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Thermoguard THERMOCOAT

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Thermocoat is a water-based intumescent paint system providing fire resistance to structural steel and cast iron of up to two hours with a minimum number of coats.

A compatible decorative overcoat system ensures the system will enhance the building’s architectural and design features.

How it works

The heat of a fire triggers a catalytic reaction, causing the expansion of an insulating char layer up to 50 times the paint thickness.

This layer keeps the steel below its critical temperature, thus maintaining the structural integrity of the building.

intumescent paint protecting steel girder



Product performance assessment is based upon UKAS/ NAMAS Fire Test Laboratory Certification to BS 476 Part 21 - Fire Resistance to load bearing elements of structures.

Please consult Technical Department 01624 825115 for detailed specification advice.

FIRE CERTIFICATIONintumescent steel


Thermoguard issue a Certificate of Supply on request for eachspecified project for insurance,Fire and Building Control Authority and Client Records.



Steel and cast iron should be free from rust and millscale and primed with Thermoguard High Build Metal Primer to 75 microns DFT (or alternative good quality anti-corrosive primer compatible with intumescent paints) in accordance with manufacturers instructions.

Galvanised steel should be degreased with a suitable etch primer like Thermoguard One Pack Etch Primer.

Thermoguard High Build Metal Primer may be left without further overcoating or decorated with appropriate conventional paint where no fire resistance is required.


Thermocoat is available ex-stock in 20kg, 5kg and 2.5kg containers.

Thermoguard Flame Retardant Finishes are available in 2.5l and 5l sizes in a wide choice of colours and finishes.

Technical Advisory and Estimating Service

Thermoguard's in-house estimators provide realistic, confidential guidance on project costings to contractors and quantity surveyors. They also provided expert advice and assistance with all aspects of specification and application.


Online: Enquiry Form

Phone: Technical Helpline - 01624 825 115
Fax: 01624 825 526


Thermoguard is ISO 9000 Registered. All products are manufactured and supplied under ISO 9000.


To Specify simply state

Apply Thermocoat to achieve...

Fire Resistance in accordance with the instructions provided by Thermoguard's Technical Department.

When steel is visible or subject to variable or damp atmospheric conditions, apply 1 coat of Thermoguard Flame Retardant Paint (available in Gloss, Eggshell or Matt finishes).


Thermocoat W may be applied by brush, roller or airless spray.

To achieve the best finish in the shortest time, spray application is recommended. Prior to application the contractor should contact Thermoguard's Technical Department and obtain a basecoat application schedule.

To assist correct application in accordance with this schedule, a wet film gauge will be supplied with the order. Further wet film gauges will be provided on request.

  • Maximum wet film thickness per brush coat – 800 microns

  • Maximum wet film thickness per spray coat – 1400 microns.


Brush/roller application

  • Surface dry: minimum 2 hours

  • Recoat: minimum 4 hours

  • Overcoating with Flame Retardant finish: minimum 10 hours

Spray application

  • Surface Dry: minimum 4 hours

  • Recoat: minimum 10 hours

  • Overcoating with Flame Retardant finish: minimum 48 hours

Spray Equipment

Airless Spray Pump
Use equipment recommended by manufacturer for the application of high viscosity intumescent paints.

Filter size
30 mesh. 10mm hose 3/8 diameter with no whip end.

Tip Size
327-329 for narrow surfaces (6” fan)
427-429 for broad surfaces (8” fan)

Care should be taken to clean filters regularly.

Cleaning should be undertaken with water.


Intumescent compounds and resin binders, with high opacity pigments.

Application Conditions

  • Maximum Relative Humidity 80%

  • Minimum ambient temperature 4°C

  • Minimum Steel Temperature 3°C above Dew Point


Thermoguard Thermocoat W is a low-odour, water-based coating, making it user and environmentally friendly. The range of topcoats are either water-based or 2010 compliant and safe to use in accordance with manufacturer's instructions.


Refer to Health and Safety Data Sheet prior to using this product.

COSHH Datasheet

Illustrations of Structural Steel Terminology

Thermoguard, Kirkby Street, Hull, HU2 0HE

Tel: 01142 768008 | Fax: 01142 381966


All materials and specifications are provided in accordance with the Terms and Conditions of Thermoguard UK Ltd.

Refer to Health & Safety Data Sheets before using these products.


LINKS - Intumescent Paint : Flame Retardant Paint : Fire Varnish : Timbercoat : Wallcoat for Walls & Ceilings : Asbestos Encapsulating Coat : Home  : Request Information