A user has purchased an ozone generator and needs to disinfect a pharmaceutical factory's clean room with ozone. They use a handheld ozone detector to measure the concentration, which is not exceeding 10ppm. What should they do if the concentration is not up to standard?
Ozone disinfection in clean rooms is widely used. It is recommended as one of the disinfection methods in GMP verification. According to the 2002 edition of technical specifications for disinfection and the latest national standards, the air ozone disinfection concentration is 10ppm ≈ 20mg/m3, and the object surface ozone disinfection concentration is 30ppm ≈ 60mg/m3. Therefore, for space ozone disinfection, the ozone concentration must exceed 10ppm to meet the standard. However, for many pharmaceutical factory clean rooms, the requirement is higher, and it must exceed 15ppm.
The situation described at the beginning indicates that the ozone yield is not enough and the ozone generator needs to be re-selected.
Ozone disinfection in clean rooms is different from that in ordinary workshops. Clean rooms have central air conditioning systems. Generally, we choose external-type ozone generators. We use PVC pipes or stainless steel pipes to directly deliver the ozone produced by the generator into the main air duct and use the pressure source of the air purification fan in the central air conditioning system to transport it throughout the clean area. This requires us to select the ozone generator again, considering the total volume of sterilization space, total delivery volume of air purification, and volume of ozone loss caused by supplementary fresh air.
The more accurate calculation method is as follows:To achieve disinfection in the clean area, the actual consumption of ozone space (denoted by V, units m³) is composed of three parts: the volume of clean area space (denoted by V1, units m³), the volume of air purification system (denoted by V2, units m³), and the volume of supplementary fresh air causing ozone loss (denoted by V3, units m³). According to practical experience, V2 is the parameter of the central air conditioning system, and V3 is generally 12‰ of the total air volume of the central air conditioning system.
V = V1 + V2 + V3The actual amount of ozone needed for disinfection and sterilization (denoted by Q, units g/h) and the concentration standard of space disinfection (denoted by C, units g/h) are calculated using the following formula:
Q = k × C × VIt should be noted that this formula is an empirical formula and does not need to be overly concerned about. The value of k is generally 2-3. The main reference standard is the standard expected to be achieved in disinfection, as well as the work efficiency of the ozone generator.
For example, if the volume of the clean area is 6000 cubic meters and the delivery volume is 50000 cubic meters, then V = V1(6000 cubic meters) + V2 (ignored) + V3 (50000 * 0.012) = 6600 cubic meters.
The yield of ozone Q = 2 * 10 * 6600 / 0.4208 = 314g/h, and we generally recommend a good ozone generator with a capacity of 350g/h.I hope that you can select the correct type of ozone generator before purchasing, to meet the requirements.
