The Fire Strategy Company Safety - Risk - Fire - Resources

A Guide to
BS 9999:2008
Code of practice for fire safety
in the design, management and
use of buildings.

BS 9999:2008

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BS 9999, which has taken over ten years to develop, was In addition to providing guidance for a range of specific
published by the British Standards Institution in October building features that were previously addressed in the BS
2008. The document builds on the existing government 5588 series, e.g. atria and fire service access, BS 9999 also
guidance to provide an enhanced design guide which is provides guidance on general fire safety design using a
based on scientific analysis and research. more flexible risk-based approach. By taking into account
the varying physical and human factors related to your
Previously, when designing a building, there was a raft building, BS 9999 allows you to develop a bespoke solution
of different guidance documents including the 12-part which provides more flexibility than previously available
BS 5588 series of documents. The BS 5588 series was under prescriptive guidance such as Approved Document B.
developed over a period of time, with different parts
being published at different times to reflect industry BS 9999 recognises the importance of a package of
requirements. This approach inevitably led to problems measures to ensure the fire safety provisions in a building
in coordinating the various parts of the series, with the work effectively. It encompasses all of the areas which
result that some elements of the series were repetitive should be taken into account when designing a building
and contradictory. BS 9999 consolidates much of the BS and advocates a solution for the life of the building,
5588 guidance into one document, reducing the size from including the level of fire safety management, provision for
over 1000 pages down to around 450 and providing one means of escape and fire fighting and structural stability in
source of reference. Except for BS 5588-1, which deals with the event of a fire.
residential buildings, BS 9999 supersedes the BS 5588 series
and replaces the previous draft standard, DD 9999. With BS 9999 there is an expected level of fire safety
management by which the suitability of a solution can
be assessed and there is a fundamental assumption that
the building will remain managed throughout its lifetime.
Fire Safety Management Approved Document B notes that the Building Regulations
BS 9999 do not impose any requirements on the management of
a building and that the proper management is assumed.
What level is your fire BS 9999 goes beyond this and recognises that having
designed a building, it is imperative that management
safety management
ensures that the building still functions as it should. The
operating at? document provides guidance on the function of fire safety
management and provides criteria against which that
BS 9999 details 3 levels
of fire safety management management function can be assessed.
performance.
So where does BS 9999 fit in as a guidance
For an independent audit with document?
full reports contact:

BS 9999 goes further than providing technical design

Rob Ellingham: 07738 767398
rob.ellingham@firestrategy.com guidance; the standard introduces and promotes a new 3-
tiered approach to fire safety design. For simple buildings,
www.firestrategy.com a design can be based on a general approach, following
The Fire Strategy Company relatively simply guidance such as Approved Document B.
Fire - Safety - Risk - Resources One of the main limitations of this type of approach is that
it is fairly generic and classifies all buildings as belonging in

1 BS 9999:2008
The Fire Strategy Company Safety - Risk - Fire - Resources

just one of the seven main purpose groups. This approach first principles, or alternatively refer to one of the many
can therefore be unnecessarily onerous or limiting for some examples provided in the document.
buildings.
Once the risk profile has been determined, BS 9999 indicates
If you require a more flexible solution, the use of an what minimum package of measures is to be provided i.e.
advanced approach, which takes into account the travel distance, stair and exit widths and level of fire alarm.
individual characteristics of the building and its occupants, The minimum package of measures is different to those
should be used, based on BS 9999. Although based on contained in Approved Document B and may be more or less
extensive scientific analysis, no fire engineering expertise onerous, depending on the perceived risk. If this minimum
is needed to adopt this approach; the standard guides package cannot be achieved, a fire engineered approach is
the reader logically through the design process using probably required, which goes beyond the scope of the BS
commentary, examples and tabular analysis. Some fire 9999 guidance document.
safety knowledge is, however, necessary to realise the full
potential of the standard, such as determining if there is a If the minimum package of fire protection measures is
clear benefit to be achieved from automatic fire detection. achievable for your building design, then those measures
can be further analysed to see if any flexibility can be
For an ultimate optimised design, which might be the only achieved through the recognition of the enhancement
solution for a complex or innovative building, the design to fire safety provided by any additional fire protection
should follow a fire engineered approach. BS 9999 is not measures. If a clear benefit can be demonstrated then certain
suitable for this approach; BS 7974 should be utilised by enhancements to the minimum levels can be applied.
those experienced and qualified in fire engineering design.

BS 9999 can be used for design of new buildings or as the

basis for assessing existing buildings. It may be that fire Solutions to all design
authorities will use the guidance within BS 9999 to assess ‘Fire’ issues
a building, e.g. in relation to the level of management, or
fire risk assessments are undertaken which adopt guidance Fire Engineering
contained within the document.
BS 7974
BS 9999 has greatly expanded on the detail relating to the
evacuation of disabled people than was provided in the • Fire Engineering aspects
of building control approval
previous DD 9999, now reflecting the ethos of inclusive
design. It advocates the use of evacuation lifts to allow • Computer modelling of fire
all occupants, regardless of their level of mobility, to self- and evacuation behaviour
evacuate without reliance on others for their safe evacuation.
For an initial discussion contact:

Ian Taylor: 07894 424415

Risk profile ian.taylor@firestrategy.com

To establish the required fire safety provisions, a user of www.firestrategy.com

BS 9999 must establish a Risk Profile for their building The Fire Strategy Company
Fire - Safety - Risk - Resources
(or part of ). If the user is equipped with sufficient fire
safety knowledge they can determine the risk profile from

BS 9999:2008 2
 The Fire Strategy Company Safety - Risk - Fire - Resources

So how are the risk profiles determined?

The first part of the risk profile is related to occupant Occupancy

Characteristic Description Examples
characteristics. This is important because if someone
A Occupants who are awake Office and industrial
is unfamiliar with the building, or perhaps asleep, then and familiar with the
they will take longer to evacuate than an occupant who building
is awake and familiar with the escape routes and layout B Occupants who are awake Shops & assembly
and unfamiliar with the
of the building. Risk categories D and E are not dealt with building
by BS 9999 and other appropriate guidance needs to be C Occupants who are likely to
referenced for any project relating to these occupancies. be asleep
Ci Long-term individual Individual flats
occupancy
Cii Long-term managed Serviced flats
occupancy
Ciii Short-term occupancy Hotels
D Occupants receiving Hospitals
medical care
E Occupants in transit Railway stations,
airports

(BS 9999 Table 1 – Occupant Characteristics)

The second part of the risk profile is related to fire growth.

The table below is available in BS 9999 to help assess the
fire growth, or alternatively somebody with a knowledge

How good are your of fire safety may be able to determine the expected fire
growth rate for your particular situation.
Fire Barriers?
Category Fire growth rate Examples
1 Slow Banking Hall - limited
• Full audits and integrity combustible materials
surveys of fire barriers and 2 Medium Wooden pallets,
doors stacked cardboard boxes
3 Fast Stacked plastic produts,
• Full photographic & status baled clothing
reports 4 Ultra Fast Flammable liquids,
expanded cellular plastics
For an initial discussion
contact: (BS 9999 Table 2 – Fire Growth Rates)

Russ Timpson: 07951 190576

The occupancy characteristic and fire growth rate can then
russ.timpson@firestrategy.com
be combined to determine an overall risk profile.
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3 BS 9999:2008
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Category Growth rate Risk profile Examples

1 Slow Abattoir
Occupants who are awake
2 Medium Office
A and familiar with the
3 Fast Filling room
building
4 Ultra fast Not allowable
1 Slow Reception area
Occupants who are awake
2 Medium Bar, gymnasium
B and unfamiliar with the
3 Fast Shop
building
4 Ultra fast Not allowable
1 Slow House conservatory
2 Medium Occupants who are likely Hotel bedroom
C
3 Fast to be asleep Hotel store room
4 Ultra fast Not allowable

(BS 9999 Table 3 – Risk Profile Table)

it is important to understand that this is a whole-package

Achieving the flexibility approach and should not be used for part of a design where
there is a single issue that you need to overcome. The
The flexibility is realised by looking at additional measures guidance must be embraced in its entirety for the design to
which could be provided beyond what is determined as be effective.
the minimum standard by the guide. For example, BS 9999
recognises the benefit to escape times that an enhanced
fire detection system provides. Also, a high ceiling provides
the occupants with a greater time to escape because the After the Fire ...
smoke will take longer to build down and impact upon the
occupants escape route.
Have you got a
The enhanced detection/warning and high ceiling height Business Continuity Plan?
allows for a number of options where flexibility can be
achieved such as an extended travel distance or a smaller
Full Plan development in
exit, stair or corridor width. The allowable options are line with BS 25999, along
clearly indicated within the guidance and are simple to use. with training, testing and
maintenance.
The provision of automatic sprinklers provides benefits by
For an initial discussion
allowing the fire growth rate to be reduced. For example,
contact:
an occupancy that was determined to be a fast fire
growth category could, with the inclusion of sprinklers, Les Mann: 07930 215545
be downgraded to a medium fire growth category. This les.mann@firestrategy.com
reduction in fire growth rate then leads to a change in the
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fire safety provisions which are required.
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Having recognised that flexibility is available using BS 9999,

BS 9999:2008 4
 The Fire Strategy Company Safety - Risk - Fire - Resources

to sprinklers) now gives increased limits of 20m and 50m.

Fire resistance These limits can be further increased by 15% because of the
benefit afforded by the automatic fire detection & alarm
Another important difference to the general approach system, and by a further 5% due to the ceiling height. The
using Approved Document B is the assessment of fire travel distance limits are therefore now 24m and 60m.
resistance performance. Approved Document B does (Approved Document B recommends limits of 18m and 45m.)
not take into account heat from a fire which is lost from
the building via ventilation openings. Based on the
concept of ‘time equivalence’, BS 9999 enables the benefit Step 4 – Exit widths
of ventilation from the fire compartment to be realised,
resulting in reduced periods of fire resistance if certain For the initial B3 risk profile, the exit width requirement
levels of ventilation can be achieved. was 6mm per person (i.e. a 1200mm wide door can
accommodate 200 people). The reduction in risk profile to
B2 (due to sprinklers) now gives a reduced requirement of
Worked example 4.1mm per person which can be reduced by 15% because
of the benefit afforded by the automatic fire detection &
This example shows how some of the fire safety provisions alarm system, and by a further 5% due to the ceiling height.
can be determined for a multi-storey shop with a maximum The exit width requirement is now 3.3mm per person – a
floor height of just under 18m, fitted with automatic 1200mm wide door can now accommodate 363 people.
sprinklers and an automatic fire detection & alarm system (Approved Document B recommends a 1200m wide door
and with ceiling heights of 3.2m. can accommodate 240 people.)

Step 1 - Risk profile Firefighter Teambuild

Experience Day
The combination of awake, but unfamiliar occupants,
and a fast rate of fire growth results in a risk profile of B3. Real fire uniforms • Real firefighting
However, the presence of sprinklers means the fire growth Real heat • Real teamwork
rate can be reduced and the risk profile is thus B2.
To discuss your next teambuild event
contact:
Step 2 – Minimum level of fire detection & alarm
system Russ Timpson: 07951 190576
russ.timpson@firestrategy.com
The Fire Strategy Company Fire>Risk>Safety - Resources

For a B2 risk profile the minimum recommendation is for a

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manual fire alarm system.

Step 3 – Travel distances

For the initial B3 risk profile, the travel distance limits were
16m in a single direction and 40m if more than one direction The Fire Strategy Company
Fire - Safety - Risk - Resources
of travel is possible. The reduction in risk profile to B2 (due

Firefighter TeamBuild – 2008

5 BS 9999:2008
The Fire Strategy Company Safety - Risk - Fire - Resources

Summary

In summary, BS 9999 is different to other guidance on fire

safety because it:

• Is intended for the life cycle of the building

applicable to both new and existing buildings
• Has an expectation relating to the fire safety
management of the building
• Allows flexibility of design by taking into account
the physical and human factors
• Takes into account a package of fire safety
measures, one of the most important measures
being management
• Sits between Approved Document B and Fire
Engineering
• Is easy to use, logical prescriptive guidance
• Introduces the risk profile concept

This article was written to highlight some of the important

differences between BS 9999 and the other guidance
available for fire safety design. For further information and
support in using this document please contact The Fire
Strategy Company.

email: info@firestrategy.com
web: www.firestrategy.com
tel: 07809 412749

BS 9999:2008 6