Pressurisation duct work is a passive fire protection system. It is used to supply fresh air to any area of refuge, designated emergency evacuation or egress route.
The purpose of pressurisation ductwork is to maintain positive pressure in critical areas, to prevent smoke penetrating from neighboring areas. It is typically used in protected stairways, corridors, fire fighting shafts and lobbies.
Typically, pressurisation ductwork is subjected to demonstrable product certification on the basis of fire testing (for example, ISO 6944). In the United States, additional hose-stream testing (only for a separate firestop test with only a 30cm or 1' length of duct exposed, is required to achieve product certification.
Pressurisation systems are evaluated for exterior fire exposure. Grease ducts, on the other hand, are evaluated for both interior and exterior fire exposures.
There are two means of providing fire-resistance rated ductwork:
The use of drywall shaft-wall systems has been common for many years. 3-D full scale fire testing (e.g., ISO 6944) resulted in the first certification listing for an inherently fire-resistant duct. Drywall systems were tested as flat walls, but not as a three-dimensional solution surrounding a real duct with four corners. Shaft-wall systems are tested to the same standards as all other fire barriers, such as ASTM E119 and ULC S101.
In Europe, where ISO 6944 originated, rock-wool systems, calcium silicate and sodium silicate bound and pressed vermiculite, as well as the proprietary Durasteel systems, have been in use for decades.
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Heating, ventilation, and air conditioning (HVAC) is the technology of indoor and vehicular environmental comfort. Its goal is to provide thermal comfort and acceptable indoor air quality. HVAC system design is a subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics and heat transfer. "Refrigeration" is sometimes added to the field's abbreviation, as HVAC&R or HVACR or "ventilation" is dropped, as in HACR.
Drywall is a panel made of calcium sulfate dihydrate (gypsum), with or without additives, typically extruded between thick sheets of facer and backer paper, used in the construction of interior walls and ceilings. The plaster is mixed with fiber, plasticizer, foaming agent, and various additives that can reduce mildew, flammability, and water absorption.
A kitchen hood, exhaust hood, or range hood is a device containing a mechanical fan that hangs above the stove or cooktop in the kitchen. It removes airborne grease, combustion products, fumes, smoke, heat, and steam from the air by evacuation of the air and filtration. In commercial kitchens exhaust hoods are often used in combination with fire suppression devices so that fumes from a grease fire are properly vented and the fire is put out quickly. Commercial vent hoods may also be combined with a fresh air fan that draws in exterior air, circulating it with the cooking fumes, which is then drawn out by the hood.
A sound attenuator, or duct silencer, sound trap, or muffler, is a noise control acoustical treatment of Heating Ventilating and Air-Conditioning (HVAC) ductwork designed to reduce transmission of noise through the ductwork, either from equipment into occupied spaces in a building, or between occupied spaces.
Fireproofing is rendering something resistant to fire, or incombustible; or material for use in making anything fire-proof. It is a passive fire protection measure. "Fireproof" or "fireproofing" can be used as a noun, verb or adjective; it may be hyphenated ("fire-proof").
An intumescent is a substance that swells as a result of heat exposure, thus leading to an increase in volume and decrease in density. Intumescents are typically used in passive fire protection and require listing, approval, and compliance in their installed configurations in order to comply with the national building codes and laws.
A fire alarm system warns people when smoke, fire, carbon monoxide or other fire-related emergencies are detected. These alarms may be activated automatically from smoke detectors, and heat detectors or may also be activated via manual fire alarm activation devices such as manual call points or pull stations. Alarms can be either motorized bells or wall mountable sounders or horns. They can also be speaker strobes which sound an alarm, followed by a voice evacuation message which warns people inside the building not to use the elevators. Fire alarm sounders can be set to certain frequencies and different tones including low, medium and high, depending on the country and manufacturer of the device. Most fire alarm systems in Europe sound like a siren with alternating frequencies. Fire alarm electronic devices are known as horns in the United States and Canada, and can be either continuous or set to different codes. Fire alarm warning devices can also be set to different volume levels.
A firestop or fire-stopping is a form of passive fire protection that is used to seal around openings and between joints in a fire-resistance-rated wall or floor assembly. Firestops are designed to maintain the fireproofing of a wall or floor assembly allowing it to impede the spread of fire and smoke.
Passive fire protection (PFP) is an integral component of the components of structural fire protection and fire safety in a building. PFP attempts to contain fires or slow the spread, such as by fire-resistant walls, floors, and doors. PFP systems must comply with the associated listing and approval use and compliance in order to provide the effectiveness expected by building codes.
Circuit integrity refers to the operability of electrical circuits during a fire. It is a form of fire-resistance rating. Circuit integrity is achieved via passive fire protection means, which are subject to stringent listing and approval use and compliance.
Ducts are conduits or passages used in heating, ventilation, and air conditioning (HVAC) to deliver and remove air. The needed airflows include, for example, supply air, return air, and exhaust air. Ducts commonly also deliver ventilation air as part of the supply air. As such, air ducts are one method of ensuring acceptable indoor air quality as well as thermal comfort.
Building insulation materials are the building materials which form the thermal envelope of a building or otherwise reduce heat transfer.
An area of refuge is a location in a building designed to hold occupants during a fire or other emergency, when evacuation may not be safe or possible. Occupants can wait there until rescued or relieved by firefighters. This can apply to the following:
The Dalmarnock fire tests are a series of fire experiments that were conducted in a real high-rise building in the United Kingdom.
Smoke exhaust ductwork, in Europe, is typically protected via passive fire protection means, subject to fire testing and listing and approval use and compliance. It is used to remove smoke from buildings, ships or offshore structures to enable emergency evacuation as well as improved firefighting. In North America, fireproofed ductwork may be used for the purpose of smoke exhaust, but it is more common to use unfireproofed return air ductwork, whereby no fire testing or listings are employed to qualify the ductwork for this use. Evidence of this North American practice can be found in the 2010 National Building Code of Canada, 126.96.36.199. Mechanical Exhaust System, as well as Sections 909.16.2 and 910 of the 2015 International Building Code.
A grease duct is a duct that is specifically designed to vent grease-laden flammable vapors from commercial cooking equipment such as stoves, deep fryers, and woks to the outside of a building or mobile food preparation trailer. Grease ducts are regulated both in terms of their construction and maintenance, forming part of the building's passive fire protection system. The cleaning schedule is typically dictated by fire code or related safety regulations, and evidence of compliance must be kept on file by the owner.
Fire dampers are passive fire protection products used in heating, ventilation, and air conditioning (HVAC) ducts to prevent the spread of fire inside the ductwork through fire-resistance rated walls and floors. Fire/smoke dampers are similar to fire dampers in fire resistance rating, and also prevent the spread of smoke inside the ducts. When a rise in temperature occurs, the fire damper closes, usually activated by a thermal element which melts at temperatures higher than ambient but low enough to indicate the presence of a fire, allowing springs to close the damper blades. Fire dampers can also close following receipt of an electrical signal from a fire alarm system utilising detectors remote from the damper, indicating the sensing of heat or smoke in the building occupied spaces or in the HVAC duct system.
Smoke dampers are passive fire protection products used in air conditioning and ventilation ductwork or installed in physical smoke barriers. This may be done to prevent the spread of smoke from the space of fire origin to other spaces in the same building. A combination of fans and dampers can exhaust smoke from an area while pressurizing the smoke-free areas around the affected area. It may also be used to maintain the required concentration of a fire suppression clean agent in a space, as installed in supply air ducts to restrict the introduction of air into the space, and as installed in return or exhaust air ducts to restrict the depletion of the clean agent from the space. Smoke dampers are usually installed by sheet metal contractors.
Penetrants, or penetrating items, are the mechanical, electrical or structural items that pass through an opening in a wall or floor, such as pipes, electrical conduits, ducting, electrical cables and cable trays, or structural steel beams and columns. When these items pierce a wall or floor assembly, they create a space between the penetrant and the surrounding structure, which can become an avenue for the spread of fire between rooms or floors. Modern building codes generally require a service penetration firestop to seal the openings around penetrants, in order to restore the fire-resistance rating of the parent assembly.
Building airtightness can be defined as the resistance to inward or outward air leakage through unintentional leakage points or areas in the building envelope. This air leakage is driven by differential pressures across the building envelope due to the combined effects of stack, external wind and mechanical ventilation systems.