Intumescent Fire Coatings

Intumescent Fireproofing

The potential damage and injury brought about by a fire in your facility can be catastrophic, no matter how large or small the incident. Preparing for this worst-case scenario by incorporating structural fire protection and spray applied fireproofing with a fire retardant or intumescent coating is absolutely crucial when building or renovating any steel structure. Always use a reputable passive fire protective company.

How intumescent paint works

Intumescent paint application gives typically between 30 to 120 minutes of fire protection to structural steel and can be up to 50 times thicker than normal paint. In the event of a fire, the intumescent coating for steel will begin to char and expand and as it does so, it insulates and slows down the transfer of heat to the structural steel, helping keep the steel structurally sound during a fire to enable the building to be evacuated.

VariBlast provides a professional fireproofing service

As professional intumescent painting contractors and one of the UK’s leading fire retardant companies, our highly skilled operatives are fully trained in the preparation and application of fireproof paint and intumescent spray fireproofing for steel structures, to include beams, columns and other structural steels. We work with our clients and principal contractors to devise the best structural steel fireproofing solution for their projects. 

Using strict guidelines for both safety and construction, we then apply the specified fire retardant paint for steel using the following processes:

1. Surface preparation

Prior to the intumescent fireproofing paint being applied, we prepare the surface to ensure that it complies with the coating manufacturer’s guidelines.

We work with specialist intumescent paint manufacturers who supply most professional passive fire protection companies. These manufacturers include:

Sherwin Williams intumescent paint

Nullifire intumescent paint

International Paints intumescent paint

Jotun Paints intumescent paint

2. Coating specification

The paint manufacturer produces steel calculations to ensure the correct amount of protection for each individual steel member. Pre-primed steel is checked to ensure that the primer has been applied correctly and is compatible with the specified intumescent coating. 

White fire retardant paint is most commonly available and some applications may require a topcoat where colour is an issue.

3. Application monitoring

Conditions such as substrate temperature, ambient temperature, dew point and humidity are monitored using electronic measuring devices regularly to ensure compliance with the coating manufacturer’s guidelines.

We use wet film gauges to ensure that the intumescent coatings are applied at the correct micron thickness and dry film gauges to ensure that the correct dry film thickness has been achieved.

4. Project documentation

On completion, we provide a documented log of all applications and inspections carried out during the course of the works to prove that, in the unfortunate event of a fire, the system has been installed correctly and complies with the manufacturer’s guidelines.

5. Certificate of conformity

Finally, we issue a certificate of conformity from the coating manufacturer to confirm that the correct quantities of coating have been purchased to satisfy the criteria of the steel calculations issued.

Intumescent Fire Coatings Case Studies

International Aviation Academy

To arrange a site meeting or discuss a quote, call VariBlast now on 01508 493320 or email