FIRETEX Application

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Technical Advisory Document TAD0009

Method Statement

For Shop Application and Subsequent Site Treatment and Repair of FIRETEX Thin Film Shop Applied Single Pack Intumescents.

1. All steel to be abrasive blasted to minimum standard Sa2.5, surface profile in the range 30 - 50 microns.
2. Apply FIRETEX C69 at 25 ± 10 microns dft and in accordance with the C69 Technical Data Sheet. The top flanges of beams can be left uncoated, but it is recommended that these are primed to prevent rusting and subsequent staining of the FIRETEX.
   
   Other approved primers can be used in accordance with their own Technical Data Sheets.
3. FIRETEX is to be applied in accordance with the relevant Technical Data Sheet. It is recommended that no more than 1000 microns wft (700 microns dft) is applied in one coat to minimise overall drying time. This is guidance only and can be adjusted to suit particular circumstances.
4. Where more than one coat of FIRETEX is required, overcoating can take place after a minimum of 4 hours at 15°C.
5. Prior to application of topcoat the dft of the FIRETEX must be checked, and be in accordance with Leighs Paints document titled 'Guidance notes for Dry Film Thickness Measurement of Intumescent Coatings'.
6. Once the FIRETEX dft has been deemed to be satisfactory, the topcoat should be applied if one is required. This requirement will be dependent on subsequent exposure and end use conditions. Only Leighs Paints approved topcoats can be used.
7. For subsequent handling of steelwork, it is recommended that this is in accordance with Section 3 (Pgs 9-12) Off–Site Application of Intumescent Coating Systems of the document titled 'Structural Fire Design: Off-Site Applied Thin Film Intumescent Coatings (Second Edition)' - SCI document.
   
   Prior to any handling of the steel after application of FIRETEX, the coating should be hard enough to minimise potential for damage. This cannot be quantified, as it depends on factors such as coating thickness, temperature, humidity, air movement, steel size, but for thicknesses up to 700 microns dft handling time may be as low as overnight. For higher thicknesses this will be extended. It may then be necessary to leave the steel for 36 - 48 hrs before handling, because of the higher dfts.
   
   Handling time may be accelerated by increasing shop temperature and air movement, conversely they will be lengthened at lower temperatures where there is poor ventilation.
8. Once at site and erected, as soon as is practical, site repairs must be carried out. Remove FIRETEX to a firm edge, wirebrush the steel if necessary to remove any rusting, then apply Leighs M600 (or other suitable approved primer). Overlap of the M600 onto existing FIRETEX should be kept to a minimum. For small areas of repair, the use of FIRETEX M72 (a repair mastic) is advised, applied by trowel (or similar). For any larger areas, the relevant FIRETEX material applied by brush or spray is recommended although due to site requirements it may be necessary to use the site applied version of the product.
   
   All areas of repair should be brought up to the same dry film thickness as the original specification for the section. For areas of 50mm² or less it should be possible to gauge this from a visual inspection and only if thickness appears to be significantly below specification should dry film thickness readings be required.
9. All bolt heads (assuming they are galvanised) should be degreased and then treated with Leighs L703 Mordant Wash in accordance with the L703 Technical Data Sheet, then the relevant FIRETEX material brush applied to the same dft as that of the section which the bolt head will be connected to.
10. All areas of repair and bolt heads should then have the relevant topcoat applied.

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