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  • Writer's pictureCliff L'Aimable _Chartered Surveyor & Building Engineer

BS 9999_An under used reference? Fire safety in the design, management & use of buildings.

Another Blog Post from University Graduate, Chartered Surveyor and Registered Building Engineer

Mr Cliff L'Aimable (Building Regulations Specialist), who has been writing construction related blog posts since 1999 and was an ex-article writer with technical publications appearing in Trinity Mirror magazines and newspapers in his column called the "Property Doctor". For building regulation advice and a fee quote for building regulations approvals click

The BS 9999: 2017 Edition framework of principles (Part 1)

In this blog and in view of the pending competency framework soon to be established and introduced to assess building inspectors in England I thought I would publish this blog overview of a document which is now on its second publication since its first introduction in 2008.

Some 15 years since its introduction I still feel there is still some inertia from the general design profession in embracing this British Standard, as the “go to” document at the beginning of a design assessment despite the gains to be had over and above the Approved Document Part B -Fire Safety.


BS 9999: 2017 - Code of practice for fire safety in the design, management and use of buildings

Is a -code of practice, for fire safety, enrolled within the title "BS 9999: Code of practice for fire safety in the design, management, and use of buildings".

Its approaches -Risk Profiling- are replicated in a sister publication BS 9991:2015. Fire safety in the design, management and use of residential buildings.

First released in 2008 it replaced an older series of standards called BS 5588 Fire precautions in the design, construction, and usage of buildings.

The most recent BS9999 edition was published in 2017.

This British Standard provides recommendations and best practice guidelines on the design, management, and use of buildings to achieve reasonable fire safety requirements for all people within and around structures.

To the following building types, which are otherwise addressed by BS 9991:

· single-family dwellings, self-contained apartments, and maisonettes;

· specialised housing.

· Residential accommodation blocks (for example, for students or hospital employees) with individual bedrooms and kitchen/sanitary facilities constructed within a fire compartment;

· It is not applicable to HMOs or buildings in which tenants get medical care. It may have restricted applicability to specific specialised buildings and building locations (e.g. areas of lawful detention).

The design of fire-safe buildings

Requires an understanding of the origins of fire, materials and systems likely to be implicated in a fire, how people use buildings, and the spread of fire.

The suggestions and guidance in this British Standard are based on the premis that, (in the absence of arson), a fire is unlikely to start in two different locations within a structure under normal conditions.

Centred around a "time and risk-based approach" that seeks to output via analysis whether occupants of a building can escape when confronted by smoke and fire well within time, before conditions untenable are encountered which could lead to movement arrest and ultimately death.

All fire safety measures, processes, etc. must take into account the unique characteristics of the building or complex infrastructure in question.

In principle, the same recommendations apply to both existing and new structures, however existing structures, especially historic structures, frequently present issues that are unlikely to develop in new structures.

Assessing the fire safety management

In assessing the fire safety management requirements of a modified existing building, it is vital to have a thorough grasp of the building's current construction, material composition, layout, and any existing fire safety provisions, as well as to consider the following:

a) any change in use of the building which could affect the fire risk profile (e.g. increased fire load and process risks, introducing the public, changes in sleeping risk, seasonal changes);

b) how the necessary fire safety levels can be practicably achieved in the existing premises and whether they are appropriate;

c) historic and environmental aspects of the premises and the extent to which they are likely to be disturbed;

d) legislation and guidance introduced since the last considered. ; and

any change in use of the premises which could affect the fire risk profile (e.g. increased fire load and process risks, introducing the public, changes in sleeping risk, seasonal changes);

In the early stages of planning for such structures, it is advisable to engage consultative agencies such as Historic England, Cadw, Historic Scotland, and the Northern Ireland Environment Agency.

In exchange for the long-term protection and preservation of the building's original fabric, the appropriate authorities sometimes agree to restricted modifications to increase life safety and should therefore be consulted early on in the design phase.

Specific concerns with historic structures can be grouped into four categories:

1) the preservation of the ambience and important features of the building, such as timber linings to accommodation stairs and slender cast iron structure, which can sometimes conflict with the desired fire safety construction but can be accommodated by suitable compensating features;

2) the introduction of relevant compensating measures can frequently meet life safety concerns, but this is not always the case for property protection and economic interests.

3) the fire resistance of the structure's construction - Although modern construction requirements seldom apply to historic buildings, action to improve the degree of fire and life safety might be essential based on change of use or owing to the necessity to lower the fire risk and potential for loss of the structure and/or interior in any other context;

4) the susceptibility to fire and smoke damage of historic structures and interiors (finishes and contents).

In both new construction and during the renovation or substantial modification of old buildings, many aspects of fire precautions will be found to be interrelated and deficits in some areas are likely to have to be compensated for by strengths in others.

One or more areas of a building may benefit from a higher standard in one of the other areas. The flexibility provided by BS 9999 permits the fire protection measures and risks to be evaluated so that practical, reasonable solutions can be devised.

Fire measures in all buildings, regardless of age, must be viewed as an integrated package aimed at achieving an acceptable level of fire safety. In modifying existing structures, if it can be demonstrated that the new work will not have a detrimental influence on the remainder, it may not be necessary to perform any additional work on the remainder, but it may be possible to propose an improvement as good practise. Existing buildings are not required to be retroactively subject to the same standards as new buildings; however, it is essential that designers apply the general principle that the safest practicable design is to be sought, and that the prior existence of an unsafe situation is not permitted to continue if it is feasible to provide a remedy.

Ideology yielding recommendations

The ideas and recommendations in this British Standard are straightforwardly applicable to properties with a single primary use, and a single building – within a defined purpose group within its scope.

However, complications may develop when a building has two or more distinct primary uses. In such situations, it is essential to understand how one risk may affect another. A fire at a store or unattended office could have severe ramifications for instance upon a residential or hotel use in the same building.

Likewise, a high fire risk in one section of a building could have devastating effects on other areas of the same building.

Among the variables that must be considered while designing a minimum package of fire safety measures are the following:

i) the potential users of the building;

ii) the hazard posed by one occupancy to another;

iii) the provision for giving warning in the event of fire, including any automatic fire detection;

iv) the provision of automatic fire suppression systems and smoke control arrangements;

v) the overall management and control of the building or development, from

a fire safety point of view;

vi) structural fire protection and compartmentation;

vii) the security of and access to the building.

The British Standard 9999: 2017 gives suggestions and guidance for the consideration of deployment of fire control and mitigation measures. The major purpose is to guarantee a sufficient level of life safety in the event of a fire in the structure.

A secondary purpose is to safeguard property and companies – occupants, from the effects of fire, such as in close proximity to residential buildings or as part of the same building complex.

These can also have the impact of aiding fire and rescue services and/or protecting the built environment.

This British Standard contains references to occupant safety, firefighter safety, and property protection drawing attention to the many difficulties that they may raise. It is, however, crucial to be aware that provisions purely for life safety are unlikely to provide the entire level of protection for buildings and property in a fully developed fire situation.

Section 2 (Risk profiles and assessing risk) explains the ideas underlying the aforementioned principles and introduces the concept of risk profiling.

The publication establishes a premis for the maintained, safeguarded availability of means of escape in case of fire, and on construction, have adequate design to take into account the nature of the occupants and the usage of the structure as a whole, as well as the expected fire growth and risks resulting from that use - the risk profile.

End of Part One Blog on BS 9999:2017

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