PIN-FR based intumescent coatings have been used to protect materials from fire since Gay-Lussac proposed ammonium polyphosphate based systems for textiles in 1821. In 2012 the world intumescent coatings market was just over 700 million US$ and is expected to rise to over 900 million US$ by 2018.
Intumescent coatings, with dry thicknesses after application of 1-30 mm can protect steel structures in fire for up to 2 hours, that is prevent the steel reaching 550°C, the temperature at which it loses its structural strength.
Intumescent coatings combine a carbon source (to generate fire-resistant char), an acid source/catalyst to ensure reaction, a blowing agent/spumific to increase volume and binding agents, often with a first undercoat on the steel to ensure adhesion and corrosion protection. Developments include low or no-solvent application, acrylic resin and epoxy resin binders, expandable graphite, synergist additives, new phosphorus based components, mineral and fibrous fillers, glass flakes and nanocomposites. These will help address the challenges of developing products with improved fire resistance, positive environmental and safety profiles and cost effectiveness of both product and application.
“Recent developments of intumescent fire protection coatings for structural steel: A review”, T. Mariappan, Journal of Fire Science, 1-44, 2016 http://dx.doi.org/10.1177/0734904115626720