BS5839-1 AFD grading

[CivvyFSO]

Rational answer AB. So you could consider it sufficiently justifiable to use a Pt6 in commercial premises in grade C circumstances?

I consider it justifiable. Even as far as grade D in certain circumstances such as giving warning to persons on a mezzanine/inner room conditions.

I believe that the down side is that there is no particular test to test the actual function of the detector. You can press the button, and that proves that it makes a sound when that button is pressed, but without the pt 1 test regime there will be no proof that the sensing element works. There is no reason why you couldn't have it tested in such a way though, and I would be tempted to say that a risk assessment should show that this test is necessary regardless of what the BS says for a part 6 system.

[AnthonyB]

non fire resistant cabling is permitted in a grade C system which is the most common type I've seen used in commercial premises

AB:  Just to quantify your statement above are you saying that in most commercial businesses you visit that non fire resistant cabling has been used opposed to fire resistant cabling as required in a Grade A system.  Does this mean that most commercial businesses out there are ignoring BS5839-1 and installing grade c systems under a part 6? or is it i wonder in most cases fitted when the AFD is installed after the original build?

Either way it seems that deviation from the standard is regularly happening

No - I didn't make it very clear    I meant that in the premises where I had found pt 6 systems used (normally single storey small retail units) they used non FR cabling.

Although I still find the odd part 1 system that is under 25 years old with call point and detector cabling in non FR (because IIRC correctly they could until 2002 although it wasn't best practice).

[AnthonyB]

I think a Part 6 grade C system with call points and a few smokes is justifiable for the large number of premises that haven't had a fire alarm (fell outside the full scope of the FP Act) but are just on the wrong side of size/layout for verbal alarm.

The preferred standard would still be a Part 1, but where a lot of these shops (and similar office buildings) are operated by SME's then the most cost effective (but suitable and sufficient) solution should be made available.

Grade D for access room with no need to be audible or trigger warning throughout the whole premises can be fine and is illustrated in the DCLG entry level guide.

[Hi Tower]

Thank you for your replies - most helpful - it does still make me wonder why the grading solution hasn't been incorporated into the part 1 BS?

[Hi Tower]

Slightly different query but still on the track of grading - I cannot see in BS5839-6 any reference for when the back up supply batteries of grade D smoke alarms should be replaced.  Clause 26 mentions cleaning but nothing else for routine maintenance.  Any reference welcome?