S605 Intumescent Basecoat is a single pack solvent-based intumescent coating for fire protection of both internal and external structural steelwork. It is suitable for universal and hollow sections and for long term durability and external use, a top seal would be required.
Nullifire S605 has been certified to provide from 60 minutes up to 120 minutes fire rating.
(BS 476:Part 2 1987.)
Ensure then surface is clean, undamaged, dry, suitably primed* and free from grease or other materials that may affect adhesion.
Special Note *
When selecting primers, please note thermoplastic primers may cause adhesion problems and should be avoided. Recommended Primers are Nullifire PM015 and PM018.
Galvanised steelwork should be prepared by an application of T-wash or mordant solution followed by a compatible primer.
If a Zinc Rich Primer is used, it is advisable to seal this with a suitable holding coat to the avoid the formation of surface salts that may build up on the steel.
These salts, if not adequately removed, may cause adhesion problems for any subsequent coating applied.
Ensure air and steel temperatures are above 5°C and below 35°C.
Relative humidity should be below 80% and the steel surface temperature should be a minimum of 3°C above the dew point.
Ensure the steel is dry and free from contact with rain or condensation during application.
If the basecoat is allowed to get wet during the drying phase it is likely to be damaged – surface patterning, blistering and wrinkling may occur.
Nullifire S605 is supplied ready for use. Do not thin.
Airless spray equipment is recommended. Typical equipment settings would be:
Operating Pressure: Min 3500psi (250 kg/cm²)
Tip Size: 19 – 23 thou
Fan Angle: 20° – 40°
Hose Diameter: 10 mm (3/8”) (internal diameter)
Hose Length: Max. 60 metres.
Inline filters should not normally be used.
Nullifire S605 can be applied up to a maximum wet film thickness (WFT) of 1.1 mm in a single spray coat comprising of several quick passes.
Build up the film thickness to achieve the loading required in several quick passes.
It may be possible to apply two coats in one day particularly if the atmospheric temperature is above 20°C and relative humidity below 70%.
However, before doing this, ensure that the previously applied coat is dry, particularly in the web/flange junctions.
Brush and Roller application
For brush application use a “laying on” technique to avoid heavy brush marking.
Maximum wet film per coat when applied using a brush or roller is 1 mm.
A short pile roller will produce a light textured finish.
During application, measure the wet film thickness (WFT) frequently with a WFT gauge to ensure the correct thickness is being applied.
Drying time will be dependent upon temperature, air movement, humidity, method of application and the thickness of the coating.
High humidity and low air movement or low steel temperatures can result in condensation on the steelwork causing prolonged drying times and possibly poor basecoat adhesion.
Heavy loadings may need longer before recoating when applying loadings in excess of 3000g/m². In these circumstances the drying times will be extended and depending on atmospheric conditions the time between basecoat and top seal may be up to 5 days for lower loadings or up to 15 days for maximum loadings.
When high loadings are specified, it is preferable to apply a greater number of thinner coats (say 1000g/ m²) allowing each to dry thoroughly before overcoating. This allows each individual coat to dry before overcoating and reduces the final drying time before application of the topseal.
Brush or roller application may add up to 20% extra to the drying and recoat times compared to spraying.
Cleaning of Equipment.
Pump, mixer and hose should be cleaned with an appropriate product such as Nullifire FC150.
Please observe the Safety Data information and for any questions please do not hesitate to call us.