BS 9999

A personal perspective from a Fire Engineer

BS 9999 vs ADB – Swings & Roundabouts….•Exits widths:

•Most (not all) cases, increased occupancies or reduced exit widths – more efficient space planning

•Treatment of sprinklers:•Life safety enhancements•Increased concessions (travel distances, exit widths, compartment areas)

•Treatment of voids•ADB exception

•Compartment areas•Useful in assembly buildings – more logical

•Management needs

•Further education college- 3 storeys- Interconnecting voids

•Two very different solutions

BS 9999 vs ADB – Swings & Roundabouts….

BS 9999 vs ADB – Swings & Roundabouts….

ADB

•Further education college – compartment area/exit widths

•Leisure centre – compartment area/exit widths

•Office refurbishments – increased occupancies

•New offices – reduced exit widths

BS 9999 – typical applications:

•Applying the travel distance and exit sizing in isolation:

•Interrelations difficult to pinpoint (voids, basement stairs etc)

•Essential that a thorough review of fire safety features in considered

•Reduced scope for fire engineering with BS 9999?

BS 9999 - pick and mix?

•Points to consider:-Efficiency of narrower 850mm exits – need to exercise judgement?

BS 9999 – A personal perspective from a fire engineer

Nightclub

4 x 850mm exits

4.5m ceiling

L2 detection system

•ADB:-Exits provide capacity for 330 people

BS 9999 – A personal perspective from a fire engineer

Nightclub

4 x 850mm exits

4.5m ceiling

L2 detection system

110

110

110

•BS 9999:-Risk profile B2?-Door widths base on minimum measures = 4.1mm/person-Reduction due to L2 detection and ceiling height = 3.3mm/person = 257 people/exit = 771 total (more than twice ADB)

BS 9999 – A personal perspective from a fire engineer

Nightclub

4 x 850mm exits

4.5m ceiling

L2 detection system

257

257

257

“Where premises contain provisions for the consumption of alcoholic beverages then a reduction in the travel distances of 25% might be advisable”

“where a room is crowded, the time to evacuate becomes less dependent upon the travel distances and more dependent upon queuing behaviour at the exits and so door capacity becomes the critical feature of the design”

BS 9999 – A personal perspective from a fire engineer

•Fire fighting measures:•Very similar to BS 5588 Part 5•Requirements for FF Shafts still based on purpose groups rather than risk•Sprinkler concessions similar to ADB•Conflict between Table 19 and Table 21?

BS 9999 – a missed opportunity?

BS 9999 – Summary

•A welcome addition to the engineers tool-kit

•A few areas of ambiguity (keeps me in a job!)

•Needs a thorough understanding to apply appropriately, and check adequacy of solutions