ANSI/ESD SP3.3-2016 pdf free download

ANSI/ESD SP3.3-2016 pdf free download.ESD Association Standard Practice for the Protection of Electrostatic Discharge Susceptible Items – Periodic Verification of Air Ionizers.
6.3 Offset Voltage The isolated conductive plate shall be momentarily grounded to remove any residual charge and to verify zero of the voltage monitoring device. The isolated conductive plate is placed within the ionized environment and monitored until the reading stabilizes or achieves an average value (for non-pulsed ionizers). Record the offset voltage. In the case of pulsed ionizers, measure and report offset voltage in peak values for both polarities. 7.0 SPECIFIC PERIODIC VERIFICATION PROCEDURES FOR IONIZERS The following sections recommend test locations and test procedures for the ionizers described in ionization standard test method ANSI/ESD STM3.1 . 7.1 Room Ionization Example test setups for performing periodic verification of room ionizers are shown in Figures 3 and 7 (AC Grid Ionizers), Figures 4 and 7 (AC, Steady DC or Pulsed DC Bar Ionizers), Figures 5 and 7 (Discrete Emitter DC Ionizers), and Figures 6 and 7 (Pulsed DC Ionizers). Measurements should be made under the ionizer at normal work height (e.g., 90 cm [36 inches], see Figure 7), as appropriate. When establishing the measurement location, consideration should be given to the location of critical processes and product placement in relationship to the ionizer source. Offset voltage should be measured after reading stabilizes (maximum 5 minutes). NOTE: When long ionizer stabilization times are anticipated (e.g., with low airflow room ionization systems), the self-decay time of section 6.2 should be correspondingly longer, or it is recommended that the CPM of STM3.1 be used for making periodic verification measurements.
6.0 GENERAL MEASUREMENT PROCEDURE Each ionization application or installation may require a different measurement procedure. Initial and final test voltages should be documented and may be changed if required. The actual measurement procedures and parameters (i.e., equipment, test voltages, test fixture distance and location, air velocity, fan speed settings, compressed gas pressure) should be documented and attached to the test data for use during subsequent periodic verifications. Procedures should be a part of the initial acceptance process to provide baseline data for comparison with future measurements. A schedule should be established for performing periodic verification. The following test steps are common elements to the periodic verification of all types of ionizers. 6.1 Setup Assess the test area after initial ionizer installation. Metal objects or obstructions to airflow are to be noted, but are not to be removed from the test area. The documented test parameters and test results from initial testing will be used for comparison during subsequent periodic verification. The test fixture may be installed within the area to be measured, or it may be held by a grounded test technician. Ground the test fixture per the manufacturer’s instructions. 6.2 Discharge Time The isolated conductive plate shall be momentarily grounded to remove any residual charge and to verify zero of the voltage monitoring device. Charge the isolated conductive plate to a value greater (e.g., ± 1 ,200 to 1 ,500 volts) than the initial test voltage (e.g., ± 1 ,000 volts) and allow it to discharge to the final test voltage (e.g., ± 1 00 volts) while in the presence of ionization. Monitor and record the time required. The discharge time measurement begins when the isolated conductive plate voltage has decayed to the initial test voltage and stops when the isolated conductive plate voltage has decayed to the final test voltage. A timer or other suitable device should be used for the discharge time measurement.
7.3 Worksurface Ionization An example of a test setup for performing periodic verification of worksurface bench top ionizers is shown in Figures 1 2 and 1 3. An example of a test setup for performing periodic verification of worksurface overhead ionizers is shown in Figures 1 4 and 1 5. Measurements of worksurface overhead ionizers should be made under the middle of the ionizer. When establishing the measurement location, consideration should be given to the location of critical processes and product placement in relationship to the ionizer source when establishing the measurement location. The test fixture should be held above the worksurface at any convenient, repeatable height (e.g., 1 5 cm [6 inches]). Measurements of worksurface bench top ionizers should be made in front of the ionizer. The distance between the ionizer and the test fixture should be any convenient, repeatable distance (e.g., 60 cm [24 inches]). The test fixture should face the ionizer at a convenient, repeatable height above the worksurface (e.g., 1 5 cm [6 inches]). Consideration should be given to the location of critical processes and product placement in relationship to the ionizer source when establishing the measurement location. Offset voltage should be measured after reading stabilizes (maximum 30 seconds).