Applied Building Services Lecture 4 PDF

Applied Building Services Dr. Ahmed Hassan 1  Lecture 4 Fire Fighting Systems 2  Fire fighting systems Fire Alarm Fire Fighting Systems Systems...

Applied Building Services Dr. Ahmed Hassan 1  Lecture 4 Fire Fighting Systems 2  Fire fighting systems Fire Alarm Fire Fighting Systems Systems 3  Fire Alarm Systems Divides the building into zones. Each zone has multiple detectors wired to a central control panel. When an alarm is triggered, it only identifies the affected zone, not the exact location. Types of Detectors Smoke Detectors Heat Detectors 4  Fire Alarm Systems Types of detectors - Smoke Detectors: Smoke alarms detect fires by sensing small particles in the air. Ionization Smoke Detectors: They have a small amount of radioactive material between two electrically charged plates, which ionizes the air and causes current to flow between the plates. When smoke enters the chamber, it disrupts the flow of ions, thus reducing the flow of current and activating the alarm. They are generally more responsive to flaming fires. Photoelectric (Optical) Smoke Detectors: They aim a light source into a sensing chamber at an angle away from the sensor. Smoke enters the chamber, reflecting light onto the light sensor; triggering the alarm. Ideal for detecting slow, smoldering fires. 5  Fire Alarm Systems Types of detectors Heat Detectors: A device used to detect any significant increase in temperature that might indicate an imminent fire. Fixed Temperature Heat Detectors: Trigger an alarm when the temperature reaches a predetermined threshold. Rate-of-Rise Heat Detectors: Detect rapid increases in temperature. Good for areas with temperature fluctuations where smoke detection might not be suitable, like kitchens or garages. 6  Fire fighting systems A firefighting system is probably the most important and often the mandatory building service aimed to protect human life and property, strictly in that order. It consists of three basic parts: A large store of water A specialized pumping system A large network of pipes connected to hydrants and/or sprinklers. 7  Codes and Standards Codes specify circumstances WHEN and WHERE a given type of protection is required. Codes are MINIMUM requirements; they can and are encouraged to be exceeded. Examples of Codes: NFPA 30 Flammable and Combustible Liquids Code. NFPA 54 National Fuel Gas Code. NFPA 70 National Electrical Code. NFPA 101 Life Safety Code. NFPA 5000 Building Construction and Safety Code. IBC International Building Codes. 8  Codes and Standards Standards detail HOW the protection required by the code is to be achieved. Examples of Standards: NFPA 10 Standard for Portable Fire Extinguishers NFPA 13 Standard for the Installation of Sprinkler Systems NFPA 14 Standard for the Installation of Standpipes and Hose Systems NFPA 20 Standard for the Installation of Stationary Pumps for Fire Protection NFPA 72 National Fire Alarm Code (This is actually a standard even though it is called a code) NFPA 72 will explain how a fire alarm system is supposed to be installed. It does not determine what type of equipment such as smoke detectors, pull stations, horns, strobes, etc. should be used. That is determined by the adopted building code. 9 Codes and Standards 10  Fire Triangle Enough OXYGEN to sustain combustion Enough HEAT to reach ignition temperature Some FUEL or combustible material Together, they produce the CHEMICAL REACTION that is fire 11  Fire Triangle Take away any of these things and the fire will be extinguished 12  Facts about fire – Fire is FAST! – Fire is HOT! – Fire is DARK! – Fire is DEADLY! 13 Classes of Fire 14  Classes of Fire Class A: House fires involving furniture, books, paper, or trees. Extinguishing Method: Typically, water or foam is used to cool the fire by removing heat. 15  Classes of Fire Class B: Gasoline spills, oil fires in a kitchen, or gas cylinder fires. Extinguishing Method: Foam, dry chemical, or carbon dioxide (CO₂) extinguishers are used to smother the fire by cutting off oxygen or disrupting the chemical reaction in the fire. 16  Classes of Fire Class C: Fires in electrical panels, faulty wiring, or fires started by short-circuits in household appliances. Extinguishing Method: Non-conductive extinguishing agents such as CO₂ or dry chemical extinguishers are used to avoid conducting electricity. Water should not be used. 17  Classes of Fire Class D They are typically encountered in laboratories, manufacturing plants, or industries that handle or work with reactive metals. These metals can ignite when exposed to air or moisture Extinguishing Method: Require specialized extinguishing agents, such as dry powder extinguishers. 18 Classes of Fire 19  Extinguishing Systems Fire extinguishing systems can be classified based on the type of extinguishing agent. Water-Based Foam-Based Gas-Based CO₂ Systems (Carbon Dioxide). Sprinkler Systems Inert Gas Systems (e.g., Nitrogen, Argon) Wet mist systems Clean Agent Systems (e.g., FM-200, Novec 1230). Wet Chemical-Based Dry Chemical-Based 20  Extinguishing Systems Extinguishing Medium Water Gases / Chemical Manual Fire Automatic Manual Fire Automatic Hoses Sprinklers Extinguishers CO2 System Automatic Fire Automatic Water Mist Foam Extinguishers FM200 System 21  Extinguishing Systems Activation method Manual Automatic Manual Fire Manual Fire Automatic Automatic Hoses Extinguishers Sprinklers CO2 System Automatic Fire Automatic Extinguishers FM200 System 22  Manual Extinguishing systems Manual Fire Extinguishers Three Types: 1. Water (APW) 2. Carbon Dioxide (CO2) 3. Dry Chemical (ABC, BC, DC) 23  Manual Extinguishing systems Manual Fire Extinguishers - Water (APW) Class A fires only. 2.5 gal. water (up to 1 min discharge time). Pressure gage is to allow visual capacity check. 30-40 ft maximum effective range. Can be started and stopped as necessary. Extinguishes by cooling burning materials below the ignition point. 24  Manual Extinguishing systems Manual Fire Extinguishers – CO2 Class B or class C fires. 2.5 to 100 Ib. of CO2 (8 to 30 seconds discharge time). Has no pressure gage, capacity verified by weight. 3-8 ft maximum effective range. Extinguishes by smothering burning materials. Effectiveness decreases as temperature of burning materials increases. 25  Manual Extinguishing systems Manual Fire Extinguishers – Dry Chemicals Class A, B or class C fires. 2.5 to 20 Ib. of dry chemicals (ammonium phosphate) (8 to 25 seconds discharge time). Has pressure gage to allow visual capacity check. 5 – 20 ft maximum effective range. Extinguishes by smothering burning materials. 26  Automatic Extinguishing Systems Automatic CO2 and FM200 FM-200 is a clean, fast-acting fire suppression agent used primarily for protecting sensitive environments from fire. Data centers. Laboratories. 27  Automatic Extinguishing Systems Automatic CO2 and FM200 28 Automatic Extinguishing Systems Panel board Fire 29  Automatic Extinguishing Systems Automatic CO2 and FM200 Typical components of the system: 1. Discharge nozzles. 2. Piping. 3. Control panel. 4. Discharge or warning alarms. 5. Hazard warning or caution signs. 6. Automatic fire detection devices. 7. Manual discharge station. 8. Storage containers. 30  Water Extinguishing Systems Water Extinguishing Systems: Most building codes require a dedicated “on-site” water storage tank, fire pump, and suppression system for large public buildings and commercial offices. 31  Water Extinguishing Systems Water Extinguishing Systems - Water Storage Tanks: The amount (volume) of water is determined by the hazard level of the building. Most building codes specify three levels, namely: ▪ Light Hazard (such as schools, residential buildings and offices) ▪ Ordinary Hazard (such as most factories and warehouses) ▪ High Hazard (places which store or use flammable materials like foam factories, aircraft hangars, paint factories, fireworks factories). The storage capacity is determined by duration of an expected incident in terms of time multiplied by the required water flow demand or pumping capacity. For example, if the fire water demand is 1500 GPM, the useable fire water storage volume for 1 hour shall be 1500 x 60 minutes = 90,000 gallons). 32  Water Extinguishing Systems Water Extinguishing Systems – Fire Pumps: Fire pumps are used to boost water pressure to sprinkler and standpipe systems. A fire pump may be driven by an electric motor or a diesel engine. Fire pumps are usually housed in a pump room very close to the fire tanks. 33  Water Extinguishing Systems Water Extinguishing Systems – Suppression systems: Firefighting systems and equipment vary depending on the age, size, use and type of building construction. A building may contain some or all of the following features: Fire extinguishers. Fire hydrant systems. Fire hose reels/standpipe systems. Automatic sprinkler systems. 34  Water Extinguishing Systems Fire Hydrant Located in streets around the buildings. One outlet Diameter 4” + two outlets 2.5”. Made from cast iron. Used for fire brigade fighters. Separating distance 70-80 m. Sometimes, a box including hose is located beside the hydrant. Could be installed on city main or fire network. 35  Water Extinguishing Systems Fire Hose Reel Cabinet with door made of 1.2 mm electro-galvanized steel sheet. Cabinet to accommodate Hose reel with 1” diameter x 30 m length hose or 3/4“ x 30 m hose. Cabinet and Hose Reel painted with red electrostatic powder coating. Recessed type door lock & handle with chrome plating. Plastic nozzle with jet/spray/shut - off. Used for normal residents. Design pressure is 65 psi (4.5 bars). A fire extinguisher might be included inside the cabinet. A pressure reducing station must be used in case of pressures exceeding 100 psi (6.8 bars). 36