I have recently been asked to provide initial fire safety views on two speculative schemes for a large Library Building of ground floor and four upper floors.
Both schemes have incorporated what the designer has called “voids” within the upper floor slabs that create openings for the full height of the building.
The designer states that because of the size of the building, compartment floors are not required and therefore as AD B3 paragraph 9.8 does not class the “voids” as Atria, BS 5588 Part 7 (the code for atria) will not be applied.
Although this interpretation may be correct according to that section of AD B3, is the designer correct in inferring that no special consideration needs or will be to be given to the voids/atria for means of escape?
Surely AD B3 is about Internal Fire Spread Structure and not means of escape. As there is no guidance on atria in AD B1 Means of Warning and Escape, the only guidance that can be used is BS 5588 Part 7.
The BS 5588 7 Definition of atria is
3.3 atrium (plural: atria)
“A space within a building, not necessarily vertically aligned, passing through one or more structural floors”.
The scope of BS 5588 7 states
The principles presented in this standard are applicable to all building types containing atria other than:
Then lists theatres, prisons, and shopping malls as not being applicable, as other guidance exists and also buildings in occupancy categories A & B containing a two-storey atrium, with one of the two storeys being at ground level, which are designed for simultaneous evacuation with storey exits remote from the atrium.
No exemption here and no mention of compartment size either.
There has been considerable research and discussions on the special considerations relating to fires in atria and it is accepted that the means of escape provisions need special considerations.
The BS 5588 part 7 acknowledges the speciail considerations of atrium and provides the guidance on what needs to be considered to protect and manage the means of escape in buildings containing an atrium. The BSI DD 9999 2005 draft Code of Practice for Fire Safety in the Design, Construction and use of Buildings devotes a whole section to the special considerations of atria.
I believe that using the AD B3 paragraph 9.8 to discount the guidance in BS 5588 part 7 is not the intention of that section in relation to means of escape.
Any one agree or am I on my own.
