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 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

4. BS 9999 – Interpretation

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

6. BS 9999 – Interpretation

7. Clause 31.2 - 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.
BS 9999 – Interpretation

9. BS 9999 – Interpretation

10. BS 9999 – Interpretation

11. Clause 31.2 - 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 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 );
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 doesn’t 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. 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

18. 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 A m 2-way
L3 Voice Alarm % 74.75m 2-way
Ceiling Height 4.1m % 82.23m 2-way
Total Floor Area ,778m
Total Persons (5m2/person)
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