L4

[Wiz]

Someone who has recently attended a Fire Risk Assessors training course has been taught that every escape route that may be available in a building must be protected by automatic fire detection (even in L4). I disagree, what do you think?

The scenario is that room A door opens onto a corridor which leads directly to a fire exit door to the open air within 10 metres travel distance. Room B also opens onto the same corridor but room B also has another door that leads directly to the open air.

I say that only the corridor needs automatic fire detection but, he says that room B requires automatic fire detection also, because it becomes part of an alternative escape route for room A. (The door leading directly to the open air in room B does have an adjacent fire alarm call point and it has been fitted with an illuminated exit sign. Room B also does not have any other doors leading into it other than the above mentioned door from the corridor and door to open area.)

The BS definition for a Category L4 system is Systems installed within those parts of the escape routes comprising circulation areas and circulation spaces, such as corridors and stairways

My point is that Room B is not a circulation area or space and it is not a corridor or stairway.

I maintain that the escape route from room A is through the corridor only and that the automatic detection fitted to it should provide early enough detection to allow its use in a fire emergency.

Comments?

[Midland Retty]

Hi Wiz

To be honest from your description it sounds as if AFD isn't required at all. But nevertheless I would agree with you and detection in room B is totally unecessary in my opinion. Is room B a circulation space? I would have to say no from your description

That said is there any further info on the use of these rooms Wiz?

[Wiz]

For arguments sake we could say they are both rooms are classrooms in a school.

I would have thought that their use didn't matter in respect of whether Room B should have an automatic detector in a BS5839-1 L4 system.

[Midland Retty]

No you're right Wiz, I just wondered if there was any special risk identified in Room B that the assessor felt warranted detection thats all. 

[nearlythere]

Wiz. Is it the case the trainer is saying that the MOE from Room A is into the corridor and then a choice between the corridor main entrance or into Room B to use its final exit?

[Wiz]

But does there have to be a choice of escape routes N.T.?, and does it become mandatory to protect all other available choices in L4 (no matter how diverse the available routes are)?

As I see it, the occupants of room A have a means of escape protected by the AFD in the corridor, surely, in the simplest situations they don't NEED another option. The occupants of room B can use the corridor OR the door to open air from room B. But the occupants of room A have their main option, and don't need to detour through room B.

In this day and age where many school classrooms have a door leading to the open air, and with the BS recommendation for a mcp adjacent to that door, many people are believing that the classrooms are part of the escape routes so have to be protected by AFD even in L4. Surely this is not what L4 is trying to meet. If it is then the cost of an L4 system in a typical fairly modern school will cost almost as much as an L3 system, so what is the point of L4?

I don't see that the classrooms are part of the escape routes from other areas which already have an escape route protected by AFD i.e. via the corridor, in this case.

The BS uses the words circulation areas and spaces such as corridors and stairways for L4, to me this does not mean classrooms, in the general sense (unless that classroom area formed the only escape route from other areas - in which case it would be a circulation area).

If it was necessary to cover every available option of escape route, then surely the recommendation would be written in a far simpler way, somrthing such as, AFD to cover all and every escape route that a person might use

Why put in more detection when it is not strictly required to meet the stated recommendations for L4? It seems to me that some people interpret everything so that it justs costs more. I believe the L4 category is purposely trying to provide the absolute minimum of coverage of AFD which it considers safe.

[nearlythere]

Can't actually see reason for having alternative for Room A. It is even stranger that Room B is regarded as an alternative from Room A when you still have to go into the corridor to get in to Room B. If the situation required A to have an alternative it would not be by using Room B via the corridor. If corridor is protected then why would anyone want to go into Room B?

Has the Trainer been on a 2 1/2 day fire risk assessment course by chance?

[Midland Retty]

Totally agree with you both. Can't see any benefit in having detection in room B, or to be fair the corridor for that matter (!).

[Golden]

AFD isn't a requirement and it all depends on the building/routes available whether it is required at all. Manual systems are fine for many buildings but it seems to be the modern way that AFD is provided as well and in my opinion its almost got to 'urban myth' proportions that all should have detection.

[nearlythere]

AFD isn't a requirement and it all depends on the building/routes available whether it is required at all. Manual systems are fine for many buildings but it seems to be the modern way that AFD is provided as well and in my opinion its almost got to 'urban myth' proportions that all should have detection.

Yep. Many seem to miss the "where necessary"  bit in the legislation.
Unfortunately many installers only know of one category of detection. Guess which?

[Wiz]

Guys, thanks for all your answers.

I appreciate that the scenario I have described might not even require AFD at all, but for the sake of my argument, we have to assume that an L4 system has been requested and therefore we need to provide AFD where necessary to comply with L4.

So the question I want an answer to is quite simply; In the L4 scenario I originally described is there any recommendation in BS5839-1 requiring AFD in Room B?   I don't think so.

All the replies so far, seem to agree with me. This is good news for me in trying to get my message across to those who I am trying to convince about my interpretation of what is required to comply with L4.

I welcome further input, and even from those who might disagree. Remember, we are not discussing whether BS is right or wrong in what it wants from an L4, but only if the published current BS recommendations require AFD in room B in my original scenario?

[CivvyFSO]

Wiz, one way to look at is is that just because there is a door to fresh air from room B, this does not automatically make it an alternative from room A. Room A's escape is covered adequately by the detector in the corridor. In the event of a fire in room B it ceases to be a valid escape route from room A, and in the event of a fire in room A the detector in room B is of no benefit. In the event of a fire in the corridor, however unlikely, the detector in room B again plays no part.

It's a useless detector apart from giving something akin to L3 coverage for anyone in room A.

[AnthonyB]

If L4 was actually needed (say room A & b are in different occupancy) then it would only be the corridor, that's the interpretation I've seen & used in loads of places.

The assessor describes what appears to be an L5 system - it's not L4 nor really L3, so is specific to a risk.

Some people  don't believe that Category M is still fine for many places until I show them BS5839 & ADB.

However it seems if you are building anything new these days, it has to be L1 (Not P1/M, which would be totally different despite from an equipment point of view being virtually the same)

[Wiz]

Civvy, you have also confirmed my feelings exactly. I am trying to explain this all to someone who is looking at something in the wrong way and might only believe me if he realises it is not only me who thinks so! This guy believes that because room B COULD be used as an escape route from someone in room A, then room B MUST have AFD, even though room A still has an escape route down the main corridor and which is sufficiently protected by AFD,

AnthonyB, you are taking the question further than I want to in this thread. Let us just assume that the system is designated (rightly or wrongly) L4 and that room A, the corridor, and room B are all we are concentrating on in respect of this question (i.e. there is detection etc. in other areas) Does room B need detection in an L4?

[nearlythere]

This guy believes that because room B COULD be used as an escape route from someone in room A, then room B MUST have AFD, even though room A still has an escape route down the main corridor and which is sufficiently protected by AFD,

Wiz. Crazy Crazy. If it ain't marked as a way out it ain't needed. If it is marked as a way out it shouldn't be.

Sometimes banging your head off a brick wall just isn't enough. In your case shake your head, push a pencil up each nostril and walk away.