Arcshield IN 260 Thin-Film Intumescent for Cellulosic Fire
A thin-film intumescent basecoat, in solvent-borne or water-borne acrylic chemistry, for structural steel columns, beams and bracing exposed to a cellulosic fire. It is used with a compatible primer beneath and a sealer topcoat above for colour and exposure durability.
Grade Arcshield IN 260 | Range Protective and Marine Coatings | Technology Solvent-borne or water-borne acrylic thin-film intumescent
Technical Data Sheet
Arcshield IN 260
Issue 2026.09
1. Product description
A thin-film intumescent basecoat, in solvent-borne or water-borne acrylic chemistry, for columns, beams and bracing exposed to a cellulosic fire, used with a compatible primer beneath and a sealer topcoat above for colour and for exposure durability. Applied thickness is not calculated from first principles: it is read from loading tables generated by third-party furnace testing of the specific product and indexed to the section factor of the member, the critical steel temperature and the required period of fire resistance. A period of fire resistance is certified for a tested system on a tested section, and it is not a property of a product on its own.
2. Features
- Solvent-borne or water-borne acrylic basecoat
- Applied thickness read from the loading tables of the tested system for each member
- Primer, basecoat and sealer specified and inspected as one system
- Sealer selected for internal dry, semi-exposed or exposed positions
3. Recommended uses
Fire protection of structural steel columns, beams and bracing where the design fire is cellulosic. A period of fire resistance is certified for a tested system on a tested section, and it is confirmed against the enquiry rather than claimed for the product alone.
Substrates. Blast cleaned or shop primed structural steel sections, over a compatible anti-corrosive primer. Internal dry, semi-exposed and exposed positions each require the sealer and system specified for that exposure, and cellular beams, hollow sections and connections are treated according to the assessment that accompanies the test evidence.
4. Typical properties
| Property | Typical value | Method |
|---|---|---|
| Technology | Solvent-borne or water-borne acrylic thin-film intumescent | Formulation |
| Appearance | Matt basecoat; colour and finish provided by the sealer topcoat | Visual, supplier protocol |
| Carrier | Solvent-borne or water-borne grade, as stated on the order and product data | Customer or supplier protocol |
| Volume solids | Typically 65 to 75 per cent | ISO 3233-1 |
| Fire exposure | Cellulosic fire; the period of fire resistance is a property of the tested system on a tested section, not of the product alone | Third-party furnace testing of the tested system to the standard named in the specification, for example EN 13381-8 |
| Applied thickness | Read from the loading table for each member, indexed to section factor, critical steel temperature and required period of fire resistance | Loading tables of the tested system, thickness measured to ISO 2808 |
| Exposure durability | Sealer and system specified for internal dry, semi-exposed or exposed positions | Customer or supplier protocol; durability class to EN 16623 where the specification calls for it |
| Drying between passes | Intermediate drying before the next pass, lengthening with film build, low temperature and high humidity | ISO 9117-1 |
Typical values, not a specification. Values for each batch are given on its Certificate of Analysis.
5. Application
| Parameter | Guidance |
|---|---|
| Method | Airless spray in multiple passes with intermediate drying; brush and roller for touch-up and detail. |
| Substrate and primer | Blast cleaned or shop primed structural steel over a compatible anti-corrosive primer. Cellular beams, hollow sections and connections are treated according to the assessment that accompanies the test evidence. |
| Applied thickness | Read from the loading table for each member. Wet film thickness logged pass by pass and dry film thickness verified per member to ISO 2808 against the loading table. |
| Records | Thickness records kept per section, because the record is the evidence for the rated period. |
| Application conditions | Steel temperature at least 3 °C above dew point (ISO 8502-4) and relative humidity normally 85 per cent or less during application and drying, held lower for the water-borne grade as stated on its product data, because it dries slowly in humid or cold conditions and the next pass cannot follow until it has dried. |
| Sealer topcoat | Applied after the basecoat has dried, for colour and for durability in the internal dry, semi-exposed or exposed position concerned. |
Process. Airless spray in multiple passes with intermediate drying, brush and roller for touch-up and detail. Wet film thickness is logged pass by pass and the dry film thickness is verified against the loading table for each member, with records kept per section, because the thickness record is the evidence for the rated period.
6. Storage and handling
Store in the original closed containers in a dry, covered store, typically between 5 and 35 °C and out of direct sunlight, and protect water-borne grades from frost. Shelf life is stated on the label and the Certificate of Analysis. Handle and use the product in line with its Safety Data Sheet.
7. Safety and regulatory information
Read the Safety Data Sheet before use. Safety Data Sheets and regulatory declarations are issued by our technical centre against the product and batch supplied, so they are sent on request rather than published. Request a Safety Data Sheet or declaration.
This Technical Data Sheet is published for on-screen reference. The information is given in good faith from laboratory and application experience and describes typical values; it is not a specification and does not replace a trial on your own substrate and line. Arctic Materials may revise this sheet without notice. Issue 2026.09.
Technical Data Sheets on this site are for on-screen viewing. For a controlled copy, write to tech@arcticmaterials.com.
Other grades in this range
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