ISO 18080-4:2015 specifies a test method using horizontal mechanical friction with measurement of friction-charged electrostatic potential on specimens of fabric and the time for that potential to decay. The test method is suitable for fabrics of all types of composition and construction that are capable of withstanding frictional charging. Some fabrics, e.g. fabrics of low strength or loose construction, may not be physically capable of withstanding the manual friction used in this test method or may give false results. In such cases, the test method described in ISO 18080-1 can be used to evaluate electrostatic propensity. The test method described may not be suitable for evaluating garments and garment materials in relation to safety of personnel and protection of electrostatic discharge sensitive devices.