For an operating clean room, the value of the end-hepa filter is not high, and all of it may add up to less than a few hours' worth of user output, but the risks and overhead of replacing the end-hepa filter can be high. To replace the filter to stop production, production loss can only be calculated by the owner himself, the loss must be higher than the cost of spare parts of the filter. Replacing a high efficiency filter is a very careful operation, anything in a clean room can be expensive, and the cost of destroying one component can be higher than the cost of the entire filter. After the replacement of the filter should be tested by professionals, and sometimes the air conditioning system debugging, but also after a period of trial operation. Testing, debugging, commissioning, the three costs together, may be comparable to the price of the filter. Smart business owners want to extend the life of their hepa filters as long as possible, not to save money on filters, but to avoid the hassle of replacing them.
To extend the service life of the high efficiency filter, the most fundamental way is to block the dust in the prefilter. There is usually no need to stop production or debug the pre-filters, so experienced owners will spend their attention and money on pre-filters and protection level intermediate filters. For class 10K and class 100K clean plants, G4 and F8 filter can be used for prefiltration (colorific method 95%). In this way, the service life of the end hepa filter can reach 5 years in general. F8 filters are the most common pre-filters for non-uniform flow cleanrooms in foreign and domestic projects.
In some cases, the service life of the hepa filter is determined not for the sake of resistance, but for other reasons. If there is hydrofluoric acid in the workshop, and the air conditioning in the workshop is not a fresh air system, the glass fiber filter paper in the hepa filter will be corroded by the return air. In order to be safe, it is necessary to replace the hepa filter regularly. Some large pharmaceutical companies change their hepa filters every year after the rainy season to prevent any possible mold contamination on the filters. Some biological laboratories, and those dealing with hazardous materials, require the use of new hepa filters in order to be reliable before embarking on a major new project.
The primary filter is generally replaced every 2-3 months and every six months, so the life of the high efficiency filter can be more than 2 years.
But to protect the high level after level filter use and guarantee the safe operation of the clean room, many intelligent owner change at the beginning of every month, every 3 months replacement in effect and the effective (or described earlier in wind cabinet end use efficient protection do filter), to ensure efficient filter more than 5 years (or even 10 years) service life, and because of the change after new filter resistance is small, air conditioning load is greatly reduced, and filter replacement is far less than the cost of air conditioning electricity needed to run, advance level before the frequent replacement of the filter is actually make air conditioning running in low resistance load, save a large amount of electricity;
