Ductile iron pipes. fittings and accessories - Epoxy coating (heavy duty) of ductile iron fittings and accessories - Requirements and test methods, BSEN14901(simple edition)
5.5 Coating thickness
When measured in accordance with the method defined in 7.1.4, except on designated zones, the localized minimum thickness shall be greater than 200 µm and the minimum average thickness shall be equal to or greater than 250 µm. For designated zones (see 3.13), localised minimum thickness of 150 µm is permissible. 5.6 Cross linkage
When tested in accordance with the test method described in 7.1.5, the degree of cross linkage of coated
fittings and accessories shall comply with the following: The aspect and colour of the cloth and of the coating surface shall be compared with the limits of discoloration,matting and/or smearing defined by wiping the reference coating sample supplied by the coating system manufacturer for his product. An acceptable degree of cross linkage is given, if the reference and the test sample do not deviate. In case of doubt or in case of change of coating material the coating shall conform to the limits of change in glass transition temperature (∆Tg) defined by the coating material manufacturer. 7.1.4 Coating thickness
The thickness of the coating shall be measured with non-destructive instruments (e.g. based on magnetic or electro-magnetic principles) with a measuring accuracy of ±1% A minimum of 10 measurements evenly distributed over the fitting or accessory shall be carried out. The
average and minimum localised thickness shall then be determined. The coating thickness over a dispersed area of the test item shall be within a range of a maximum 40% above the minimum coating thickness 7.1.5 Cross linkage The test shall be conducted using Methyl Iso-Butyl Ketone (MIBK). On the dust free coating an MIBK drop shall be exposed and after 30±5 sec. be wiped away by one wipe
with a clean white cloth . The aspect and colour of the cloth and of the coating surface shall be noted. The limits of discoloration, matting and/or smearing can be compared by wiping the reference coating sample supplied by the coating system manufacturer for his product. The change in glass transition temperature ∆∆Tgof this reference sample is determined by differential scanning calorimetry (DSC). 7.2.2 Impact resistance The impact resistance shall be tested by dropping a weight on the coating with a given energy and checking the absence of damage. The specimen shall be supported by a rigid construction such that the impact energy caused by the impact of the falling weight is absorbed by the specimen. The front surface of the falling weight shall be a section of a sphere of hardened steel with a diameter of 25 mm. Ten impacts separated by at least 30 mm shall be carried out. The test shall be carried out at an ambient temperature of (23±2) °C. The impact energy E shall be
5 Nm ±5% The height of fall of the weight (500 g) shall be 1 m. Care shall be taken to ensure that little
friction occurs when the falling weight is dropped and that the impact energy is maintained at a constant level. The absence of impact damage shall be tested after each impact using the non porosity test according
to 7.2.4. | 
