BS 50348:2010 pdf download – Stationary electrostatic application equipment for non-ignitable liquid coating material — Safety requirements
5.2.3 Protection against too high discharge energy After disconnection of the high voltage all live parts shall be discharged to a discharge energy of less than 350 mJ before these parts can be reached. The discharge time shall be defined considering the operational and local conditions. 5.3 Spraying area 5.3.1 The forced ventilation of the spraying area shall satisfy the requirements of EN 12215:2004.
5.3.2 When using walls, enclosures, signs and labels made of non-conductive material, the occurrence of propagating brush discharges shall be prevented. Thin sheets of plastic material less than 9 mm thick in contact with large areas of grounded metal (or other conductors) can give rise to propagating brush discharges. Where such thin sheets are used, the breakdown voltage through the sheet shall not exceed 4 kV to avoid the occurrence of propagating brush discharges. NOTE The use of thin layers of non-conductive plastic material on conductive surfaces may cause hazards due to the formation of propagating brush discharges.
5.3.3 Inside spray booths and in a radius of 2,5 m around the openings of the booths an antistatic floor shall be installed. The resistance shall not exceed 10 8 Ω. Its resistance shall comply with the test conditions of EN 61340-4-1:2004. When using elastic floor the requirements of EN 1081:1998 shall be observed. 5.4 High voltage supply
5.4.1 The high voltage supply shall be safeguarded against unauthorized switching on. Switching-off shall be possible at any time. NOTE Suitable safeguards against unauthorized switching on are e. g. key locks or hardware and software authorisations. 5.4.2 On all doors and openings of the spraying area where the hazard of contact with parts under high voltage exists the presence of the high voltage shall be indicated by an optical or acoustic signal. Every access to the spraying area provided for operators shall be safeguarded in such a way that the high voltage is disconnected when entrance is gained. The interlock shall satisfy the performance level d of EN ISO 13849-1:2008. Other openings of the spraying area through which parts under high voltage could be contacted shall be locked in such a way to be only opened by keys or tools. When using systems of type B-NL an interlock of the high voltage with all doors and openings shall be installed to prevent an electric shock of persons.
5.4.3 If exposed parts of the high voltage supply system are located outside the spraying area or outside a closed electrical operating area, complete protection against direct contact shall be provided. In addition, appropriate measures (e. g. closed, grounded housing) shall be taken to avoid persons or objects being charged by the influence of a present electrical field.
5.4.4 Components within the spraying area which are not at high voltage potential for operational reasons, shall be connected with the ground contact of the high-voltage supply system with a separate conductor of low impedance.
5.4.5 High voltage cables shall comply with the tests of 6.1.
5.4.6 Parts of the spraying system under high voltage located outside the spraying area shall be installed in such a way to prevent occurrence of discharges hazardous for persons.
5.4.7 The minimum distance in air between the parts under high voltage and the grounded parts shall not be less than 0,25 cm/kV. These minimum distances are not applicable both for the distance between the electrostatic spraying device and the workpiece, and the design-specific distances of the spraying devices. NOTE Possible occurrence of surface discharges at the spraying device could have an influence on the minimum distances.
5.5 Electric requirements The electric equipment shall comply with the requirements of EN 60204-1:2006.
5.6 Grounding measures
5.6.1 All conductive components of the equipment, like floors, walls, ceilings, fences, conveyors, workpieces, containers for coating material, reciprocators or elements of construction etc. within the spraying area, except for parts under high voltage for operational reasons, shall be connected to the grounding system. Parts of the booth shall be grounded in compliance with EN 12215:2004. 5.6.2 The resistance to earth from the suspending point of each workpiece shall not exceed 1 MΩ. The voltage during measurement shall be 500 V or 1 000 V. The design of hangers shall ensure that the workpieces remain grounded during the coating process.