BS ISO 15727:2020 pdf download – UV-C devices – Measurement of the output of a UV-C lamp
1 Scope
This document specifies the measurement of the output of a UV-C lamp, types of UV-C lamp, lamp ballast, and safety issues. It is applicable to the output measurement of linear UV-C disinfection lamps. This document specifies a measurement method for evaluating output power of UV-C lamps installed in heating, ventilation and air conditioning (HVAC) systems. The method includes the simulation measurement of UV-C output power of UV-C lamps under various temperatures and various air velocities, and under conditions that the axial direction of the lamp is parallel or perpendicular to the air flow direction. It can reliably evaluate and compare the UV-C output power of UV-C lamps in the ultraviolet germicidal irradiation (UVGI) device based on the testing results. If the microbial inactivation rate of a particular UVGI device equipped with the same type of UV-C lamp is known, the microbial inactivation rate of the UVGI device at various temperatures and at various air velocities can be evaluated.
4.3.2 Magnetic ballasts
Magnetic ballasts are used to start the UV-C lamp and may be either standard electromagnetic or energy-efficient electromagnetic. The ballast provides a time-delayed inductive kick with enough voltage to ionize the gas mixture in the tube after which the current through the tube keeps the filaments energized. The starter will cycle until the tube lights up. While the UV-C lamp is on, a preheat ballast is just an inductor which at the main frequency (50 Hz or 60 Hz) has the appropriate impedance to limit the current to the UV-C lamp to the proper value. Ballasts shall be fairly closely matched to the UV-C lamp in terms of tube wattage, length, and diameter.
4.3.3 Electronic ballasts
Electronic ballasts are basically switching power supplies, which eliminate the large, heavy, ‘iron’ ballast in favour of an integrated high frequency inverter/switcher. Current limiting is then done by a very small inductor, which has sufficient impedance at the high frequency. Properly designed electronic ballasts are relatively reliable, which depend on the ambient operating temperature, location with respect to the heat produced by the UV-C lamp as well as other factors.
6.4 Ozone production
Ozone is a hazardous indoor pollutant that can be produced by the UV-C lamp. Some UV-C lamps are designed with a narrow spectral range of UV-C output and produce little or no ozone. Other UV-C lamps, especially the more common UV-C lamps that produce a broad-range UV-C spectrum, can produce enough ozone that it can be smelled in the indoor air. Ozone can cause damage to the lungs from prolonged or chronic inhalation and can also cause certain types of damage or degradation to materials. Although there are no known cases in which ozone produced by a UV-C lamp has caused any major health problem, the possibility exists and any undue levels of indoor ozone noted after a UV-C installation shall be investigated. Before testing, ozone sensors shall be set up to monitor the ozone leakage.