PAUL HAY Capital Projects
Smoke Management, Fire Suppression & Continued Operation
Author: Paul Hay
profile: www.linkedin.com/in/phcjam
1.0 SMOKE SHOULD BE MANAGED
1.1 Smoke barriers (i.e. curtain boards) are effective in containing smoke in the early stage of a fire.
1.1.1 An alarm system should already be in place.
1.1.2 Fire suppression systems should also be used.
1.2 Dilution is another strategy that can be implemented.
1.2.1 Fire dampers are used to contain the spread of smoke through A/C ducts.
1.2.2 Fire-rated doors are used to contain the spread of smoke through corridors, shafts, and like spaces.
1.2.2.1 Spaces should be compartmentalized.
1.2.2.2 Doors left open for extended periods will not be effective.
1.2.3 Concealed spaces, such as ceiling spaces, can also paths via which smoke spreads.
1.2.3.1 Spaces should be compartmentalized.
1.2.3.2 Fire detection and suppression systems can be installed within them.
1.2.4 During a fire, areas adjacent to the affected zone should be pressurized.
1.2.4.1 VAC systems must be coordinated with smoke control requirements.
1.2.4.2 VAC systems should control smoke by placing positive pressure in exit corridors, stairwells, refuge areas and service shafts.
1.3 Special exhaust systems can be used.
1.3.1 During a fire, air should be exhausted from the affected zone.
1.3.2 On detection of a fire, dampers should close the return air duct and VAC systems should be switched to use only fresh air.
2.0 EXTINGUISHERS MUST SUIT THE FIRE
2.1 Fire extinguishers are available as water-based or non-water based mixtures.
2.1.1 Water damages most contents.
2.1.2 Water conducts electricity; and
2.1.3 Flammable oils float on it and are not extinguished.
2.2 Class A extinguishers use water, water-based, or multipurpose chemical agents.
2.2.1 They are used to extinguish fires to wood, trash, paper and textiles.
2.2.2 Class A extinguishers should be no further than 33 m from a hazard.
2.2.3 Schools, Offices and public buildings are classified as “Light Hazard” occupancy and require a. Class A extinguisher for each 300 m2.
2.2.4 Dry-goods shops and warehouses are classified as “Ordinary Hazard” occupancies requiring a Class A extinguisher for each 150 m2.
2.2.5 Paint shops and like buildings are classified as “Extra Hazard” occupancies and require a Class A extinguisher for each 100 m2.
2.3 Class B extinguishers use smothering or flame-interrupting chemicals.
2.3.1 They use Carbon Dioxide, Sodium and Potassium Bicarbonate dry chemicals, foam or halogenated agents.
2.3.2 These are especially suited for extinguishing flammable liquids.
2.3.3 Class B extinguishers should be no further than 15 m from a hazard.
2.4 Other extinguishers should be no further than 9 m from a hazard.
. 2.4.1 Class C extinguishers use non-electrically-conducting chemicals such as Carbon Dioxide, Sodium and Potassium Bicarbonate dry chemicals, or halogenated agents and are used for fires on or adjacent to electrical equipment.
2.4.2 Class A:B:C is a dry chemical extinguisher using ammonium phosphate agents which, though classified as “multi-purpose”, is not suitable for electrical fires because it leaves a hard residue.
2.4.3 Class D extinguishers use dry powders such as graphite and sodium chloride and is used for combustible metals.
3.0 WATER-BASED SUPPRESSION IS COMMONLY USED.
3.1 Water storage tanks may be provided for fire protection.
3.1.1 Overhead supply is very effective.
3.1.2 Fire storage can also be combined with domestic supply storage to prevent water becoming stale; however
3.1.3 Provision must be made to prevent depletion by domestic use.
3.2 Wet stand-pipes are intended for use of the buildings occupants not the Fire Department.
3.2.1 They.are connected to a water supply system at one end and hose connections at each floor up to the roof.
3.2.2 Risers should provide 200 kPa pressure of water at two outlets for 25 minutes.
3.2.3 Fire hoses are usually located near or adjacent to stairs.
3.2.4 Hoses must be long enough to reach the whole building.
3.2.5 Hoses may be installed in hose cabinets.
3.3 Dry stand-pipes are intended for the use of the Fire Department.
3.3.1 A siamese connection at the street level permits connection of two pumper trucks at the same time.
3.3.2 Hose connections are provided at the first floor level up to the roof.
3.3.3 Electrical fire pumps may be required if the pressure of the public main is insufficient.
3.4 Combination stand-pipes are intended for both the building occupant and the Fire Department.
3.4.1 Siamese connections are provided at the street level;
3.4.2 Stand-pipes are also connected to the water supply system.
3.4.3 Check valves from fire storage tanks close when check valve to the siamese connection opens
3.5 Sprinkler systems are installed to lower temperature
3.5.1 Storage tanks for sprinklers should provide at least 20 minutes of supply to a quarter of the sprinkler heads, until the Fire Department arrives.
3.5.2 Sprinklers consist of a horizontal layout of pipes placed near the ceiling having sprinkler heads at regular intervals throughout.
3.5.3 Sprinkler heads can be (a) upright, (b) pendant or (c) side-wall types.
3.5.4 Ordinary sprinklers have fusible plugs set to open at high temperature.
3.5.4.1 Individual heads are independently activated.
3.5.4.2 Activated heads must be replaced after use;
3.5.4.3 The main valve has to be used to turn them off.
3.5.5 Flow control sprinklers automatically close when temperature reduces.
3.5.6 Sprinkler heads are spaced 3.6 to 4.5 m apart, depending on the occupancy rating for the building.
3.5.7 There are four arrangements used for sprinkler system installations:
3.5.7.1 The wet pipe system is the most common.
3.5.7.2 The dry pipe system is used where there is a risk of water freezing.
3.5.7.3 Pre-action systems admit water before sprinkler heads open; and
3.5.7.4 Deluge systems activate all sprinkler heads simultaneously in areas where there is a risk of flame spreading rapidly, such as airplane hangars.
4.0 NON-WATER BASED SUPPRESSION SYSTEMS ARE AVAILABLE
4.1 Use of non-water-based suppression systems can be hazardous to human occupation.
4.1.1 Oxygen is suppressed with use of foam or dry chemicals that cover the fuel.
4.1.2 Oxygen is displaced with use of Carbon Dioxide and halogenated agents; and
4.1.3 They may cause dizziness in high concentrations
4.2 Carbon Dioxide systems are often used in localized fire hazard areas, such as over stoves.
4.3 Halon systems are expensive and used to protect valuable areas, such as computer rooms, that would be damaged with use of other extinguishing systems.
4.3.1 Halon is a CFC gas stored in cylinders that is more dense than air.
4.3.2 It is more effective at protecting a building’s contents than its structure.
4.3.3 Halon 301 is widely used on special building applications such as Computer Rooms, Museums, Libraries, Telephone Exchanges, and commercial Kitchens.
5.0 CONTINUITY OF OPERATIONS NEEDS TO BE PLANNED
5.1 Special alarm and suppression systems must be installed for critical areas.
5.2 Ventilation systems must be used to purge smoke after a fire and replace it with fresh air, and
5.3 Provision must be made to quickly drain water used by sprinkler systems.
FURTHER READING
Mechanical and Electrical Equipment for Buildings, 8th edition, Benjamin Stein, John S. Reynolds, John Wiley & Sons Inc., USA, 1992
Construction Materials & Processes, Don G. Watson, McGraw Hill Book Co., USA, 1978;
Ramsey/Sleeper Architectural Graphic Standards, A.I.A., Robert T. Packard (ed), John Wiley & Sons Inc., USA, 1981;
Architectural Handbook, Alfred M. Kemper, John Wiley & Sons Inc., USA, 1979
National Building Code of Jamaica, 2nd edition, Ministry of Finance and Planning, 1992.
Thanks for sharing blog i will share it my friends and thanks to give information for PAUL HAY Capital regarding GPS Tracker ProviderFire Alarm/ Smoke Detector in Ahmedabad keep sharing
ReplyDelete