BS5839 part 6 Grade D in office building?

[Guest paulfalk]

I have just surveyed a small office comprising of ground and 1st floor. There are 3 offices on the ground floor, a flight of stairs to 1st floor, and 2 offices upstairs. Could I install a type D fire alarm system to cover the dwelling, ie: a mains from an MCB in twin earth, then link the heads as required. I would cover each office with s/heads and fit 3 to the staircase as there is a dogleg half way up

[Safelincs]

I cannot judge if BS5839-pt6 Grade D is adequate( see http://www.safelincs.co.uk/pages/bs5839-6.html ), however, if from your assessment you have concluded that this is Grade D then yes, you can use interlinked mains powered smoke detectors. The power can come from the central power board or you can feed each unit from the nearest light fitting. The connection between the alarms can be with wire or with radio-interlink (see http://www.safelincs.co.uk/Radio-Interlinked-Smoke-Alarms/ ) You still need to work out if you need LD1 etc

I hope this helps

Harry

[Tom Sutton]

Paul you haven't given sufficient information about the building. You need to describe the whole building and the compartmentation. Where is the dwelling located and are there any other occupancies in the building. You haven't mentioned manual call points there just isn't sufficient detail to make a decision whether it should be a part 1 or part 6 system installed.

Check out the DCLG guide Offices and shops which requires a part 1 system in the offices, if required, and part 6 system in the dwelling is also acceptable.

[Guest Ryan mcmullan]

Hi BS 5839 part 1 should be consulted, BS5839 part 6 is for dwellings. Without me actually assessing the premises myself its hard to specify which type/grade of system is to be fitted.

P.S if the stairway is a protected stairs it may not need any AFD, hope this helps

[Safelincs]

Hi Ryan

I agree with you for larger businesses and obviously in this case we do not know how big exactly the premises are etc. However, I think that it is important to point out that it is ultimately the decision of the business and its responsible person how to cover the fire risks identified in their Fire Risk Assessment. Many small to medium businesses have installed BS5839 part 6 systems with full approval of their local fire brigades etc. British Standards are mostly recommendations and whilst they reflect best practice, business owners do not have to follow them unless there is additional governmental guidance or insurance requirements stating so. For small businesses without special risks, where the fire brigade does not benefit from pin-pointing the source of a fire, a panelled system is a bit of an overkill in my eyes.

Harry

[Ryan Mcmullan]

Hi Harry

The size of the premises does not govern what part of BS 5839 is used, it is governed by the use of the building (i.e risk based). I have also never heard of a F&RS giving consent of such, it would make no sense. A conventional fire alarm system (1-2 zones) in place of an addressable fire alarm system as you mention would satisfiy the requirements of BS 5839-1 in most small offices. Regarding british standards, though they are not law, using them may help prove due diligence in a court of law (if the correct one is used).

I would imagine that any suitable and sufficient FRA would also recommend the catagory/grade of AFD to be fitted, though ultimetely what suitable and sufficient means is a matter for the courts to interperet. If the responsible person (non competaent person most likely in this scenario) decides to specify an AFD system not in line with British standards they would be in contrevention of artical 13 of SI 2005/1541 and find it hard to prove due diligence.

[Safelincs]

Hi Ryan

the systems I have seen approved for otherwise classical part 1 situations were categorized BS5839 part 6 grade D (mostly radio-interlinked), although they had call points and sometimes control switches for silencing and identification which takes them closer to panelled systems. These can be well suited for small business premises of low risk. The size of the building is important in this consideration, as one part of the role of a central control panel is to provide directions to fire fighters, which of course is pointless in small office buildings. The other advantages of panels of course are system monitoring and call facilities.

Harry

[Ryan Mcmullan]

Hi Harry

I agree that the size of the building does play a part, though the use of the building is primarily where to start. All detectors have to have a CIE, if your talking about a system that does not have this then you are talking about a smoke alarm and not a smoke detector. The CIE is not just for the F&RS it is for the staff also e.g if a staff alarm was in place. If you could clarify also what is meant by a panelled system as there is no reference for such a term within the standards.

I understand your point that there is not a need for an addressable system within a small premises, though if smoke detectors and not smoke alarms are to be installed you will still need a CIE, though this can be a convenional system i.e. 1 zone for the premises.

Ryan