Description
Thermocoat WO Hollow Section Steel Fire Protection
Thermoguard Thermocoat WO is a water-based intumescent coating developed specifically for hollow section structural steel and cast iron. It is designed to help protect load-bearing steelwork by slowing the speed at which steel temperatures rise during a fire.
When exposed to intense heat, Thermocoat WO expands to form a highly insulating char layer. This protective barrier helps the steel retain strength for longer, supporting structural stability and helping to meet fire protection requirements.
What It Does
- Provides fire protection for hollow section structural steel.
- Designed for CHS, SHS and RHS steel sections.
- Can achieve up to 90 minutes fire resistance when specified correctly.
- Expands during fire conditions to create an insulating protective layer.
- Suitable for use within approved Thermoguard steel protection systems.
Why Choose Thermocoat WO?
- Optimised for hollow sections: specially formulated for circular, square and rectangular hollow steel sections.
- Water-based technology: lower odour and easier to work with than traditional solvent-heavy systems.
- Architectural finish compatibility: works with decorative Thermoguard topcoats for exposed steelwork.
- Professional specification support: Thermoguard can calculate the correct coating build-up for your project.
- Efficient application: designed to achieve fire protection with a minimal number of coats where possible.
Where It Can Be Used
- CHS hollow section steel
- SHS square hollow section steel
- RHS rectangular hollow section steel
- Architectural exposed steelwork
- Internal structural steel
- Commercial and public buildings
- Refurbishment and new-build projects
Ideal For
- Modern architectural steelwork
- Commercial developments
- Office buildings
- Retail and leisure projects
- Schools and colleges
- Industrial units
- Visible feature steelwork
Fire Performance
- Can provide up to 90 minutes fire resistance when correctly specified.
- Designed for load-bearing structural steel fire protection.
- Tested for structural steel fire performance applications.
- Film thickness requirements vary depending on steel section size and required fire rating.
- Always request a project-specific specification before large applications.
How It Works
- Under fire conditions, the coating reacts to heat and rapidly expands.
- The expanded char layer can grow many times thicker than the original coating.
- This insulating barrier helps delay the steel reaching critical failure temperature.
- By slowing heat transfer, the structural integrity of the steel can be maintained for longer.
Application Information
- Apply by brush, roller or airless spray.
- Airless spray application is recommended for larger projects and smoother finishes.
- Wet film thickness must be monitored during application.
- Do not overspread the coating, as this can compromise fire performance.
- Application schedules should always follow Thermoguard technical guidance.
Surface Preparation
- Steel and cast iron must be clean, dry and free from rust, grease and millscale.
- Apply over a compatible anti-corrosive primer suitable for intumescent systems.
- Galvanised steel requires suitable pre-treatment and priming before coating.
- Correct preparation is essential for both adhesion and certification compliance.
Decorative Finishes
- Can be overcoated using compatible Thermoguard Flame Retardant finishes.
- Available decorative options include gloss, eggshell, satin and matt finishes.
- Suitable colour systems include RAL and BS colour ranges.
- Ideal where exposed steelwork forms part of the visible building design.
Environmental Conditions
- Suitable for dry internal environments when used as specified.
- Occasional damp internal areas may require additional protective topcoats.
- External under-cover steel may require further protective coats.
- For full external exposure, contact Thermoguard technical support before application.
You May Also Need
- Thermoguard Steel Fire Paint Primer for correctly prepared steel surfaces.
- Thermoguard Flame Retardant Topcoat for decorative and protective finishing.
- Project-specific film thickness calculations from the Thermoguard technical department.
Good To Know
- Thermocoat WO is specifically formulated for hollow section steels rather than open steel sections.
- The required coating thickness changes depending on steel dimensions and fire rating targets.
- Applying insufficient coating thickness may invalidate fire performance.
- Water-based technology helps reduce odour during application.
- For certification support, accurate records of products and application rates should be retained.
Need Help Calculating Your Steel Protection System?
Hollow section steel requires accurate film thickness calculations to achieve compliant fire protection. Thermoguard can help specify the correct coating system for your project before ordering.
Technical Support: 01142 768008
Email: technical@thermoguard.co.uk
