60 people in a room

[lyledunn]

I have a feeling that I asked this before but cannot find it in the forum; where did the figure of 60 come from in restricting occupancy in a room with only one MOE?

[kurnal]

I believe it came from the Building Regulations, the original definition was of small rooms and lage rooms and the number of 60 persons was used to illustrate the maximum threshold for a small room. The number itself is more than likely arbitrary. Thats my recollection anyway.

[Tom Sutton]

It was in the old blue guide used under the FPA it limit a room to 60 if only one exit, also travel distance had to be considered.

[Dinnertime Dave]

I believe it came from the Building Regulations, the original definition was of small rooms and lage rooms and the number of 60 persons was used to illustrate the maximum threshold for a small room. The number itself is more than likely arbitrary. Thats my recollection anyway.

I'm sure your right that it is an arbitrary figure. But I understand that it used to be 50 and was increased.

[colin todd]

Yes, Suppers, it was traditionally 50 but increased. 

[kurnal]

In which document was it set at 50? I remember the numbers of 50 and 60 in repect of outward opening exits but I can only remember the number of 60 being used in this context?

[lyledunn]

So do you feel that if it is simply an arbitrary figure, a higher occupancy could be considered following a FRA? The number seems to be chiseled in stone and one dare not exceed it. The reason I ask is because a small first floor social club that I have an interest in has been restricted to 60 following a FRA. The club needs 80 to survive. 80 is never exceeded. Now the club lounge is essentially one single room with two exits available but they are side by side. However, the two exit doors offer two alternative means of escape from the story, one down the main entrance stairs and one down a short corridor to an external stair. Total travel distance from the furthest point in the room to the side by side doors is about 16m with total travel to final exit being only another 6 or 7m. The building is recent, concrete floors, stairs and has a good package of fire safety measures.
A chat with the assessor revealed that the justification for the restriction to 60 was that this figure was generally accepted.
The club is finished if the figure cannot be increased to 80!

[Tom Sutton]

The Post War Studies paragraph 298 state that inward opening doors should be limited to 40 persons. Just another figure to play with.

Two exits next to each other cannot be excepted as alternative MoE but the travel distance is within the one direction travel distance, they are still two exits.

[wee brian]

I found an old LCC guide once that had 18 people! thats inflation I suppose.

80 sounds like a lot though.

[Tom Sutton]

The blue guide, para 14.20 limited to 60 persons with one exit and para 14.83 limited to 50 persons for inward opening door.

Another rule we used in relation to one way travel distance in rooms was the 1/3 rule. The width of the room should be a minimum of a third of the depth of the room, this was to allow person to skirt the fire if it was between them and the door.

[kurnal]

A risk assessment could be used to evaluate the risks. As a starting point for the evaluation I would point out that were the exits on opposite sides of the room then means of escape would not be an issue - a room with 2 exits can accommodate up to 600 persons all other things being equal (table 3 ADB). A room with 2 exits must be ten  times safer than a room with 1 exit all other things being equal (Table 3). For the club to continue and for 80 persons to occupy the room safely you need to show that your room with 80 persons it is no less safe than a room compliant with benchmark guidance with 60 persons present- that there are factors that compensate for the weakness.

A room with one exit could accommodate 60 persons, yours has two separate routes so it must be safer to some extent. In setting the limit of 60 persons, the possibility of a fire elsewhere in the building must have been taken into account because no comment is made on this in ADB. The number of 60 takes people through all 3 stages of the means of escape. Your situation is certainly safer should a fire occur elsewhere in the building- the only problem is in the room itself.

 You need to evaluate if there is additional benefit of having two exit routes albeit they are too close together.
 
The closer the exits are to each other the greater the risk that should a fire occur in the room persons will be trapped by the fire or its effects.

So how is the room laid out, how is it used, how high is it, what is the nature of the furnishings and contents,  what is the density factor, where are the people in relation to the exits, is alcohol served, is it Ibiza foam parties  or shove Hapenny*, if you apply the 45 degree rule diagram what proportion of the room and persons are in a dead end?  How wide are the exits, how will the evacuation be initiated and how will it proceed, is there any liklihood of queues forming at the exits?

* Shove Hapenny is a game only very old people such as Toddy are likely to recall. (I had to look it up)

[lyledunn]

Thank you Kurnal. I remember shove h'penny well. My dad introduced me to it. That along with wheel and cleat. We couldn't afford a proper football so dad rolled up rags and pages from old Belfast Telegraphs to make a ball of sorts! Sometimes I think that it was an advantage to be less well off; you were happy with your lot!

[Phoenix]

I like the 1/3 rule!  Never heard of that one.  Or a limit of 18!

I recall that the figure used to be 50 for Building Regulations (20+ years ago or so) but, as has been stated, the fire brigades' blue guide was a bit more generous and allowed 60.  The blue guide was a standard that was required for fire certification.  It changed to 60 in ADB to be in line with the fire cert standard - in about 96, 97??  That's what my failing memory is telling me, but then I have a memory of seeing two suns in the sky when I was a boy.

It didn't happen.

I have allowed a hundred people in a room with a single exit but there were strict rules. 

It was a castle and a second exit was out of the question for a number of reasons.  The room was used as a disco and wouldn't work with a limit of 60.  The room was not big, it was circular and maybe 8 - 10m across.  There was a step at the entrance and there was not room for a ramp to accommodate people in wheelchairs.  The ceiling was about 6m high.  The exit door was single width but we got it increased to 1500mm.  The only fire loading in the room was the dsico equipment and it was at the opposite end of the room to the exit.   The exit went straight to fresh air.  There was a resident DJ who was suitably trained in emergency procedures.

I reasoned that the limit of 60 was there so that the last person to leave the room could, even if the fire was right next to the single exit, get past and escape whilst the fire was still reasonably small.  So I made a computer model of a 3m high room of similar size with a 800mm single exit and I put 60 computer people in it and ran it to see how long it took for the last person to leave.  It took about a minute or so, just less I think.

Then I built a circular room with a 1500mm single exit and I put 100 people in it to see how long it would take for the last person to step out the door.  I also put a few people with mobility problems in there - not in wheelchairs but slow movers.  This group of people evacuated the room in less time than the code compliant room.

It seemed safe to me.  It still does.

[lyledunn]

I guess your example sums up what I mean Phoenix. You used your professional judgement to counter  the 60 max rule, a rule that seems to be treated as sacrosanct by many in fire safety. It might be reasoned that my little social club has sufficient measures in place to allow 80 if not 100. After all, there is nothing much to burn, no serious ignition sources, the building is relatively new and well compartmentalised, exit width is satisfactory, travel distances to final exits are short, detection is likely to be immediate, there is only one patron with mobility issues, staff are trained in use of fire extinguishers and there is an automatic fire alarm and emergency lighting. To top it all, on a Saturday night when the club is at maximum capacity, the doorman is a retained firefighter!
Nonetheless, the assessor and indeed the local council officer in charge of entertainment licence will not budge from the 60 ceiling.  I do not blame them, it is in my DNA to look for another way out no matter what room I am in.  I would argue that a single exit from any club room or bar that could potentially hold over 60 should not be allowed to open to the public, irrespective of the fire safety measures. But the question I ask myself is why am I content with 60, why not 61 or 65 or 80 or even more. I guess it is simply because the figure of 60 has been an accepted upper limit by everyone for a long time, no different perhaps to the mindsets of our fire risk assessor and the council officer. Then along comes Phoenix, a frontiersman in fire risk assessment and a man of obvious knowledge in fire safety measures who almost doubles the 60 figure in a specific situation. I might trust his decision but I am not sure that could be said for other fire risk assessors who might not just be so competent.
Fire is one thing, but any one who has smelt the stink of a bomb will always value the availability of another way out!

[kurnal]

But you do have two separate routes out of the building Lyle. Don't overlook that- its a very significant benefit even if both exit doors are close to each other. Its significant because you only have to address your argument to stage 1 of the means of escape.