ANSI ESD-S4.1-2006 pdf download For the Protection of Electrostatic Discharge Susceptible Items Worksurfaces – Resistance Measurements
6.0 TEST METHODS
This section describes the test methods to be used to measure the worksurface materials:
A) prior to installation
B) during initial worksurface installations
C) for periodic worksurface testing
6.1 Apparatus Requirements
6.1.1 Resistance Measuring Apparatus
Self-contained resistance meter or meters or power supplies and current meters shall be used in the appropriate configuration for resistance measurement with ± 1 0% accuracy.
6.1 .1 .1 For the material evaluation tests of 6.2, this apparatus shall have open circuit voltages 5 of 1 0 ± 1 V and 1 00 ± 1 0 V, and be able to measure resistance values from 1 .0 x 1 0 ohms to 1 .0 x 1 0 1 1 ohms.
6.1 .1 .2 For the installed worksurface tests of 6.3 and 6.4, this apparatus shall be capable of an open circuit voltage of 1 00 ± 1 0 V and be capable of reading resistance values at least a factor of ten higher and a factor of ten lower than the expected resistance values of the worksurface. In addition, both test leads should be isolated from ground.
6.1.2 Electrodes Two cylindrical 2.27 ± .06 kg (5 pound ± 2 oz) electrodes with a diameter of 63.5 ± .25 mm (2.5 ± .1 inches) each having contacts of electrically conductive material with a Shore-A (IRHD) durometer hardness between 50 and 70. The resistance between the two electrodes placed on a metallic surface should be less than 1 ,000 ohms when measured at 1 0 V.
6.1.3 Environmental Chamber An enclosed chamber capable of controlling relative humidity to 1 2 ± 3% RH and 50 ± 5% RH and temperature to 23 ± 1 °C. The humidity indicating instrumentation shall be accurate to ± 3% RH in the operational range and traceable to NIST.
6.1.4 Specimen Support Surface A surface that has a point-to-point resistance of greater than 1 .0 x 1 0 1 2 ohms such as PMMA, PTFE or polycarbonate.
6.2 Material Evaluation
6.2.1 Specimen Preparation A total of six specimens with minimum dimensions of 25.4 x 61 cm (1 0 x 24 inches) are required. These specimens should be labeled numerically from 1 to 6. Each sample should have two ground connections that simulate end-use grounding procedures.