Fire Detection Sound Warning Levels in HMOs

[lyledunn]

"Most fire detection and fire alarm systems in dwellings comprise smoke alarms, which are usually fitted in,
at least, the circulation areas, such as hallways and landings. BS 5446-1:2000 requires that the sound
output of a smoke alarm be at least 85 dB(A) at three metres. Most domestic doors attenuate sound by
around 20 dB; greater attenuation can occur in the case of solid doors, such as fire doors. It is therefore
unlikely that a smoke alarm on, for example, the upstairs landing of a two-storey house will produce a sound
level of 75 dB(A) at the bedhead in each bedroom, particularly if the bedroom doors are shut; levels of 55
dB(A) to 65 dB(A) are more likely. There appears to be no evidence to show that lives are being lost due to
inadequate audibility of the fire alarm signal from smoke alarms, except where people are incapacitated to
such a degree that even much higher sound levels would not waken them".
The quote above is from BS5839-6 2004. The Standard is for dwellings and the comment may be justified. The problem is that the same Standard is often used in HMOs. Althought it does acknowledge the minimum 75dbA at the bedhead recommended in 5839-1 2002 it introduces ambiguity where I believe none should be.
My daughter moved in to an HMO (ordinary 2-storey dwelling with 3 separate bedrooms). Incredibly it did not have smoke detectors fitted. Apparently the HMO Licence Scheme hadnt reached that far at the time! Any way the Landlord was quick to respond to my intervention. A LD3 Grade D system was fitted and certification issued by the diligent contractor. A quick inspection by Daddy smoothed some furrows. However, as always I frowned upon the prudence of relying on a single smoke detector fitted in the landing outside the 3 bedrooms. Sound pressure levels were 63dbA at the bedhead. A couple of months later, all the doors in the property were changed as the Licence system eventually extended its reach to that part of the city. Well of course, the inevitable attenuation caused by the new doors has resulted in sound levels being reduced to 44dbA in one bedroom! The Authority controlling the Licence are happy as they have the recently issued Fire Alarm Certificate and all the remedial fire safety work required by them has been carried out.
I do not know who the made the comments in BS5839-6 quoted above or on what statistical information he or she was assessing the risk but fire safety takes on a different hue when your own daughter is involved. The limited cover offered by a LD3 Grade D system may satisfy the lily-livered approach taken in normal dwellings but do we really have to suffer a disaster before we insist that ALL bedrooms in HMOs should be fitted with both detector and sounder!
Regards,
Lyle Dunn

[colin todd]

I wrote it. It's really cool isn't it. It is based on the fact if something is proven not to be broken, there is no need to fix it. But you forgot to quote the rest of the text, which goes on to talk about HMOs. A little reading is a dangerous thing.

[lyledunn]

Colin,
Cool is not the word I would use but I thoroughly respect your expertise and the courage needed to make comments that are often blindly followed by the faithful. I do read with the diligence inherent in the over 50s but if you are any where near that vintage then you will know that "diligence" is a subjective notion.
Any how, is this the part to which you refer?: "f) The recommendation of 13.2e) applies to many houses in multiple occupation of limited size and with
straightforward means of escape. However, in some houses in multiple occupation, ambient noise levels
or other factors might justify the need for a sound pressure level of 75 dB(A) at the bedhead of each
bedroom within a dwelling unit, particularly in the event of a fire in an area beyond the dwelling unit,
as is recommended by BS 5839-1 for premises such as hotels. The need for this significantly higher sound
pressure level within any or all bedrooms should be determined as part of a fire risk assessment".
Now if I had been asked to pen a recommendation it might have read something like this; " f) Oi, listen all you penny-pinching, measly
landlord gits, heres what you gotta do. You have to make damn sure that in any HMO (yes any) that a minimum sound pressure level at the bedhead of 75dbA is achieved. I dont give a flying stuff what your risk assessment says (unless it needs more), you have to have 75. Got it!"
I did a law degree at QUB but perhaps I wasnt cut out for the legalistic nuances of Standards jargon!
Regards,
Lyle Dunn

[Clevelandfire 3]

Lyle that sounds rather bitter. And before you understand the complexities of fire warning and detection systems in HMOs you also need to understand words like 'shared house' as well, then read the various guides out there which should be read to support and compliment 5839 part 6. An LD3 cat alarm in some cases is perfectly acceptable. So for once i side with Colin Todd which doesn't happen often. He is of course the greatest risk assessor in the whole of..... his own house. Its not a shared house though. Accept for a few cats.

[lyledunn]

Cleaveland,
Oh dear, it wasnt meant to be bitter or beligerent. I do apologise even perhaps before Colin reads it. To be clear, I thoroughly respect the advice and views that I read on this forum and often put them to good effect. I have a deep interest in fire safety, especially with respect to detection systems and so it is not unreasonable that I feel the need to probe Mr Colin Todd now that I have been granted access to this wonderful forum.
So Colin, please believe me, I have no intention to cause offence of any kind. I value your deliberations on the subject but l trust that you will have no concern about the odd contra-opinion that may sometimes batter the fort door.
Regards,
Lyle Dunn

[colin todd]

Dont worry, it has never bothered me what people say or do, so long as they are kind to cats.  We have been unable to find any death in a dwelling from having smoke alarms in the hallway. When little Libby was a baby, she used to cry and her mum woke and then went and fed her, but she was not crying such as to produce 75dB(A) at the ears of Mrs Dunn. Of course now that Miss Dunn is a big girl if she takes drugs or gets out of her head on alcohol nothing will wake her. All this is explained in my wee book on BS 5839-6, which goes into more detail than I can here.

[lyledunn]

Colin,
Well thats me on your wrong side.... I cant stand cats! Miss Dunn is a Christian so drugs and alchohol do not feature in her life. Nonetheless she sleeps soundly. If there is an incident I want her and all the other kids who are not off their heads on such substances to be afforded every opportunity to react. I trust that you wont have to change the wording in the commentary or indeed in your book as a result of death or serious injury caused by inappropriate audibility at some future time. Meanwhile, as an inspecting engineer, I shall continue to robustly recommend 75dbA in all HMOs!
Regards,
Lyle Dunn

[colin todd]

In view of the latest information on Miss Dunn, I am able to assure you on the basis of Australian research that there is around about a 100%  chance that she ill be roused by as low as 65dB(A). Personally, I would be more worried if I were you that she will convert to hari krishna, though being from NI she will remain either a protestant hari kirishna or catholic hari krishna. In either case, I am sure she will be fine and I hope she gets a good degree.

[lyledunn]

Colin,
Well at least 65dbA is a definite figure. It may be arbitrary to some extent but if it has been derived from robust evidence and is satisfactory to you and the BS committee responsible for Part 6 then it would seem a useful datum.
Can I ask you a simple question relating to this? Take three average HMOs with straightforward MOE. A fire detection system using domestic smoke alarms provides 47dbA at the bedhead in one and
55 and 61 in each of the others. Since you wrote the Standard, which (if any) fail to meet the Clause relating to audibility in 5839-6 2004?
Regards,
Lyle Dunn

[colin todd]

depends on the attenuation through the doors and whether it is considered that the 75 dB is warranted, but its not looking clever for the the 47 is it.

[lyledunn]

Colin,
Thanks for your reply.
The attenuation  on the lower recorded level is close to 40 but the sounder is producing slightly more than 85dbA at the open door of the bedroom. Thus the audibility would seem to comply with Part 6 but had the HMO been fitted with a Part 1 system it definitely would not. Apparently this matter has never been raised before as an issue with the Housing Authority responsible.
The HMO with the 55dbA at the bedhead sits right next door to an HMO with a Part 1 system that I have already declared as not meeting the threshold of 75dbA required by that Part. I am recording circa 60dbA in that property. I have asked for a meeting with the chap who wrote the fire safety standard for HMOs for the Housing Authority in question. I will keep you posted.
By the way, I have ordered your booky wook on Part 1 so I am looking forward to that!
Cheers, and I genuinely appreciate your input.
Regards,
Lyle dunn