ISO 15727:2020 pdf free.UV-C devices – Measurement of the output ofa UV-C lamp.
4.3 Type of ballasts
4.3.1 General
The ballast provides the high initial voltage required to create the starting arc and then limits the current to prevent the UV-C lamp from self-destructing. UV-C lamp ballast can be either magnetic or electronic.
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.
5 Measurement of the output of a UV-C lamp
5.1 Measurement method classification
There are two methods to measure the output of a UV-C lamp:
1. Measurement of the output of a UV-C lamp in a darkroom: Tests in laboratory (also known as static darkroom test) are conducted to ensure the accuracy and consistency of the measured results;
2. Measurement of the output of a UV-C lamp in a test chamber: For industrial application, the tests in a test chamber shall take account of the impact of environmental changes in field (such as temperature change and air velocity change). This method is described in Annex B.
6 Safety issues
6.1 General
This clause addresses basic safety issues that relate to UVGI systems. The basic safety shall be in accordance with ISO 15858. Some aspects have regulations while others are recommended or represent current industry practice.
6.2 Protective clothing and eyewear
It is not recommended that any personnel be subject to direct UV-C exposure, but in the event such exposure is likely, personnel shall wear protective clothing, including full coverage of exposed skin if possible and protection of eyes with eyewear. Gloves shall be used to protect the hands. Most eyewear, including prescription glasses, are sufficient to protect the eyes from UV-C, but not all will offer complete coverage and standard issue protective goggles can be the most suitable alternative.
6.3 UV-C photodegradation of organics
Prolonged UV-C exposure can discolour or damage various types of organic materials and plants. In general, UV-C radiation will not only impact aesthetic effects, but also damage substances such as clothes, discolouring and embrittlement of plastic-coated wires with the result of potential fire hazard.ISO 15727 pdf download.