Hospital air conditioning filter and operating room HEPA filter replacement requirements？

Hospital/health industry is a very large and special industry, it has a high requirement of air cleanliness. In general, the minimum requirement for hospital air is filtration using a combination of a 30% efficiency prefilter and a 90% efficiency final filter. In general, HEPA air filters are not required for filtration, but in special cases such as isolation rooms, specific testing and care areas, HEPA filters are required.

Many HVAC systems in hospitals use 100% outdoor air, which is a good strategy to prevent patients from getting cross-infection from suspended microorganisms in the HVAC system. However, 100% use of outdoor air can not eliminate the growth of microorganisms in the air filtration medium and its adverse effects on the nursing environment. As a result, many hospitals are still in great need of advanced HVAC systems.

The clean room of the health system was first used in the operating room. At first, it was widely used only in orthopedic surgery, which takes a long time and tends to cause infections. The ideal level of control is when the air near the operating table is 100 level clean. It is generally recommended to use a top HEPA filtration system that covers at least 3 m. An area of 3 meters to include the operating table and the person.

Operating room high efficiency air filter

Other areas where clean rooms have been applied include delivery rooms, nursery rooms, burn rooms, cardiac patient care units, etc. One of the latest developments is the use of dental cleanrooms, which reduce the risk of infection among medical staff during long-term operations.

The high efficiency air filter of the operating room purification system is an important guarantee for the sterile environment of surgery. According to the relevant national standards, the high efficiency filter of the operating room needs to be replaced every 2-3 years to ensure the purification effect.

Preparation for replacement of HEPA filter in the operating room:

1. Manage personnel and items in and out of the operating room.

2. Powder gloves shall not be used in the laminar flow operating room.

3. It is strictly prohibited to fold all kinds of cloth dressings or bring personal belongings, books and newspapers into the operating room.

4. Emergency surgery should be performed in the outermost operating room of the operating department, and infection surgery should be performed in the operating room near the dirt channel.

5. Continuous operation of the operation equipment shall be ensured with sufficient self-cleaning time at intervals.

(2 Infection prevention and management)

6. All cleaning work shall be wiped with a wet cloth during the operation of the purification system.

7. All kinds of instruments and equipment entering the operating room should be installed and wiped clean before entering.

8. Clean up, wipe and organize all kinds of items immediately after the operation.

9. After the operation, remove all kinds of dirt, seal the bag inside, and transport it out of the dirt channel.

10. Wipe the surface and ground of shadowless lamp, instrument cart, anesthesia table, operating bed, wall cabinet and other equipment with disinfectant once a day before and after operation.

11. Quarantine shoes worn by staff members shall be cleaned and disinfected after use.

12. Thoroughly wipe, disinfect, clean and maintain all equipment and ground once a week.

13. Clean coarse filter, medium filter and return air outlet device once a week.

14. Wet wipe the coarse filter, medium filter and return air net with 500 mg/L chlorine-containing disinfectant once every two weeks.

15. Sample the air and equipment surface of the clean operation department for bacteria culture every month, and test the temperature and humidity once a month. And record the results.

16. Replace the primary and medium effect filters once every 6 months. Replace the HEPA filter every year.

[3 Monitoring management]

17. The infection control team in the operating room shall conduct monthly monitoring and sampling of air, hands, table and disinfectant, and summarize the rectification of monitoring work.

18. The air cleanliness monitoring adopts the “multi-point distribution sampling” detection method. Static method is the main method, dynamic method is auxiliary.

Install high efficiency filter in operating room to avoid dust operation:

The installation of high efficiency air filters in the operating room shall comply with the following provisions:

1. After the appearance inspection of the HEPA filter in the operating room is qualified, it should be installed immediately;

2 Installation of HEPA filter frame should be smooth, clean, the flatness of each filter installation frame deviation, shall not exceed 1 ~ 2㎜;

3 The direction of the filter installation must be correct, after installation of the filter around and interface, should be tight and leak-free;

4 HEPA filter using mechanical seal, should use airtight pad seal, its thickness is 6~8㎜, and close to the filter frame; After installation, the compression of pad should be uniform, and the compression rate is 25~50%; Scan for leak detection after installation;

5 When the HEPA filter adopts hydraulic seal, the groove frame is installed horizontally, and there shall be no leakage phenomenon; There is no dirt or moisture in the tank. The height of the sealing liquid in the tank should be 2/3 of the depth of the tank, and the melting point of the sealing liquid should be higher than 50℃.

The main factors affecting the performance of HEPA filter are: filter material performance, filtered air properties, air velocity and filter structure. These influencing factors can be summarized, and according to a large number of measurement data, the theoretical calculation formula of air filter efficiency and resistance can be obtained. However, there is a certain error between the actual measured value and the theoretical calculation value, so it is necessary to analyze the main factors affecting the performance of the air filter from the actual test results. This paper analyzes the test results of the high efficiency air filter test system and finds out the main factors that affect its performance.