Areas need to be about 100x100mm. Ensure areas for test are free of dust and loose debris. The support fixture holds test specimens on an earthed conducting surface in a defined position relative to the test aperture of the JCI 155v5. The fixture should allow new specimens to be easily mounted without scuffing or sliding of surfaces as such actions may easily tribocharge surfaces. A suitable support may be a cradle lined with aluminium foil.
Different supports are likely to be needed for different shape and size specimens.
It is best for the central part of the area to be tested to lie directly under the centre of the test aperture, as this is the main area where charge will be deposited. The charge decay characteristics of materials can easily be affected by surface contamination and moisture. It is therefore important to test samples and materials in the 'as received' condition without any handling, cleaning or removal of dust or dirt. The areas to be tested should not be contacted by hand or by other surfaces and care should be taken not to blow or breath on the test surface. For laboratory testing the samples or materials shall be exposed to constant standard conditions of temperature and humidity for at least 24 hours before testing with measurements carried out in these same environmental conditions.