Part 4 4-63 Fire Protection

Appendix A Fire Drill and Evacuation Procedure

A 1 INTRODUCTION

Each and every building shall have an emergency evacuation protocol, first aid firefighting plan, training and responsibilities of the occupants complemented with the provisions provided therein.

A 2 EVACUTION PLAN The egress system of a building shall be designed for systematic evacuation. The evacuation procedure of a building is developed considering the fire design scenario. At the time of occurrence of fire the area of incident shall be evacuated first and the probability of aggravation of fire beyond the area of incident shall get the priority and so on. All evacuation procedures shall be performance based and documented as a fire protection and evacuation in a manual with description in vernacular with appropriate diagrams. This document shall be distributed among the occupants. The fire protection and evacuation manual shall be approved by the authority having jurisdiction.

A 3 FIRE REPORTING Any occupant of a building discovered smoke or fire shall immediately act without any delay through manual call points or voice communication system or as per instruction provided thereof. Buildings where provisions of manual call points are not applicable occupant shall report directly to the fire service and civil defense department.

A 4 FIRST AID FIREFIGHTING All occupants of buildings shall be trained for first aid firefighting where the equipment is installed to do so. A 4. 1 Buildings of Occupancy groups of Mercantile, Office, Industrial, Institutions of care shall have

formation of teams of first aid firefighters, evacuation leaders among the employees for each shift of work schedule. List of such team members shall be submitted to the authorities having jurisdiction with proper identification and the consent letter of the person, volunteered to perform the responsibility in case of any emergency.

A 4. 2 Buildings of occupancy group of healthcare facilities shall have special formation of first aid firefighter and evacuation leaders among all the doctors and the nursing and management staffs complying with the performance based design scenarios and number of ambulatory patients to be relocated.

A 4. 3 Buildings of occupancy group of Educational facilities shall have schemes at all levels to train all

students by forming first aid firefighting team including evacuation procedure. Duties and responsibilities during any emergency situation.

A 5 FIRE DRILL

A 5. 1 Fire drill shall be conducted as per design scenarios in presence of the representative of the authority having jurisdiction.

A 5. 2 The essence of a fire drill is orderly evacuation training not the time of evacuation.

A 5. 3 Simulation fire drill is an accepted method in health facilities and institution for care occupancy group where patients or inmates shall not participate in evacuation drill only the staff and all attending personnel shall follow the fire drill manual.

A 5. 4 Training of first aid firefighting is a part of fire drill.

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A 5. 5 A log book shall be maintained where each and every fire drill shall be recorded and duly signed by the representative of the authorities having jurisdiction.

A 5. 6 Frequencies of fire drills shall be decided by the authorities having jurisdiction.

Recommended minimum frequency of fire drill shall be as follows:

Fire Drill Frequency

Occupancy Group Frequency A: Residential Yearly B: Educational Facilities Monthly C: Institution for Care Yearly D: Health Facilities Quarterly E: Business Twice a year F: Mercantile Yearly G:Industrial Building As per laws of the land I: Assembly Yearly J: Hazardous Building As per laws of the land K: Garage Yearly M: Miscellaneous As per laws of the land

A 6 PRIVATE FIRE BRIGADE In any private industrial zone or industrial park or any community of business or mercantile or private housing society intends to establish a private fire bridge for advanced firefighting (more than first aid firefighting) shall follow the guidelines stated below.

A 6.1 The formation of such bridge shall be approved by the fire service and civil defense department.

A 6.2 Organogram of the bridge shall be approved by the authority of jurisdiction. A 6.3 Staff training of the bridge member shall be done according to the standard and

recommendations of fire service and civil defense department. A 6.4 The list of equipment to be procured for the bridge shall be approved authority of

jurisdiction. A 6.5 The size of the bridge depends on the area to be covered. A 6.6 Attending any fire call the bridge shall inform instantaneously to the fire service and civil

defense department. A 6.7 The formation of first aid firefighting and evacuation team of the inmates of the building

shall not be exempted by establishing such bridge.

Part 4 4-65 Fire Protection

Appendix B Fire Protection Considerations for Venting in Industrial and Storage Buildings

B.1 SCOPE B1.1 This appendix covers venting requirements in industrial buildings. Provisions contained herein shall be

applicable to factory and storage facilities requiring large floor areas without dividing walls and enclosures. B1.2 This appendix shall not apply to ventilation designed for personnel comfort, commercial cooking operation,

regulating odor or humidity in toilet and bathing facilities, to regulate cooling equipment. B1.3 This appendix shall apply to fire and smoke of two criteria (a) Fire or smoke layer that does not enhance the

burning rate. (b) Deflagration B2 VENTING OF FIRE AND SMOKE THAT DOES NOT ENHANCE THE BURNING RATE B2.1 Precise venting shall be based on fire dynamics and needs detail calculation, considering variables like rate

of combustion, composition of the combustion product, shape, size and packaging of the combustible materials as well the size, height and disposition of the stacks of materials are involved with it.

B2.2 Vent system designs shall be computed by calculating the vent area required to achieve a mass rate of flow

through the vent that equals the mass rate of smoke production. B2.3 Venting devices are to be so designed and installed that they operate automatically at the earliest sign of fire

or smoke. B2.4 The smoke and fire venting system shall be so designed and installed as to keep the temperature of the

combustion product as low as possible, preferably below 150oC. B2.5 To achieve full efficiency in vents total area of all vents must be more than the inlet area for cold air. Ideally

the inlets should be as close to the floor level as possible. B2.6 The area of unit vent shall not exceed 2d2, where d is the design depth of the smoke layer. For vents with

length to width ratio more than two, the width shall not exceed the design depth of the smoke layer. B2.7 The center-to-center spacing of vents within a curtained area shall not exceed 2.8 H, where H is the ceiling

height. For different shape of the roof the ceiling height can be calculated as per provision of NFPA 204. B2.8 The spacing of vents shall be such that the horizontal distance from any point on a wall or draft curtain to

the center of the nearest vent, within a curtained area does not exceed 1.4 H. B2.9 The total vent area per curtained area shall be sized to meet the design objectives and the performance

objectives relative to the design fire or smoke, determined in accordance with NFPA 204. B2.10 The design of venting for sprinkled building shall be based on performance analysis acceptable to the

authority having jurisdiction, demonstrating that the established objectives are met. B2.11 Smoke and heat venting systems and mechanical exhaust systems shall be inspected and maintained in

accordance with NFPA 204. B2.12 Venting systems are complement to fire extinguishing system. Where automatic sprinklers are installed as

fire extinguishing system, the sprinklers shall operate before the vent system comes into operation. B2.13 In industrial buildings exterior wall windows alone shall not be accepted as satisfactory means of venting,

but may be reckoned as additional means of venting when located close to the eaves and are provided with ordinary glass or movable section arranged for both manual and automatic operation.

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B2.14 Vents shall be automatic in operation unless where designed specifically for both manual and automatic operation.

B2.15 Release mechanism of vent closure shall be simple in operation and shall not be dependent on electric

power. B2.16 The automatic operation of vents can be achieved by actuation of fusible links or other heat or smoke

detectors or by interlacing with the operation of sprinkler system or any other automatic fire extinguishing system covering the area. The vents can be so designed as to open by counterweights utilizing the force of gravity or spring loaded level following its release.

B2.17 When vents and automatic sprinklers where installed together, sprinkler shall go into operation first before

vents open, in order to avoid delay in sprinkler operation. B2.18 Materials used in hinges, hatches and other related parts in vents shall be noncorrosive in nature for long

trouble free operation. B2.19 Vents shall be properly sited, at the highest point in each area to be covered. B2.20 If possible, vents shall be sited right on top of the probable risk area to be protected to ensure free and

speedy removal of smoke and other combustion product. B2.21 Minimum vent opening shall not be less than 1250 mm in any direction. B2.22 Vent spacing shall be designed considering the fact that higher number of smaller vents is better than

smaller number of large vents. B 3. DEFLAGRATION VENTING B3.1 Deflagration is the propagation of a fire or smoke at a velocity less than the sound wave. When this velocity

of combustion increased beyond sound velocity then the combustion is said to be detonated and explosion occurred with the rupture of an enclosure or a container due to the increase of internal pressure from a deflagration.

B3.2 The design of deflagration vents and vents closures necessitates consideration of many variables, only some of which have been investigated in depth. No Venting recommendations are currently available for fast-burning gases with fundamental burning velocities greater than 1.3 times that of propane, such as hydrogen. Recommendations are unavailable and no venting data have been generated that addresses condition that fast-burning gas deflagrations. The user is cautioned that fast-burning gas deflagrations can readily undergo transition to detonation.

B3.3 Deflagration venting is provided for enclosures to minimize structural damage to the enclosure itself and to reduce the probability of damage to the other structures.

B3.4 Venting shall be sufficient to prevent the maximum pressure that develops within the enclosure from exceeding enclosure strength.

B3.5 The vent area shall be distributed as symmetrically and as evenly as possible. B3.6 The need for deflagration vents can be eliminated by the application of explosion prevention techniques

described in NFPA 69. B3.7 The vent closure shall be designed to function as rapid as is practical. The mass of the closure shall be as low

as possible to reduce the effects of inertia. The total mass of the moveable part of the vent closure assembly shall not be exceeded 12.2kg/m2.

B3.8 When an enclosure is subdivided into compartments by walls, partitions, floors, or ceilings, then each compartment that contains a deflagration hazard should be provided with its own vent closure(s).

B3.9 It is possible to isolate hazardous operations and equipment outside of buildings with a pressure resisting wall which will reduce risk of structural damage. Such operations and equipment may be housed in a single storey building having appropriate venting facilities and a device to absorb explosion shock from blowing through the duct back to the building.

Appendices

Bangladesh National Building Code 4-67

B3.10 Sometimes it may not be possible to house hazardous operations and equipment outside of the building, in which case the separation from other parts and equipment shall be achieved by pressure resisting walls and such units shall be ventilated outdoors. If suitable vents are integrated, external walls may be of heavy construction or of heavy panel which may be blown off easily.

B3.11 Unobstructed vent opening is the most effective pressure release vent structures. B3.12 Explosion relief vents may be provided with open or unobstructed vents, louvers, roof vents, hanger type

doors, building doors, windows, roof or wall panels or marble/fixed sash. Any or more than one of these may be adopted depending on individual situations and requirements.

B3.13 Roof vents covered with weather hoods shall be as light as possible and attached lightly, so that it is easily blown off as and when an explosion occurs.

B3.14 Doors and windows used as explosion vents shall be so fixed as to open outward. Doors shall be fitted with friction, spring or magnetic, latches that function automatically at the slight increase in internal pressure.

B3.15 Placed at the top or bottom, the hinged or projected movable sash shall be equipped with latch or friction device to prevent accidental opening due to wind action or intrusion. Such latches or locks shall be well maintained.

B3.16 Venting shall be so planned as to prevent injury to inmates and damage to enclosure. In populated locations, substantial ducts or diverts shall be provided to channelize the blast towards a pre-determined direction.

B3.17 If explosion are probable within the duct, they shall be equipped with diaphragm to rupture at predetermined locations. The duct system shall not be physically connected to more than one collector.

B3.18 Skylight with moveable sash that opens outward or fixed sash having panes of glass or plastic that blow out readily under pressure from within can be used to supplement wall vents or windows, provided their resistance to opening or displacement may be kept as low as possible consistent with structural requirement of the building.

B3.19 For equivalent explosion pressure release, larger closed vents will be required compared to open vents. B3.20 As far as possible hazardous areas shall be segregated be means of fire walls or party walls to prevent

spread of fire.

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Part 4 4-69 Fire Protection

Appendix C Selection and Sitting of Fire Detection System

C 1 GENERAL This appendix provides information for selection and sitting of equipment for fire detection in buildings. C 2 CHOICE OF FIRE DETECTORS Fire detectors may respond to any one manifestation of combustions such as heat generation, smoke and

flames. Smoke detectors are not naturally suitable in places where the production process produces smokes. Application of flame detectors are restricted due to the fact that all combustions do not necessarily

accompany flame and that clear line of sight is desirable as radiation from flames travel in straight lines for actuation of sensitive element.

No single detector is able to meet the need of all types of fires and all types of occupancies. As such, based

on needs arising out of various situations and occupancies, judicious selection is extremely important for the reduction of fire hazards.

C 2.1 Heat Detectors "Point" or "Spot" type detectors are actuated by heat at layer adjacent to it over a limited area. "Line" type

detectors are sensitive to the effect produced by heated gas along any portion of the detector line. Both the types operate on two broad principles: one, the heat sensitive elements is actuated by temperature rising beyond a predetermined level; while the second system is actuated by predetermined rate of rise of temperature.

C 2.2 Flame Detectors Flame detectors are sensitive to radiation emitted by flames. Since heat, smoke and flame are produced during a fire, detectors responding to all these are accepted as

general purpose detectors. Fixed temperature heat detectors are suitable for use where ambient temperatures are high and or may rise

and fall rapidly over a short period. C 2.3 Rate of Rise Heat Detectors These are suitable for use where ambient temperatures are low and/or may rise over a wide range slowly.

Abnormally sharp rise in temperature during a fire actuates this alarm. As such it cannot be used with confidence where ambient temperatures reaches in the neighborhood of 40oC, but are best used where ambient temperatures are in the range of about 40oC.

C 2.4 Smoke Detectors Three types of smoke detectors are commonly used. First type is actuated by absorption or scattering of

visible or near-visible light by combustion product and known as "optical detector". The second type is actuated by the production on ionization current within the detector and referred to as "ionization detector". The third type is sensitive to carbon monoxide or other products of combustion and is known as "chemically sensitive detector". In general, these should be used at places where ambient temperature varies between 0o to 35oC.

C 2.4.1 Optical Smoke Detectors

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Invisible smoke from a clear burning shall not actuate such detectors. But they respond quickly where smoke is optically dense and as such suitable for use in dust free clean atmosphere. Over a period of time, due to dust and dirt, the sensitive surface of photo sensitive element and/or executor lamp of optical detectors may loss its efficiency and as such optical detectors should be cleaned and maintained regularly.

C 2.4.2 Ionization Chamber Smoke Detectors

These responds quickly to invisible smoke of clear burning, but may not respond to fire producing dense smoke. These can be used in dust free, humidity controlled area. Smoke and other fumes, dust including slow accumulated and disturbed aerial dust, fiber, steam and condensation produced by normal processes and vehicle engines may cause false alarm. Warehouses exposed to fast air flows can also cause false alarm. Burning of polyvinyl chloride will not sensitize the detector in time and may provide late warning or no warning at all.

C 2.4.3 Chemically Sensitive Smoke Detectors

Chemically coated sensitive elements react to carbon monoxide or other products of combustion present in smoke. Dust or moisture adversely affects the sensitive elements and are not very suitable for residential use.

C 3 SITING OF DETECTORS Considering the prevailing weather condition of the occupancies and the problem of false alarm, the type of

detectors and the area of coverage shall be decided. Area of coverage of detectors is dependent on many factors. The following aspects shall be taken into considerations in the design of detectors.

a. Various forms of overhead heating b. Exhaust air from air cooling equipment blowing out into the room or factory area c. Deep beams d. Roofs and ceiling of unusual shape e. Building with ground areas above 10 m and up to 30 m in height f. Staircases g. Canteen and Restaurants h. Plant Rooms i. Ambulant air currents