Steve Chanter from Watco explains the range of tests that a floor coating can go through to obtain CE accreditation, after Watco puts its own coatings through a series of rigorous tests
When choosing floor paint, there are various things to take into consideration. What is important to one customer, may be different to another. Probably the three most important qualities in a coating are just how durable it is, how well it bonds to the floor and how well it stands up to scratching. Because painting a floor is inconvenient and time consuming, the longer the paint lasts the better.
To give customers more insight into the products they are buying, Chemists at Watco completed a series of tests across the whole coating range, to relevant ISO standards. Nearly 800 tests later, Watco can claim to be the most highly qualified floor paint range available. They’re also the widest range of floor coatings carrying a CE Mark.
Four critical tests are required to obtain a CE Mark for a coating:
ABRASION RESISTANCE ISO5470-1
IMPACT RESISTANCE ISO 6272
ADHESION EN 1542
WATER PERMEABILITY EN1062-3
Abrasion Resistance test. To find out just how abrasion resistant or hard wearing a coating is, the Taber Abrasion Test replicates years of actual use in just a few hours.
A metal plate is coated, left to cure and put onto a turntable. As the turntable rotates at a fixed speed, two abrasive wheels, applied at a specific pressure, are then lowered onto the coating.
The plate is then weighed to see how much coating has been worn by the two wheels and the result is expressed in milligrams. The lower the milligram value the more abrasion resistant the coating is. To obtain a CE marking, the results have to be less than 3000 milligrams. (Watco Epoxy Gloss Coat, Best Ever Formula, lost only 57 milligrams, and Watco Concrete Floor Paint, Best Ever Formula, lost only 127)
Another way of illustrating how hard wearing a coating is the Wolff-Wilborn ‘Hardness’ Test. Interestingly it’s based on the same scale as pencil hardness.
Pencils are pushed into the sample and the hardness of the coating is identified by any scratch mark left. Various pencils are used until no mark or trace is left on the coating.
Impact Resistance test. Coatings are used in many different environments, and for certain environments like workshops or garages, how impact resistant a coating is, can be a real factor when deciding which one to use.
The test shows how much impact is needed before the coating shows signs of cracking or disbonding altogether. A 2kg weight on a rail is dropped from a pre-determined height, onto a coated metal sheet. If the coating shows signs of impact but hasn’t actually cracked, it’s classed as a pass, but if it cracks it’s a fail, so therefore the test has to be carried out again varying the weight and height, until it gets to a point where the paint film is still intact.
So, impact resistance, is determined by the calculation between the height from which the weight has been dropped, and the size of the weight itself.
The results are expressed in Newton meters (NM), and the higher the Newton meters, the better the impact resistance. To pass the CE marking threshold, coatings must have a minimum of 4 Newton meters which equates to a Class 1 rating. (Watco Concrete Floor Paint, Best Ever Formula, which is a single pack floor paint, has in excess of 20 Newton meters and that equates to Class 3 which is excellent and well exceeds the pass mark.)
There are two tests to determine how well a coating sticks to the floor, the Adhesion Pull Off Test and the Adhesion Cross-Cut Test.
Adhesion Resistance: Cross-Cut Test determines how much resistance a coating has, when a special serrated tool, used at right angles, is used to cut through the coating in a criss-cross type pattern. The Adhesion Pull Off Test measures how much force is needed to pull a coating off the floor.
Water Permeability Test: The Water Permeability/Capillary Absorption test to EN1062-3, indicates how effectively a coating will prevent ingress of water into the substrate, or how well it will waterproof and protect the substrate.
Scratch resistance: The Sclerometer Test can determine scratch resistance. A Sclerometer is an instrument for measuring the hardness of a coating, by working out just how much pressure is needed to cause a point to scratch the surface.
A tungsten carbide tip is drawn over the coating and applied at a pre-determined pressure. If a mark is visible then this is classed as a fail. The pressure is changed using the slide or by changing the spring, to get to the point where no mark or scratch is visible. This then gives you the test result. The results are expressed in Newtons as it’s a measurement of force. The higher the result the more scratch resistant the coating is.
Slip Resistance Test/The DIN Test is designed to replicate a person walking backwards and forwards over a contaminated floor coating, to determine the point at which they slip over.
Chemical Resistance Test: coatings are tested to see just how resistant they are when subjected to chemical attack.
Flex Test: Having a coating which is flexible is particularly important for areas around vibrating machinery or on ‘flexible’ mezzanine floors. The more flexible a coating is the more crack resistant it will be when subject to any movement.
Food Taint Test: The aim of the Food Taint Test is to determine whether or not a coating has the potential to taint food after it has cured. You do not need special equipment to carry this test out, just good old fashioned chocolate
Potable Water Test: If something is water potable, it means it can come into contact with drinking water without contaminating it. Having a coating which is non-toxic and doesn’t support fungal or bacterial growth, is particularly important in environments such as hospital kitchens, canteens, schools and laundries where hygiene is paramount. Testing to see if a coating is water potable is carried out by a recognised company called WRAS, (Water Regulations Advisory Scheme).
The WRAS carry out 5 tests, and if all 5 pass then the coating is given a BS6920 Water Potability certificate
One of the biggest environmental issues facing the paint industry today is that of VOC emissions (Volatile Organic Compounds), and the effect that the solvents contained in paints have on the air we breathe. All our products have been tested for VOC levels and the VOC information is put onto our labels and safety data sheets. This means that we are also compliant with BREEAM.
BREEAM stands for Building, Research, Establishment, Environmental, Assessment, Method.
It’s impossible to say exactly how long a coating will last, but using a product that has undertaken extensive testing to achieve a CE Mark standard, will extended the lifespan of the floor, and reduce the cost of maintenance.