Hospital Air Purification Management Specification

1 Scope

This standard specifies the management and hygienic requirements, air purification methods and air purification effects of hospital air purification. This standard applies to hospitals of all levels and categories. Other medical institutions may refer to it for implementation.

(Figure 1: Hospital air purification management)

2 Normative references

The following documents are essential for the application of this document. For all dated references, only the dated documents are used. For all undated references, the latest version (including all amendments) applies to this document.

• GB15982 Hospital Disinfection and Hygiene Standards

• GB50333 Technical Specifications for the Construction of Clean Operating Rooms in Hospitals

• Hygienic Standards for Central Air Conditioning and Ventilation systems in Public Places Ministry of Health

• Hygienic Evaluation Standards for Central Air Conditioning and Ventilation Systems in Public Places Ministry of Health

• Cleaning Standards for Central Air Conditioning and Ventilation Systems in Public Places Ministry of Health

3 Terms and Definitions

The following terms and definitions apply to this document.

3.1 Air purification

Technology or methods to reduce microorganisms, particulate matter, etc. in indoor air to make them harmless.

3.2 Clean operating room (room)

An operating room (room) that adopts certain air purification technologies to make the air colony count and dust particle count meet the corresponding cleanliness grade standards.

(Figure 2: Clean operating room)

3.3 Natural ventilation

Ventilation that uses the heat pressure or wind pressure caused by the density difference between the air inside and outside the building to promote air flow.

3.4 Central air conditioning and ventilation system

The sum of all equipment, pipelines and accessories, instruments and meters for processing, transportation and distribution in order to make the parameters such as air temperature, humidity, cleanliness and air flow velocity in the room or closed space meet the set requirements.

3.5 Air purification and disinfection device

A device that removes microorganisms, particulate matter and gaseous pollutants in the air supplied by the central air conditioning and ventilation system.

(Figure 3: Air purification and disinfection device)

4 Management and hygiene requirements

4.1 Air purification management requirements

• The hospital should formulate corresponding air purification management system in accordance with the provisions of laws, regulations and standards related to air purification and disinfection, combined with the actual situation of the hospital, and organize its implementation.

• The hospital should train the users and managers of air purification and disinfection facilities and medical staff on the knowledge of laws, regulations and standards related to air purification and disinfection, clarify their respective responsibilities and tasks, and ensure the normal operation of air purification facilities.

• Hospitals should take appropriate air purification measures based on infection risk assessment of clinical departments to ensure that indoor air quality meets the requirements of relevant national standards.

• Hospitals should inspect and guide the air quality of relevant clinical departments throughout the hospital.

4.2 Air purification and hygiene requirements

• Clean operating rooms (rooms) and other clean places (such as clean bone marrow transplant wards), during new construction and renovation acceptance, after replacing high-efficiency filters, and during daily monitoring, the total number of bacterial colonies in the air should meet the requirements of GB50333.

• The total number of bacterial colonies in the air of non-clean operating rooms (rooms), non-clean bone marrow transplant wards, delivery rooms, catheter rooms, neonatal rooms, organ transplant wards, burn wards, intensive care units, and hematology wards is ≤4cfu/(15min diameter 9cm plate).

• The total number of bacterial colonies in the air of pediatric wards, mother-child rooms, obstetrics and gynecology examination rooms, abortion rooms, treatment rooms, injection rooms, dressing rooms, blood transfusion departments, disinfection supply centers, hemodialysis centers (rooms), emergency rooms, laboratories, various general wards, infectious disease clinics and their wards is ≤4CFu/(5min diameter 9cm plate).

(Figure 4: Air purification and disinfection monitoring)

5 Air purification methods

5.1 Ventilation

5.1.1 Natural ventilation

Ventilation should be carried out in a timely manner according to the season, outdoor Wind speed and temperature.

5.1.2 Mechanical ventilation

5.1.2.1 Working principle

By installing ventilation equipment, the power generated by the operation of fans and exhaust fans is used to make the air flow.

5.1.2.2 Ventilation methods

• Mechanical air supply and natural exhaust are suitable for places where pollution sources are dispersed and indoor air pollution is not serious. The mechanical air supply outlet should be away from doors and windows.

• Natural air supply and mechanical exhaust are suitable for places with heavy indoor air pollution. Indoor exhaust vents should be far away from the door and should be placed on the wall opposite the door.

• Mechanical air supply and mechanical exhaust are suitable for places with high requirements for sanitary conditions. Set the number of air changes or maintain positive or negative pressure in the room according to the needs of ventilation.

5.1.3 Precautions

• The functional requirements of the room, the sanitary conditions of adjacent rooms and the environmental factors indoors and outdoors should be fully considered to select the ventilation method and the positive and negative pressure in the room.

• Mechanical ventilation equipment should be cleaned regularly and cleaned and disinfected in time when contaminated.

(Figure 5: Central air conditioning ventilation system)

5.2 Central air conditioning and ventilation system

5.2.1 Central air conditioning and ventilation systems should strengthen health management and comply with relevant national regulations.

5.2.2 The sanitary requirements and testing methods of central air conditioning and ventilation systems should comply with the provisions of the "Sanitary Standards for Central Air Conditioning and Ventilation Systems in Public Places".

5.2.3 The hygienic evaluation of the central air conditioning and ventilation system shall comply with the provisions of the "Hygienic Evaluation Standards for Central Air Conditioning and Ventilation Systems in Public Places".

5.2.4 The cleaning of the central air conditioning and ventilation system shall comply with the provisions of the "Cleaning Standards for Central Air Conditioning and Ventilation Systems in Public Places".

(Figure 6: Air purification technology)

5.3 Air Cleaning Technology

5.3.1 Design Requirements

The design of clean operating rooms (rooms) and other clean places shall follow the requirements of GB50333:

5.3.2 Maintenance and maintenance requirements

• Air handling units and fresh air units should be inspected regularly and kept clean.

• The coarse filter of the fresh air unit should be cleaned every 2 days; the coarse filter should be replaced every 1 to 2 months; the medium filter should be checked weekly and replaced every 3 months; the sub-high efficiency filter should be replaced every year. If contamination and blockage are found, replace them in time.

• The terminal high-efficiency filter should be checked once a year and replaced when the heat exceeds the design initial heat of 160Pa or has been used for more than 3 years.

• The medium-efficiency filter in the exhaust fan unit should be replaced every year. If it is found to be contaminated or blocked, it should be replaced in time.

• Regularly check the return Air Filter, clean it once a week and replace it once a year. In case of special pollution, replace it in time and wipe the inner surface of the return air outlet with disinfectant.

• Set up special maintenance management personnel to perform maintenance and maintenance according to the instructions for use of the equipment; and formulate an operation manual with inspection and records.

5.4 Ultraviolet disinfection

5.4.1 Scope of application

Applicable to the disinfection of indoor air in an unmanned state.

5.4.2 Disinfection method

Ultraviolet lamps are suspended or mobile for direct irradiation. During installation, the UV lamp (30w UV lamp, intensity >70yW/cm2 at 1.0m) should be ≥1.5W/m3, and the irradiation time should be 230min.

(Figure 7: Ultraviolet disinfection)

5.4.3 Precautions

• The surface of the UV lamp should be kept clean and wiped once a week with 75%~80% (volume ratio) ethanol cotton balls. If dust or oil is found on the surface of the lamp tube, it should be wiped in time

• When the UV lamp disinfects the indoor air, the room should be kept clean and dry to reduce dust and water mist. When the temperature is <20℃ or >40℃, or the Relative humidity is >60%, the irradiation time should be appropriately extended.

• UV lamps should not be used for disinfection when there are people in the room.

5.5 Circulating air UV air disinfector

5.5.1 Scope of application

Applicable to indoor air disinfection when there are people.

5.5.2 Disinfection principle

The disinfector consists of a high-intensity ultraviolet lamp and a filtration system, which can effectively kill microorganisms entering the narrow air of the disinfector and effectively filter out dust particles in the air.

5.5.3 Usage

The product instructions approved by the Ministry of Health for disinfection products should be followed and correctly installed and used in the specified space.

5.5.4 Precautions

• Doors and windows should be closed during disinfection.

• The air inlet and outlet should not be covered or blocked by objects

• When cleaning the machine with a wet cloth, the power supply must be turned off first.

• The inspection and maintenance of the disinfector should follow the product instructions.

• The disinfector should obtain the Ministry of Health's disinfection product sanitation license.

(Figure 8: Electrostatic adsorption air sterilizer)

5.6 Electrostatic adsorption air disinfector

5.6.1 Scope of application

Applicable to the purification of indoor air when there are people.

5.6.2 Disinfection principle

Electrostatic adsorption and filtration materials are used to eliminate dust and microorganisms in the air.

5.6.3 Usage

Follow the product instructions approved by the Ministry of Health for disinfection products, and install and use them correctly in the specified space

5.6.4 Precautions

• Doors and windows should be closed during disinfection.

• The air inlet and outlet should not be covered or blocked by objects.

• The circulating Air volume (m3/h) of the disinfector should be more than 8 times the volume of the room.

• The disinfector should obtain the Ministry of Health's disinfection product hygiene license.

• The inspection and maintenance of the disinfector should follow the product instructions.

5.7 Chemical disinfection method

5.7.1 Ultra-low volume spray method

5.7.1.1 Scope of application

Applicable to indoor air disinfection in an unmanned state.

(Figure 9: Chemical disinfection method)

5.7.1.2 Disinfection principle

The disinfectant is atomized into tiny particles below 20um, and sprayed evenly in the air to make it fully contact with the microbial particles in the air to kill the microorganisms in the air.

5.7.1.3 Disinfection method 

Use 3% hydrogen peroxide, 5000mg peracetic acid, 500mg gas dioxide and other disinfectants, add them to the electric ultra-low volume sprayer at a dosage of 20mL/m3~30mL/m3, turn on the power, and spray disinfection. Close the doors and windows before disinfection. When spraying, spray from top to bottom, left to right, inside to outside, surface first and space later, step by step. Action time: 30min~60min for hydrogen peroxide and gas dioxide, h for peracetic acid. After disinfection, open the doors and windows for thorough ventilation.

5.7.1.4 Precautions

• When spraying, the disinfection personnel should take personal protection, wear protective gloves and masks, and wear gas masks and protective clothing when necessary.

• Before spraying, the indoor corrosive instruments and equipment, such as monitors and displays, should be covered.

5.7.2 Fumigation method

5.7.2.1 Scope of application

Applicable to indoor air disinfection in an unmanned state

5.7.2.2 Disinfection principle

Use the volatility of chemical disinfectants to evaporate them in a certain space by heating or other methods to achieve air disinfection.

5.7.2.3 Disinfection method

Use 0.5%~1.0% (5000mg/~10000mg/L) peracetic acid aqueous solution (1g/m3) or gas dioxide (10mg/m3~20mg/m3), heat and evaporate or add activator; or use ozone (20mg/m3) for fumigation disinfection. The amount of disinfectant, disinfection time, operation method and precautions should follow the instructions for use of the product. Close the doors and windows before disinfection, and open the doors and ventilate thoroughly after disinfection.

5.7.2.4 Precautions

• The temperature and humidity of the room should be appropriate during disinfection

• The container for the disinfectant should be corrosion-resistant and of appropriate size.

(Figure 10: Air purification device)

6 Air purification methods for different departments

6.1 The operating department (room) can choose the following methods to purify the air:

• Central air conditioning and ventilation system with air purification and disinfection equipment installed;

• Air purification technology;

• Circulating air ultraviolet air disinfector or electrostatic adsorption air disinfector or other air disinfectors that have obtained the sanitary license for disinfection products from the Ministry of Health;

• Ultraviolet light disinfection;

• Other air disinfection products that can make the total number of bacteria in the air after disinfection ≤4CFU/(15min diameter 9cm plate) and have obtained the sanitary license for disinfection products from the Ministry of Health.

6.2 Delivery rooms, catheter rooms, neonatal rooms, organ transplant wards, burn wards, intensive care units, hematology wards, etc., can use the following methods to purify the air:

• Ventilation;

• Centralized air conditioning and ventilation systems equipped with air purification and disinfection devices;

• Air purification technology;

• Circulating air ultraviolet air disinfector or electrostatic adsorption air disinfector or other air disinfectors that have obtained the Ministry of Health's disinfection product health license;

• Ultraviolet light disinfection;

• Other air disinfection products that can make the total number of bacteria in the air after disinfection ≤4CFU/(15min diameter 9cm square four) and have obtained the Ministry of Health's disinfection product health license. 

6.3 The following methods can be used to purify the air in pediatric wards, mother-child rooms, obstetrics and gynecology examination rooms, abortion rooms, injection rooms, treatment rooms, dressing rooms, blood transfusion departments, disinfection supply centers, hemodialysis centers (rooms), emergency rooms, laboratories, various general wards, infectious disease clinics and their wards:

• Ventilation;

• Central air conditioning and ventilation system;

• Circulating air ultraviolet air disinfector or electrostatic adsorption air disinfector or other air disinfector that has obtained the Ministry of Health's disinfection product health license;

• Ultraviolet light disinfection;

• Chemical disinfection;

• Other air disinfection products that can make the total number of bacteria in the air after disinfection ≤4CFU/(5min?9cm diameter plate) and have obtained the Ministry of Health's disinfection product health license.

(Figure 11: Mechanical ventilation in general ward)

7 Air purification methods in different situations

7.1 The following methods can be used when there are people

• Natural ventilation is preferred for general wards; if natural ventilation is poor, mechanical ventilation should be used directly:

• Central air conditioning ventilation system;

• Circulating air ultraviolet air disinfector or electrostatic adsorption air disinfector or other air disinfector that has obtained the sanitary license for disinfection products from the Ministry of Health;

• Air purification technology;

• Other air disinfection products that have obtained the sanitary license for disinfection products from the Ministry of Health and are harmless to human health.

7.2 The following methods can be used when there are no people

• The air purification method in 7.1 can be used;

• Disinfection with ultraviolet light;

• Chemical disinfection;

• Other disinfectants that have obtained the sanitary license for disinfection products from the Ministry of Health and are suitable for ultra-low volume spray disinfection are used for spray disinfection. The usage methods, precautions, etc. of the disinfectants should be followed according to the instructions for use of the products.

7.3 The following methods can be used in places where patients with respiratory infectious diseases are located

• Hospitals limited by objective conditions can use ventilation, including natural ventilation and mechanical ventilation, and mechanical exhaust can be used directly:

• Negative pressure isolation wards;

• Central air conditioning ventilation system with air purification and disinfection equipment installed;

• Use air purification Equipment that has obtained the sanitary license for disinfection products from the Ministry of Health, and its operation methods, precautions, etc. should follow the instructions for use of the product.

(Figure 12: Respiratory Infectious Diseases)

7.4 The following methods can be used in wards after ordinary patients are discharged or die

• Ventilation;

• Ultraviolet light irradiation disinfection;

• Use air purification equipment that has obtained the sanitary license for disinfection products from the Ministry of Health, and its operation methods, precautions, etc. should follow the instructions for use of the product.

7.5 The following methods can be used in wards after patients with respiratory infectious diseases are discharged or die

• Ultraviolet light irradiation disinfection;

• Chemical disinfection;

• Use air purification equipment that has obtained the sanitary license for disinfection products from the Ministry of Health, and its operation methods, precautions, etc. should follow the instructions for use of the product.

(Figure 13: Air purification effect monitoring)

8 Monitoring of air purification effect

8.1 Monitoring department 

Hospitals should monitor the air purification and disinfection quality of high-risk infection departments such as operating departments (rooms), delivery rooms, catheter rooms, laminar flow clean wards, bone marrow transplant wards, organ transplant wards, intensive care units, neonatal rooms, mother-child rooms, hemodialysis centers (rooms), and burn wards.

8.2 Monitoring requirements

8.2.1 Monitoring frequency

Hospitals should monitor high-risk infection departments every quarter; clean operating departments (rooms) and other clean places should be monitored during new construction and renovation acceptance and after replacing high-efficiency filters: when hospital infection outbreaks are suspected to be related to air pollution, monitoring should be carried out at any time, and corresponding pathogenic microorganisms should be tested.

8.2.2 Monitoring methods and result determination

• Clean operating departments (rooms) and other clean places should reasonably arrange the number of rooms to be monitored each time according to the total number of clean rooms to ensure that each clean room can be monitored at least once a year. The monitoring methods and result determination should meet the requirements of GB50333.

• For departments that do not use clean technology to purify the air, the monitoring methods and results should comply with the requirements of GB15982.