ANSI ESD SP3.2-2006 pdf download Periodic Verification of Air Ionizers
7.0 GENERAL MEASUREMENT PROCEDURE Each type of ionizer will require a different test setup for periodic verification testing. Initial and final test voltages may be changed as desired. The actual test procedures and parameters (e.g.. equipment, test voltages, test plate distance and location, air velocity, fan speed settings, compressed air pressure, etc.) should be documented and attached to the test data for use during subsequent verification testing. Periodic verification 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 periodic verification testing.
The following test steps are common elements to the periodic verification testing of all types of ionizers:
7.1 All test areas are to be surveyed just after initial installation. Large 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.
7.2 The test technician and test fixtures are to be properly grounded during the test. The test fixture may be held by the test technician in the test location during testing.
7.3 The test plate is to be charged to a convenient voltage in excess of the initial test voltage for each polarity (e.g-. 1200-1500 volts).
7.4 The discharge time measurement begins when the test plate voltage has decayed to the initial test voltage (e.g., 1000 volts) and stops when the test plate voltage has decayed to the final test voltage (e.g., 100 volts). Repeat 7.3 and 7.4 for the opposite polarity. A stopwatch or other suitable device should be used for the time measurement.
7.5 The test technician momentarily grounds the test plate to verify zero, then disconnects the plate from ground, and waits for the offset voltage reading to stabilize. Peak offset voltage readings for both polarities should be recorded for pulsed ionization systems.
8.0 SPECIFIC PERIODIC VERIFICATION PROCEDURES FOR IONIZER TYPES The following sections recommend test locations and test procedures for the four types of ionizers described in ionization standard ANSI/ESD STM3.1.
8.1 Room lonization
8.1.1 Example test setups for periodic verification testing of room ionizers are shown in Figures 3 and 7 (AC Grid lonizers), Figures 4 and 7 (AC, Steady DC or Pulsed DC Bar lonizers), Figures 5 & 7 (Discrete Emitter DC lonizers), and Figures 6 and 7 (Pulsed DC lonizers).
8.1.2 Measurements should be made under the ionizer at normal work height (e.g.. 90 cm [36 inches], see Figure 7), as appropriate. Consideration should be given to the location of critical processes and product. 8.1.3 Oftset voltage should be measured after reading stabilizes (maximum 5 minutes).