Thermocoat WO

Thermoguard Thermocoat WO: Efficient Fire Protection

Thermoguard Thermocoat WO is a high-performance, water-based intumescent paint providing up to 90 minutes of fire resistance for structural steel and cast iron. Ideal for CHS, SHS, and RHS hollow sections, it ensures rapid application and reduced costs.

Key Benefits

  • Economical: Fewer coats needed, lowering labor and material costs.
  • Fast Drying: Quick application and project completion.
  • Certified: Meets BS 476 Part 21 standards for fire resistance.


  • Methods: Brush, roller, or airless spray.
  • Preparation: Clean surfaces and apply primer.
  • Recoating: Specific times for brush/roller and spray applications.

For technical support or a Certificate of Supply, contact our technical department.

Protect your structural steel with Thermoguard Thermocoat WO. Purchase now for certified fire resistance.


Thermoguard Thermocoat WO: Premier Fire Protection for Structural Steel

Product Overview

Thermoguard Thermocoat WO is an advanced, water-based intumescent paint system, designed to offer up to 90 minutes of fire resistance for structural steel and cast iron. This high-performance coating is optimized for rapid application, making it an economical and efficient solution, especially suited for CHS (Circular Hollow Section), SHS (Square Hollow Section), and RHS (Rectangular Hollow Section) structural elements.

Key Benefits

  • Optimized for Hollow Sections: Specifically designed for CHS, SHS, and RHS hollow sections, ensuring thorough fire protection for these structural forms.
  • Economical Application: Requires fewer coats, significantly reducing labor and material costs.
  • Fast Drying and Application: Enables quick project turnaround, minimizing downtime and operational disruption.

How It Works

Thermocoat WO activates under fire exposure, initiating a catalytic reaction that causes the paint to expand and form an insulating char layer up to 50 times the original paint thickness. This char layer insulates the steel, maintaining its structural integrity by keeping it below critical temperatures during a fire.

Fire Testing and Certification

  • Certified by UKAS/EGOLF Fire Test Laboratory: Adheres to BS 476 Part 21 standards for fire resistance of load-bearing structural elements.
  • Reliable Fire Resistance: Ensures compliance with safety regulations, providing peace of mind for building owners and occupants.
  • Certificate of Supply: Issued upon request for insurance records, fire and building control authorities, and client records.

Preparation and Pre-Treatment

Proper surface preparation is critical for the effectiveness of Thermocoat WO:

  • Surface Cleaning: Ensure steel and cast iron surfaces are free from rust, mill scale, and other contaminants.
  • Priming: Apply Thermoguard Steel Fire Paint Primer to a thickness of 75 microns DFT. For galvanized surfaces, treat with Teamac Mordant Solution (T Wash) before priming. The primer can remain uncoated or be overcoated with conventional paint where no fire resistance is required.


Application Environments

  • Dry Internal Areas: Apply Thermocoat WO according to the film thickness schedule provided by the technical department to achieve 30, 60, or 90-minute fire protection.
  • Visible or Occasional Damp Internal Areas: Apply one good coat of Thermoguard Flame Retardant Topcoat, available in Gloss or Eggshell finishes.
  • Wet or External Under Cover: Apply a second coat of Thermoguard Flame Retardant Topcoat, available in Gloss or Eggshell finishes.
  • Full External Exposure: Contact the technical department for specific guidance on application in fully exposed external conditions.

Application Methods

Thermocoat WO can be applied using various methods for optimal results:

  • Brush Application: Maximum wet film thickness of 800 microns per coat.
  • Roller Application: Similar application thickness as brush.
  • Airless Spray Application: Recommended for the best finish and fastest application, with a maximum wet film thickness of 1400 microns per coat.

Steps for Application:

  1. Contact Technical Department: Obtain an application schedule tailored to your project needs.
  2. Use Wet Film Gauge: Ensure correct application thickness using a wet film gauge, available upon request.

Recoating Times

Different application methods have varying recoating times:

  • Brush/Roller Application:
    • Surface Dry: Minimum 2 hours
    • Recoat: Minimum 4 hours
    • Overcoating with Thermoguard Flame Retardant Topcoat: Minimum 10 hours
  • Spray Application:
    • Surface Dry: Minimum 4 hours
    • Recoat: Minimum 10 hours
    • Overcoating with Thermoguard Flame Retardant Topcoat: Minimum 48 hours

Spray Equipment

For optimal spray application, use the following equipment:

  • Airless Spray Pump: Manufacturer-recommended for high-viscosity intumescent paints.
  • Filter Size: 30 mesh
  • Hose: 10mm hose, 3/8” diameter with no whip end.
  • Tip Sizes: 319, 321, 419, 421
  • Maintenance: Regularly clean filters with water to ensure smooth operation.

Application Conditions

To ensure the best results, adhere to these conditions:

  • Maximum Relative Humidity: 80%
  • Minimum Ambient Temperature: 4°C
  • Minimum Steel Temperature: 3°C above Dew Point

Steel Terminology

Understanding the terminology is essential for correct application:

  • CHS (Circular Hollow Section): A type of hollow structural section with a circular cross-section.
  • SHS (Square Hollow Section): A hollow structural section with a square cross-section.
  • RHS (Rectangular Hollow Section): A hollow structural section with a rectangular cross-section.

Request a Certificate of Supply

To request a Certificate of Supply, click HERE. This certification is essential for:

  • Insurance Records: Ensures compliance with insurance requirements.
  • Fire and Building Control Authorities: Provides necessary documentation for regulatory compliance.
  • Client Records: Maintains detailed records for future reference.

For further assistance, detailed technical support, or to request a Certificate of Supply, please contact our technical department or click HERE.

Ensure the highest standard of fire protection for your structural steel and cast iron components with Thermoguard Thermocoat WO. Buy now and safeguard your project with reliable, certified fire resistance.

Technical Data Sheet

Thermocoat WO TDS

Health & Safety Data Sheet

ThermoCLPThermocoat WO140722