4.1 Basis of design

a) Fire Growth and Spread:

● Fires start small and localized but can grow with sufficient fuel and ventilation.

● Fires typically begin in accommodation spaces, not in protected routes or stairwells.

b) Hazard Assumptions:

● Under normal circumstances, fires are expected to start in a single location.

● Any fire within a building compartment poses a hazard to all occupants, regardless of initial threat perception.

c) Factors Influencing Compartment Safety:

● Key factors include spatial volume, geometry, fuel load, fire growth rate, and fire precautions.

● Considerations are critical for buildings with large, diverse, and potentially unfamiliar occupants.

d) Facilitating Escape:

● Warn occupants in the compartment of origin.

● Consider the occupants' profiles, including mobility and familiarity with surroundings.

● Minimize travel time to protected routes or exits.

● Ensure adequate and safeguarded escape routes.

e) Protecting Remote Occupants:

● Alert individuals in other parts of the building.

● Subdivide the building to delay or prevent fire spread.

● Implement fire suppression systems.

f) Support for Fire-Fighting:

● Buildings should have facilities to assist in firefighting, fire extinguishment, and search and rescue operations.

4.2 Variation of recommendations

a) Flexibility in Means of Escape:

● Travel distances and door/stair widths can vary based on additional fire prevention/protection measures.

b) Building Structure Design Variations:

● Certain structural design variations are permitted if measures like automatic sprinkler systems are implemented.

c) Flexibility with Limits:

● Designers, occupiers, and approving authorities have flexibility in fire safety measures within the limits set by the British Standard.

NOTE A fire safety engineering approach as detailed in BS 7974 gives greater flexibility and might be more appropriate in the design of complex buildings and spaces.

4.3 Property protection and business continuity

a) Primary Focus:

● The British Standard focuses primarily on protecting life.

b) Property and Business Protection:

● Fire safety systems for life safety may not adequately protect property or ensure business continuity.

c) Risk Assessment:

● The potential for property and business loss should be assessed.

d) Guidance for Assessment:

● Risk assessment should be conducted as outlined in Annex A.

NOTE Recommendations for the provision of fire precautions for the protection of property and the continuity of the business can also be found in Annex A (see also 43.8 and 43.9).

4.4 Environment

a) Environmental Impact of Fires:

● Fires and emissions from combustion processes can harm the environment.

● The contents and activities within a building can cause more pollution than the building materials.

b) Design Stage Considerations:

● Design measures can minimize the environmental impact of accidental fires.

● Emphasis should be on the building's contents, but the use of combustible materials should also be considered.

4.5 Mixed-use buildings incorporating residential use

a) Standard for Wholly Residential Premises:

● Design should follow BS 9991 for wholly residential buildings.

b) Mixed-Use Buildings:

● Separate and independent fire safety design for residential and non-residential areas is ideal.

c) Applying Standards:

● If separation is achieved, apply BS 9991 for residential and BS 9999 for non-residential parts.

● If separation is not possible, use BS 9999 for shared parts of the building.

d) Mixed Dependencies:

● If fire safety in one part depends on another, implement the stricter recommendations of BS 9991 and BS 9999.

e) Escape Strategy:

● The escape plan for residential areas should not assume simultaneous evacuation with non-residential areas.

NOTE For this reason, BS 9999 contains some recommendations relevant to residential use, even though its scope is primarily non-residential.

4.6 Additional recommendations for specific building types/occupancies

a) General Recommendations:

● Sections 4 to 9 provide general guidance.

b) Specific Building Types and Occupancies:

● Atria: Follow recommendations in Annex B; design solutions and examples are in Annex C.

● Theaters, Cinemas, and Similar Venues: Follow recommendations in Annex D.

● Shopping Complexes: Follow recommendations in Annex E.

● Process Plant and Structures: Follow recommendations in Annex F.

● Refuges: Follow recommendations in Annex G.

4.7 Inclusive design

a) Integration in Design:

● Accessible means of escape should be an integral part of the design process, not a separate issue.

b) Inclusive Design for Egress:

● Facilities for access should also enhance egress arrangements.

c) Fire Safety for Disabled People:

● The standard includes guidance for a wide range of disabilities, not just for wheelchair users.

d) Specific Recommendations:

● Means of Escape: Detailed in sections 16.7 and 17.8.

● Fire Safety Procedures for People at Risk: Covered in section 43.3.

● Evacuation Measures: Discussed in Clause 45.

e) Protection Facilities:

● Include warning systems, management planning, alternative format instructions, way-finding systems, evacuation lifts, protected refuge areas, and devices for stair evacuation.

f) Special Management Procedures:

● Required when a high proportion of disabled people is expected, or in venues likely to host groups of wheelchair users, such as sports, entertainment, transport, or public assembly buildings.

g) Guidance Reference:

● Refer to Sections 4 and 9 for additional recommendations on building management.

NOTE 1 Attention is drawn to the Equality Act 2010 [12], which places a duty on all employers and service providers not to discriminate against disabled people. It is vital to ensure that when making plans for the fire safety and management of buildings, the requirements of disabled people are properly taken into account at all times. It is important to note that the recommendations given in this British Standard are for escape not access. For example, certain dimensions might not provide suitable access for all people with impairments. Recommendations for access are given in BS 8300, which explains how the built environment can be designed to anticipate, and overcome, restrictions that prevent people making full use of premises and their surroundings.

NOTE 2 Attention is drawn to the Regulatory Reform (Fire Safety) Order 2005 [2], which requires suitable means of escape to be provided for all occupants. Attention is also drawn to the Fire (Scotland) Act 2005 [13], the Fire Safety (Scotland) Regulations 2006 [6] and the Fire Safety Regulations (Northern Ireland) 2010 [7].

4 General recommendations and background