What Is Intumescent Heat-Resistant Paint? (and the Best Brands for Steelwork). Author - Andy Potts October 6th 2020 (reading time 5 mins)
(Heat Resistant Coatings - Displayed as a cutaway on a substrate)
Intumescent heat-resistant paint provides an efficient and cost-effective method of protecting structural steel, timber, concrete and composite elements against fire damage. It is widely used in the steel fabrications, construction, marine and aerospace industries as a passive heat protection system that complies with building regulations requirements for fireproofing.
This article provides an overview of:
Intumescent paint is a specialist protective coating that expands (intumesces) when exposed to temperatures above 120øC. For this reason, it is also known as reactive paint, and fire-resistant paint. It is not the same as high-temperature heat-resistant paint such as Jotan Resist, Jotan Solvalitt and Ultrimax Ultritemp. These coatings are designed to be used on metal items such as metal chimneys, exhausts, furnaces and chimineas that get very hot and need to be protected from corrosion.
When structural materials reach a critical temperature in a fire, they lose their load-bearing capacity and collapse. An intumescent coating delays this process, giving the people inside the building and the emergency services more time to safely evacuate. The paint swells up to 50 times its original thickness to form a carbon layer, or char, that prevents oxygen from reaching the substrate for a given period. In the case of a steelwork roof, for example, the char prevents the metal from bending too quickly, and therefore delays its collapse. Fire-resistant paint products commonly provide 30, 60, 90 or 120+ minutes of protection.
A newly constructed building must have adequate fire protection to comply with the Building Regulations 2010. Intumescent paint is cost-effective, easy to apply and readily available, making it the most widely used method of fire protection for steel structures.
Unprotected steelwork can lose its load-bearing capacity and become structurally unsafe within minutes when exposed to extreme heat. The image below demonstrates how an underground car park becomes structurally unsound without adequate heat protection in the event of a fire.
(When the Paint Coating fails on a steel substrate in an underground car park.)
Fire-resistant paints only provide their stated level of time protection and meet building regs when applied correctly. The steps below describe the coating system for applying intumescent paint to steelwork.
Prepare and blast clean the steelwork in accordance with the requirements of any industry-specific standards. Ensure that the surfaces to be coated are free of contaminants such as grease, oil, rust and dirt.
Use a suitable anti-corrosive primer to protect the substrate and to provide the intumescent coating with a good surface for adhesion.
Choose a fire-resistant paint that meets your fire protection requirements. Follow the manufacturer's preparation, drying times and wet film thickness requirements on the product datasheet to prevent the film from failing.
Most intumescent coatings can be applied by spray, brush or roller. For speed and quality of finish, use a spray gun.
How to Use a Dry Film Thickness Gauge
How to Use a Wet Film Thickness Gauge
If required (see below), choose a suitable topcoat that protects the fire-resistant coating and substrate from environmental and use conditions. Follow the manufacturer's preparation and application information on the product datasheet.
Most topcoat products can be applied by spray, brush or roller. For speed and quality of finish, use a spray gun.
Unless desired for aesthetics, it is not necessary to add a protective topcoat as the fire-resistant coating will not be exposed to environmental conditions that might cause it to degrade prematurely.
In these environments, a topcoat is necessary to protect the intumescent paint from being exposed to conditions that may affect its durability and performance.
Your choice of fire-resistant paint will depend on the type of project that you're working on. Our customers report having superb results with Jotun and Ultrimax products.
Jotun is a well-known and trusted brand. The Norwegian-borncompany has an excellent track record for producing high-performance coatings that meet heavy industry marine specifications.
Jotun Steelmaster 600WF Intumescent Paint is a one component waterborne acrylic thin film heat resistant coating.
Steelmaster 60SB is a high-solids (solvent-borne) single-pack, thin-film intumescent coating. It is designed to be used as the reactive mid-coat in a full passive 90-minute fire protection system for steel constructions.
Ultrimax has been manufacturing industrial paints since 2006. The company has gained a reputation for Jotun-style quality, easy-to-use online ordering and direct customer service from their Yorkshire HQ.
Give our friendly Total Paint Shop Support Team a call on 01302 856666 or drop us an email at email@example.com.
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