Intumescent paint protects crucial steel and wooden structures from fire
Strength is one of the main reasons we use steel in building construction. Steel is a tough construction material, used in high rise buildings across Qatar from the Aspire Tower to the Dubai Towers. Another commonly used material is wood which is usually chosen due to its strength and natural beauty. However, the strength of both steel and wood is challenged by the severe heat of a fire. In a fire, it can take only minutes for unprotected steel to reach critical failure temperatures of 540ºC, at which point it loses its load bearing capacity, leading to structural collapse. In fact, above 260ºC steel begins to lose strength. Wood in turn catches fire already in 250°C – 300°C. Which is why you should consider applying intumescent paint for steel structures.
Intumescent paint for steel and wood are used in buildings, offshore structures, ships and aircrafts as well as interior design elements such as wooden wall panels, and it can provide the following advantages:
- Allowing firefighters more time to get the fire under control
- Extending crucial evacuation time
- Fire protection for up to 120 minutes
- Preventing structural collapse
In this article we will explain intumescent paint and outline the different types of intumescent coating for wood and steel, how to comply with fire resistance regulations, and where to find intumescent coating products and contractors in Qatar.
Explaining intumescent paint – the swelling reaction
The term ‘intumescent’ refers to a substance which increases in volume and decreases in density when exposed to high temperatures. Thus intumescent paint is a fire barrier coating which, in the event of fire, forms a non-conductive carbon char to insulate the substrate from the heat and flames. The swelling reaction starts usually at about 90°C and the coating can expand up to 50 times its thickness. Intumescent coatings for wood and steel can postpone structural collapse for up to 120 minutes; the different coatings are usually given 30, 60, 90, or 120 minute guarantee of fire resistance. Some industrial coatings guarantee fire protection up to 4 hours on steel. Intumescent coating for wood does not provide protection for such long time, 2 hours is the maximum.
Standards and classification of intumescent coatings
Each building type requires different level of fire protection, and the intumescent coatings should be chosen by the required level. According to the international standards, materials (including paints) are classified based on the rate at which they allow flame to spread under test conditions. The intumescent paint fire rating classes go from Class A (best) to Class E (worst). In Qatar the Fire Prevention Department provides Fire and life safety guidelines for buildings of different kinds. Also other governmental bodies are concerned with fire prevention in the design and construction phases.
A certified inspector or architect usually defines which type of coating your building or structure requires. Once your coating is applied, you should obtain a certificate to show you have complied with all relevant regulations and used the correct protective surface coating. If you do not obtain the correct certificate(s) then, in the event of a fire, you may be held liable and prosecuted.
Intumescent paint for steel – hard and soft char coatings
The main task of intumescent paint for steel is to create an insulating layer between the fire and the substrate to protect the steel from temperatures that might compromise its load bearing capacity. The intumescent paint thickness for steel is dependent on the required resistance and the type of coating used. Intumescent steelwork coating exists in two types: soft and hard char intumescent coatings.
1. Hard char intumescent coatings for steelwork
The hard char intumescent paint for steel is also known as thick film intumescent paint due to the fact that it is applied in much thicker layers than soft char solutions. These intumescent coatings for steel were developed for combating hydrocarbon fires, however, nowadays they can be modified for other uses. These coatings are now also available in attractive yet limited color range. The char they form results from sodium silicate and graphite.
Expansion ratio: 5:1
Uses: as intumescent paint for steel in harsh environments such as marine and offshore. Also used as intumescent paint for steelwork in exteriors of high rise buildings. Not suitable for interior use.
Fire resistance: class A coating for 90- 120 minutes fire protection (some industrial intumescent coatings up to 4 hours protection)
2. Soft char intumescent paint for steel
The soft char intumescent coatings for steel are also known as thin film intumescents. They are lightweight coatings which, when heated, create a foam-like char layer which is a poor conductor of heat and thus slows down the heat transfer. The char results from a chemical reaction between ammonium, polyphosphate, pentaerythritol and melamine; however, there are also other possible compositions; water and solvent based systems exist. The thin film intumescent coating for steel can be given a fire retardant topcoat to postpone the activation of the swelling reaction.
Expansion ratio: 50:1
Uses: as intumescent steelwork coating on structural steel in constructions
Fire resistance: class A and B coatings for 30, 60 and 90 minutes protection (also industrial 120 minute coatings are available)
Intumescent coating for wood – 3 methods to fireproofing wood
Intumescent paints were originally developed for metal structures, however, today they are suitable for softwoods, hardwoods, even chipboard and MDF, in both interior and exterior settings, the exterior intumescent paint commonly has a higher fire rating. The products for wood exist as clear and pigmented paints and varnishes as well as wood preservatives which soak into the wood. Intumescent coating for wood can be divided into onsite and offsite applications as well as products for home applications.
- Onsite: the onsite applied intumescent wood coatings are applied on wooden surfaces as the first coating or on a special primer which enhances adhesion. These coatings belong to class A or B and protect for 60 to 120 minutes depending on the building’s requirements.
Product example: Sayerlack (Sherwin Williams) and Envirograf intumescent varnish for wood
- Offsite/ prefabrication: industrial intumescent paint for wood is often applied as part of the wood processing (prefab.) in order to cover as great area as possible, and guarantee optimal protection. The prefab intumescent coatings for wood are class A fire rated and protect for up to 120 minutes.
Product example: TEKNOS Teknosafe 2407-00
- At home: the consumer intumescent paint for wood exists in two types; one that can be applied to previously painted substrates and another that is suitable for direct to wood applications. The consumer products range from class B to C and protect for 30 – 60 minutes.
Product example: Fire Retardants Inc. Burn Barrier 20-20
Tip: any intumescent wood paint can be topped with a compatible fire retardant wood coating to increase the fire resistance. In such a system the intumescent paint for wood is a base coat (usually applied on a primer) which provides the best protection. The top coat however, keeps the flames at distance to postpone the swelling reaction extending the time the wood remain unaffected.
Intumescent paint for steel and wood in Qatar – Manufacturers and contractors
There are many intumescent paint products available in Qatari market. When it comes to the global manufacturers of intumescent paint Sherwin Williams, AkzoNobel, Jotun, FireOFF and Thermoguard are on the top. The coverage and fire resistance of intumescent coating for steel and wood are dependent upon correct application. If you would like any more information regarding intumescent paint, or would like to be connected with one of our partners for your project, contact us! Our experts are here to help, just use the “Request a quote” button at the bottom of this article and take advantage of our 100% free quote service.
The certified contractors also rely on for example AkzoNobel and Sherwin Williams intumescent paint products which are distributed to multiple intumescent paint suppliers. Note that the cost of intumescent paint is a sum of many factors; the coating type, film thickness, required resistance and application to name a few. Below you can find a short list of intumescent coating contractors operating in Qatar.
|Intumescent paint company||Address in Qatar|
|Jascon Engineering WLL||P.O.Box 55795, Doha, 103, 104, Block 16, Arkan Building,, Barwa Commercial Avenue, Doha, Qatar|
|DicoTech||P.O.Box: 23106, Doha, Qatar|
|Rise & Shine Trad. Cont. Co. Wll||Office No-1, Bin Mahmood Bldg, Al Rawabe Street, Doha, Qatar|