Fireproofing

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Spray gypsum-based plaster fireproofing being installed. Fireproofing.jpg
Spray gypsum-based plaster fireproofing being installed.
Circuit integrity fireproofing of cable trays, using calcium silicate boards. Promat signum tray cladding 1.jpg
Circuit integrity fireproofing of cable trays, using calcium silicate boards.
Damaged spray fireproofing Damaged fibrous spray fireproofing toronto.png
Damaged spray fireproofing

Fireproofing is rendering something (structures, materials, etc.) resistant to fire, or incombustible; or material for use in making anything fire-proof. [1] 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").

Contents

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

Applications

History

Asbestos 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 missiles (ICBMs) and re-entry vehicles, such as the Space Shuttles.

Fireproofing of structural steel

In a building fire, structural steel loses strength as the temperature increases. In order to maintain the structural integrity of the steel frame, several fireproofing measurements are taken:

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): [7]

Alternative methods

Intumescent spray fireproofing product has expanded. Unitherm2.jpg
Intumescent spray fireproofing product has expanded.

Among the conventional materials, purpose-designed spray fireproofing plasters have become abundantly available the world over. The inorganic methods include:

Gypsum plasters include chemical additives to create bubbles that displace solids, thus reducing the bulk density. Lightweight polystyrene beads may be 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[ clarification needed ] combustibility rating as per DIN4102.[ full citation needed ] Fibrous plasters, containing either mineral wool, or ceramic fibres tend to simply entrain more air, thus displacing the heavy fibres.

Proprietary boards and sheets, made of gypsum, calcium silicate, 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 temperature below the critical strength limit is to use liquid convection cooling in hollow structural members. [9] This method was patented in the 19th century although the first prominent example was 89 years later. [10]

Traffic tunnels

Traffic tunnels may be traversed by vehicles carrying flammable goods, such as petrol, liquefied petroleum gas 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.

Concrete exposed to hydrocarbon fires

Concrete cannot, by itself, withstand severe hydrocarbon fires. In the Channel Tunnel 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.[ citation needed ] 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 hydrates 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. [11]

Fireproof vaults

Fireproof vaults to protect important paper documents are usually built using concrete or masonry blocks as the primary building material.[ citation needed ] 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.[ citation needed ] This steam also helps keep the temperature inside the vault chamber below the critical 176.7 °C (350 °F) threshold, which is the point at which information on paper documents is destroyed.[ citation needed ] The paper can later be remediated with a freeze drying process if the fire is extinguished before internal temperatures exceed 176.7 °C (350 °F).[ citation needed ] An alternate less expensive and time-consuming construction method is using dry insulating material.[ citation needed ]

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 65.5 °C (149.9 °F) (a.k.a. Class 150)[ citation needed ] and magnetic media (such as data tapes) lose data above 51.7 °C (125.1 °F) (a.k.a. Class 125).[ citation needed ] Fireproof vaults built to meet the more stringent Class 125 requirement are called data-rated vaults.[ citation needed ]

All components of fireproof vaults must meet the fire protection rating of the vault itself, including doors, HVAC penetrations and cable penetrations. [12]

See also

Related Research Articles

<span class="mw-page-title-main">Concrete</span> Composite construction material

Concrete is a composite material composed of aggregate bonded together with a fluid cement that cures over time. Concrete is the second-most-used substance in the world after water, and is the most widely used building material. Its usage worldwide, ton for ton, is twice that of steel, wood, plastics, and aluminium combined.

<span class="mw-page-title-main">Masonry</span> Building of structures from individual units of stone, bricks, or blocks

Masonry is the craft of building a structure with brick, stone, or similar material, including mortar plastering which are often laid in, bound and pasted together by mortar. The term masonry can also refer to the building units themselves.

<span class="mw-page-title-main">Earth shelter</span> House partially or entirely surrounded by earth

An earth shelter, also called an earth house, earth bermed house, or underground house, is a structure with earth (soil) against the walls, on the roof, or that is entirely buried underground.

<span class="mw-page-title-main">Vermiculite</span> Hydrous phyllosilicate mineral which expands significantly when heated

Vermiculite is a hydrous phyllosilicate mineral which undergoes significant expansion when heated. Exfoliation occurs when the mineral is heated sufficiently; commercial furnaces can routinely produce this effect. Vermiculite forms by the weathering or hydrothermal alteration of biotite or phlogopite. Large commercial vermiculite mines exist in the United States, Russia, South Africa, China, and Brazil.

<span class="mw-page-title-main">Mortar (masonry)</span> Workable paste which hardens to bind building blocks

Mortar is a workable paste which hardens to bind building blocks such as stones, bricks, and concrete masonry units, to fill and seal the irregular gaps between them, spread the weight of them evenly, and sometimes to add decorative colors or patterns to masonry walls. In its broadest sense, mortar includes pitch, asphalt, and soft mud or clay, as those used between mud bricks, as well as cement mortar. The word "mortar" comes from Old French mortier, "builder's mortar, plaster; bowl for mixing." (13c.).

<span class="mw-page-title-main">Plaster</span> Broad range of building and sculpture materials

Plaster is a building material used for the protective or decorative coating of walls and ceilings and for moulding and casting decorative elements. In English, "plaster" usually means a material used for the interiors of buildings, while "render" commonly refers to external applications. The term stucco refers to plasterwork that is worked in some way to produce relief decoration, rather than flat surfaces.

<span class="mw-page-title-main">Building material</span> Material which is used for construction purposes

Building material is material used for construction. Many naturally occurring substances, such as clay, rocks, sand, wood, and even twigs and leaves, have been used to construct buildings. Apart from naturally occurring materials, many man-made products are in use, some more and some less synthetic. The manufacturing of building materials is an established industry in many countries and the use of these materials is typically segmented into specific specialty trades, such as carpentry, insulation, plumbing, and roofing work. They provide the make-up of habitats and structures including homes.

<span class="mw-page-title-main">Seismic retrofit</span> Modification of existing structures to make them more resistant to seismic activity

Seismic retrofitting is the modification of existing structures to make them more resistant to seismic activity, ground motion, or soil failure due to earthquakes. With better understanding of seismic demand on structures and with recent experiences with large earthquakes near urban centers, the need of seismic retrofitting is well acknowledged. Prior to the introduction of modern seismic codes in the late 1960s for developed countries and late 1970s for many other parts of the world, many structures were designed without adequate detailing and reinforcement for seismic protection. In view of the imminent problem, various research work has been carried out. State-of-the-art technical guidelines for seismic assessment, retrofit and rehabilitation have been published around the world – such as the ASCE-SEI 41 and the New Zealand Society for Earthquake Engineering (NZSEE)'s guidelines. These codes must be regularly updated; the 1994 Northridge earthquake brought to light the brittleness of welded steel frames, for example.

This page is a list of construction topics.

<span class="mw-page-title-main">Steel frame</span> Building technique using skeleton frames of vertical steel columns

Steel frame is a building technique with a "skeleton frame" of vertical steel columns and horizontal I-beams, constructed in a rectangular grid to support the floors, roof and walls of a building which are all attached to the frame. The development of this technique made the construction of the skyscraper possible.

<span class="mw-page-title-main">Formwork</span> Molds for cast

Formwork is molds into which concrete or similar materials are either precast or cast-in-place. In the context of concrete construction, the falsework supports the shuttering molds. In specialty applications formwork may be permanently incorporated into the final structure, adding insulation or helping reinforce the finished structure.

<span class="mw-page-title-main">Autoclaved aerated concrete</span> Lightweight, precast building material

Autoclaved aerated concrete (AAC) is a lightweight, precast, cellular concrete building material, eco-friendly, suitable for producing concrete-like blocks. It is composed of quartz sand, calcined gypsum, lime, portland cement, water and aluminium powder. AAC products are cured under heat and pressure in an autoclave. Developed in the mid-1920s, AAC provides insulation, fire, and mold-resistance. Forms include blocks, wall panels, floor and roof panels, cladding (façade) panels and lintels. It is also an insulator.

<span class="mw-page-title-main">Structural steel</span> Type of steel used in construction

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, chemical composition, mechanical properties such as strengths, storage practices, etc., are regulated by standards in most industrialized countries.

<span class="mw-page-title-main">Intumescent</span> Substance that swells as a result of heat exposure

An intumescent is a substance that swells as a result of heat exposure, leading to an increase in volume and decrease in density. Intumescence refers to the process of swelling. Intumescent materials 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.

<span class="mw-page-title-main">Passive fire protection</span> Component or system to passively prevent the spread of fire

Passive fire protection (PFP) is components or systems of a building or structure that slows or impedes the spread of the effects of fire or smoke without system activation, and usually without movement. Examples of passive systems include floor-ceilings and roofs, fire doors, windows, and wall assemblies, fire-resistant coatings, and other fire and smoke control assemblies. Passive fire protection systems can include active components such as fire dampers.

A fire-resistance rating typically means the duration for which a passive fire protection system can withstand a standard fire resistance test. This can be quantified simply as a measure of time, or it may entail other criteria, involving evidence of functionality or fitness for purpose.

<span class="mw-page-title-main">History of structural engineering</span>

The history of structural engineering dates back to at least 2700 BC when the step pyramid for Pharaoh Djoser was built by Imhotep, the first architect in history known by name. Pyramids were the most common major structures built by ancient civilizations because it is a structural form which is inherently stable and can be almost infinitely scaled.

<span class="mw-page-title-main">Types of concrete</span> Building material consisting of aggregates cemented by a binder

Concrete is produced in a variety of compositions, finishes and performance characteristics to meet a wide range of needs.

Concrete has relatively high compressive strength, but significantly lower tensile strength. The compressive strength is typically controlled with the ratio of water to cement when forming the concrete, and tensile strength is increased by additives, typically steel, to create reinforced concrete. In other words we can say concrete is made up of sand, ballast, cement and water.

<span class="mw-page-title-main">Structural clay tile</span> Class of building block

Structural clay tile describes a category of burned-clay building materials used to construct roofing, walls, and flooring for structural and non-structural purposes, especially in fireproofing applications. Also called building tile, structural terra cotta, hollow tile, saltillo tile, and clay block, the material is an extruded clay shape with substantial depth that allows it to be laid in the same manner as other clay or concrete masonry. In North America it was chiefly used during the late 19th and early 20th centuries, reaching peak popularity at the turn of the century and declining around the 1950s. Structural clay tile grew in popularity in the end of the nineteenth-century because it could be constructed faster, was lighter, and required simpler flat falsework than earlier brick vaulting construction. Each unit is generally made of clay or terra-cotta with hollow cavities, or cells, inside it. The colors of terracotta transform from gray to orange, red, yellow, and cream tones. This is due to an effect of the firing process which hardens the clay so it can be used for structural purposes. The material is commonly used in floor arches, fireproofing, partition walls, and furring. It continues to be used in Europe to build fire-resistant walls and partitions. In North America the material has largely been replaced by concrete masonry units.

References

  1. Oxford English Dictionary 2nd ed
  2. Allen 2009, p. 885
  3. Allen, Edward; Iano, Joseph (2009). Fundamentals of building construction : materials and methods. Iano, Joseph. (5th ed.). Hoboken, N.J.: Wiley. p. 884. ISBN   9780470074688. OCLC   209788024.
  4. Allen 2009, p. 878
  5. Paleja, Ameya (22 August 2022). "A fireproof wood achieves the highest class in burning test thanks to an invisible coating". interestingengineering.com. Retrieved 18 September 2022.
  6. "An invisible coating to make wood 'fireproof'". Nanyang Technological University via techxplore.com. Retrieved 18 September 2022.
  7. 1 2 3 Allen 2009, p. 459
  8. 1 2 3 4 5 6 7 8 Allen 2009, p. 460 - 463
  9. Fisher, Arthur (May 1970). Water-Filled Columns Keep Building Frames Cool in Fires. Popular Science. Retrieved 27 Jan 2012.
  10. see U.S. Steel Tower
  11. "Scope for UL 1709". ulstandardsinfonet.ul.com. Archived from the original on 2001-03-29.
  12. National Fire Protection Association 232 "Protection of Records"