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Material Description
Cafco SPRAYFILM® WB3 is a water-based intumescent
coating consisting of polyvinyl acetate resins and fillers for the fire protection of structural steel. It can be sealed
and protected with a decorative top coat.
Cafco SPRAYFILM® WB3 is applied directly to the contour
of primed I and H section columns, angles, channels and beams and hollow sections, to provide fire protection for up
to 120 minutes. In a fire, a chemical reaction takes place causing the Cafco SPRAYFILM® WB3 to expand and form an
insulating layer which slows the temperature of the steel rising to a critical level.
Advantages
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Provides fire resistance for up to 120 minutes in accordance with BS476: Part 21 and AS1530: Part 4 and up to 180 minutes
in accordance with ASTM E119. |
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Durable and decorative finish. |
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Steelwork may be left exposed to view. |
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Chemical and abuse resistant. |
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Can be top coated to match surroundings. |
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Easy application and clean up with water. |
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Fast drying time. |
Fire Protection Thickness
The thickness of the fire protection for a given period of fire resistance in a cellulosic type fire, relates to
the Hp/A ratio of the steel section. Hp/A is the ratio of the heated perimeter of a steel section exposed to fire
to the cross-sectional area of the same steel.
All column and beam sections have their own specific Hp/A ratio. Please consult Promat to establish the Hp/A ratio
for a particular beam or column section and to ascertain the required thickness of Cafco SPRAYFILM® WB3.
For advice on thickness calculations for I and H section beams and columns, castellated sections, composite floors,
upgrading of concrete slabs and more complex situations, please contact Promat.
Click to see the tables bellow on thickness for the fire resistance required.
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Table 1 |
Cafco SPRAYFILM® WB3 thicknesses for H section
columns (4-sided exposure). Critical temperature 550ºC. (AS1530: Part 4) |
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Table 2 |
Cafco SPRAYFILM® WB3 thicknesses for I section
beams (3-sided exposure). Critical temperature 620ºC, continuous concrete topping. (AS1530: Part 4) |
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Table 3 |
Cafco SPRAYFILM® WB3 thicknesses for hollow section
beams and columns (4-sided exposure). Critical temperature 550ºC. (AS1530: Part 4) |
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Table 4 |
Cafco SPRAYFILM® WB3 thicknesses for I section
beams (3-sided exposure). Critical temperature 620ºC, continuous concrete topping. (BS476: Part 21: 1987) |
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Table 5 |
Cafco SPRAYFILM® WB3 thicknesses for I section
beams (4-sided exposure). Critical temperature 550ºC. (BS476: Part 21: 1987) |
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Table 6 |
Cafco SPRAYFILM® WB3 thicknesses for H section
columns (4-sided exposure). Critical temperature 550ºC. (BS476: Part 21: 1987) |
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Table 7 |
Cafco SPRAYFILM® WB3 thicknesses
for hollow section beams and columns (4-sided exposure). Critical temperature 550ºC. (BS476: Part 21: 1987) |
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Typical Mechanical Properties
| Properties and
performance |
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Colour and finish |
White with flat matte finish. Preferably spray applied with airless paint equipment for speed and quality of finish.
Brush and roller application is also possible. |
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Maximum thickness per coat |
Wet film thickness (WFT) at 1.6mm using spray and 0.76mm using brush. For airless spraying, several thin coats
as opposed to one heavy coat will give greater control over finish and thickness. |
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Practical coverage |
Dependent on surface texture, substrate, application method and technique. |
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Theoretical coverage |
Approximately
18.79m² per container (1mm per litre) at 1mm WFT = 0.7mm DFT (Dry film thickness) = 1 litre per m² 1mm = 1000μm (microns) |
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Number of coats |
One or more as required |
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Cure |
By air drying |
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Initial set |
Approximately 6 hours at 20°C and 50% RH for 0.4mm WFT |
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Solids by weight |
70% ± 2% |
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Density |
1.33kg/litre |
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Surface burning |
Flame spread 5, smoke development 35 when tested to ASTM E84. |
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Durometer hardness |
80 shore D when tested to ASTM D2240 |
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Impact resistance |
18kg/m when tested to ASTM D2794 |
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Abrasion resistance |
0.6505g/1000 cycles when tested to ASTM D4060 |
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pH value |
8.0 ± 0.2 at 25°C |
| Fire resistance |
Structures protected with Cafco SPRAYFILM® WB3 have
undergone fire resistance tests at approved independent laboratories to recognised standards throughout the
world, including:
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UK (BS476: Part 21: 1987) |
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Canada and USA (ASTM E119 and
ASTM E84) |
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Australia (AS1530: Part 4) |
Assessed in accordance with ASFP “Fire protection for structural steel in buildings” procedures.
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Please consult nearest Promat office for specific details related to local, prevalent conditions.
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| Typical substrates |
Primed steel |
| Substrate preparation |
The substrate shall be clean, dry and free from dust, oil and any other condition preventing good adhesion.
Before applying Cafco SPRAYFILM® WB3 to structural steel, the
steel must be blast cleaned to SA 2.5 (ISO 8501-1: 1998), primed with a compatible primer approved by Promat Sprays Division
and applied in full compliance with the manufacturer’s recommendations.
Primers compatible with Cafco SPRAYFILM® WB3 are generally
of the following types:
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Alkyd zinc phosphate |
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Epoxy polyamide zinc phosphate |
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Zinc silicate (inorganic zinc)* |
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Epoxy zinc rich (organic zinc)* |
* Tie coat required
If left exposed for long periods zinc rich epoxies may form a layer of zinc salts on the surface. These salts must be
completely removed before applying Cafco SPRAYFILM® WB3.
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| Methods |
Cafco SPRAYFILM® WB3 is supplied ready for use and
should not be diluted. The primer thickness should be measured and recorded prior to the application of Cafco
SPRAYFILM® WB3, in order to be able to accurately check
the thickness of Cafco SPRAYFILM® WB3 during and after application.
Stir Cafco SPRAYFILM® WB3 thoroughly with a drill
type mixer prior to application by either airless spray, brush or roller.
Protect from rain and high humidity during application and drying. |
| Thickness checking during |
To ensure the correct thickness is being applied, frequent measurements should be taken using a wet film thickness gauge.
To determine approximate dry film thickness (DFT) based on wet film thickness (WFT), multiply WFT by 0.72.
For example: 1.3mm WFT x 0.72 = 0.936mm DFT |
| Limitations |
Take a dry film thickness reading as soon as the coating is fully cured. An Elecometer 211 permanent magnetic banana gauge or
Elecometer 456 electromagnetic (electronic gauge) type may be used. Ensure primer thickness is deducted from final thickness
reading.
If Cafco SPRAYFILM® WB3 is left exposed, it must be
protected from rain and high humidity or sealed with a topcoat appropriate for the environmental conditions. Please contact
Promat for appropriate product details. |
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Top coating |
In exposed and semi-exposed exterior environments, Cafco SPRAYFILM® WB3
should be coated with a compatible water resistant finish coat in order to give the desired colour and to seal the
Cafco SPRAYFILM® WB3.
The topcoat system must be suitable for the environment in which it is to be used, and should be a good quality, long oil alkyd,
silicone, acrylic latex or polyurethane type. All topcoats should be applied in accordance with the topcoat manufacturer's specific recommendations.
Ensure that the correct DFT of Cafco SPRAYFILM® WB3 is applied
and is thoroughly dry before application of any top coat.
Typically, allow a minimum of 7 days for the Cafco SPRAYFILM® WB3
to fully cure before application of any top coat system.
For the top coat compatibility and minimum thickness requirements, always consult Promat. |
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Packaging |
25kg plastic pails. |
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Storage |
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Indoors in dry conditions between 10°C and 38°C. |
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Protect from frost, excessive heat (above 45ºC) and strong radiant sunlight. |
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Shelf life |
Maximum 10 months in original sealed containers. |
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Environmental |
Do not discharge into drains, watercourses or soil. |
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Download full product description in PDF file. |
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