FireNet Community
FIRE SERVICE AND GENERAL FIRE SAFETY TOPICS => Technical Advice => Topic started by: lyledunn on November 08, 2014, 10:18:09 AM
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Consider a very large reception area in a hotel, occupant capacity could be around 500. The proposal is to form a more compact lounge bar in the central core of it. This bar area will accommodate 200 and will be designed to be young and noisy. The area will be partitioned off, thereby blocking direct access to existing final exit escape doors. Doors of adequate dimensions will be provided but escape will not be so obvious as the doors will spill out in to the adjoining space which is likely to be used as lounge for more sedate customers. I guess on the face of it nothing much has changed other than customers in the core bar will no longer have direct sight of the existing final exits. My role is just to provide the changes required to services but I felt that the proposals were a tad counter intuitive from a fire safety perspective. I suppose I am more used to escape from rooms going in to corridors rather than through another room. The project is only at the scribble stage from a design point of view.
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If I read this right it sounds like an inner room is being created by the construction of the new bar and the only escape routes from the new bar will be via the reception area. If this interpretation is correct this would limit the capacity of the new bar to a maximum of 60 persons, unless an alternative escape route was available separated from the reception area by fire resisting construction.
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Kurnal,
Is it an inner room if escape can be had from it in several directions albeit in to the volume of the original space? Even if it wasn't an inner room, is it reasonable to evacuate 200 people through adjoining lounge space?
This is just of academic interest to me, I have no part in the plan other than stated in my original post.
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Yes it's still an inner room if all the exits lead into the same space. It would be ok in principle subject to the exits having capacity for all occupants in both areas but only if there was also an alternative route capable of taking 200 people to an alternative exit via a route separate from the reception area.
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Where do true limits lie when considering inner rooms?
Suppose we had an arena, capable of holding, say, 16,000 people in one space under one roof. Suppose that in the middle of that very high ceilinged arena a relatively small room is constructed. It has a relatively low ceiling and a number of exits leading in different directions and it is capable of holding 200 people. Suppose that we fill the room with 200 people. We won't put anyone in the outer space so let's say the outer walls of the room are entirely glazed, giving everyone in the room good vision over the area outside the room, just in case a fire starts out there.
This room is an inner room and subject to a maximum of 60 people according to guidance but would we object to there being 200 in the room if there were sufficient exits from the room for 200 people and if they could disperse freely though the arena to use any of the multiple exits?
Normally we restrict inner room populations to a maximum of 60 because of the dead end element usually associated with them, i.e. we like there to be no more than 60 in a dead end. But my hypothetical room has no dead ends so is the limit of 60 relevant?
Suppose now that we take the glass walled room and the 200 people and put them in a much smaller low ceilinged function room. The function room has enough exits for more than 200 and people from the inner room can move in different directions to different exits when escaping through the function room. Now we have a situation where, in the event of a fire, due to the low ceiling, lateral spread of fire and smoke through the access room could have much more of an effect on means of escape. Should we limit the inner room to 60 now? No one's in a dead end but perhaps we should examine the possibility that a single fire could affect all escape routes from the inner room through the access room.
However, suppose that the inner room is full of 200 people and the outer room is full of another 300 people, as in the scenario given by Lyle above. If we were to dissolve the walls of the inner room, leaving everyone in the same place as they were before, would the removal of the walls make any difference to the risk the people are exposed to?
In fact, I have come across a few situations where largish inner rooms (population > 60) discharge through a number of separate exits into larger access rooms and each time I have considered the distribution of fire loading in the access room, the height of the ceiling, the distribution of exit routes both from the inner room and from the access room as well as the more usual exit widths, facilities for people with impaired mobility, etc. If I'm not happy, stipulations are imposed, maybe I limit them to 60.
Maybe they don't pay any attention.
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Doesn't the guidance say, consider limiting to 60 persons, in your situations you ave considered it and discounted or accepted it?
In addition, the following points should also be considered:- Restrict the number of people using an inner room to 60.
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Well, Tom, I'm not sure the CLG guidance does say consider limiting the population to 60. The language used is very imprecise and can be interpreted in a couple of ways.
If I was supervising a party of people visiting Beachy Head, I could give them the following instructions on arrival, "Consider the following points:
Don't jump off the cliff,
Keep back from the edge,
Don't fool around near the edge"
I would not want them to interpret my instruction as
Consider not jumping off the cliff
Consider keeping back from the edge
Consider not fooling around near the edge.
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If you did give an instruction as you state you would be giving them a choice and I have been to Beachy Head consequently I would be giving a direct instruction, taking no chances.
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As I said above, the language is imprecise. However, I do not accept that telling people to consider something is necessarily giving them a choice. To consider something means to think about it.
You're interpreting the word 'consider' as, 'think about the available alternatives and make some decision based on your thoughts' and that is a possible interpretation, except that when it is used to mean this the word 'consider' usually refers to a verb and not a noun as it does in the guidance.
For example, you could consider closing the door, consider getting your hair cut or consider having an argument about semantics and we would all agree that you're thinking about the alternatives with a view to making a decision. But if you consider the door or consider your hair or consider an argument you are merely thinking about those things, you're not weighing up alternatives.
Now, the guidance says that the 'following points should be considered.' You should consider the following points (a noun), you should think about them.
I'm not going to pursue this argument any further for three reasons:
1) I'm not at all sure what was in the tiny, tiny, little mind of the person who wrote this guidance;
2) I'm arguing against what I said in my earlier post(!);
3) I do agree with you that the guidance should be in the form of a direct statement to eliminate ambiguity;
4) It's late and I'm fed up arguing; and
5) I never could count.
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I agree to some of what you say and we should allow the rest of the forum to decide for themselves.
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The language is precise in TBE (I am in NI) where it says that an inner room is not permitted unless the capacity is 60 or less. The same exactness is used in 9999. However, Phoenix makes the point better than me as to the way I was thinking about the situation. It just seemed plain wrong to me to permit large numbers of people to spill from one room in to another and expect them to flow in a controlled way towards emergency exits in the access room.
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Consider; Discharge exit positions (and direction of openings) from inner room in relation to exits (and direction of opening) from access room. Travel distances. Floor space factors and therefore max numbers of persons. Widths of egress routes. Appropiate signage and illumination.
If the above equations fit...