Thanks TW and Buzz for confirming what the 2002 edition said.
Buzz, I'm sure I am not alone in being able to look at detector spacings and being able to tell within about 10% accuracy of their actual distances. I don't know if this comes from years of working out cable distance requirements when estimating prices, but I can do it. Obviously, I get my tape measure out when the smoke detector spacing is clearly more than about 6.5m to a point, or more than about 13m between detectors.
I'm beginning to think that the BS assumes that the designer and installer must have got things right so there is no need for a commissioning engineer to re-check these things. But this doesn't explain why there are other things the commissioning engineer is required to re-check. Unless of course, it is considered that only some things are likely to vary between design and installation. I will revist the the clauses that commissioning engineers are meant to check when I have a bit more time and see if I can work it out.
I would say that any assumption that the designer and installer would obviously got things right is probably flawed. The designer invariably uses small scale drawings and therefore invariably indicates detector positions in any space in a way where there is room on the drawing to show it (i.e avoiding the text for the room description and drawing sysmbols for other equipment). Also many installers don't know the BS requirements and will site a detector exactly where the designer has shown it on the drawing even if it is the wrong position.
To stick to the hard and fast 15 metres max between heads and declaring as such within a commissioning cert then anything greater than 15 metres would be unacceptable and leave the commissioning engineer wide open - there is no tolerance given as far as Im aware so 15.1 M would not be acceptable.
Buzz, I think your answer is more in response to David than my post which you have highlighted.
In response to David's post, I would agree with Buzz. Anything that we are asked to check which doesn't comply needs to be highlighted.
The way I look at it is, even though BS recommendations are not 'written in stone' and recommended distances are arbitary, I would always highlight anything that didn't meet the recommendations, as a variation. I would then let others decide if that variation was acceptable or not.
As Buzz states if commissioning engineers go around making desicions of 'that will be alright', and not recording the non-compliance, then they could be held accountable.
However mr C.T. has previously suggested on this forum that competent people can, and should be able, to identify what is a minor 'infringement' and what is a real problem. I would personally highlight both a 15.1m spacing and a 50m spacing as a variation. to my customer If my customer asked me what it meant in real terms of fire safety, I would explain the former is a minor varaition and probably not anything to be concerned about, but the latter could be a major variation and a real problem in detecting smoke quickly. It would still be their desicion if they wanted to do anything about either variation.. However, I would have recorded the problem whether it was 15.1 or 50.
Although we have been discussing the 15m rule, I would once again confirm my original post that it would appear (strangely) that checking compliance with this particular recommendation is not required of a commissioning engineer in BS anyway
