Description
Thermocoat WI Interior Structural Steel Fire Protection
Thermoguard Thermocoat WI is a water-based intumescent coating for interior structural steel and cast iron. It is designed to help protect load-bearing steelwork by slowing the rise in steel temperature during a fire.
When exposed to high heat, Thermocoat WI expands to form an insulating char layer. This helps the steel retain strength for longer, supporting fire safety requirements in commercial, industrial, public and residential buildings.
What It Does
- Provides fire protection for internal structural steel and cast iron.
- Can achieve up to 90 minutes fire resistance when applied to the correct specification.
- Expands under fire conditions to help insulate the steel beneath.
- Helps protect beams, columns and open steel sections.
- Works as part of a complete Thermoguard steel protection system.
Why Choose Thermocoat WI?
- Made for interior steelwork: ideal for steel beams, columns and open sections inside buildings.
- Water-based formula: low odour and easier to work with on occupied or sensitive sites.
- Project-friendly specification: suitable for larger jobs where exact coating quantities and film thickness need to be calculated.
- Flexible application: apply by brush, roller or airless spray.
- Decorative finish options: can be completed with compatible Thermoguard flame retardant finishes.
Where It Can Be Used
- Interior structural steel
- Cast iron
- Universal beams
- Steel columns
- Open section steelwork
- Commercial and public buildings
- Refurbishment and new-build projects
Important External Use Note
- Thermocoat WI is intended for interior steel protection.
- For exterior exposed steel environments, use Thermoguard Thermocoat S instead.
- If the steel location is unclear, ask Thermoguard for specification guidance before ordering.
Ideal For
- Commercial buildings
- Schools and colleges
- Public sector buildings
- Industrial units
- Residential developments
- Offices and retail spaces
- Large steel upgrade projects
Fire Performance
- Can provide up to 90 minutes fire resistance when correctly specified.
- Designed for structural steel and cast iron fire protection.
- Correct dry film thickness must be calculated for the steel section and required fire rating.
- Thermoguard can provide a basecoat application schedule for suitable projects.
- A wet film gauge may be used to help confirm correct application during the project.
Application Information
- Apply by brush, roller or airless spray.
- Airless spray is recommended where a smoother finish and faster application are required.
- Brush and roller application may be suitable for smaller areas or site repairs.
- Do not exceed the recommended wet film thickness per coat.
- Always follow the project-specific application schedule provided by Thermoguard.
Preparation
- Steel and cast iron must be clean, dry and free from rust, millscale, grease and loose material.
- Steel should be primed with Thermoguard Steel Fire Paint Primer or a compatible anti-corrosive primer suitable for intumescent coatings.
- Galvanised steel requires suitable pre-treatment and priming before application.
- Correct preparation is essential for adhesion, finish and fire performance.
Drying and Overcoating
- Drying time depends on application method, coating thickness, temperature, airflow and humidity.
- Allow each coat to dry fully before recoating.
- Allow the system to cure correctly before applying a compatible Thermoguard flame retardant finish.
- For large projects, confirm drying and overcoating times with the technical team before scheduling follow-on trades.
You May Also Need
- Thermoguard Steel Fire Paint Primer for correctly prepared steel and cast iron.
- Thermoguard Flame Retardant Topcoat where a decorative or protective finish is required.
- A project-specific specification to confirm product quantities, film thickness and coating build-up.
Good To Know
- Thermocoat WI is best suited to internal structural steel projects.
- The amount of coating required depends on the steel size, section factor and fire rating needed.
- Do not estimate fire protection coverage from tin size alone.
- For 60 or 90 minute protection, project-specific advice is strongly recommended.
- Certificate support may be available where the product has been specified, purchased and applied correctly.
Need Help With Your Steel Specification?
Structural steel fire protection must be matched to the steel section, required fire rating and site conditions. If you are unsure how much Thermocoat WI you need, contact Thermoguard before ordering.
Technical Support: 01142 768008
Email: technical@thermoguard.co.uk
