Qualifications in respect of BS5839 part 1

[Wiz]

Well........

If you imagine a very large open plan office lets say the size of a football pitch, and at one end is a partioned office (occupying the 18 yard box), and lets say the exit from this floor is in the opposite goal mouth.

L4 means the escape route requires protection, in this case the complete football pitch or access room (excepting our partitioned 18 yard box) or inner room.

L3 would include L4 and in addition, the 18 yard box, or inner room, although only a single detector would be required near the door from this office.

(The above description ignores vision panels and 500mm gaps etc etc.)

Hope this analogy has come across !!

Thanks for this David. I understand your analogy and the problem. This is a good one and I hope that someone will say there is a definitive answer, which if they are right will help us all out. I would like to add some more info to this query.

Firstly, should the open plan office to be covered by automatic detection anyway in a L4 system?

Is it considered to be a Circulation Area? A Circulation Area is defined as an 'area (including stairway) used mainly as a means of access between a room and an exit from the building or compartment' Would this include the open plan office because it has the inner office area such as you mention?

The Category L4 is for 'systems installed within those parts of the escape routes comprising circulation areas and circulation spaces, such as corridors and stairways'. there is no definition provided for a circulation space so do we assume it is the same as a circulation area and does the category description mean that  only corridors and stairways are considered as these circulation areas/spaces in this category?

The Category L3 is generally considered to add automatic detection rooms leading on to the escape routes but even allows you to site the detector in an 'unusual' (can't be bothered to explain this - i'm sure you know what I mean!) position near the door leading to the escape route and it is not necesary to include rooms leading  onto a short lengths of corridor containing automatic detection and fire resisting construction.

In these L3 circumstances does the inner room require automatic detection? And does this also mean only a single automatic detector installed in the open plan office close to the exit door to the corridor is sufficient, even though the open plan office is, say, 150 sq m?

For those considering these questions, I would also refer them to BS5839 part 1 2002 8.2 d) Note 5 which states 'An open plan area of accomodation, in which occupants will quickly become aware of fire, need not be protected in a Category L3 or L4 system, even though occupants within this area clearly need to pass through the area in the first stage of escape, unless it forms part of the escape route from other areas. However in a Category L3 system an automatic detector should be installed on the accomodation side of any door that opens into an escape stairway, a corridor of more than 4 metres in length (or alternatively, where staircases are approached through low fire risk lobbies, and door that opens onto the lobby).

i agree with David that it all gets a bit confusing because the open plan office might be considered part of the escape route for someone in the inner office.

Would anyone like to add their opinions or a definitive answer with a clear (!) explanation?

[kurnal]

In my opinion the only issue with inner rooms is that it is important for the occupant of the iner room to be made aware of a fire in the access rooom so that they can make a safe escape in case of fire. So there is always a need for a detector in the access room (or a vision panel in the absence of a detection system), but it will not normally be required in the inner room.

I would not describe the main office as circulation space,or as an escape route,  it is an office and an access room  and in my opinion to meet the requirements for the L3 system it is only necessary to give early warning by providing  detectors in the vicinity of the doors to the escape routes. However if it has an inner room it will need detection throughout for the benefit of the occupant of the inner room ( or vision panels) unless someone can prove that a fire in a remote area of the office will not pose a threat to the occupant of the inner room.

[Wiz]

In my opinion the only issue with inner rooms is that it is important for the occupant of the iner room to be made aware of a fire in the access rooom so that they can make a safe escape in case of fire. So there is always a need for a detector in the access room (or a vision panel in the absence of a detection system), but it will not normally be required in the inner room.

Kurnal thanks for your input.
 
I'm not disagreeing with any of the above, but just opening a debate for us all to consider; What do you think about the point of view that as soon as you designate the main (access) room as part of the escape route for the inner room, then in a L3 system, the inner room would also need detection on the basis that it is now a room opening on to an escape route! ( I appreciate that a detector in the inner room would probably be a definte requirement if the access room was part of an escape route from other seperate areas, than just that inner room)

[kurnal]

Wiz
I think if you extend your argument to the next stage you would end up requiring total coverage as per L1 because every room through which a person may pass may therefore be construed as an escape route.
So I think you need to consider the fire safety package as a whole- travel distances, protected routes, structural safety, nature of occupancy, nature of contents.

Its this assessment that determines the level of coverage appropriate and from there you select an appropriate category of  fire detection. To do it the other way round  puts the cart before the horse, designing the building round the categories of system rather than making the alarm fit the needs of the building and its users.  And as you say the BS is flawed because we do not have clear definitions for some of the terms used.

[David Rooney]

....in my opinion to meet the requirements for the L3 system it is only necessary to give early warning by providing  detectors in the vicinity of the doors to the escape routes.

Now that is interesting as that used to be the way I thought of it, but was "corrected" by our NSI BAFE Inspector!

In the old days, using the analogy above, we would have installed a detector in the inner room (our 18 yard box) one detector on the accommodation side of the storey exit near the door (the opposite goal mouth) and that essentially would have satisfied the old L3 definition. The detector being used to warn if that escape door became threatened by smoke.

Our BAFE man says (as you say wiz) the access room is the escape route therefore the complete area requires AFD.

[Wiz]

Our BAFE man says (as you say wiz) the access room is the escape route therefore the complete area requires AFD.

David,  Actually I'm not sure that what Kurnal is saying is wrong. I think in some circumstances it is totally right.

The point of view that I put forward as a question to Kurnal, which, in fact, your own BAFE man advised you is right, is very common, and I therefore highlighted it to see what further thoughts Kurnal had.

You had raised a good initial query and I have realised that there are some very 'able' people on this forum. Therefore I felt it will be good to get some friendly and helpful debate and opinions going on a subject that may help us all. We might even conclude with an agreed interpretation that we could all even 'rely on' in the future!

I hope some other members also join in on with some views.

[Wiz]

Wiz
I think if you extend your argument to the next stage you would end up requiring total coverage as per L1 because every room through which a person may pass may therefore be construed as an escape route.
So I think you need to consider the fire safety package as a whole- travel distances, protected routes, structural safety, nature of occupancy, nature of contents.

Its this assessment that determines the level of coverage appropriate and from there you select an appropriate category of  fire detection. To do it the other way round  puts the cart before the horse, designing the building round the categories of system rather than making the alarm fit the needs of the building and its users.  And as you say the BS is flawed because we do not have clear definitions for some of the terms used.

Thanks for this Kurnal. I didn't necessarily disagree with what you originally said. My question wasn't 'my argument' but a widely-held understanding of the COP, so I thought it would be good to request opinons about for everyone's benefit. I understand David has been told by his BAFE man that you must always install detection in the analogy given.

I'm glad you highlighted how the recommendations need to used as part of an overall package of considerations and, not least of all, some commonsense. Whilst I wouldn't agree with you that including access rooms, in some circumstances, in the coverage of an L3 system, is virtually creating a L1 system, I fully understand and agree with where you are coming from.

In the precise analogy that David presented I agree with your views entirely, in as much as we are trying to protect escape routes, and the access area may not actually really form part of an escape route for the building overall. However, In my own model of my agreement I'm assuming that the partioned inner office is half-glazed and contains a couple of workers.
But, if that inner office was made of fully fire-resistant walls and doors with no, or virtually no, vision ability to the main (access) room and it contained a dozen workers, and if they would have to travel, say, 20 metres through the access room to reach the escape door, I would consider this an escape route, and then I would definitely install automatic detection coverage to the whole of the access room to provide sufficient early warning to the inner office workers. In this second example, I would never include a detector in the inner room, even under L3, because if a fire started in it, when occupied, it would be noticed immediately, and if unoccupied, smoke escaping from it into the main (access) room would be highly unlikely to prevent people from escaping the main room. However, if the main room was connected to yet another area from which people might pass through the main room when escaping, and past the door to the inner room previously described, I would then include a detector in the inner room for a L3 system.

[kurnal]

Wiz- I totally agree with you.
And as far as Daves BAFE man is concerned I think he could be missing the point. I wonder if he has overlooked the fact that for an inner room situation on its own,  an L5 system is the answer and that this more than anything else will determine the siting and number of detectors? Now if the building also needs an L3 system then the two needs have to be combined but lets not lose sight of why we are installing the detectors in the first place.

This brings another point to mind over third party accreditiation. The BAFE man may be an absolute expert on fire alarms and the relevant standards but does he also have an understanding of other issues such as building design codes, fire characteristics and growth, human behaviour in fires, structural fire protection? The same thing goes for extinguishers , electrical work and so on. If we are not careful with these accreditation schemes we may end up with a committee of specialists looking at their individual aspects of a building and nobody taking an overall view with a more rounded but less in depth knowledge. Perhaps more based in common sense?
Hey wiz- reel me in!!

But if I have got you wrong Mr BAFE please forgive me. For I know not of your background or qualifications.

[Mike Buckley]

Just to highlight kurnal's point about the holistic approach. The example of the office within the big room where the occupants would have to travel 20m to get to the one exit goes counter to building regs and the RRO on travel distance. Also both these documents call for an automatic smoke dectector in the outer room unless there is a gap between the top of the wall to the inner room so that smoke can be seen or there is a vision panel giving adequate vision from the inner room to give an indication of the conditions in the outer room and the means of escape.

If the right don't get you the left hand will.

[Wiz]

Kurnal I've now put the brake on, and hopefully it's stopped you from spiralling away!!!!!!!   =)

With reference to both Kurnal's and Mike's recent posts; Can any one person know everything?

I mean, for example, is it possible for a Fire Officer to understand the electronic principles used in fire alarms in depth, or the problems in installing cables or for a fire alarm engineer to understand how various materials burn or in-depth building regulations.

Can any one type of person have the passion to learn, in reasonable depth, all these different disciplines? I'd like to think there is and I'd really appreciate having them around as a source of answers! But I wonder if it is too  rare a species that can know and do it all to a sufficiently  in-depth level!  As Kurnal said it might then be better to have a reasonable level of knowledge in everything necessary, than an in-depth knowledge in one subject

I love Mike's byline of ' if the left don't get you the right hand will!'  I know what he means and there always seems that if you follow BS 5839 someone will say 'but why haven't you taken into consideration the local guidelines produced by the Red Watch of the Isle of Nowhere's FRS recommending that if the wind is in the west on alternate Thurdsdays then MCP's can be mounted at a height of 795mm without an Agreed Variation!

Is it really impossible to incorporate the important parts of every discipline in respect of fire alarm and detection systems and incorporate them in one set of recommendations? Forget the fact that they would probably be impossible to interpret, but at least it would be a start and then maybe training and qualifications could be based on the 'holistic' approach.

Mike, having no training in building regs. can you please advise me, if 20m is obviously too far a travel distance to an exit from a room, what is the maximum such travel distance? And what happens in big areas such as airports? I'm sure I've often been more than 20m away from an exit in such places.

Again Mike, if BS5839 seems to allow no detection in the analogy we worked on, but you confirm that building regs may demand it anyway, why didn't the latest revision of BS incorporate it as standard to also comply with the building regs(assuming that it is not a more recent building reg)?

Guys, thanks for all your input on these questions. I'm enjoying it and I'm sure that David, who started it all is interested as well. I'm also pretty sure that I'm not the only one who is getting fed up with that unexpected 'right' crashing in just after I've avoided the 'left'!

[kurnal]

Thanks Wiz  theres a lot to be said for vallium.
The BS5839 is a bit like the Approved Document B- it gives design solutions for most situations commonly encountered but cannot possibly cover every situation. And was never intended to. All that matters is that people are as safe as reasonably practicable if a fire breaks out. ( This is one of the Functional requirements of the building Regs- how you achieve it is up to you but if you follow the approved document you wont go far wrong)

If you choose to stray from the standard approach you have to be able to prove that your method gave a level of safety at least as good as the approved document. So neither the ADB or any BS is a  design bible- I dont think one exists. We do  now have BS9999 which is the nearest thing yet to the idiots guide to  fire engineering ( even though most of it is beyond me) but starts to give guidance on equivalence eg trading off structural protection for detection or suppression.

The guidance Mike refers to is that in ADB they recommend that the furthest distance from any point in the inner room to the exit from the access room is a maximum actual travel distance of 18m- but may be measured with a stretchy tape.

You mention airports- I have some plans in front of me of a proposed building with a long walkway the centre of which is 140metres from an exit. But on the other hand it is a protected route with nothing but people in it. no conveyor, no luggage, nothing but lights. We would stop counting travel distance in a protected route so why should I be concerned? How far would you travel in a high rise building down a tower staircase- possibly even having to pass the fire?

[Mike Buckley]

Wiz,

I agree with you I don't think it is possible for one person to fully comprehend the whole fire issue. The best pattern would seem to be the health system where the first point of contact is a GP who then refers you on to specialists if needed.

This to a great degree is how it used to work with the Local Authority Fire Prevention Officer, who would apply the Fire Precautions Act and then make recommendations based on this. If the recommendation was for a detection system then the occupier would need to contact a fire alarm installer who could work out all the BS technicalities.
An advantage of the system was that the FPO was independent so the advice would not be tempered by commercial interests.

With regard to travel distances these vary depending on the use of the premises, but if we stick with offices the rule was escape in one direction only the maximum distance you needed to travel to a place of safety was 18 metres, starting at the furthest point away from the entry to the place of safety. If you could escape in more than one direction then you can be 45 meters away. Then the fun starts with what is meant by the escape in more than one direction? If you start with escape in one direction then you reach an area where you can escape in more than direction? What is a place of safety? What are protected routes etc.? As kurnal says the tape can be stretchy depending on what else is in place i.e. sprinkler protection.

The travel distances are still in the ADB and are in the proposed new edition consultation document. They are also in the RRO Guides.

However they do not appear in the LPC Design Guide for the Fire Protection of Buildings but this is more relevent to saving the building and reducing the loss from fire.

Given this it is easy to see why the Fire Brigades were never really able to keep up with the work and parts of the FPA were never enacted.