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IAED 204. Spring 20 13-2014. Construction and Materials II. WEEK 14. Principles of Fire Safety Design for Fire Safety Fire Suppression. PRINCIPLES OF FIRE SAFETY. Combustion For a fire to exist, you need three things: fuel, oxygen, and high temperatures.
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IAED 204 Spring 2013-2014 Construction and Materials II
WEEK 14 Principles of Fire Safety Design for Fire Safety Fire Suppression
PRINCIPLES OF FIRE SAFETY • Combustion • For a fire to exist, you need three things: fuel, oxygen, and high temperatures. • The fire consumes fuel and oxygen as it burns, and gives off gases, particles, and large qualities of heat.
PRINCIPLES OF FIRE SAFETY • Oxidation is a process in which molecules of fuel are combined with moleculaes of oxygen. The result is a mixture of gases and the release of energy. • Oxidation is how our bodies turn food into energy. • Rust is the oxidation of iron. • However, the process of combustion involves a chemical change that releases energy as heat and light. When oxygen mixes with a combustible substance rapidly and continually, you have a fire. Smoke is produced when incompletely burned particles are suspended in the air. • There are variety of ways to ignite a fire: chemical combustion, electrical fire, ligtning, etc.
PRINCIPLES OF FIRE SAFETY • Prevent fire from starting • Limiting one element of the triangle (fuel, oxygen, or high temperature) • Fire suppression systems can work by covering the fuel or by displacing the oxygen with another gas, thus limiting the supply of oxygen. High temperatures can be controlled by cold water from sprinkler systems. • However, the primary way that we strive to prevent and control fire in a building is by controlling the fuel: the building’s structure and contents. Building codes and zoning ordinances regulate the combustibility of materials in different areas of a city, and also the conditions for storage of flammable and explosive substances in or near buildings. Heating devices, chimneys, electrical systems, electrical devices, and hazardous industrial processes are controlled especially.
PRINCIPLES OF FIRE SAFETY • Products of Combustion • The thermal products of a fire are flame and heat, and people exposed to them are subject to burns, shock, dehydration, heat exhaustion, and the blocking of the respiratory tract (Carbon dioxide, hydrogen sulfide, sulfur dioxide, ammonia, oxides and nitrogen, cyanide, and phosgene). • Specially, plastic materials found in furniture, carpet, draperies, wall coverings, plumbing systems, electrical wiring and other products and equipments cause many gases (PVC produces over 60 gases) in combustion.
PRINCIPLES OF FIRE SAFETY • Fire Safety Codes • As an interior designer, you can face occasions when you have to check the building codes for fire safety requirements. • International Building Code (IBC) • Codes govern how spaces are planned and how materials are used. They dictate the location and number of fire alarms and exit signs. Sprinkler system requirements affect the layout of ceiling designs and lighting.
DESIGN FOR FIRE SAFETY • Fire protection requires the coordination of the architecture and interiors, the mechanical, electrical, and plumbing systems, and the signal system. • The best design for fire safety is also good design for lighting, thermal, acoustic, and water systems. • Most thermally massive massive materials don’t burn easily, and thermal mass also benefits passive heating and cooling, and acoustic isolation. • High ceilings allow large quantities of smoke to collect before reaching the occupant’s level and allow smoke and flames to be seen from a greater indoor distance. High ceilings also aid daylight distribution and ventilation. • Windows provide firefighting and rescue access and escape routes and dilute soke with fresh air. They also offer daylight, ventilation, and view.
DESIGN FOR FIRE SAFETY • Solid, noncombustible overhangs above windows that • discourage the vertical spread of fire over the building face can serve as an emergency exterior refuge and also double as sun shading. • Fire safety concerns can conflict with other building design issues, however. • High ceilings and low partitions in spaces without sprinklers can allow fire and smoke to spread. • Fire builds up faster in small, enclosed rooms that retain heat. • Buildings without operable windows or with sunscreens covering windows block access by firefighters and escape by occupants. • Broken windows can fall and hit people below.
DESIGN FOR FIRE SAFETY • Creating a safe building starts with the design of fire-resistant exterior walls. How close a building is to its neighbours governs both the types of building materials and the extent and treatment of windows and doors. • Protecting the structure
DESIGN FOR FIRE SAFETY • Compartmentation and Fire Barriers • This compartmentatiton prevents the spread of fire, smoke, and heat beyond a restricted area of the building. • Larger areas must be subdivided with fire-rated walls and doors.
DESIGN FOR FIRE SAFETY • In one-story factories and warehouses where firewalls are not practical, incombustible curtain boards are hung from the roof to catch and contain rising hot gases.
DESIGN FOR FIRE SAFETY • Areas of Refuge • Refuge areas are provided in high rise buildings. In large buildings, not everyone (specially wheelchairs) can evacuate in time, and refuge areas provide a place to wait that is protected from smoke. • Ideally, refuge areas should remain free of smoke, gases, heat, and fire throughout the fire and until rescue. The structure and essential sevices in refuge areas are intended to be maintained at all times, but these goals are almost impossible to achieve in practice.
DESIGN FOR FIRE SAFETY • Horizontal Exits • A horizontal exit does not lead to the exterior of the building. Instead, it provides a protected exit to a safe area of refuge in another part of the building or an adjoining building without a change in level. The horizontal exit uses fire-rated walls and doors to subdivid a building into separate areas, which are then treated as separate buildings.
DESIGN FOR FIRE SAFETY • Vertical Openings • Because the vertical spread of a fire through a building is the biggest problem, compartmentation requirements around vertical openings tend to be especially strict in order to prevent the convection of fire and combustion products through the building. (open shafts)
DESIGN FOR FIRE SAFETY • Vertical Openings • Atrium however must be provided with fans with dampers that open and turn on automatically to bring fresh air and exhaust smoke at ceiling level.
DESIGN FOR FIRE SAFETY • Construction Assemblies • Fire rated assemblies are given by codes in constructions. • -Doors :Door closers are hydraulic or pneumatic devices that automatically close doors quickly but quietly.
DESIGN FOR FIRE SAFETY • Construction Assemblies • -Windows :Building codes regulate the clear opening of any operable window that serves as an emergency exit for a residential sleeping space. • -Stairs: The design of stairs is strictly regulated by building codes.
ESCAPE ROUTES FOR FIRE SAFETY • In order to design safe exits from a building, we must first create safe exit paths. • Interior designer must plan the means of egress carefully on interior projects and coordinate the means of egress requirements with fire and smoke separation requirements. Once a building occupant enters the protected portion of a means of egress, the level of protection can’t be reduced or eliminated unless the code authorities allow an exemption.
ESCAPE ROUTES FOR FIRE SAFETY • For residential buildings, the One and Two Family Dwelling Code requires a minimum of one regulated exterior exit door per residence 92 by 203 cm, with a specified type of landing on each side. Minimum widths are specified for hallways and exit accesses. Most homes rely on exterior windows as a means of egress and codes restrict the size, height and operation of windows used as exits. Stairs and ramps are also regulated, but not as strictly as in the model building codes for commercial buildings. Smaller tread and riser sizes are allowed, and a single handrail is permitted. • In a low rise building, the primary goal is to evacuate all occupants in time between the detection of the fire and the arrival of the firefighters.
ESCAPE ROUTES FOR FIRE SAFETY • Occupant Loads: Building codes use the occupant load to establish the required number and width of exits for a building. The occupant load determines the maximum number of people allowed in a specific occupancy at any one time. • The minimum total egress widths for all the exits from that floor added together. To determine the minimum total egress width for a floor, you first calculate the net or gross floor area by the occupant load factor (assigned by the code as a predetermined amount of space required per occupant within specific occupancies ans building uses). This gives you the number of occupants per floor. Then check the code to get the number of inches of egress width requires for each occupant of the floor. Multiply this number by number of occupants, then divide to egress amount you plan to have from the floor. End up with exact minimum number & sizes.
ESCAPE ROUTES FOR FIRE SAFETY • Other important issues are • Exits • Exit Stairs • Exit Passageways • Exit discharges and Exit Signs
LIMITING FUELS • The Life Safety Code has a table for finish materials, for requirements of fire safety as limiting combustible materials. • Noncombustible building materials are composed of steel, iron, concrete, adn masonry. • Combustible materials will ignite and continue to burn when a flame source is removed. Wood can be chemically treated for some fire resistance. It is then called fire-retardant treated wood (FRTW). • Flame-resistant or fire-resistant materials include gypsum wallboard, gypsum concrete, plaster and mineral fiber products. • Fire-rated means that a product has been tested to obtain an hourly fire rating. The Interior designer should ask suppliers how materials have performed in real fire. Modern polymer materials i.e. can have good fire-retardance yet have high toxicity and smoke.
LIMITING FUELS Using Materials Safely Finish Classes and Test Ratings Vertical Treatments Upholstered Furniture Testing of Nontested Finishes are main issues which need to be concerned and treated by the interior designer. If manufacturer did not tested the material for rating of codes, the interior designer should make it tested before using it according to fire safety.
FIRE SUPPRESSION • Everbody knows that water will put out a fire. Water cools, smothers, emulsifies, and dilutes the fire, but it also damages building contents, and can conduct electricitywhen used as a stream. • Automatic sprinkler systems extinguish ancipient fires before they have a chance to get out of control. The sprinkler system consists of a network of pipes in or below the ceiling. The pipes are connected to a water supply and have valves or sprinkler heads that are made to open automatically at a certain temperature. • Building Codes commonly allow sprinklered buildings to have greater distances between exits, eliminating one or more stairways in a large building. By allowing allowing larger floor areas between fire separations.
FIRE SUPPRESSION • A light hazard occupancy is required to have one sprinkler head per 18.6 m² with maximum 4.6 m in between supply lines. (apartment, hospital, church, library, office, restaurant, school, theater) • Interior designer should work closely with the sprinkler system designer to verify sprinkler head locations and provide adequate clearance at each sprinkler. 46 cm should be left below the sprinkler and must be checked by interior designer.
FIRE SUPPRESSION Sprinkler System Components:
FIRE SUPPRESSION Sprinkler System Components:
FIRE SUPPRESSION Sprinkler System Components:
FIRE SUPPRESSION Sprinkler System Components:
FIRE DETECTION & ALARMS • A fire progresses through four stages: • Incipient : Just starting • Smoldering: Burning starting from inside • Flame: Where flames are seen • Heat: Excess heat coming out