Rank: New forum user 
|
I have had a discussion with an architect regarding calculating capacity in a restaurant. I have been told that to calculate a capacity you can either use BS 9999 or Building Regulations, however you can only use one and can not mix or jump between the guidance. Can anyone tell me if this is true and also how the Building Regulations differ from BS 9999 when considering capacity ?
Any help appreciated please
|
|
|
|
|
|
Rank: Forum user
|
Graeme,
This is correct. If you apply BS9999, you cannot then apply Approved Document B. You must use either one or the other.No mixing of the two documents. As for the capacity calculation, you would have to read both documents to determine which is best suited to the premise that you need it for.
|
|
|
|
|
|
Rank: Super forum user
|
On a boring train journey so I thought I would respond
Graeme,
You are not obliged to use either document and it is entirely possible to jump between documents.
In the case of the Restaurant the occupancy is calculated in both documents using the same floor space factor of 1.0 m^2 per person.
BS 9999 allows for a slightly increased travel distance giving 20 metres in the case of a single means of escape and 50 metres in the case of additional exits. (ADB 2 specifies travel distance of 18 and 45 m respectively).
Both documents have the limit of single exit permitted for < 60 people or <30 in the event of assisted evacuation being required.
Exit width depends on aggregate with BS 9999 specifying 800 mm min and ADB 2 750 mm for occupancy up to 60 persons.
BS 9999 allows increase of travel distance where additional fire protection is provided (24 metres single exit and 75 metres for additional exits).
|
|
|
|
|
|
Rank: Super forum user
|
Of course if we are considering an existing but structurally unaltered building your occupancy should be based on your existing exit or exits as opposed to floor area.
|
|
|
|
|
|
Rank: Super forum user
|
Consider the following example
Restaurant provided with 3 exits each of 850 mm width.
BS 9999 would result in an exit capacity of 207 people per single door resulting in a total exit capacity of 414.
ADB 2 would result in an exit capacity of 110 per single door and a total of 220.
So if you had a floor surface area of 414 metre ^2 based on ADB 2 and provision of the 3 exits of 850 mm width your max occupancy would be 220.
|
|
|
|
|
|
Rank: Super forum user
|
Also note the part that risk assessment plays as that's the route we should lead by to design anything. However I have yet to find an architect etc that will put their head above the parapet and do as 'bleve' has rightly stated along side the risk assessment
Time and time again the 'approved' documents via the building regs and various BSEN guides [please note that approved docs and BSEN codes etc are just guides and not the law!] are used instead of risk assessment which is noted as the law; guides which on many an occasion provide different opinions and measurements to each other! So talk to your designer and ensure that your client is getting what they want as against a second best solution abet a solution that the designer can hide behind
Also note that likelihood must also be accounted for as its not what is there today but what could be there tomorrow that we must design for as again the B-regs etc do not account for this area
A combination of all factors should be used to reach your design solution
|
|
|
|
|
|
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.