Intumescent · exterior exposure
Exterior-grade intumescent systems
Steel outside the building envelope needs an intumescent system proven to keep its fire performance after weathering.
- Exterior / semi-exposed
- Exposure
- EAD 350402 type X or Y
- Durability
- Primer + intumescent + topcoat
- System
Supplied by World Steel with your steel building or on its own – one order, one shipment, one partner.
Overview
About Exterior-grade intumescent systems
The European assessment document EAD 350402 classifies reactive coatings for durability: type X for all conditions including exterior, type Y for internal and semi-exposed, Z1 and Z2 for internal conditions; EN 16623 sets durability requirements as well.
Exterior systems are usually solvent-based or epoxy intumescents with a compatible sealer or topcoat; the whole system – primer, basecoat and topcoat – is what was tested.
Corrosion protection of the steel underneath follows ISO 12944 for the environment.
Key benefits
- Proven fire performance after weathering
- Protects exposed steel and canopies
- Works with ISO 12944 corrosion systems
- Shop or site application
World Steel · building envelope hub
How we use Exterior-grade intumescent systems in steel buildings
World Steel specifies the full coating system from blast cleaning to topcoat and applies it in the shop where practical.
Product-specific test reports, classification reports and certificates are supplied for the product selected for each project – this page describes the product type, not a certified product.
- 01Specified with the structure – thickness, density and facing matched to the roof, wall and fire design.
- 02Quantities taken from the same 3D model as the steel, purlins and cladding.
- 03Packed and shipped with the steel package – one delivery schedule to site.
Applications
Where Exterior-grade intumescent systems is used
- External steel frames and canopies
- Open car parks and walkways
- Semi-exposed industrial structures
Technical data
Exterior-grade intumescent systems – technical properties
Typical properties and standards
| Property | Unit | Value |
|---|---|---|
| Durability | — | EAD 350402 types X / Y / Z1 / Z2 · EN 16623 |
| Fire test | — | EN 13381-8 · UL 263 · BS 476-20/21 · AS 1530.4 |
| Corrosion | — | ISO 12944 primer and topcoat compatible with the intumescent |
Values as published by the manufacturer for this market. Always check the current data sheet and the approvals required for your project before ordering.
FAQ
Frequently asked questions
Can an interior intumescent be used outside with a topcoat?
Only if that complete system has been tested for exterior durability – otherwise choose an exterior-qualified system.
Is this product certified?
Certification belongs to a specific manufacturer’s product or tested system. We supply the test report, classification or listing accepted in your market for the product selected – it is confirmed per project, never assumed.
One partner for structure and envelope
Send us your drawings or bill of quantities – we quote the steel, insulation, boards and ceilings together and ship them as one package.

