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

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Presentation on theme: "BS 9999 – The LFB Experience Fire Engineering Group London Fire Brigade."— Presentation transcript:

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

2 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 General Comments

3 Clause 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

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5 Clause Minimum levels of fire resistance BS 9999 – Interpretation

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7 Clause Minimum levels of fire resistance BS 9999 – Interpretation

8 Buildings over 30 m high All buildings with an occupied storey over 30 m above access level should be sprinkler-protected.

9 BS 9999 – Interpretation

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11 Clause Minimum levels of fire resistance BS 9999 – Interpretation

12 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

13 Clause 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 ); b) all other fire-fighting shafts should be provided with a pressure differential system (see ), 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 ). BRE Report doesnt make this distinction BS 9999 – Arbitrary Values

14 Additional fire protection measures Clause 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

15 Additional fire protection measures Clause 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

16 Additional fire protection measures Clause 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

17 BS 9999 – Positive Aspects 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

18 BS 9999 – Finally, the importance of management and proper regulation Imagine a square, open-plan, single-storey, office, 4 Exits Floor area of >60m 2 A255m 2-way SprinklersA1 65m 2-way L3 Voice Alarm+15%74.75m 2-way Ceiling Height 4.1m +10%82.23m 2-way Total Floor Area13,778m Total Persons (5m 2 /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

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