BS 9999 – The LFB Experience Fire Engineering Group London Fire Brigade

Main issue - lack of development/use – DD 9999? ‘Advanced approach’ but not fire engineering guide Replaces most of the BS 5588 series except Part 1 Residential Buildings, but still refers to flats? Large document, needs interpretation – 26 Annexe's Contains some arbitrary figures, without apparent justification Much supplementary information in ‘Notes’ to main text For Designers, Fire Engineers and Fire Safety Managers, but; expected to be of use to others including non-fire experts Needs a level of fire safety expertise to interpret/use Can/should it be used as a ‘Black Box’ – Computer Software BS 9999 - General Comments

Clause 31.2 - Minimum levels of fire resistance Interpretation of Table 25 and Table 26 Good piece of work. Table 25 (ADB) is not ideal – 2hrs maximum fire resistance for tall buildings Table 26 reduces the fire resistance for lower buildings and increases the fire resistance as the building gets higher. Logical approach, derived from deterministic and probabilistic analysis of the issue BS 9999 – Interpretation

BS 9999 – Interpretation

Clause 31.2 - Minimum levels of fire resistance BS 9999 – Interpretation

BS 9999 – Interpretation

Clause 31.2 - Minimum levels of fire resistance BS 9999 – Interpretation

31.2.2 Buildings over 30 m high All buildings with an occupied storey over 30 m above access level should be sprinkler-protected. BS 9999 – Interpretation

BS 9999 – Interpretation

BS 9999 – Interpretation

Clause 31.2 - Minimum levels of fire resistance BS 9999 – Interpretation

17.4 Travel distance – Application to entertainment occupancy NOTE - Where premises contain provisions for the consumption of alcoholic beverages then a reduction in the travel distances of 25% might be advisable for those particular parts of the premises. BS 9999 – Arbitrary Values

Clause 28.2 - Smoke control for fire-fighting shafts General Fire-fighting shafts should be provided with smoke control systems as follows: a) fire-fighting shafts serving basements more than 10 m below ground level should be provided with a pressure differential system (see 28.2.2); b) all other fire-fighting shafts should be provided with a pressure differential system (see 28.2.2), except that natural ventilation can be used in fire-fighting shafts less than 10 m below ground level or up to 30 m above ground level (see 28.2.3). BRE Report 79204 doesn’t make this distinction BS 9999 – Arbitrary Values

Additional fire protection measures Clause 19.2 - Automatic detection and informative warning systems Example Office Open Plan Fitted with L2 Alarm Detection System Upgrade alarm to L1 standard only to justify; Extended travel distances & narrow exits & stairs BS 9999 – Misinterpretation

Additional fire protection measures Clause 19.2 - Automatic detection and informative warning systems ‘Depending on the type of occupancy and level of management within the building, the provision of an automatic detection and alarm system, primarily utilizing smoke detectors and incorporating an informative warning system such as a voice alarm, might allow longer travel distances and narrower doors’’ Where a clear benefit resulting from the addition of detection and warning systems is demonstrated and is appropriate to the circumstances, a 15% increase in allowable travel distance and a 15% reduction in door width, corridor width and stair width can be applied. BS 9999 – Misinterpretation

Additional fire protection measures Clause 19.2 - Automatic detection and informative warning systems NOTE 2 - Where detection and warning systems are required as part of the minimum package of fire protection measures recommended in Clause 16, no variation is permitted to the travel distances, door widths, corridor widths and stair widths recommended therein BS 9999 – Misinterpretation

A new chapter in fire safety guidance Bold and Intrepid Document - has pushed the boundaries of ‘prescriptive’ design Genuine attempt to codify ‘flexibility’ in Fire Safety Does assist in quantifying what has traditionally been a qualitative process. As a ‘Trade-Off’ reference document it is a good benchmark From a fire service perspective it recognises the benefits of Sprinklers, gives design incentives and encourages their use. With time, some refinement and experience of use could prove to be a popular way of addressing fire safety design BS 9999 – Positive Aspects

For A1 Risk Profile a Level 3 Management Regime is the default level Imagine a square, open-plan, single-storey, office, 4 Exits Floor area of >60m2 A2 55m 2-way Sprinklers A1 65m 2-way L3 Voice Alarm +15% 74.75m 2-way Ceiling Height 4.1m +10% 82.23m 2-way Total Floor Area 13,778m Total Persons (5m2/person) 2755 Storey Exit Width (discounting 1 exit) 2.2m Flow Time through each exit (Equal distribution) 5.84 minutes For A1 Risk Profile a Level 3 Management Regime is the default level Periodic change management, unlikely that FS systems are kept functional without help, poor staff-occupant ratio, poor security, only general periodic fire training, basic work control system, basic communications, no PPM regime, no liaison with fire service, no effective contingency planning BS 9999 – Finally, the importance of management and proper regulation