Pressurisation ductwork
Encyclopedia
Pressurisation ductwork
is a passive fire protection
system
. It is used to supply a steady stream of fresh air to any area of refuge
or designated emergency evacuation
or egress route.
on the basis of fire test
ing (for example, ISO 6944
). In the United States
, additional hose-stream testing is required to achieve product certification, as the system includes not just a section of ductwork tested in a full scale floor furnace, but also a firestop
, which must survive the hose.
Pressurisation systems are evaluated for exterior fire exposure. Grease duct
s, on the other hand, are evaluated for both interior and exterior fire exposures.
Grandfathering
The use of drywall
shaftwall 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 and a three-dimensional solution surrounding a real duct with four corners was never done. Shaftwall systems are tested to the same standards as all other fire barriers, such as ASTM E119 and ULC S101. These standards mandate thermocoupling in the middle of the test assemblies, in each quadrant and joints. However, no thermocouples go at the interface between the test assemblies and the surrounding structure, which is the closest thing to a corner. Wall Interfaces are in fact fireproofed by the test labs before fire testing, a fact worth consideration in permitting corners in on-site configurations.
In Europe
, where ISO 6944 originated, rockwool systems, calcium silicate
and sodium silicate
bound and pressed vermiculite
as well as the proprietary Durasteel systems, have been in use for decades .
Duct (HVAC)
Ducts are used in heating, ventilation, and air conditioning to deliver and remove air. These needed airflows include, for example, supply air, return air, and exhaust air. Ducts also deliver, most commonly as part of the supply air, ventilation air...
is a passive fire protection
Passive fire protection
Passive fire protection is an integral component of the three components of structural fire protection and fire safety in a building. PFP attempts to contain fires or slow the spread, through use of fire-resistant walls, floors, and doors...
system
System
System is a set of interacting or interdependent components forming an integrated whole....
. It is used to supply a steady stream of fresh air to any area of refuge
Area of refuge
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 by firefighters...
or designated emergency evacuation
Emergency evacuation
Emergency evacuation is the immediate and rapid movement of people away from the threat or actual occurrence of a hazard. Examples range from the small scale evacuation of a building due to a bomb threat or fire to the large scale evacuation of a district because of a flood, bombardment or...
or egress route.
Purpose
- To ensure a positive pressurePressurePressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...
environment of clean outside air, free from smokeSmokeSmoke is a collection of airborne solid and liquid particulates and gases emitted when a material undergoes combustion or pyrolysis, together with the quantity of air that is entrained or otherwise mixed into the mass. It is commonly an unwanted by-product of fires , but may also be used for pest...
to enable people to either hold out until rescued or to escape with a minimum of dangerous smoke exposure.
Requirements
Typically, pressurisation ductwork is subject to demonstrable product certificationProduct certification
Product certification or product qualification is the process of verifying that a certain product has passed performance tests and quality assurance tests or qualification requirements stipulated in contracts, regulations, or specifications...
on the basis of fire test
Fire test
A fire test is a means of determining whether or not fire protection products meet minimum performance criteria as set out in a building code or other applicable legislation. Successful tests in laboratories holding national accreditation for testing and certification result in the issuance of a...
ing (for example, ISO 6944
International Organization for Standardization
The International Organization for Standardization , widely known as ISO, is an international standard-setting body composed of representatives from various national standards organizations. Founded on February 23, 1947, the organization promulgates worldwide proprietary, industrial and commercial...
). In the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, additional hose-stream testing is required to achieve product certification, as the system includes not just a section of ductwork tested in a full scale floor furnace, but also a firestop
Firestop
A firestop is a passive fire protection system of various components used to seal openings and joints in fire-resistance rated wall and/or floor assemblies, based on fire testing and certification listings....
, which must survive the hose.
Pressurisation systems are evaluated for exterior fire exposure. Grease duct
Grease duct
A grease duct is a duct that is specifically designed to vent grease-laden vapors from commercial cooking equipment such as stoves, pizza ovens, 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...
s, on the other hand, are evaluated for both interior and exterior fire exposures.
Systems
There are two means of providing fire-resistance rated ductwork:- 1. an inherently fire-resistant duct, or proprietaryPropertyProperty is any physical or intangible entity that is owned by a person or jointly by a group of people or a legal entity like a corporation...
factory assembled chimney pipes, which tend to be made of sheet metalSheet metalSheet metal is simply metal formed into thin and flat pieces. It is one of the fundamental forms used in metalworking, and can be cut and bent into a variety of different shapes. Countless everyday objects are constructed of the material...
shells filled with mixtures of rockwool, or ceramic fibre and silicon dioxideSilicon dioxideThe chemical compound silicon dioxide, also known as silica , is an oxide of silicon with the chemical formula '. It has been known for its hardness since antiquity...
- or
- 2. ordinary ductwork equipped with exterior fireproofingFireproofingFireproofing, a passive fire protection measure, refers to the act of making materials or structures more resistant to fire, or to those materials themselves, or the act of applying such materials. Applying a certification listed fireproofing system to certain structures allows these to have a...
materials, such as blanket rockwool, ceramic fibre or intumescentIntumescentAn intumescent is a substance which swells as a result of heat exposure, thus increasing in volume, and decreasing in density. Intumescents are typically used in passive fire protection and, in America, require listing and approval use and compliance in their installed configurations in order to...
paintPaintPaint is any liquid, liquefiable, or mastic composition which after application to a substrate in a thin layer is converted to an opaque solid film. One may also consider the digital mimicry thereof...
.
GrandfatheringGrandfather clauseGrandfather clause is a legal term used to describe a situation in which an old rule continues to apply to some existing situations, while a new rule will apply to all future situations. It is often used as a verb: to grandfather means to grant such an exemption...
The use of drywallDrywall
Drywall, also known as plasterboard, wallboard or gypsum board is a panel made of gypsum plaster pressed between two thick sheets of paper...
shaftwall 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 and a three-dimensional solution surrounding a real duct with four corners was never done. Shaftwall systems are tested to the same standards as all other fire barriers, such as ASTM E119 and ULC S101. These standards mandate thermocoupling in the middle of the test assemblies, in each quadrant and joints. However, no thermocouples go at the interface between the test assemblies and the surrounding structure, which is the closest thing to a corner. Wall Interfaces are in fact fireproofed by the test labs before fire testing, a fact worth consideration in permitting corners in on-site configurations.
In Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
, where ISO 6944 originated, rockwool systems, calcium silicate
Calcium silicate
Calcium silicate is the chemical compound Ca2SiO4, also known as calcium orthosilicate and sometimes formulated 2CaO.SiO2. It is one of group of compounds obtained by reacting calcium oxide and silica in various ratios e.g. 3CaO.SiO2, Ca3SiO5; 2CaO.SiO2, Ca2SiO4; 3CaO.2SiO2, Ca3Si2O7 and...
and sodium silicate
Sodium silicate
Sodium silicate is the common name for a compound sodium metasilicate, Na2SiO3, also known as water glass or liquid glass. It is available in aqueous solution and in solid form and is used in cements, passive fire protection, refractories, textile and lumber processing, and automobiles...
bound and pressed vermiculite
Vermiculite
Vermiculite is a natural mineral that expands with the application of heat. The expansion process is called exfoliation and it is routinely accomplished in purpose-designed commercial furnaces. Vermiculite is formed by weathering or hydrothermal alteration of biotite or phlogopite...
as well as the proprietary Durasteel systems, have been in use for decades .
See also
- Heat and smoke ventHeat and smoke ventHeat and Smoke Vents are installed in buildings as an active fire protection measure. They are openings in the roof which are intended to vent the heat and smoke developed by a fire inside the building by the action of buoyancy, such that they are known as "gravity vents".-Regulatory...
- Fire protectionFire protectionFire protection is the study and practice of mitigating the unwanted effects of fires. It involves the study of the behaviour, compartmentalisation, suppression and investigation of fire and its related emergencies, as well as the research and development, production, testing and application of...
- Passive fire protectionPassive fire protectionPassive fire protection is an integral component of the three components of structural fire protection and fire safety in a building. PFP attempts to contain fires or slow the spread, through use of fire-resistant walls, floors, and doors...
- Duct (HVAC)Duct (HVAC)Ducts are used in heating, ventilation, and air conditioning to deliver and remove air. These needed airflows include, for example, supply air, return air, and exhaust air. Ducts also deliver, most commonly as part of the supply air, ventilation air...
- Smoke exhaust ductworkSmoke exhaust ductworkSmoke Exhaust Ductwork 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.-Means of...
- Grease ductGrease ductA grease duct is a duct that is specifically designed to vent grease-laden vapors from commercial cooking equipment such as stoves, pizza ovens, 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...
- Emergency evacuationEmergency evacuationEmergency evacuation is the immediate and rapid movement of people away from the threat or actual occurrence of a hazard. Examples range from the small scale evacuation of a building due to a bomb threat or fire to the large scale evacuation of a district because of a flood, bombardment or...
- Area of refugeArea of refugeAn 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 by firefighters...
- FireproofingFireproofingFireproofing, a passive fire protection measure, refers to the act of making materials or structures more resistant to fire, or to those materials themselves, or the act of applying such materials. Applying a certification listed fireproofing system to certain structures allows these to have a...
- FirestopFirestopA firestop is a passive fire protection system of various components used to seal openings and joints in fire-resistance rated wall and/or floor assemblies, based on fire testing and certification listings....
- Underwriters LaboratoriesUnderwriters LaboratoriesUnderwriters Laboratories Inc. is an independent product safety certification organization. Established in 1894, the company has its headquarters in Northbrook, Illinois. UL develops standards and test procedures for products, materials, components, assemblies, tools and equipment, chiefly dealing...