Occupant Capacity

[Meerkat]

Came across an interesting one today in a licensed premises, while doing a FRA.  The owners are interested in understanding what their maximum safe occupancy is (for functions/live music) and their premises licence gives no guidance.

So using ADB as a starter I came up with a maximum occupancy figure (based solely on the density and the area) of 120.

Obviously then I have to look at whether the existing exits can cope and this is where the problem starts.  The bar area has two exits, one at each end.  One is more than 750mm wide and opens outwards with suitable door furniture, the other opens inwards and requires a handle to be turned.

As I understand it, if both doors were compliant, then assuming normal risk, the maximum occupancy would be 100 (2.5 minutes, 40 people per minute).  However as they are not, and as the standard method is to assume one exit will be unavailable am I correct in thinking that the maximum occupancy must be reduced accordingly to 60, (since it would be wrong to assume the compliant exit will be the available one)?

To make matters more complex, when they have live bands, one of the exits isn't accessible anyway, as the only place for the band to set up is right across this exit!  Luckily it's the non-compliant one.  So in this circumstances the room is treated as only having one available exit and that reduces the maximum occupancy to 60 anyway?

Not the answer the client was hoping for I don't think.  But am I correct in my line of reasoning in coming up with this figure of 60?

[Golden]

That sounds perfectly logical to me, for existing premises exit widths are normally the weak link and the numbers have to be calculated accordingly. Licenses used to specify the permitted numbers but I believe its now down to the licensee to make provisions for means of escape including deciding on how many people can be accommodated, it is possible to apply some common sense and/or use other fire safety features as compensatory measures.

[Dinnertime Dave]

Came across an interesting one today in a licensed premises, while doing a FRA.  The owners are interested in understanding what their maximum safe occupancy is (for functions/live music) and their premises licence gives no guidance.

The premises licence will not give a number because you can`t put fire safety conditions on a licence anymore. However, the Police can put number conditions on a licence.

60 is the occupancy I would expect to see. 

[Meerkat]

The police haven't said anything in this case.

As far as I can make out they already have in excess of 60 people in on live music nights 

I see two realistic actions for them to increase this occupant capacity.

1. Sort out the non-compliant exit - i.e. get it opening outwards and with appropriate door furniture.
2. Bring a third exit (once the main door to the premises) back into use for live music nights, so there really are two available exits at all times.

This then should allow an occupancy of 100 I think?

[Mike Buckley]

As I understand it, if both doors were compliant, then assuming normal risk, the maximum occupancy would be 100 (2.5 minutes, 40 people per minute).  However as they are not, and as the standard method is to assume one exit will be unavailable am I correct in thinking that the maximum occupancy must be reduced accordingly to 60, (since it would be wrong to assume the compliant exit will be the available one)?

No Meerkat, the interpretation I was taught was that if there are two fire exits from a room, then the widest exit is discounted and the capacity is based on the width of the remaining door. Three exits, widest is still discounted and the occupancy based on the capacity of the two remaining doors etc. It is not based on the idea that if there are two exits and one exit is discounted, then the figure used is for a single exit only i.e. 60.

However have a look at ADB 5.14 Direction of opening: 'The door of any doorway or exit should, if reasonably practical, be hung to open in the direction of escape and should always do so if the number of persons that might be expected to use it at the time of a fire is more than 60.'

Where does this leave you? In my view, maximum of 60 based on ADB, as you might reasonably expect the other exit to be unavailable. If the door can be turned round then it will be based on the exit capacity.

[lancsfirepro]

Explained quite clearly here  https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&ved=0CD0QFjAB&url=http%3A%2F%2Fwww.thegrid.org.uk%2Finfo%2Fhealthandsafety%2Fdocuments%2Ffire_capacity_calculation_apr12.doc&ei=SmX1UIvtO7GV0QWg5oHYAw&usg=AFQjCNGFkbiVg__AVUWLSk2Kap0aPOPbBQ&sig2=vJAcQx5unzWVmJzNHWHi4Q

[Meerkat]

Mike - thanks yes that's what I was saying although I apparently did not explain it very well!

The occupancy figure of 100 would be the correct one for this premises using the "there are two exits so discount one" calculation, but only if both doors were at least 750mm wide, opened outwards and had suitable door furniture.

The figure of 60 in my original post does indeed come from the ADB comment on what to do if the door opens the wrong way.

What I was trying to say was that I cannot use the 100 figure even though there are two exits, because one of them opens the wrong way and that might be the only one available in a fire. So while this situation remains, 60 is what I am advising the client.

Lancsfire - thanks I had seen similar guidance on a number of Council / Fire Service websites and this is what I had followed although I had also gone looking for the original source of the info which seems to be ADB.

[Golden]

Quote: "I had also gone looking for the original source of the info which seems to be ADB"

I believe the original comes from the post war building studies which is one of the reasons why you can apply a bit of fire engineering to the problem in specific circumstances.

[Midland Retty]

Short answer Meerkat is that if you could have the inward opening door changed to open outwards you would then go the exit width and base your capacity / numbers on that.

Do the inward opening doors lead directly to outside or do they form part of a lobby?

[Meerkat]

The inward opening door leads to a small enclosed "porch" area with another inward opening door then leading direct to outside.  I've already suggested to the client that they investigate the possibility of changing this.  It's a listed building which seems to make everything take twice as long

[Midland Retty]

In which case rather than changing both sets of doors to open outward you could consider having the final exit doors opening outward and the first set of door entering the lobby from the bar pinned back.

[Meerkat]

Midland - yes we could indeed.  I'm waiting for the client to get over the shock of me telling them their current recommended "safe" occupancy figure before we start delving too much into alternatives!

It's a lovely old building but this is just the tip of the iceberg sadly (E lighting - none, fire alarm system and AFD - none). Still at least they had the sense to ASK for some advice - I know there are many out there in their business who don't even do that.

[Tom Sutton]

Something more to add to the pot http://www.firesafe.org.uk/basic-means-of-escape-from-fire/ not sure if it will help?

[lancsfirepro]

Playing Devil's Advocate here.  Does an exit door opening inwards not have any worth at all?  Does it have to be totally discounted?  From the CLG guidelines "All doors on escape routes should open in the direction of escape, and ideally be fitted with a safety vision panel. This is particularly important if more than 60 people are expected to use them at any one time or they provide an exit from an area of high fire risk."  So it would seem that this is less important where there are less than 60 people.  So is that then saying that for up to 60 people the door can open inwards?  And if this is the case, say you had 3 exits, 1 at 750mm opening outwards, 1 at 850mm opening outwards and 1 at 750mm opening inwards.  If we disregard the largest exit at 850mm we have two exits remaining but do we also disregard the one that opens inwards?  So that leaves us with an occupancy of 100 from the single 750mm door?  Is that right?  If up to 60 people can get through an inwards opening door, how can that extra capacity disappear when there are over 60 persons in the room?

[Midland Retty]

Its based on the premise that if you have more than 60 people going to an inward opening door you could get a crush and you would struggle to open the door against the flow of people.

So to take your scenario - even if you had more exits available, if they were all inward opening you would still have to limit the pub to 60, because you couldn't guarantee only a max of 60 would go to any one particular door.

People tend to exit the building by the the route they entered the building. So it would be reasonable to assume the vast majority of your occupants head for one particular exit. Its unlikely the use of fire marshalls will eleviate that problem either.