BS EN ISO 8289-1:2020 pdf free.Vitreous and porcelain enamels – Low-voltage test for detecting and locating defects.
The test electrode for method A consists of a sponge made of plastic, cellulose or similar material. For rough scanning of large enamelled surfaces, test electrodes with an area of not greater than 100 cm2 shall be used. Any defects that are detected shall then be more precisely located using a test electrode with an area of about 1 cm2 or by using an edge or corner of the larger electrode.A sensitive microammeter or an electronic circuit that produces an acoustical signal that indicates when the electrical restance of the vitreous enamel drops below 90 k2土9 kQ shall be used to detect and locate defects in the coating.The power source for method B shall consist of a source of direct voltage (DC voltage), 24 V土4 V. Alternatively, a voltage divider, or three transistor radio batteries, 6 F 100, as specified in IEC 60086-2, connected in series may be employed.Wet paper, for example, kitchen tissue, with an area of at least 500 cm2, shall be used as the test electrode for method B.The test specimen may be a commercial item, a part thereof or a sample plate especially prepared for this test. In any case, the test specimen shall have an uncovered (not enamelled) area of metal for contact with the negative electrode.The test specimen shall be cleaned with a detergent solution, rinsed with tap water and dried by dabbing with a sheet of cloth or paper. When the specimen is tested within 24 h of firing, cleaning with detergent solution is not necessary. The enamel coating shall have a temperature not greater than 30 °C.The test report shall contain the following information: a) reference to this document, i.e. ISO 8289-1; b) the test method used, i.e. method A or method B; c) the identification of the article tested;d) the number of defects per square metre; e) if applicable, a record of the location of the defects;BS EN ISO 8289-1 pdf download.