Intumescent paint

intumescent paint

Intumescent paint: Coatings contribute to passive firefighting 

A substance that tends to swell when heated (such as on fire) is called an “intumescent”. In other words, its volume increases and density decreases. There are some intumescent substances that can expand to almost 100 times their original thickness. Intumescents are ideal insulators and fire protectors due to lower density when expanding. These substances are mostly used in passive fire protection. There are two main types; soft char and hard char. Intumescent paint applications are often preferred due to their fire protective properties.

intumescent paintIntumescent coatings are applicable on wood, tiles, steel, concrete and many other surfaces depending on the product. Depending on the application, they are suitable for the substrates as topcoat or base coat. For the maximum protection, a flame damping top coat can be applied. When fire breaks, the coating system becomes subject to high heat, which activates the prevention system. The topcoat releases flame damping gas to protect the underlying intumescent layer, which starts to expand and for insulating char which in turn, keeps the underlyingsubstrate safe from the heat and flames. Intumescent coating systems can offer even 240 minutes longer gap between fire breaking and taking hold.

Intumescent paint and fire safety regulations in the UK

In the UK the responsibility of providing fire safety in business and other non-domestic premises is given to the employers, owners, landlords and other parties in control of the premises. Their contribution to increasing fire safety includes assessing and minimising fire hazards, evacuation and escape route planning and providing training and information on fire hazards, fire prevention and procedures in case of fire.

Also the UK government is concerned with fire safety especially in work places and provide a guide for making premises safe from fire, to offer guidance for identifying and dealing with fire hazards. Additionally, fire resistance standard BS 476 encourages coating manufacturers to produce coatings with sufficient ability to withstand and stop fire.

British standardStandards

BS 476 divides intumescent coatings into class 1 and class 0 coatings. Class 1 is the lower standard and it requires that the coatings and other construction materials do not allow fire to spread. This is the standard for example for coatings applicable on walls and ceilings.

Class 0 is the highest fire standard required from high risk areas such as corridors and fire escape routes. The class 0 coatings automatically must comply to class 1 requirementsö they additionally should have a very low tendency to catch fire and burn. They should have very low fire propagation index according to BS 476 Part 6.

Ability to withstand fire

The intumescent coatings can also be classified by the protection they offer. Therefore, there are 30 and 60 minutes fire protection coatings. This means thus, that a 30 minute fire rated coating should provide 30 minutes additional time between the fire breaking and taking hold.

Certification for intumescent paint

If you wish to apply or let intumescent coatings applied in a building, you should always make sure the product and coating job are certified. Many service providers and intumescent coating manufacturers provide a certificate together with the service or product.

The certificate of fire safety paint application is needed for example when discussing insurance policies. It can additionally, come in handy if actual damage needs to be claimed from the insurance. 

Advantages of intumescent paint

Since the invention of intumescent paint, the systems have been tried out and tested, and have proved to be real game changers in fire protection. The advantage is of course that they protect buildings and structures. They also provide valuable escape time and can ultimately save people’s lives. They are mandatory according to the latest legal building regulations and more and more people choose to apply the coating in their homes.

The main benefits of intumescent coatings include:

  • Infused with advanced technology
  • Much safer to use than primitive methods
  • Easy application
  • Cost efficient
  • Tried out and tested, and proven effective

Additionally, many intumescent coatings have also other properties which protect specific substrates for example intumescent steelwork coatings are often rustproof and intumescent wood paint  provides protection from weathering and UV radiation.

Intumescent paint

Intumescent paint suppliers and manufacturers in the UK

As the popularity of intumescent coatings keeps increasing, there are also more and more manufacturers of these products including big international companies and smaller business which spesialise in fire prevention coatings. The following table introduces several intumescent paint manufacturers, whose products are available in the UK.

Intumescent paint manufacturers Product line
 3M  Scotchkote
Akzo Nobel  International, Interchar
Bollom  Intulac, Fireshield, Broflame, Brosteel
 Crown Trade  Trimonox
 Envirograf  All products
 Jotun  Steelmaster
Nullifire  All products
 PPG  Steelguard
Sherwin Williams  Firetex
Sika  Unitherm
Thermoguard  All coatings
 Zero Flame  All products

The intumescent paint suppliers are active online and in physical shops. The online intumescent paint suppliers include for example Rawlins Paints and Promain. Also some intumescent paint manufacturers offer their products on their own websites. These include companies such as Envirograf and Thermoguard.

Intumescent paint cost UK

The intumescent paint price varies depending on the quantity and quality of the substance as well as on the client’s requirements. The intumescent paint cost can be only £20, however, it can also reach the amount of as much as £600.

For projects requiring larger volumes of intumescent paint, it is advised to request specified quotes from several suppliers to get the best price quality ratio.

Manufacturer Product Price Packaging Coverage
 Zero Flame  Aquasteel WB +  £55.67  2.5 L  2.3 sq m /litre (30 min)

0.5 sq m/ litre (60 min)

 Bollom  Fireshield Ultra Universal  £368.66  10 L  Dependent on layer thickness
 Jotun  Steelmaster 60WB  £156.62  18.5 L  1.4 sq m / litre
 3M  Scotchkote  £165.90  5 L  4 sq m / litre
 Akzo Nobel  International; Interchar 212  £756.02  20 Kg  1 sq m / Kg
 Sherwin Williams  Firetex FX9500  £283.68  15 L  Dependent on layer thickness
 Nullifire  S707  £139.00  25 Kg  1.4 sq m / litre
 Thermoguard  Timbercoat  £153.60 2.85 L 7 sq m / litre
 Bollom  Intulac Ultra Basecoat  £187.60  5 L   5 sq m / litre

Crown intumescent paint for at home

intumescent paint

Grown Trade Timonox Upgrade Basecoat

Crown trade is one of the many intumescent paint manufacturers. One of their most well known products on this sector is water-based Timonox Upgrade Base Coat which upgrades surfaces to class 0 fire resistance. This Crown intumescent paint is an easy to apply, solvent free system which protects structures from flames and fire by swelling and forming an insulating char layer. However, the Timonox coating requires a top coat to provide the surface with an appealing, durable finish.

The paint is available only in the colour white and it is applicable by brush, roller or spray. It does not require any professional coating equipment. The coating also dries rather fast; it is namely touch dry in 1 hour after application and recoatable in 4-6 hours after application. This intumescent paint costs about £100 per 5 litres depending on the supplier.

Intumescent paint for concrete structures

Although concrete already has fire protective properties, it is still a wise option to use a protective coating for negating the impact of fire. Intumescent coating on concrete helps protect concrete structures from rapid heating which otherwise causes the structure to collapse. However, if coated, it is likely that the concrete surface will retain its strength to a greater extent and prevent damage on a larger scale. Making concrete fireproof with intumescent coating is easy with brush, spray or roller applications.Also, removal of electrical installations isn’t necessary when coating.