Numbers in a room

[SidM]

In a room with a double door and a single inward opening door at opposite ends of the room, how many people would you be allowed in a normal risk office/shop.  If you take the largest one out for fire you are left with one inward opening door.  Are you allowed to have 60 or 100 in the room?  Some say 60 because the door only opens inwards.  Others say it is 100 because the width allows this.  What's the answer & why.

[nearlythere]

In a room with a double door and a single inward opening door at opposite ends of the room, how many people would you be allowed in a normal risk office/shop.  If you take the largest one out for fire you are left with one inward opening door.  Are you allowed to have 60 or 100 in the room?  Some say 60 because the door only opens inwards.  Others say it is 100 because the width allows this.  What's the answer & why.

The recommendation rule suggests 60 persons for the reasons you say.
Generally a room needs two ways out for more than 60 persons and doors on escape routes should open in the direction of escape for more than 60. If the two sets of doors, you describe, opened out then you could increase to 100.
Are you trying to increase from 60 without changing doors?

[SidM]

Nearlythere - I am assuming the inward opening door cannot adjusted to open in the direction of escape.  My notes from the college say that you can still have 100 in the room because the width allows it; the separate rule being that doors are to open in the direction of escape.  My question is, if you can't adjust the door can you still have 100 or are you limited to 60?

[nearlythere]

Nearlythere - I am assuming the inward opening door cannot adjusted to open in the direction of escape.  My notes from the college say that you can still have 100 in the room because the width allows it; the separate rule being that doors are to open in the direction of escape.  My question is, if you can't adjust the door can you still have 100 or are you limited to 60?

According to practically all guidance you are limited to 60 for an inward opening door. However, in this age of risk assessment over prescriptive FS measures you could consider an increase if the risk in the room is low and that the adequacy of the means of escape, via an inward opening door, would not be compromised so as to constitute a risk to the users.
This could depend on the nature of the occupiers and the fire risk in the room. You could argue that the behaviour of staff in a fire situation would be much different to that from members of the public, the former, through fire awareness training, expected to more calm and composed during an evacuation.
Additionally, if the fire risk in the room is much lower than normal you could equally argue that the need to evacuate the room within the usually recommended 2 - 3 minutes could be extended as occupiers waiting to leave the room would not be at risk until much longer.
Of course the fire may not be in that room and if it was elsewhere factors relating to other parts of the building would have to be taken in to considered.

[SidM]

It seems odd that despite an additional door the number is still limited to 60.

[nearlythere]

It seems odd that despite an additional door the number is still limited to 60.

Not really odd as your weakness is the single unit door width. But even if this were increased to double unit you are still, according to the guides, restricted by them opening inwards.
Look at it another way. If your room was split in two by a partition with each side having a single exit door then, depending on the size and use, you could have 60 persons in each area and thus 120 person in that part of the building. If you removed the partition, according to the guides, you are still restricted to 60 persons in that single, albeit much bigger, space.
Sometimes the guides are a little irrational but then they are only guides.

[CivvyFSO]

I disagree NT. You would have to size the final exit accordingly to account for the numbers who might be expected to use it, which would involve totalling up all people in rooms and compartments that would potentially need to use the final exit.

[Midland Retty]

Agreed Civvy but I also understand where Nearlythere is coming from - his argument holds true.

SidM going back to your original question...in addition to Nearlythere's excellent replies just be aware that if the building constitutes a licensed premises (i.e pub, restaurant etc) then other factors may also determine the occupany factors. e.g Environmental Health officers can limit numbers based on available toilet facilities and other provisions, numbers may be determined based on any pinch points / bottle necks on escape routes (which sort of links into what Civvy was saying),and don't forget that floor space factors may limit the numbers too thus determining door widths required.

I'm sure the above does not apply in your scenario, but it's worth remembering for future reference.

[kurnal]

The guides are just simple guides. If you can prove that you can get everybody out safely and in a reasonable time then thats fine.
As the others have said, there loads of other factors you should also consider. You could take the BS9999 approach and determine how quickly the room needs to be evacuated. Most guides are based on everybody passing through that door in 2.5 minutes. High ceilings low fire loading low combustibility could make this inappropriate.

One other factor  that hasn't been mentioned is the disposition and density of people in the room, how quickly they will respond and move, how far they will have to travel, how quickly. Is the door self closing?  Will there be time to open the door before the crush arrives? Is there anybody to control the evacuation- such as a fire warden?

[Phoenix]

Just to chuck my p.o.v. in on top of everyone else's...  

The reason doors should open in the direction of escape for more than 60 people is so that a rush of people to the door will be able to flow freely through that door without being hindered by the need to interrupt their flow and pull the door towards them.  And, further than that, it is to avoid the possibility of the crush of people stopping the door from being able to be opened at all.

If there are a large number of people in this room then, unless it is a very large room, once the occupants start filing out of the open door the door is likely to remain open whilst the file continues.  An open door will allow 100 to flow out in the prescribed time and it makes no difference to those 100 whether the door has swung towards them or away from them when it was initially opened.  It only made a difference to the person who opened it in the first place.

As people have already stated in this thread there are a lot of variables that should be considered in making your assessment.  Amongst them should be: 1) the density of the people in the room (are they likely to initially arrive in such a sudden rush that the person at the front is unable to get the door open? or are they thinly spread out so that they will arrive at the door in dribs and drabs making it easy for each drib (or drab) to open the door and escape?); 2) if the door is at the bottom of a slope or flight of stairs this will increase the likelihood that the first person cannot open the door; 3) is there a staff member on hand who can proceed to the door immediately on alarm and open the door in time for the mob to flow through; 4) like kurnal said, if the door is self closing it may shut between groups of people and have to be continually re-opened (that may or may not be a problem); 5) if it's not self closing then once it's open, it's open and the only concern is the initial opening of the door immediately after the evacuation signal.

Kurnal alluded to most of this, I've just elaborated a bit.

There you go.  Make your own mind up.

Stu

[SidM]

Phoneix - Brilliant & thorough answer with no shirking.  Thanks

[BB]

ADB Table 3 only allows a maximum number of persons of 60 if you only have one escape route. therfore regardless of room size, occupancy factors this would be the determining factor..on new build

[jokar]

There is always the Small Premises clause in ADB to consider as well.