Download - BS 9999 Tables
OCCUPANCY CHARACTERISTICSDescription Examples
A Office and industrial premises
B
C Occupants who are likely to be asleep:Ci
Cii
Ciii HotelsOccupants receiving medical careOccupants in transit Railway stations, airports
Occupancy characteristic
Occupants who are awake and familiar with the building
Occupants who are awake and unfamiliar with the building
Shops, exhibitions, museums, leisure centres, other assembly buildings, etc.
• Long-term individual occupancy Individual flats without 24 h maintenance and management control on site
• Long-term managed occupancy Serviced flats, halls of residence, sleeping areas or boarding schools
• Short-term occupancyD A) Hospitals, residential care facilities B)
E C)
A) Currently occupancy characteristic D, medical care, is dealt with in other documentation and is outside the scope of this British Standard.B) Under some circumstances, residential care facilities may be classified as occupancy characteristic Cii.C) This occupancy characteristic is included for completeness within this table but is not referred to elsewhere in this British Standard.
FIRE GROWTH RATES
Category Fire growth rate Examples
1 Slow 0.0029
2 Medium 0.012
3 Fast 0.047
4 Ultra-fast 0.188
Fire growth parameter A) kJ/s3
Banking hall, limited combustible materials
Stacked cardboard boxes, wooden pallets
Baled thermoplastic chips, stacked plastic products, baled clothing
Flammable liquids, expanded cellular plastics and foam
A) This is discussed in PD 7974-1.
RISK PROFILES
Occupancy characteristic (from Table 2) Fire growth rate Risk profile
A 1 Slow A1
2 Medium A2
3 Fast A34 Ultra-fast
B 1 Slow B1
2 Medium B2
3 Fast B34 Ultra-fast
C 1 Slow
(Occupants who are likely to be asleep) 2 Medium
3 Fast4 Ultra-fast
(Occupants who are awake and familiar with the building)
A4 A)
(Occupants who are awake and unfamiliar with the building)
B4 A)
C1 B)
C2 B)
C3 B), C)
C4 A), B)
A) These categories are unacceptable within the scope of BS 9999. Addition of an effective localized suppression system or sprinklers will reduce the fire growth rate and consequently change the category (see 6.5).B) Risk profile C may be divided into sub-categories, viz. Ci1, Cii1, Ciii1, etc.C) Risk profile C3 will be unacceptable under many circumstances unless special precautions are taken.
MINIMUM LEVEL OF FIRE ALARM/DETECTION SYSTEM FOR PREMISESRisk profile Minimum acceptable alarm/detection system A1 MA2 MA3 L2
MML2
Ci1 Automatic fire detection in individual unitsCi2 Automatic fire detection in individual units
L3Cii1 L2Cii2 L2
L1Ciii1 L1Ciii2 L1
L1
NOTE Type M, L3, L2 and L1 systems are defined in BS 5839 1:2002+A2:2008.
A4 A) Not applicable A)
B1 B)
B2 B), C)
B3 B)
B4 A) Not applicable A)
Ci3 A)
Cii3 A)
Ciii3 A)
C4 A) Not applicable A)
A) See Table 4.B) In some circumstances where people are in an unfamiliar building the provision of a voice and/or visual alarm system can help reduce evacuation time.
C) Not including primary or special needs schools – L3 system advisable.
Risk profile Travel distance, in metres (m) Two-way travel One-way travel
A1 65 26A2 55 22A3 45 18
B1 60 24B2 50 20B3 40 16
C1 27 13C2 18 9
14 7
A4 B) Not applicable B) Not applicable B)
B4 B) Not applicable B) Not applicable B)
C3 B)
C4 B) Not applicable B) Not applicable B)
Where exact travel distances are not known, direct distances should be taken as two thirds of the travel distance.
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.
A) This is the maximum travel distance that is allowable when the minimum level of fire protection measures is provided (see Clause 16). For example, the maximum length of one-way travel is 22 m for a category A2 risk according to Table 12. By fitting sprinklers, this risk is changed to A1, so the maximum length of one-way travel is increased to 26 m. If additional fire protection measures are provided then the travel distance may be increased (see Clause 19).
B) See Table 4.
DOOR WIDTHS WHEN MINIMUM FIRE PROTECTION MEASURES ARE PROVIDED
Risk profile
A1 3.3A2 3.6A3 4.6
B1 3.6B2 4.1B3 6
C1 3.6C2 4.1
6
Minimum door width per person mm
A4 A) Not applicable A)
B4 A) Not applicable A)
C3 A)
C4 A) Not applicable A)
A) See Table 4.
ABSOLUTE MINIMUM WIDTH OF STAIRSDimensions in millimetres
A 1000 1200B (except assembly) 1000 1200B (assembly only) 1100 1200C 1000 1200
Occupancy characteristic Width of stair for downward travel
Width of stair for upward travel
MINIMUM WIDTH OF ESCAPE STAIRS FOR SIMULTANEOUS EVACUATIONDimensions in millimetres
Minimum width of stair per person served over total number of floors served
1 floor 2 floors 3 floors 4 floors 5 floors 6 floors 7 floors 8 floors 9 floors 10+ floors
A1 3.9 3.4 2.95 2.45 2.15 2 1.8 1.7 1.5 1.4A2 4.5 3.8 3.25 2.75 2.45 2.2 2 1.9 1.7 1.6A3 5.4 4.6 4 3.5 3.1 2.8 2.6 2.3 2.1 2
— — — — — — — — — —B1 4.2 3.6 3.1 2.6 2.3 2.1 1.9 1.8 1.6 1.5B2 4.8 4 3.4 2.9 2.6 2.3 2.1 2 1.8 1.7B3 7 6 5.3 4.6 4.2 3.7 3.4 3.1 2.8 2.6
— — — — — — — — — —C1 4.2 3.6 3.1 2.6 2.3 2.1 1.9 1.8 1.6 1.5C2 4.8 4 3.4 2.9 2.6 2.3 2.1 2 1.8 1.7
7 6 5.3 4.6 4.2 3.7 3.4 3.1 2.8 2.6— — — — — — — — — —
Risk profile
A4 A)
B4 A)
C3 A)
C4 A)
NOTE The widths of stairs have been calculated on the assumption that all floors are evacuating simultaneously. This is conservative, as the occupants on the fire floor are likely to move more quickly than on the other floors. The flow times on the stairs are based on research data. A) See Table 4.
MINIMUM FIRE RESISTANCE PERFORMANCEPart of building Method of exposure
Integrity Insulation Integrity Insulation
Structural frame, beam or column Not applicable Not applicable Not applicable Not applicable Exposed faces
Load-bearing wall element Not applicable Not applicable Not applicable Not applicable Each side separately
Between a shop and a flat above
Roof Any part forming an escape route 30 30 30 30 30 30
External wall Each side separately
15 15
30 30 30 30
Compartment wall Each side separately
Any other compartment walls
Not applicable 30 Not applicable 30 Each side separately
30 30 30 30 30 30 Each side separately
Minimum provisions when tested to the relevant parts of BS 476, in minutes A)
Minimum provisions when tested to the relevant European standard, in minutes B)Load-bearing
capacity C)Load-bearing capacity C)
See Table 25 or Table 26
See Table 25 or Table 26
See Table 25 or Table 26
See Table 25 or Table 26
Floor D) 60 or see Table 25 or Table 26 F)
60 or see Table 25 or Table 26 F)
60 or see Table 25 or Table 26 F)
60 or see Table 25 or Table 26 F)
60 or see Table 25 or Table 26 F)
60 or see Table 25 or Table 26 F)
From underside E)
Any other floor, including compartment floors
See Table 25 or Table 26
See Table 25 or Table 26
See Table 25 or Table 26
See Table 25 or Table 26
See Table 25 or Table 26
See Table 25 or Table 26
From underside E)
Any roof that performs the function of a floor
See Table 25 or Table 26
See Table 25 or Table 26
See Table 25 or Table 26
See Table 25 or Table 26
See Table 25 or Table 26
See Table 25 or Table 26
From underside E)
Any part less than 1 m away from any point on the relevant boundary
See Table 25 or Table 26
See Table 25 or Table 26
See Table 25 or Table 26
See Table 25 or Table 26
See Table 25 or Table 26
See Table 25 or Table 26
Any part 1 m or more from the relevant boundary G)
See Table 25 or Table 26
See Table 25 or Table 26
See Table 25 or Table 26
See Table 25 or Table 26
From inside the building
Any part adjacent to an external escape route
No provision H), I) No provision H), I) From inside the building
Walls separating occupancies other than occupancies in occupancy characteristic A (office)
60 or see Table 25 or Table 26 J)
60 or see Table 25 or Table 26 J)
60 or see Table 25 or Table 26 J)
60 or see Table 25 or Table 26 J)
60 or see Table 25 or Table 26 J)
60 or see Table 25 or Table 26 J)
See Table 25 or Table 26
See Table 25 or Table 26
See Table 25 or Table 26
See Table 25 or Table 26 See Table 25 or Table 26
See Table 25 or Table 26
Each side separately
Protected shaft, excluding any fire-fighting shafts
Glazed screen separating protected shaft from lobby or corridor
No provision K), L) No provision K), L)
Any other part between the shaft and a protected corridor/lobby
Any other part not described above Each side separately
Fire-fighting shaft 120 120 120 120 120 120
60 60 60 60 60 60 From shaft side60 60 60 60 60 60 Each side separately
Enclosure 30 30 30 30 Each side separately
30 30 30 30 Each side separately
Subdivision of a corridor 30 30 30 30 Each side separately
Fire-resisting construction 30 30 30 30 Each side separately
Enclosing places of special fire hazard 30 30 30 30 30 30 Each side separately
30 30 30 30 30 30 Each side separately
Cavity barrier Not applicable 30 15 Not applicable 30 15 Each side separately
Not applicable 30 No provision Not applicable 30 No provision From outsideNot applicable 30 No provision Not applicable 30 No provision From outsideNot applicable Not applicable From outside
Fire door See Table 30 See Table 30 See Table 30 See Table 30 See Table 30 See Table 30Construction enclosing a roadway 120 120 120 120 120 120
See Table 25 or Table 26
See Table 25 or Table 26
See Table 25 or Table 26
See Table 25 or Table 26
See Table 25 or Table 26
See Table 25 or Table 26
Construction separating fire-fighting shaft from rest of building
From side remote from shaft
Construction separating fire-fighting stair, fire-fighting lift shaft and fire-fighting lobby
Not forming part of a compartment wall or a protected shaft, to a protected lobby or a protected corridor
30 K) 30 K)
In a flat, to a protected entrance hall or a protected landing
30 K) 30 K)
30 K) 30 K)
Enclosing communal areas in sheltered housing
30 K) 30 K)
Between store rooms and sales area in shops
Duct M) Casing around a drainage system N) Flue walls O) Half the period
given in Table 25 or Table 26 for compartment wall/floor
Half the period given in Table 25 or Table 26 for compartment wall/floor
Half the period given in Table 25 and Table 26 for compartment wall/floor
Half the period given in Table 25 and Table 26 for compartment wall/floor
From the roadway side
A) Part 21 for load-bearing elements, Part 22 for non-load-bearing elements, Part 23 for fire-protecting suspended ceilings, and Part 24 for ventilation ducts. BS 476-8 results are acceptable for items tested or assessed before 1st January 1988.B) The national classifications do not automatically equate with the equivalent classifications in the European column, therefore products cannot typically assume a European class unless they have been tested accordingly.C) Applies to load-bearing elements only.
D) Guidance on increasing the fire resistance of existing timber floors is given in DG 208 [34].E) If a suspended ceiling is used it should conform to 31.2.5 and 35.1.4.F) Whichever is greater.G) The guidance in Clause 36 allows such walls to contain areas which need not be fire-resisting (unprotected areas).H) Unless needed to meet the recommendations given in Clause 36.I) Except for any limitations on glazed elements given in 31.3.J) Whichever is less.K) See 31.3.1 for permitted extent of uninsulated glazed elements.L) See 31.3.2.M) See 34.4v).N) See Figure 31.O) See Figure 30.
PROVISION OF FIRE-FIGHTING SHAFTSType of building (qualifying storeys) Content of fire-fighting shaft
Buildings with a height of 11 m or more, but less than 18 m Escape stairUnvented fire-fighting lobby provided with a fire mainFire-fighting stair
Fire-fighting lobbies provided with a fire main
Fire-fighting stairFire-fighting lobbies provided with a fire mainFire-fighting lift installationFire-fighting stairFire-fighting lobbies provided with a fire mainFire-fighting lift installationFire-fighting stairFire-fighting lobbies provided with a fire main
Buildings intended to be used as shops, factories or for assembly and recreation where the height of the topmost storey exceeds 7.5 m, with the floor area of any storey above the ground storey not less than 900 m2
Buildings or parts of buildings A) where the height of the surface of the floor of the topmost storey (excluding any storey consisting entirely of plant rooms) exceeds 18 m
Buildings where the depth of the surface of the floor of the lowermost storey exceeds 10 m
Buildings where there are two or more basement levels, each with a floor area exceeding 900 m2
A) The reference to parts of buildings covers situations such as tower blocks rising above a podium.