Chapter 4 — Equipment and In-built Facilities
Superseded by BNBC 2020 (in force from 11 February 2021) — see note.
Sections in this chapter
Equipment and In-built Facilities
4.1 Scope
The provisions of this chapter shall control the design, installation and management of equipment and in-built facilities required for fire fighting within a building and its premises. The regulations of this chapter shall be applicable for all buildings (whether the system will be required by the Code or by owner's request) and the provisions stated herein shall not cover the fire fighting requirements outside the building premises.
4.2 FIRE PROTECTION PLUMBING
4.2.1 Water Requirement for Interior Fire Protection
The minimum quantity of water for sprinkler and hose use within the building according to their occupancy classification shall be in accordance with Table 4.4.1 or on the basis of the hydraulic design of the system.
4.2.2 Water Sources for Fire Protection
Water required for interior fire protection of a building shall be supplied from one or a combination of the following sources.
4.2.2.1 Direct Connection to Water Main : For continuous water supply (public water supply system or independent system only for fire protection) with sufficient quantity and pressure to feed fire fighting equipments during peak demand period, direct connection of fire fighting system to the water main may be adopted (Fig 4.4.1).
4.2.2.2 Roof Gravity Tanks : For water supply system with inadequate quantity or pressure during peak demand period but with sufficient pressure to feed roof tank, a roof gravity tank shall be provided to feed fire fighting equipments (Fig 4.4.2).
4.2.2.3 Storage Tank : For water supply system with inadequate pressure to feed fire fighting equipments or roof gravity tank, the building premises shall have a ground (or underground) tank to store water for fire fighting and one of the combinations shown in Fig 4.4.3, 4.4.4 and 4.4.5 shall be adopted.
Table 4.4.1
Fire Protection Flow Requirements
|
Building Type |
Sprinkler System (l/min.)* |
Standpipe and hose System (l/min.)* |
Duration** (minute, min.) |
|
Light hazard- I Light hazard- II Ordinary hazard- I Ordinary hazard - II Ordinary hazard - III |
1000 1900 2650 3200 4800 |
1000 1900 1900 1900 1900 |
30 50 75 75 75 |
|
Notes: * Values will be for one riser serving floor area of 1000 m2. * * These durations shall be for a building up to the height of 51 m. For greater height of 51-102 m and above 102 m, the duration will be 1.25 times and 1.5 times of the specified values respectively. Light hazard - I : Occupancy groups, A1, A2, A4 Light hazard - II : Occupancy groups, A3, A6, A7, A8, B, C, D, E2, E4, E7, F1 & F2 Ordinary hazard - I : Occupancy groups, E1, E3, E5, F3, F4, F5, F6, F7, G1 & G4 Ordinary hazard- II: Occupancy groups, G2 & H1 Ordinary hazard- III : Occupancy groups, G3 & H2 Extra hazard : Occupancy group, j - pressure and flow requirement for this group shall be determined by Fire Department but shall not be less than required value for Ordinary hazard-III | |||
The system only for fire fighting purpose may be designed with automatic fire pump as shown in Fig 4.4.3. The water supply system for domestic use and fire protection may be designed with roof gravity tank and manually controlled pump as shown in Fig 4.4.4. The pressure tank with automatic fire pump and compressor may be used for supplying water to the fire fighting equipments as shown in Fig 4.4.5 and 4.4.6. The location of pressure tank shall be such that it will provide the required pressure at the highest fire fighting equipment.
The water stored in storage tank for fire fighting operation shall not be used for other purposes (see Fig 4.4.7).
The ground storage tank shall be easily accessible to fire engine of Fire Department. In absence of space available for fire engine, the cover slab of ground storage tank shall be designed to withstand a vehicular load of local fire engine.
4.2.2.4 Individual Water Sources : In absence of public water supply system, the building premises shall have individual water sources specified in Sec 6.19 of Part 8. The individual water sources with adequate yield during peak demand period will serve as a fire service ground tank as shown in Fig 4.4.3, 4.4.4 and 4.4.5. Otherwise, the water shall the individual sources shall have to be stored in a storage tank specified in Sec 4.2.2.3.
4.2.3 Design Considerations for Standpipe and Hose System
4.2.3.1 The fire protection system shall be designed for their effective use either by amateur or trained fire fighting personnel or both.
4.2.3.2 All standpipes in standpipe system shall be sized so that they will provide a minimum flow specified in Table 4.4.1. In standpipe system with more than one standpipe, the supply piping shall be sized for the minimum flow specified in Table 4.4.1 for the first standpipe plus 1000 litre per minute for each additional standpipe. The total number of such additional standpipes shall not be more than 8. All standpipe risers shall be connected through a gate valve with a main of size equal to that of the largest riser.
4.2.3.3 The minimum pressure for standpipes supplying a 50 mm or larger hose shall be at least 300 kPa. For standpipe supplying first aid hose (38 mm nominal) may have a minimum pressure of 200 kPa.
4.2.3.4 The size (diameter) of standpipes for various building height may be as shown in Table 4.4.2 or hydraulically designed to provide the required flow (Sec 4.2.3.2) and pressure (Sec 4.2.3.3) at the topmost outlet.
4.2.3.5 The water supply required for combined system (for partial automatic sprinkler and Fire Department hose) shall be calculated in accordance with Sec 4.2.3.2 plus an amount equal to the hydraulically calculated sprinkler demand or 550 litre per minute for light hazard occupancy groups or 1900 litre per minute for ordinary hazard occupancy groups.
4.2.3.6 The size of combined system shall be at least 150 mm or hydraulically designed to provide the required flow (Sec 4.2.3.5) and pressure.
4.2.3.7 The standpipe shall be located in noncombustible enclosure such that it will be able to provide hose stream to the most remote area of the floor served.
Table 4.4.2
Standpipe Sizes
|
No. of Storeys |
Building Height (m) |
Size of Standpipe (mm) |
|
Up to 5 Up to 10 10 to 20 20 to 54 |
Up to 17 Up to 33 33 to 63 63 to 165 |
75* 100 150 200 |
|
* This size may be used only for occupancy groups A1, A2 and A4 | ||
4.2.3.8 The hose shall be connected to the standpipe within 1.5 m from the floor. Hose stations shall be easily accessible for inspection and testing.
4.2.3.9 The hose connection to a standpipe for large stream shall be at least 100 mm nominal and that of small stream may be 63 mm or 50 mm on each floor. The size of first aid hose shall be 38 mm nominal. The hose length shall not be more than 30 m.
4.2.3.10 The static pressure in standpipe shall not exceed 650 kPa at hose outlet. Where pressure reducing valves are used, the design of pressure reducing valve shall be so that the pressure with the following stream shall not exceed 650 kPa .
4.2.3.11 Different piping materials and fittings for standpipe system presented in Tables 4.4.3 and 4.4.4 shall conform to the standard or one of the standards cited against them. The standard requirements for other materials not provided in these tables shall be subject to the approval of the Authority.
4.2.3.12 The standpipe riser shall be supported at the top and at the lowest level. The riser shall also be provided with support at the alternate level in between top and bottom level of the standpipe riser. The support shall be of adequate strength to support the water-filled pipe load and an additional load of 110 kg.
The horizontal standpipe shall have hangers with a spacing not more than 5m. The hanger shall be able to carry a load of five times the weight of the water-filled pipe and an additional load of 110 kg.
Table 4.4.3
Piping for Standpipe System
|
Material |
Standard |
|
Copper Tube Copper and Copper-Alloy Tube Steel Pipe Wrought Steel or Iron |
ASTM B75, ASTM B88 ASTM B251 ASTM A55, ASTM A120, ASTM A135 ANSI B36.10 |
Table 4.4.4
Standpipe Fittings
|
Material |
Standard |
|
Cast Iron Copper Malleable Iron Steel |
ANSI 616.1, ANSI B16.4 ANSI B16.18, ANSI B16.22 ANSI B16.3 ANSI B16.5, ANSI B16.9, ANSI B16.11, ANSI B16.25, ASTM A234 |
4.2.3.13 There shall be Siamese connection to the standpipe or to the delivery pipe of the gravity roof storage tank. The Siamese connection shall be easily accessible to fire engine.
4.2.3.14 The system shall be provided with adequate drainage piping to discharge under pressure. The drain pipe shall not discharge into sanitary sewer.
4.2.3.15 All control valves shall be designed to withstand the pressure specified in Sec 4.2.7.2a.
4.2.4 Design Consideration for Sprinkler System
4.2.4.1 The pipe schedule sizing to supply different number of sprinklers for their different uses may be in accordance with Tables 4.4.5 and 4.4.6.
4.2.4.2 Each sprinkler shall serve a maximum ceiling area specified in Table 4.4.7 for different types of building according to their uses.
4.2.4.3 The recommended pressure for sprinkler system will be 100 kPa. The location of gravity storage tank to serve sprinkler system shall be at least 10 m above the top most line of sprinklers.
4.2.4.4 Water supply pipings and fittings for sprinkler system shall conform to the standard or one of the standards cited against them in accordance with Tables 4.4.4 and 4.4.8. The standard requirements for other pipe materials not provided in these tables shall be subject to the approval of the Authority.
4.2.4.5 The sprinkler system shall be provided with adequate support or made flexible to prevent pipe breakage during earthquake.
4.2.4.6 The hanger in sprinkler system shall be designed to carry a load equal to five times the weight of the water-filled pipe plus an addition load of 110 kg.
The support shall be designed to support a load equal to the weight-filled pipe plus and additional load of 110 kg.
Table 4.4.5
Size of Water Supply Steel Pipe to Sprinklers
|
Pipe Size mm (inch) nominal |
No. of Sprinkler Connection for Light Hazard* |
No. of Sprinkler Connection Ordinary Hazard * |
No. of Sprinkler Connection Ordinary Extra Hazard * |
|
25 (1) |
2 |
2 |
1 |
32
|
3 |
3 |
2 |
38
|
5 |
5 |
5 |
|
50 (2) |
10 |
10 |
8 |
63
|
30 |
20 |
15 |
|
75 (3) |
60 |
40 |
27 |
88
|
100 |
65 |
40 |
|
100 (4) |
NL** |
100 |
55 |
|
125 (5) |
- |
160 |
90 |
|
150 (6) |
- |
275 |
150 |
|
200 (8) |
- |
400*** |
225*** |
* Definition of these terms are given in Table 4.4.1. ** No limit. *** One sprinkler system riser or combined system riser shall serve the floor area not more than 4850 m2 for light and ordinary hazardous occupancy and 2325 m2 for extra hazardous occupancy | |||
Table 4.4.6
Size of Water Supply Copper Pipe to Sprinklers
|
Pipe Size mm (inch) nominal |
No. of Sprinkler Connection for Light Hazard* |
No. of Sprinkler Connection Ordinary Hazard * |
No. of Sprinkler Connection Ordinary Extra Hazard * |
|
25 (1) |
2 |
2 |
1 |
32
|
3 |
3 |
2 |
38
|
5 |
5 |
5 |
|
50 (2) |
12 |
12 |
8 |
63
|
40 |
25 |
20 |
|
75 (3) |
65 |
45 |
30 |
88
|
115 |
75 |
45 |
|
100 (4) |
NL** |
115 |
65 |
|
125 (5) |
- |
180 |
100 |
|
150 (6) |
- |
300 |
170 |
|
200 (8) |
- |
*** |
*** |
* Definition of these terms are given in Table 4.4.1. ** No limit. *** One sprinkler system riser or combined system riser shall serve the floor area not more than 4850 m2 for light and ordinary hazard occupancy and 2325 m2 for extra hazard occupancy | |||
Table 4.4.7
Ceiling Area for a Sprinkler
|
Building Type |
Light Hazard ** Area, m2 |
Ordinary Hazard ** Area, m2 |
Extra Hazard ** Area, m2 |
|
Roof or Floor on Trusses, Girders or Beam With High Piling *** |
20(4.5*) - |
12(4.5*) 9.3(3.5*) |
8.4(3.5*) 8.4(3.5*) |
|
Open Wood Joists With High Piling *** |
12(4.5*) - |
12(4.5*) 9.3(3.5*) |
8.4(3.5*) 8.4(3.5*) |
|
Other Type of Construction With High Piling *** |
15.6(4.5*) - |
12(4.5*) 9.3(3.5*) |
8.4(3.5*) 8.4(3.5*) |
|
Notes: * Maximum distance in m between sprinklers and between line of piping. * * The definitions of these terms are given in Table 4.4.1. ** * Storage facilities which permit closely piled materials over 4.5 m or materials on rack over 3.6 m. | |||
Table 4.4.8
Piping for Sprinkler System
|
Material |
Standard |
|
Copper and Copper-Alloy Steel |
ASTM B32, ASTM B75 ASTM B88, ASTM B25 ANSI B36.10, ASTM A53 ASTM A120, ASTM A 135, ASTM A795 |
4.2.4.7 There shall be Siamese connection to the sprinkler system located outside the building and accessible to the Fire Department connection.
4.2.4.8 All risers shall be connected through a gate valve with a main of size equal to that largest riser.
4.2.4.9 The sprinkler system shall be provided with adequate drainage arrangement. The drain pipe shall not discharge into sanitary sewer.
4.2.4.10 All control valves and fittings shall be able to withstand the pressure specified in 4.2.7.2b.
4.2.5 Water Supply for Fire Protection in Tall Building
The quantity, sources and mode of water supply in tall building shall be in accordance with Sec 4.2.1 and 4.2.2. In tall buildings fittings and equipments for fire fighting may be subject to excessive pressure. Pressure on fire fighting equipments (Sec 4.2.3.10) in tall building shall be reduced by one or a combination of the following methods:
a) Water Supply Zones with Automatic Fire Pump : The building shall be divided into different water supply zones so that the fire fighting equipment will serve within their maximum allowable limit of pressure (Fig 4.4.8). Separate automatic fire pump or combination of pressure tank and automatic pump shall be installed for supplying water to the fire fighting equipments in each zone.
b) Water Supply Zones with Intermediate Gravity Tank : The building shall be divided into different water supply zones in accordance with 4.2.5a. Each water supply zones shall be provided with separate gravity overhead tank and manually operated pump (Fig 4.4.9). The fire fighting equipments in each water supply zone shall be supplied with water from their respective overhead gravity tanks.
c) Using Pressure Reducing Device : The water required by fire fighting equipments shall be supplied from roof gravity tank (Fig 4.4.10). Pressure on different fire fighting equipments shall be reduced by using pressure reducing valves (Fig 4.4.10).
4.2.6 Fire Pump
The fire pump shall be so designed that it shall satisfy the required pressures and flow for fire fighting equipments at the highest and most remote part of the protected premises during their peak demand hour or for pressure tank or for roof storage tank. The pump shall be housed in a readily accessible position in a building of non combustible construction. The pump shall be adequately protected against mechanical damage.
A manually controlled pump may be used to feed water into gravity overhead tank with fire reserve. There shall be provision for standby fire pump driven by a compression ignition (diesel) engine or electric pump with own generator.
The fire fighting equipments directly fed by fire pump shall be designed with automatic fire pump. Once the pump starts it shall run continuously until stopped manually. The pump shall be fully operational within 30 seconds after starting. There shall be provision for manual starting. The pump shall be compression ignition type or electricity driven with own generator. Where priming is necessary, automatic priming equipment shall be provided to ensure priming with water at all times. The fire pump shall not be used for other purpose.
4.2.7 Inspection, Testing and Maintenance
4.2.7.1 Inspection : All pipings and equipments shall be inspected for satisfactory supports (in accordance with Sec 6.13 in Part 8 of this Code) and protection from damage and corrosion. All outlets shall be free from obstruction.
4.2.7.2 Testing : Fire protection plumbing system or part thereof shall be tested and approved after installation by the Authority.
a) Testing of Standpipe System : The system shall be tested for a pressure 25% in excess of the highest working pressure for at least 2 hours. The system shall be able to maintain above test pressures. The system shall be also be tested for the required flow at the highest outlet.
b) Testing of Sprinkler System : This system shall be tested for at least 2 hours for a pressure of 1000 kPa or at 350 kPa in excess of normal working pressure when normal working pressure will be more than 650 kPa. The system shall be able to maintain above test pressures. The system shall also be tested for the required flow at the highest outlet.
c) Testing of Pump : The pump used for fire fighting purpose shall be tested for their performance characteristics. The pump shall be restored or repaired to its original condition if their performance characteristics fall below more than 10 per cent of the supplier's test characteristic curve or as specified for the fire protection water supply system.
4.2.7.3 Maintenance : The system shall be maintained for safe operating conditions and tested at least once a year.
4.3 FIRE PROTECTIVE SIGNALLING OR FIRE ALARM SYSTEM
Fire protective signalling or fire alarm system, where required by the Code, shall specify plans and clearly delineate the locations and number of all alarm-initiating devices and alarm-indicating appliances. The plan shall also provide details of all equipment to be used, proposed zoning, list of auxiliary control functions, location of the control panel and enunciators and a complete sequence of operation for the system.
Fire protective signalling or fire alarm system, wherever required and installed shall be maintained in full operating condition.
4.4 AUTOMATIC FIRE AND SMOKE DETECTION SYSTEM
The installation of automatic fire and smoke detection system shall be a necessity when the size, arrangement and occupancy of a building become such that a fire itself can not provide adequate warning to its occupants.
The automatic fire and smoke detection system shall include, spot or line type heat sensitive detectors and optical, ionized or chemical sensitive type of smoke detectors. A guideline for selection and siting of fire detection system is provided in Appendix C.
4.5 FOAM EXTINGUISHING SYSTEM
4.5.1 General
Foam extinguishing system shall be of an approved type and shall be installed in accordance with the provisions of this Code. The foam extinguishing system is designed to discharge fire suppressive foam concentrates over the area to be protected.
4.5.1.1 A foam extinguishing system shall be automatically actuated during a fire with provision of manual actuation.
4.5.1.2 Warning sign and discharge alarm system shall be provided with the foam extinguishing system, which shall be actuated during the use of the system.
4.5.1.3 The system shall be provided for protection of boiler rooms with its ancillary storage of furnace oils in basement and other areas where hazardous liquids are stored.
4.6CARBON DIOXIDE EXTINGUISHING SYSTEM
4.6.1 General
Carbon dioxide extinguishing system shall be of an approved type and shall be installed as per provisions of this Code. The system supplies CO2 from a pressurized vessel through fixed pipes and nozzles.
4.6.1.1 The system is used where water or foam cannot be used for fire extinguishing because of the special nature of the contents within the building or areas to be protected.
4.6.1.2 The system shall be automatically actuated and shall be equipped with manual actuation devices as well.
4.6.1.3 Warning signs and discharge alarm shall be provided where persons are likely to be trapped in an area made hazardous by carbon dioxide discharge.
4.7 HALOGENATED EXTINGUISHING SYSTEM
4.7.1 General
Halogenated extinguishing system shall be of an approved type and shall be installed in accordance with the provisions of this Code. The system comprise pipes, nozzles and halogenated chemical container under pressure.
4.7.1.1 When carbon dioxide extinguishing systems are not proved suitable for special fire risk zones, halogenated extinguishing system shall be installed. The system shall be automatically actuated during a fire and shall be equipped with manual actuation devices as well.
4.7.1.2 Warning sign and discharge alarm shall be provided where persons are likely to be trapped in an area made hazardous by halogenated hydrocarbons.
4.8 DRY CHEMICAL EXTINGUISHING SYSTEM
4.8.1 General
Dry chemical extinguishing system shall be of an approved type and shall be installed in accordance with the provisions of this Code and manufacture's instruction.
4.8.1.1 The system shall be automatically actuated during a fire and shall be equipped with manual actuation device as well.
4.8.1.2 Warning signs and discharge alarm shall be provided where persons are likely to be exposed to dry chemical discharge.
4.8.1.3 The dry chemical agent of the system shall be nontoxic.
4.9 WET CHEMICAL EXTINGUISHING SYSTEM
4.9.1 General
A wet chemical system is a solution of water and potassium carbonate or acetate based chemical which forms the extinguishing agent. The system shall be installed in accordance with the provisions of this Code and manufacturer's installation instruction.
4.9.1.1 The system shall be automatically actuated during a fire and shall be equipped with manual actuation device as well.
4.9.1.2 In case of wet chemical range hood extinguishing system, label of an approved agent shall be affixed.
4.9.1.3 Warning signs and discharge alarm shall be provided where persons are likely to be exposed to wet chemical discharge.
4.10 PORTABLE FIRE EXTINGUISHER
4.10.1 General
Potable fire extinguisher shall be of an approved type and shall be installed as per manufacturer's instruction.
4.10.1.1 Portable fire extinguisher shall be installed in private and public buildings as per specification and requirements of BDS 825 : 1991 (BDS 825 : 91).
4.10.1.2 The portable extinguisher shall be placed near the path of exit travel and it shall be easily accessible.
4.10.1.3 Fire hazard areas of a building like kitchen, public area, storage, electrical distribution point etc. shall be installed with portable fire extinguishers.
Related Appendix
Appendix C Detailed Guidelines for Selection and Siting of Fire Detection System
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Source: Bangladesh National Building Code 2006 (Housing and Building Research Institute). Superseded by BNBC 2020 — provided for reference. For design or official work, refer to the printed code.