of a compromise, and may be associated with all sorts of things that do not quite meet modern building regs.. As you say as worded the regs could be read as  excluding the most vulnerable cases. (Thinking back to my own uni accommodation that had originally been for gentleman and their batmen, with oak paneled rooms built in the 1700s, and the remains of about 3 different other sorts of lighting predating the late 1950s electrics ). There are also loads of crummy Victorian town houses that have been partitioned into flats and things - again clearly not purpose built, unless you accept 'purpose built for an entirely different purpose'

Mike

So, first draft in modifying my response for the other two similar buildings still to be done. Would love someone who extols the virtues of these devices to visit site and explain in a detailed report the level of enhancement to be expected.

Chris Pearson said:

By contrast, the ancient university colleges have bought buildings and converted them into student accommodation. Clearly they were not "purpose built" so they do not fall under 421.1.7.

Clearly they were not, but after conversion are they not then purpose-built student accommodation?

If not, what are they?

Just asking.

well, 'converted', as in "a town house conversion to flats" or "an office conversion to flats" for example.Unless perhaps most of the  original building was knocked down and rebuilt. I'd read 'purpose built' to normally mean built from the ground up for the current purpose. Otherwise you could have  "our state of the art clinic is housed within a purpose built chicken shed", which would read a bit oddly, and reminds me of a comedy sketch, but as I can't remember by whom I'll ignore that thought for now.

Mike.