Fire Protection in High-rise Buildings

Transcription

1 Fire Protection in High-rise Buildings By: Dante B. Verano 1.0 General Design Approach 1.1 All fire protection and detection systems design and installation shall be in accordance with local Authority Having Jurisdiction (AHJ) by laws, regulations, orders, codes, requirements and to International Standards such as NFPA. 1.2 When a conflict between the various code requirements exist, the most stringent/conservative standard shall apply. 1.3 Occupancy hazard fire control approach in combination with the density/area method is the common method to determine the water demand requirements. 2.0 Building Height Categories Building Categories Height Low - rise Mid - rise High - rise Super high - rise up to 15 meters between 15 meters to 23 meters between 23 meters to 90 meters more than 90 meters 3.0 Occupancy Classification 3.1 Light Hazard The areas and occupancies which and contain low quantity and low combustible materials which are expected to release low heat release rates during fire condition shall be classified as light hazard occupancies. Occupancies considered as light hazard may include: a) Residential - Residential buildings, Apartments, Staff Accommodation b) Assembly, Group B & Group C - Mosques, Churches, museums, amusement parks, Airport Terminal Buildings, Restaurant seating areas, Food court seating areas c) Detention and Correctional Facilities d) Animal Housing, Group A & Group C Pet Shops, Animal market, Zoo e) Industrial Group C metal products fabrication assembly, brick and masonry fabrication, telephone exchanges and GSM switching stations. 3.2 Ordinary Hazard, Group 1 The areas and occupancies which contains medium quantity and moderate combustible materials and the storages up to 2.4 meters which are expected to release moderate heat release rates during fire condition shall be classified as Ordinary Hazard Group-1. Occupancies considered as ordinary hazard are: a) Hotel, Group A & Group B & Group C - Hotels, Hotel Apartments, Dormitories, Motels, Lodging House, Resorts... b) Mercantile, Group A, Group B Department Stores, Supermarkets, Hardware Stores c) Storage, Group C - Parking garages, Frozen food, dairy products d) Industrial, Group B Appliances, Athletic equipment, automobiles, bakeries, boat building a) Assembly, Group A Night Clubs, Banquet Halls, Restaurant with more than 50 people, Pubs, Bars, Theater, Concert Halls, Cinemas

2 3.3 Ordinary Hazard, Group 2 The areas and occupancies which are used for commercial & industrial uses and contain medium quantity and moderate to high combustible materials and the storages up to 3.6 meters which are expected to release moderate heat release rates and the storages up to 2.4 meters which are high heat release rates during fire condition shall be classified as Ordinary Hazard Group-2, such as: a) Animal Housing, Group B - Stables, Animal Sheds, Livestock Shelters and slaughterhouses. b) Malls, Group A Covered Malls c) Industrial, Group B Repair Garages, textile Manufacturing, Printing and Publishing, Wood machining and wood product assembly 3.4 Extra High Hazard, Group 1 The areas and occupancies which are used for industrial uses and contains high quantity and very high combustible material which will support fast development of fire and are expected to release very high heat release rates during fire condition and having less or no combustible or flammable liquid & gases shall be classified as Extra High Hazard Group 1, such as: a) Storage / Industrial, Group B - Storage and activities involving aircraft hanger, leather, linoleum, and motor vehicle repair garages 3.5 Extra High Hazard, Group 2 The areas and occupancies which are used for industrial uses and contain moderate to high quantity of flammable & combustible liquids and gases, which will support rapid growth of fire and expected to release very high heat release rates during fire condition shall be classified as Extra High Hazard Group 2, such as: a) Storage / Industrial, Group A - Storage and activities involving explosives, detonators, pyrophoric materials, fireworks, pyrotechnic material, flammable spraying b) Group B Plastics c) Group C Plastics d) Combustible & Flammable Liquids e) Parking, Group B Robotic and Mechanical Parking f) Commodities 4.0 Fire Protection Systems High-rise building having building height of more than 23m but less than 90m, of any occupancy classification shall be provided with the following fire protection systems; 4.1 Automatic Sprinkler System (AS) Sprinkler shall be provided throughout the building including basements and podium (open as well as closed). 4.2 Wet Riser System (WRS) Class III Hose System shall be provided. The maximum pressure anywhere in the wet riser system shall not exceed 24bars with a fire pump set to cut-off at 140% of the rated operational pressure. When the vertical wet riser system pressure exceeds 12 bar with a fire pump set to cut-off at 140% of the rated operational pressure, or when most remote landing valve is located at a height 45m from the fire pump location, the risers shall be zoned in to High Zone and Low Zone.

3 The wet risers shall be interconnected both at the lowest level and highest level of each zone. When the vertical wet riser system pressure exceeds 24 bars with fire pump set to cut-off at 140% of the rated operational pressure, or when the most remote landing valve is located at a height of 90 meters from the fire pump location, the second set of fire pumps and dedicated water tanks shall be provided to feed such risers from that level. 4.3 Yard Hydrant Systems (YHS) All new developments with Plot Area greater than 20,000 m² shall be provided with private yard hydrant system. 4.4 Auxiliary rooms and various areas of the building shall be protected by other acceptable fire protection systems, such as; Other Fire Protection Systems Fire Hose Reel / Rack System (FHS) Dry Riser System (DRS) Pre-action Sprinkler System (PSS) Water Spray System (WSS) Water Mist System (WMS) Water Deluge System (WDS) Foam Sprinkler System (FSS) Foam Monitor System (FMS) Foam Injection System (FIS) Clean Agent Based Fire Protection System Dry Chemical System (DCS) Wet Chemical System (WCS) Portable Fire Extinguisher (FE) 5.0 Water Demand (Total Demand) The water requirements for a sprinklers building are based on sprinkler system and inside and outside hose streams demands. 5.1 Sprinkler Demand:

4 5.2 Hose Demand: Two (2) numbers of landing valves on top most point of the hydraulically most unfavorable wet riser proving 250gpm flow at 6.9bar (7bar) per outlet and one landing valve outlet on the topmost point of the adjacent wet risers providing 250gpm flow at 7bar outlet. If a horizontal wet riser system provides supply for 3 or more landing valve outlets in a floor, the hydraulic calculation shall be based on 3 numbers of landing valve at remotes point of the hydraulically most unfavorable wet riser pipe providing 250gpm flow at 7bar per outlet and one landing valve outlet at the topmost point of each adjacent wet riser pipes providing 250gpm flow at 7bar per outlet. 5.3 Hydrant Demand: The minimum flowrate for each fire hydrant shall be 500 gallons per minute at 250gom per outlet. Two (2) number of fire hydrants shall be considered for hydraulic demand calculations which is a total flow requirement of 1000gpm per single yard hydrant system. The minimum pressure required for the most remote fire hydrant in the system loop is 6.9bars. 5.4 Combined Fire Water Tank Capacities Without Yard Hydrants shall have a capacity of 60 minutes of operation With Yard Hydrants shall have a capacity of 90 minutes of operation

5 6.0 Fire Pump Sizing Formula: 1) WHP = Q x TDH ) BHP = WHP Ɛff. 3) Motor HP = BHP Ɛff. Where: WHP = Water Horse Power BHP = Brake Horse Power Motor HP = Motor Horse Power Ɛff. = Efficiency Q = Total Water Demand, GPM TDH = Total Dynamic Head, FT 7.0 Reference Code and Standards 7.1 UAE Fire and Life Safety Code of Practice NFPA 1 : Fire Code 7.3 NFPA 13: Standard for Installation of Sprinkler Systems 7.4 NFPA 14: Standard for the Installation of Standpipe and Hose System 7.5 NFPA 5000: Building Construction and Safety Code Ending thoughts; Sharing will enrich everyone with more knowledge. Ana Monnar If you have knowledge, let others light their candles in it. Margaret Fuller A candle loses nothing by lighting another candle. Father James Keller