Intumescent

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A charred marshmallow is a familiar example of intumescence Roasted-Marshmallow.jpg
A charred marshmallow is a familiar example of intumescence

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. [1] 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.[ citation needed ]

Contents

The details for individual building parts are specified in technical standards which are compiled and published by national or international standardization bodies like the British Standards Institute (BSI), the German Institute for Standardization (DIN), the American Society for Testing and Materials (ASTM) or the International Organization for Standardization (ISO).

Intumescent coatings for steel constructions must be approved in standardized fire tests.

Types

Soft char

These intumescent materials produce a light char which is a poor conductor of heat, thus retarding heat transfer. Typically the light char consists of microporous carbonaceous foam formed by a chemical reaction of three main components: ammonium polyphosphate, pentaerythritol, and melamine. [2] The reaction takes place in a matrix formed by the molten binder which is typically based on vinyl acetate copolymers or styrene acrylates.

Ablative coatings contain a significant amount of hydrates. When the hydrates are heated, they decompose, and water vapour is released, which has a cooling effect. Once the water is spent, the insulation characteristics of the char that remains can retard heat transfer through the fire stop assembly.

Soft char products are typically used in thin film intumescent materials for fireproofing protection of structural steel as well as in firestop pillows.

Hard char

Harder char is produced with sodium silicates and graphite. These products are suitable for use in plastic pipe firestops in which applications it is necessary to exert expansion pressure to fill the gap left in the middle of the fire stop assembly left by the melting plastic pipe.

Intumescent coatings

Intumescent coatings may be designed for protection of metals from fire, such as structural steel. Reviews of the technology are available. [3] They may be based on a number of resin binders including epoxy, and silicone. [4] Melamine-formaldehyde resin systems have been used using layered double-hydroxide modified phosphate esters that improved the intumescent properties. [5]

Problems

Some intumescent materials are susceptible to environmental influences such as humidity, which can reduce or negate their ability to function.[ citation needed ]

See also

Related Research Articles

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<span class="mw-page-title-main">Epoxy</span> Type of material

Epoxy is the family of basic components or cured end products of epoxy resins. Epoxy resins, also known as polyepoxides, are a class of reactive prepolymers and polymers which contain epoxide groups. The epoxide functional group is also collectively called epoxy. The IUPAC name for an epoxide group is an oxirane.

<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">Thermosetting polymer</span> Polymer obtained by irreversibly hardening (curing) a resin

In materials science, a thermosetting polymer, often called a thermoset, is a polymer that is obtained by irreversibly hardening ("curing") a soft solid or viscous liquid prepolymer (resin). Curing is induced by heat or suitable radiation and may be promoted by high pressure or mixing with a catalyst. Heat is not necessarily applied externally, and is often generated by the reaction of the resin with a curing agent. Curing results in chemical reactions that create extensive cross-linking between polymer chains to produce an infusible and insoluble polymer network.

<span class="mw-page-title-main">Fire door</span> Fire resistant door

A fire door is a door with a fire-resistance rating used as part of a passive fire protection system to reduce the spread of fire and smoke between separate compartments of a structure and to enable safe egress from a building or structure or ship. In North American building codes, it, along with fire dampers, is often referred to as a closure, which can be derated compared against the fire separation that contains it, provided that this barrier is not a firewall or an occupancy separation. In Europe national standards for fire doors have been harmonised with the introduction of the new standard EN 16034, which refers to fire doors as fire-resisting door sets. Starting September 2016, a common CE marking procedure was available abolishing trade barriers within the European Union for these types of products. In the UK, it is Part B of the Building Regulations that sets out the minimum requirements for the fire protection that must be implemented in all dwellings this includes the use of fire doors. All fire doors must be installed with the appropriate fire resistant fittings, such as the frame and door hardware, for it to fully comply with any fire regulations.

Fusion bonded epoxy coating, also known as fusion-bond epoxy powder coating and commonly referred to as FBE coating, is an epoxy-based powder coating that is widely used to protect steel pipe used in pipeline construction from corrosion. It is also commonly used to protect reinforcing bars and on a wide variety of piping connections, valves etc. FBE coatings are thermoset polymer coatings. They come under the category of protective coatings in paints and coating nomenclature. The name fusion-bond epoxy is due to resigning cross-link and the application method, which is different from a conventional paint. In 2020 the market size was quoted at 12 billion dollars.

<span class="mw-page-title-main">Fireproofing</span> Rendering something (structures, materials, etc.) resistant to fire, or incombustible

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").

<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.

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 fire-resistance rating of a wall or floor assembly intended to impede the spread of fire and smoke.

<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.

<span class="mw-page-title-main">Firestop pillow</span>

Firestop pillows are passive fire protection items used for firestopping holes to achieve fireproofing. The various kinds of firestop pillows are intended to slow the spread of fire. They are often used to meet fire-resistance ratings in conduits that need frequent access.

<span class="mw-page-title-main">Cable tray</span> Electrical-cable-supporting structure

In the electrical wiring of buildings, a cable tray system is used to support insulated electrical cables used for power distribution, control, and communication. Cable trays are used as an alternative to open wiring or electrical conduit systems, and are commonly used for cable management in commercial and industrial construction. They are especially useful in situations where changes to a wiring system are anticipated, since new cables can be installed by laying them in the tray, instead of pulling them through a pipe.

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">Fire test</span>

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 certification result in the issuance of a certification listing.

<span class="mw-page-title-main">Smoke exhaust ductwork</span>

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.

<span class="mw-page-title-main">Ammonium polyphosphate</span> Chemical compound

Ammonium polyphosphate is an inorganic salt of polyphosphoric acid and ammonia containing both chains and possibly branching. Its chemical formula is H(NH4PO3)nOH showing that each monomer consists of an orthophosphate radical of a phosphorus atom with three oxygens and one negative charge neutralized by an ammonium cation leaving two bonds free to polymerize. In the branched cases some monomers are missing the ammonium anion and instead link to three other monomers.

<span class="mw-page-title-main">Fire damper</span> Type of passive fire protection

Fire dampers are passive fire protection products used in heating, ventilation, and air conditioning (HVAC) ducts to prevent and isolate 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.

A thermoset polymer matrix is a synthetic polymer reinforcement where polymers act as binder or matrix to secure in place incorporated particulates, fibres or other reinforcements. They were first developed for structural applications, such as glass-reinforced plastic radar domes on aircraft and graphite-epoxy payload bay doors on the Space Shuttle.

Fire-safe polymers are polymers that are resistant to degradation at high temperatures. There is need for fire-resistant polymers in the construction of small, enclosed spaces such as skyscrapers, boats, and airplane cabins. In these tight spaces, ability to escape in the event of a fire is compromised, increasing fire risk. In fact, some studies report that about 20% of victims of airplane crashes are killed not by the crash itself but by ensuing fires. Fire-safe polymers also find application as adhesives in aerospace materials, insulation for electronics, and in military materials such as canvas tenting.

References

  1. Merriam-Webster Dictionary, intumescence, accessed 13 March 2023
  2. Werle, Peter; Morawietz, Marcus; Lundmark, Stefan; Sörensen, Kent; Karvinen, Esko; Lehtonen, Juha (2008). "Alcohols, Polyhydric". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a01_305.pub2. ISBN   978-3527306732.
  3. Puri, Ravindra G.; Khanna, A. S. (2017-01-01). "Intumescent coatings: A review on recent progress". Journal of Coatings Technology and Research. 14 (1): 1–20. doi:10.1007/s11998-016-9815-3. ISSN   1935-3804. S2CID   138961125.
  4. Cardoso, de Sa, Beraldo, Hidalgo and Ferreira (November 2020). "Intumescent coatings using epoxy, alkyd, acrylic, silicone and silicone-epoxy hybrid resins for steel fire protection". Journal of Coatings Technology and Research. 17 (6): 1471–1488. doi: 10.1007/s11998-020-00366-9 . S2CID   220375908.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  5. Xu, Deng and Lang (January 2020). "Flame retardancy and smoke suppression properties of transparent intumescent fire-retardant coatings reinforced with layered double hydroxides". Journal of Coatings Technology and Research. 17 (1): 157–169. doi:10.1007/s11998-019-00249-8. S2CID   199473315.