- Intumescent
An intumescent is a substance which swells as a result of
heat exposure, thus increasing involume , and decreasing indensity . Intumescents are typically used inpassive fire protection and, in America, requirelisting and approval use and compliance in their installed configurations in order to comply with thelaw .Types of intumescents
oft char producers
These intumescents produce a light char, which is a poor conductor of
heat , thus retarding heat transfer. Typically, these materials also contain a significant amount ofhydrate s. As the hydrates are spent, water vapour is released, which has a cooling effect. Once the water is spent, it is only the insulation characteristics of the char that was produced, which can slow down heat transfer from the exposed side to the unexposed side of an assembly. Soft char producers are typically used in thin film intumescents forfireproofing ofstructural steel as well asfirestop pillow s. Typically, the expansion pressure that is created for these products is very low, because the soft carbonaceous char has little substance, which is beneficial if the aim is to produce a layer of insulation.Hard expanding char producers
Harder chars are produced with
sodium silicate s andgraphite . These products are suitable for use inplastic pipe firestop s as well as exterior steel fireproofing. In those applications, it is necessary to produce a more substantial char, with a quantifiable expansionpressure . In the case of the firestops, a melting, burning plastic pipe must be squeezed together and shut so that there will be no hole for fire to go through an opening in an otherwise fire-resistance rated wall or floor assembly. In the case of the exterior fireproofing, a hydrocarbon fire must be held off with quite potentially more kinetic energy than a house fire. Intumescents that produce hard chars are not typically used for interior spray fireproofing as they are not suitable for that application.Uses of intumescents in passive fire protection
Applications
*
firestop ping,
*fireproofing
*gasketing applications
*windows*
building s
*offshore construction
*ship s
*aircraft .Problems with intumescents
Some intumescents are susceptible to environmental influences such as humidity, which can reduce or negate their ability to function. DIBt approvals quantify the ability of intumescents to stand the test of
time against various environmental exposures. DIBt approved firestops andfireproofing materials are available inCanada and the U.S. [ [http://www.dibt.de/ DIBt - Deutsches Institut für Bautechnik ] ]Gallery
References
ee also
*Fire test
*Fire-resistance rating
*Hydrate
*Fire protection
*Passive fire protection
*Firestop s
*Putty
*Fireproofing
*Firestop pillow
*Endothermic
*Sodium silicate
*Graphite
*Penetrant
*Bounding
*Construction External links
Wikimedia Foundation. 2010.
