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Fireproofing is rendering something ( structures, materials, etc.) 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"). Applying a certification listed fireproofing system to certain structures allows them to have a fire-resistance rating. The term "fireproofing" may be used in conjunction with standards, as reflected in common North American construction specifications. An item classed as fireproof is resistant in specified circumstances, and may burn or be rendered inoperable by fire exceeding the intensity or duration that it is designed to withstand.


Markets

* Commercial construction * Residential construction * Industrial construction * Marine ( ships) * Offshore construction * Aerodynamics * Tunnel concrete walls and ceilings or linings * Under- and above-ground mining operations


Applications

*
Structural steel Structural steel is a category of steel used for making construction materials in a variety of shapes. Many structural steel shapes take the form of an elongated beam having a profile of a specific cross section. Structural steel shapes, sizes, ...
to keep below critical temperature ca. 540 °C * Electrical circuits to keep critical electrical circuits below 140 °C so they stay operational * Liquified petroleum gas containers to prevent a
BLEVE A boiling liquid expanding vapor explosion (BLEVE, ) is an explosion caused by the rupture of a vessel containing a pressurized liquid that has reached temperature above its boiling point. Because the boiling point of a liquid rises with p ...
(boiling liquid expanding vapour explosion) * Vessel skirts and pipe bridges in an oil refinery or
chemical plant A chemical plant is an industrial process plant that manufactures (or otherwise processes) chemicals, usually on a large scale. The general objective of a chemical plant is to create new material wealth via the chemical or biological transform ...
to keep the
structural steel Structural steel is a category of steel used for making construction materials in a variety of shapes. Many structural steel shapes take the form of an elongated beam having a profile of a specific cross section. Structural steel shapes, sizes, ...
below critical temperature ca. 540° * Concrete linings of traffic tunnels * Fireblocking: In a wood frame construction, gaps are created by joists or studs in floor or wall partitions. These hollow spaces allow fire to travel easily from one area to another. Fireblocks are installed internally to divide these areas into smaller intervals. Common materials used include solid lumber,
plywood Plywood is a material manufactured from thin layers or "plies" of wood veneer that are glued together with adjacent layers having their wood grain rotated up to 90 degrees to one another. It is an engineered wood from the family of manufactured ...
, OSB, Particle board, gypsum board, cement fiberboard, or glass fiber insulation batts. *
Firewall (construction) A firewall is a fire-resistant barrier used to prevent the spread of fire. Firewalls are built between or through buildings, structures, or electrical substation transformers, or within an aircraft or vehicle. Applications Firewalls can be us ...
is a common method employed to separate a building into small units to restrict or delay the spread of fire from one section to the next. Fire walls usually extend the full length of a building, from foundation to roof. * Fire barriers and fire partitions: They are similar to fire walls in operation; however, their height is limited to a single floor, from the slab of one floor to the underside of the next. * Coatings, e.g. to fireproof wood.


History

Asbestos Asbestos () is a naturally occurring fibrous silicate mineral. There are six types, all of which are composed of long and thin fibrous crystals, each fibre being composed of many microscopic "fibrils" that can be released into the atmosphere b ...
was one material historically used for fireproofing, either on its own, or together with binders such as cement, either in sprayed form or in pressed sheets, or as additives to a variety of materials and products, including fabrics for protective clothing and building materials. Because the material was later proven to cause cancer, a large removal-and-replacement industry has been established. Endothermic materials have also been used to a large extent and are still in use today, such as gypsum, concrete and other cementitious products. More highly evolved versions of these are used in aerodynamics,
intercontinental ballistic missile An intercontinental ballistic missile (ICBM) is a ballistic missile with a range greater than , primarily designed for nuclear weapons delivery (delivering one or more thermonuclear warheads). Conventional, chemical, and biological weapons c ...
s (ICBMs) and re-entry vehicles, such as the Space Shuttles. The use of these older materials has been standardised in "old" systems, such as those listed in BS476, DIN4102 and the National Building Code of Canada.


Fireproofing of structural steel

In a building fire,
structural steel Structural steel is a category of steel used for making construction materials in a variety of shapes. Many structural steel shapes take the form of an elongated beam having a profile of a specific cross section. Structural steel shapes, sizes, ...
loses strength as the temperature increases. In order to maintain the structural integrity of the steel frame, several fireproofing measurements are taken: * restrictions on the amount of exposed steel set by building codes.Allen 2009, p. 459 * encasing structural steel in
brick A brick is a type of block used to build walls, pavements and other elements in masonry construction. Properly, the term ''brick'' denotes a block composed of dried clay, but is now also used informally to denote other chemically cured cons ...
masonry or concrete to delay exposure to high temperatures. Historically, these masonry encasement methods use large amounts of heavy materials, thus greatly increasing the load to the steel frame. Newer materials and methods have been developed to resolve this issue. The following lists both older and newer methods of fireproofing steel beams ( i-beams): * complete encasement in concrete square column.Allen 2009, p. 460 - 463 * wrapping the i-beam in a thin layer of metal lath and then covering it with gypsum plaster. This method is effective because gypsum plaster contains water crystals that are heat resistant. * applying multiple layers of gypsum board around the i-beam. * applying spray-on fireproofing around the i-beam. Also called spray-applied fire-resistive materials (SFRM) using air pressured spray gun, which can be made from gypsum plaster, mineral fibers mixed with inorganic binder or a cementitious formula using magnesium oxychloride cement. * enclosing the i-beam in sheet metal and fill with loose insulation. * hollow columns filled with liquid water or antifreeze. When part of the column is exposed to fire, the heat is dissipated throughout by the convection property of the liquid. * encasing the i-beam in rigid concrete slab. * a layer of suspended plaster ceiling isolating the i-beam


Alternative methods

Among the conventional materials, purpose-designed spray fireproofing plasters have become abundantly available the world over. The inorganic methods include: * Gypsum plasters * Cementitious plasters * Fibrous plasters The industry considers gypsum-based plasters to be "cementitious", even though these contain no
Portland Portland most commonly refers to: * Portland, Oregon, the largest city in the state of Oregon, in the Pacific Northwest region of the United States * Portland, Maine, the largest city in the state of Maine, in the New England region of the northeas ...
, or
calcium aluminate Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...
cements. Cementitious plasters that contain Portland cement have been traditionally lightened by the use of inorganic lightweight aggregates, such as vermiculite and perlite. Gypsum plasters have been lightened by using chemical additives to create bubbles that displace solids, thus reducing the bulk density. Also, lightweight
polystyrene Polystyrene (PS) is a synthetic polymer made from monomers of the aromatic hydrocarbon styrene. Polystyrene can be solid or foamed. General-purpose polystyrene is clear, hard, and brittle. It is an inexpensive resin per unit weight. It is a ...
beads have been mixed into the plasters at the factory in an effort to reduce the density, which generally results in a more effective insulation at a lower cost. The resulting plaster has qualified to the A2 combustibility rating as per DIN4102. Fibrous plasters, containing either mineral wool, or ceramic fibres tend to simply entrain more air, thus displacing the heavy fibres. On-site cost reduction efforts, at times purposely contravening the requirements of the
certification listing A certification listing is a document used to guide installations of certified products, against which a field installation is compared to make sure that it complies with a regulation (e.g., a building code). Typically, products or items are requ ...
, can further enhance such displacement of solids. This has resulted in architects' specifying the use of on-site testing of proper densities to ensure the products installed meet the certification listings employed for each installed configuration, because excessively light inorganic fireproofing does not provide adequate protection and, thus, could be in violation of the listings. Proprietary boards and sheets, made of gypsum,
calcium silicate Calcium silicate is the chemical compound Ca2SiO4, also known as calcium orthosilicate and is sometimes formulated as 2CaO·SiO2. It is also referred to by the shortened trade name Cal-Sil or Calsil. It occurs naturally as the mineral larnite. ...
, vermiculite, perlite, mechanically-bonded composite boards made of punched sheet-metal and cellulose-reinforced concrete have all been used to clad items for increased fire resistance. An alternative method to keep building steel below its softening temperature is to use liquid convection cooling in hollow structural members. This method was patented in the 19th century although the first prominent example was 89 years later.


Substandard

Money can be saved fraudulently by using apparently suitable fireproofing that is not built to the required standard. Such fraud can be prevented when documentation is required and checked to ensure that all installed configurations meet the certification standards. Possible cases include: * Entraining too much air in inorganic systems, thus reducing densities below fire-tested, saving on materials and labour. * Spraying inorganic fireproofing materials over through-penetrations and building joints that should be firestopped, not ''fireproofed''. This practice negates fire-separation integrity. Firestops must precede spray fireproofing. * Substitution of intumescent and/or endothermic fireproofing coatings by less expensive paints of similar appearance, sometimes in the packaging of the correct materials. * The American and Canadian nuclear industries have, historically, not insisted on listing and approval use and compliance, on the basis of the use of accredited certification laboratories. This has allowed the use of Thermo-Lag 330-1, for which the basis of testing has been proven to be faulty, requiring millions of dollars of remedial work. The Thermo-Lag scandal came to light as a result of disclosures by
American American(s) may refer to: * American, something of, from, or related to the United States of America, commonly known as the "United States" or "America" ** Americans, citizens and nationals of the United States of America ** American ancestry, pe ...
whistleblower Gerald W. Brown, who reported the deficiencies in
fire test A fire test is a means of determining whether 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 ...
ing to the
Nuclear Regulatory Commission The Nuclear Regulatory Commission (NRC) is an independent agency of the United States government tasked with protecting public health and safety related to nuclear energy. Established by the Energy Reorganization Act of 1974, the NRC began operat ...
.
certification Certification is the provision by an independent body of written assurance (a certificate) that the product, service or system in question meets specific requirements. It is the formal attestation or confirmation of certain characteristics of a ...
of fireproofing and firestopping remained optional for systems installed in
nuclear power plant A nuclear power plant (NPP) is a thermal power station in which the heat source is a nuclear reactor. As is typical of thermal power stations, heat is used to generate steam that drives a steam turbine connected to a electric generator, generato ...
s in Canada and the United States. * Reuse of older materials from demolished buildings, in newer buildings.


Work staging

Spray fireproofing products have not been qualified to the thousands of firestop configurations, so they cannot be installed in conformance of a certification listing. Therefore, firestopping must precede fireproofing. Both need one another. If the structural steel is left without fireproofing, it can damage fire barriers and a building can collapse. If the barriers are not firestopped properly, fire and smoke can spread from one compartment to another.


Traffic tunnels

Traffic tunnels may be traversed by vehicles carrying flammable goods, such as petrol,
liquefied petroleum gas Liquefied petroleum gas (LPG or LP gas) is a fuel gas which contains a flammable mixture of hydrocarbon gases, specifically propane, propylene, butylene, isobutane and n-butane. LPG is used as a fuel gas in heating appliances, cooking e ...
and other hydrocarbons, which are known to cause a very rapid temperature rise and high ultimate temperatures in case of a fire (see the hydrocarbon curves in fire-resistance rating). Where hydrocarbon transports are permitted in tunnel construction and operations, accidental fires may occur, resulting in the need for fireproofing of traffic tunnels with concrete linings. Traffic tunnels are not ordinarily equipped with fire suppression means, such as
fire sprinkler system A fire sprinkler system is an active fire protection method, consisting of a water supply system, providing adequate pressure and flowrate to a water distribution piping system, onto which fire sprinklers are connected. Although historically on ...
s. It is very difficult to control hydrocarbon fires by active fire protection means, and it is expensive to equip an entire tunnel along its whole length for the eventuality of a hydrocarbon fire or a
BLEVE A boiling liquid expanding vapor explosion (BLEVE, ) is an explosion caused by the rupture of a vessel containing a pressurized liquid that has reached temperature above its boiling point. Because the boiling point of a liquid rises with p ...
.


Concrete exposed to hydrocarbon fires

Concrete cannot, by itself, withstand severe hydrocarbon fires. In the
Channel Tunnel The Channel Tunnel (french: Tunnel sous la Manche), also known as the Chunnel, is a railway tunnel that connects Folkestone (Kent, England, UK) with Coquelles ( Hauts-de-France, France) beneath the English Channel at the Strait of Dover. ...
that connects the United Kingdom and France, an intense fire broke out and reduced the concrete lining in the undersea tunnel down to about 50 mm. In ordinary building fires, concrete typically achieves excellent fire-resistance ratings, unless it is too wet, which can cause it to crack and explode. For unprotected concrete, the sudden endothermic reaction of the
hydrate In chemistry, a hydrate is a substance that contains water or its constituent elements. The chemical state of the water varies widely between different classes of hydrates, some of which were so labeled before their chemical structure was understo ...
s and unbound humidity inside the concrete generates pressure high enough to spall off the concrete, which falls in small pieces on the floor of the tunnel. Humidity probes are inserted into all concrete slabs that undergo fire testing to test for this, even for the less severe building elements curve (DIN4102, ASTM E119, BS476, or ULC-S101). The need for fireproofing was demonstrated, among other fire protection measures, in the European "Eureka" Fire Tunnel Research Project, which gave rise to building codes for the trade to avoid the effects of such fires upon traffic tunnels. Cementitious spray fireproofing must be certification-listed and applied in the field as per that listing, using a hydrocarbon fire test curve such as the one used in UL1709.


Fireproof vaults

Fireproof vaults to protect important paper documents are usually built using concrete or masonry blocks as the primary building material. In the event of a fire, the chemically-bound water within the concrete or masonry blocks is forced into the vault chamber as steam, which soaks the paper documents to keep them from igniting. This steam also helps keep the temperature inside the vault chamber below the critical threshold, which is the point at which information on paper documents is destroyed. The paper can later be remediated with a freeze drying process if the fire is extinguished before internal temperatures exceed . An alternate less expensive and time-consuming construction method is using dry insulating material. This vault construction method is sufficient for paper documents, but the steam generated by concrete and masonry structures will destroy contents that are more sensitive to heat and moisture. For example, information on microfilm is destroyed at (a.k.a. Class 150) and magnetic media (such as data tapes) lose data above (a.k.a. Class 125). Fireproof vaults built to meet the more stringent Class 125 requirement are called data-rated vaults. All components of fireproof vaults must meet the fire protection rating of the vault itself, including doors, HVAC penetrations and cable penetrations.National Fire Protection Association 232 "Protection of Records"


See also

*
BLEVE A boiling liquid expanding vapor explosion (BLEVE, ) is an explosion caused by the rupture of a vessel containing a pressurized liquid that has reached temperature above its boiling point. Because the boiling point of a liquid rises with p ...
* Brominated flame retardant * Cable tray *
Channel tunnel The Channel Tunnel (french: Tunnel sous la Manche), also known as the Chunnel, is a railway tunnel that connects Folkestone (Kent, England, UK) with Coquelles ( Hauts-de-France, France) beneath the English Channel at the Strait of Dover. ...
* Circuit integrity * Compartmentalisation * Construction * Endothermic * Fire * Fire protection * Fire-resistance rating * Firestop * Flame retardant *
Hydrate In chemistry, a hydrate is a substance that contains water or its constituent elements. The chemical state of the water varies widely between different classes of hydrates, some of which were so labeled before their chemical structure was understo ...
s * Intumescent * Liquified petroleum gas * Listing and approval use and compliance * Passive fire protection * Plaster * Product certification *
Sodium silicate Sodium silicate is a generic name for chemical compounds with the formula or ·, such as sodium metasilicate , sodium orthosilicate , and sodium pyrosilicate . The anions are often polymeric. These compounds are generally colorless transparent ...
*
Fireproof banknote Fireproof banknote is a demonstration of putting a banknote, previously soaked in 50% ( v/v) alcohol fuel solution, to a flame. The fire is lit and later extinguished by itself without the banknote being burnt. This demonstration can be used to t ...


References


External links

* National Fireproofing Contractors Association http://www.nfca-online.org/ * Structural Fire Protection - American Institute of Steel Construction https://www.aisc.org/globalassets/modern-steel/archives/2002/12/2002v12_fire.pdf * Additional Fireproofing Methods https://www.thebalance.com/fireproofing-method-structural-members-845033
NFPA Standards
{{HVAC Flame retardants Passive fire protection