Effects of natural weathering on the fire properties of intumescent fire‐retardant coatings

Abstract

Summary Fire‐retardant coatings could be one option for providing enhanced protection to buildings during a wildfire, particularly when applied to combustible siding and in under‐eave areas. Limited studies have been conducted on their effectiveness but maintaining adequate performance after weathering has been questioned. This paper reports on a study evaluating the effect of natural weathering on the performance of intumescent‐type fire‐retardant coatings. The main concerns were (a) the reduction of ignition resistance of the coating after weathering and (b) the coating might contribute as a combustible fuel and assist the fire growth after weathering. This study evaluated the performance of 3 intumescent coatings that were exposed to natural weathering conditions for up to 12 months. A bench‐scale evaluation using a cone calorimeter was used to evaluate the performance of the coatings at 3 heat flux levels (30, 50, and 70 kW/m2). Our results showed that weathering exposure reduced the effectiveness of fire protection of intumescent coatings, but the weathered coatings did not act as additional fuels. Weathering orientation showed much less effect on the performance of intumescent coatings in comparison to other parameters. There was statistical evidence that weathering duration, heat flux level, and coating type affected the combustion properties.

Effect of Fire-Retardant Coatings and Accelerated-Weathering on the Flammability of Wood-Based Materials in Wildland-Urban Interface (WUI) Communities

“…Some examples of these short-term strategies could comprise of protecting structures from ignition and decreasing fire spread within a community. The short-term mitigation approaches can be divided into active (e.g., extinguishers and sprinklers) and passive (e.g., pre-applied water, gel, or foam wetting agents or fire resistance coating and composite layers) fire protection methods [16,17].…”

“…The current market offers many FRCs (film-forming and stain) to protect wood-based materials for outdoor applications. A few comparative studies have been performed on commercial FRCs' fire retardancy and/or weathering performances which mostly show that the weathering exposure is decreasing the effectiveness of fire protection of intumescent coatings [17,24]. For weathering, coatings can be exposed to temperature, humidity, freezing cycles, etc.…”

A chain is no stronger than its weakest link: Weathering resistance of water-based intumescent coatings for steel applications

“…Some intumescent coatings exhibit poor paint properties, as is reported in Mariappan, 18 and especially the water-based systems are sensitive to weathering, as is reported in the literature 3,18,19 and examined in Maciulaitis et al 2 and Bahrani et al 22 The high polarity of the ingredients causes poor compatibility with the coating resin or polymer matrix of the binder. 19 Under natural conditions, humidity, temperature, and solar radiation cause aging of the composite and may lead to the reduction of fire resistance.…”

Effect of Environmental Conditions on the Dehydration and Performance of Fire-Protective Gels

“…These coatings can swell 20 to 50 times their original thickness, forming a carbonaceous-rich layer between the substrate material and heat source. A study reported that weathering drastically reduced their effective service life of the intumescent coating much less than that reported in the product marketing literature [2].…”