In 2006, the Ministry of Health promulgated the Hygienic Code for Central Air Conditioning and Ventilation System in Public Places. 20 1 September 19 Wei Tong [20 12]No. 16 The Ministry of Health issued the compulsory health industry standard WS 39420 12 "Hygienic standard for central air conditioning and ventilation systems in public places" April 20 13. The 2006 edition of Hygienic Code for Central Air Conditioning and Ventilation System in Public Places was abolished on April 20 12 1 day.
2 1.？ General Provisions In order to prevent central air-conditioning and ventilation systems in public places (hereinafter referred to as air-conditioning systems) from spreading infectious diseases and protect human health, this Code is formulated in accordance with the Law of People's Republic of China (PRC) on the Prevention and Control of Infectious Diseases, the Regulations on Hygiene Management in Public Places, the Emergency Regulations on Public Health Emergencies and the Administrative Measures for the Prevention and Control of Infectious atypical Pneumonia.
This specification specifies the general hygiene requirements of air conditioning system in public places, hygiene requirements during epidemic period of infectious diseases, hygiene requirements of purification and disinfection devices, hygiene evaluation and hygiene management requirements.
3 2.？ Scope of Application This specification is applicable to air conditioning systems used in public places, and air conditioning systems in other places can be used for reference.
4 3.？ Normative reference documents The clauses in the following documents become the clauses of this specification by referring to this specification. For dated reference documents, all subsequent modifications (excluding errata) or revisions are not applicable to this specification. However, parties who have reached an agreement according to this specification are encouraged to study whether the latest versions of these documents can be used. For undated reference documents, the latest edition is applicable to this specification.
GB/T？ 18883? Indoor Air Quality Standard
GB？ 96639673? Hygienic standard of public places
GB/T？ 18204. 1? Test method of air microorganism in public places
Ministry of Health? Technical specification for disinfection
5 4.？ Terms and definitions 4. 1? Central air conditioning ventilation system
In order to make the air temperature, humidity, cleanliness and airflow speed in a room or enclosed space meet the given requirements, the sum of all equipment, pipes, accessories and instruments that process, convey and distribute air and control its parameters.
4.2? Airborne infectious diseases
Infectious diseases mainly transmitted by air.
4.3? air purification
Some technologies or methods are used to remove particulate matter, microorganisms and gaseous pollutants in indoor air.
4.4? Inhalable particulate matter (PM 10)
Particles with median diameter of 10 micron and aerodynamic equivalent mass that can enter human respiratory tract.
6 5.？ Hygienic requirements for air conditioning system 5. 1? general requirements
5. 1. 1? The fresh air volume and operation parameters of the air conditioning system should meet the national health standards and requirements, and the setting of the fresh air outlet should ensure that the inhaled air is outdoor fresh air, and the fresh air outlet should be far away from the building exhaust port and the open cooling water tower. It is strictly prohibited to indirectly suck fresh air from air conditioning and ventilation rooms, building corridors and suspended ceilings.
5. 1.2? The fresh air inlet and air return of the air conditioning system should be equipped with rodent and insect prevention facilities.
5. 1.3? The filter (net), surface cooler, heater (wet) and condenser plate of air conditioning system should be inspected, cleaned or replaced once a year.
5. 1.4? The air supply and exhaust ports of air-conditioned rooms should be scrubbed frequently to keep them clean, and the surface is free of dust and mold.
5. 1.5? The air conditioning system room should be kept dry and clean, and it is forbidden to pile up irrelevant items.
5. 1.6? Newly built or rebuilt air conditioning systems should be equipped with emergency treatment facilities or equipment such as controllable closed return air.
5. 1.7? Hygienic requirements for cooling water, condensed water and air supply in air conditioning system.
5. 1.8? The cooling tower of air conditioning system should be kept clean and cleaned once every six months.
5. 1.9? After cleaning (flushing), the cleanliness of the air conditioning system should reach: the amount of dust per square meter of pipeline surface area > 1.0? Gram (wiping method).
5. 1. 10 Operators of public places shall formulate emergency plans to prevent air-conditioning systems from spreading diseases. The emergency plan should include isolation control measures in different air supply areas, maximum fresh air volume or fresh air operation scheme, cleaning and disinfection methods of air conditioning system, etc.
5.2? Hygienic requirements during the epidemic of airborne infectious diseases
5.2. 1 When there is an epidemic situation of airborne infectious diseases that may spread through the air conditioning system in the local area, the emergency plan should be started according to the requirements of the health administrative department.
5.2.2? When cases or suspected cases of airborne infectious diseases are found in public places, the air-conditioning system in the relevant areas shall be shut down in time, and the epidemic situation shall be reported in accordance with the requirements of the Law of People's Republic of China (PRC) on the Prevention and Control of Infectious Diseases, and the public places and their air-conditioning systems shall be disinfected in accordance with the requirements of the local health administrative department.
5.2.3? There is no case of using air conditioning system in public places.
5.2.3. 1 The air conditioning system with controllable return air should be turned off according to the need of preventing and controlling the spread of infectious diseases, so as to prevent the air in each room and area in the building from being mixed with each other and sent indoors.
The total air system in 5.2.3.2, which is dominated by circulating air, supplemented by fresh air and exhaust air, should be operated at the maximum fresh air volume or fresh air volume according to the needs of disease control. When running with fresh air, if there is only one fan in the air conditioning unit, the air return port of the air conditioning unit should be closed; If the air conditioning unit has both blower and return fan, the air mixing valve from the return fan to the air supply channel should be closed. When fresh air cannot be used, it should be operated according to the maximum fresh air volume of the system, and the return air or air supply should be continuously disinfected and purified by safe and effective methods.
5.2.3.3 ? Air-water air conditioning system (fan coil unit+fresh air system) with dedicated fresh air and exhaust system should operate at the maximum fresh air volume.
5.2.3.4 ? When the air conditioning system is running, the room should be properly ventilated.
The filter screen (net) of air conditioning and ventilation system in 5.2.3.5 should be cleaned or replaced once a week, and the filter screen should be disinfected before replacement.
5.2.3.6 air conditioning system surface cooler, humidifier, fresh air unit, condenser should be cleaned and disinfected once a week.
5.2.3.7 ? The open cooling tower of air conditioning system should be cleaned and disinfected once a week.
5.2.3.8 ? Condensed water and cooling water of air conditioning system shall be disinfected and shall not be discharged at will.
5.2.3.9 ? Various chlorine-containing disinfectants can be used to disinfect the surface of air conditioning system components, and peracetic acid or ozone can be used to disinfect the inner wall of air duct under the condition of ensuring the safety of personnel.
5.2.3. 10? When the air conditioning system needs cleaning and disinfection, the system or components should be cleaned (flushed) first, and then disinfected after reaching the corresponding sanitary requirements.
5.3 Hygienic requirements for purification and disinfection equipment
5.3. 1? When the air conditioning system is equipped with purification and disinfection devices, chemical disinfection methods should not be selected, but physical methods that can continuously purify and disinfect the air, such as filtration, electrostatic adsorption, ultraviolet rays, etc. Do not use purification and disinfection devices that may produce harmful substances.
5.3.2? In an air conditioning system equipped with an air purification and disinfection device, the purification and disinfection device itself should not produce harmful substances that can enter the air conditioning system, and the purification and disinfection device should meet the following hygiene requirements.
5.3.3 Cleaning and disinfection devices used in air conditioning systems shall have inspection reports issued by professional institutions.
5.3.4 The purification and disinfection device of air conditioning system should be checked frequently. If it does not meet the hygiene requirements in Table 3, it shall be repaired or replaced in time.
7 6. Hygienic evaluation 6. 1? Pollution detection
6. 1. 1? Check, detect and analyze the sanitary conditions of cooling water, condensed water and air supply of air conditioning.
6. 1.2 Inspect, detect and analyze the pollution (including dust particles, debris, dirt, bacteria and mold, etc.) of system units (including air conditioning boxes, filters, humidifiers, surface coolers, fan coils, etc.). ), pipes and their accessories (valves, etc.). ).
6.2? criteria for evaluation
6.2. 1? Legionella, hemolytic streptococcus and other pathogenic microorganisms detected in cooling water, condensed water and air-conditioning air supply are seriously polluted.
6.2.2? Determination of pollution degree of air conditioning system units and ventilation pipes.
6.3? assessment result
6.3. 1? Determine the pollution level of the air conditioning system.
6.3.2? The cleaning and disinfection scope and methods of air conditioning system are put forward.
8 7.？ Health management 7. 1? Operators in public places shall establish and improve the responsibility system for health management, formulate the health management system for air-conditioning systems, do a good job in regular inspection, daily maintenance and cleaning, and ensure the health and safety of air-conditioning systems.
7.2? Operators in public places are responsible for organizing the inspection, evaluation, cleaning and disinfection of cooling water, condensed water, air supply, air ducts, purification and disinfection devices and other related system components of air conditioning systems in public places. Maintenance, cleaning, disinfection, sanitary inspection and evaluation of air conditioning system should be carried out by professionals.
7.3.？ After testing, if the air supply of air conditioning does not meet the hygiene requirements of PM 10 and the total number of bacteria and fungi specified in 5. 1.7 of this specification, the air conditioning system should be evaluated hygienically first, and then the ventilation systems such as fresh air ducts, air supply ducts, return air ducts, air conditioning boxes and other related equipment and devices should be maintained, cleaned (washed) and disinfected according to the hygienic evaluation results.
7.4? After evaluation, the air conditioning system is moderately polluted, so the filter screen should be replaced and some equipment parts should be cleaned and disinfected.
7.5 In any of the following circumstances, the public place operator shall immediately shut down the air conditioning system for cleaning and disinfection:
1. Legionella and other pathogenic microorganisms were detected in condensed water;
2. Pathogenic microorganisms such as hemolytic streptococcus were detected in the air supply of air conditioning;
3. The air conditioning system is seriously polluted;
4. Other circumstances stipulated by the health administrative department at or above the provincial level.
After evaluation, the air conditioning system can be reused only after it meets the hygienic requirements specified in 5. 1.7 of this specification.
7.6? Professional and technical institutions engaged in health inspection and evaluation, air conditioning system cleaning (washing) and disinfection shall obtain the qualification certification of the provincial health administrative department.
9 8.？ See Appendix A 8. 1 Technical Requirements for Cleaning of Air Conditioning System for sanitary inspection and testing.
8.2? See appendix b for the inspection and analysis methods of Legionella in air conditioning system.
8.3? See appendix c for the detection method of inhalable particles in air supply of air conditioning system.
8.4? See GB/T 18204.438+0 for the inspection method of microorganisms in air supply of air conditioning system.
8.5? See Technical Specification for Disinfection of Ministry of Health for the evaluation method of disinfection effect of disinfection devices and disinfectants used in air conditioning system.
10 9.？ The Ministry of Health is responsible for the interpretation of this specification. 1 1 10.？ This specification shall come into force as of the date of promulgation. 12 appendix a: technical requirements for air conditioning system cleaning this appendix specifies the technical requirements for central air conditioning system cleaning.
A 1？ Cleaning (washing) equipment
Special mechanical cleaning (flushing) equipment shall be used for the cleaning (flushing) of ventilation pipeline system, including observation and recording (camera and video recording) equipment inside the air duct and mechanical cleaning equipment (pneumatic brush, electric brush, manual brush, high-pressure air gun, high-pressure water gun, etc.). ), pollutant capture equipment with high efficiency filter (the purification efficiency of 0.3 micron particles is 99.97%) and other supporting equipment, tools and instruments.
A2？ working range
Air conditioning ventilation system includes: return air outlet, return air duct, air filter box, coil assembly, condensation and drainage tank, humidifier and dehumidifier, fresh air duct, fan, filter, etc.
A3？ On-site inspection and on-site preparation of central air conditioning system
A3. 1？ On-site inspection: Before cleaning the air conditioning system, the cleaning construction unit shall inspect the whole system to determine the appropriate cleaning methods, cleaning tools and equipment.
A3.2？ Site preparation: the cleaning construction unit shall consult relevant technical data, conduct on-site investigation, and formulate a detailed cleaning work plan.
A4？ Cleaning work requirements
A4. 1？ Pollutant control: effective measures should be taken to control sensitive odor during cleaning, and dust is not allowed to fly. Pollutants removed during cleaning must be collected and properly treated.
A4.2？ Cleaning of components: ensure that all components of air conditioning system meet the requirements of relevant standards. After completion, all components must be put back to the positions recorded before cleaning. The cleaning method shall be implemented according to the method specified in Table 4 of this specification.
A4.3？ Ventilation duct system: use special mechanical cleaning equipment to remove all visible pollutants in ventilation ducts.
A4.4 Operation entrances and exits: The cleaning construction unit can access manpower and machinery through operation entrances and exits in different parts of the air conditioning system for corresponding cleaning and inspection. If necessary, other entrances and exits can be cut and closed after construction.
A4.5？ Disinfection: when necessary, disinfect the ventilation pipes, equipment and components of the air conditioning system.
A5？ Cleaning condition inspection
After the air conditioning system is cleaned, the cleaning construction unit shall conduct self-inspection according to the relevant hygiene requirements, and if necessary, professional institutions shall conduct inspection and acceptance.
A6？ Safety measures, pollutant treatment
A6. 1？ The clean construction unit shall abide by the relevant safety regulations and formulate safety measures to protect the safety of construction personnel and personnel in the building and protect the environment.
A6.2？ All dirt removed from the air conditioning system should be properly preserved and disposed of according to relevant regulations.
13 appendix b:? Inspection and analysis methods of Legionella in air conditioning system This appendix specifies the inspection methods of Legionella in cooling water of air conditioning system and its sediments, sludge and other external environmental samples.
B 1？ Definition: Legionella is a gram-negative bacterium, which usually grows on BCYE agar medium containing L- cysteine and ferric pyrophosphate for more than two days, and grows into a white colony or turns from purple to blue or grayish green colony, and can emit fluorescence under long-wave ultraviolet irradiation. Under low power microscope, the colony is ground glass-like. It can't grow on the medium without L- cysteine.
B2？ Principle: Concentrate the bacteria in water samples by filtration membrane or centrifugation. In order to reduce the growth of miscellaneous bacteria, some of the concentrated samples were treated with acid and heating, and some were not treated. The above-mentioned treated and untreated samples were inoculated into BCYE agar plate for culture. When formed on selective medium, typical colonies were considered as Legionella.
B3？ Main instruments and equipment:
B3. 1？ Plate: 90 ~ 100 mm
B3.2？ Incubator: 35 or 37 0.5℃
B3.3？ Ultraviolet lamp: wavelength 360 2 nm.
B3.4？ Membrane filter: 45 mm diameter membrane can be installed.
B3.5？ Filter membrane: pore size, 0.22 ~ 0.45 μ m.
B3.6？ peristaltic pump
B3.7？ centrifuge
B3.8？ Eddy current oscillator: it can reach more than 200 rpm.
B3.9？ Microscope, fluorescence microscope, stereoscope
B4？ Sampling:
B4. 1？ Sampling container: glass bottle or polyethylene bottle, sterilized before use. Sediments and mud need wide-mouth bottles, and any container needs to be screwed or ground.
B4.2？ Sampling quantity: take 100200mL water from each sampling point.
B4.3？ Neutralization of residual chlorine: before sterilization, add a small amount of sodium thiosulfate solution to the sampling container to neutralize the residue in the water sample.
Chlorine.
B4.4？ Transportation and storage of samples: it is best to send the samples to the laboratory within 2 days, and do not freeze them, but turn off the lights and protect them from heat, and keep them at room temperature for no more than 15 days.
B5？ Sample treatment: If there are impurities, they can be settled or removed by 1000r/min centrifugation 1min.
B6？ Methods and steps:
B6. 1 filter membrane filtration of water sample: filter the pretreated water sample through a filter membrane with a pore size of 0.22 ~ 0.45μ m, remove the filter membrane and put it into 15mL water sample for full elution. The eluted sample was divided into three parts, one for heat treatment, one for acid treatment and one for no treatment.
B6.2 heat treatment of water sample: take 65438±0.5ml eluted sample and put it in a water bath at 50 65438 0℃ for 30±5min.
B6.3 Acid treatment of water sample: take 5mL of eluted sample, add the same amount of 1.2mol/L acid buffer, adjust the pH to 2.2 0.2, gently shake and let stand for 5min.
B6.4 Inoculation culture: Take 0.65438 0 ml of the samples after the above three treatments and inoculate them on GVPC plates respectively. The inoculation plate was placed still. When the culture was observed, the plate was turned over and incubated at 35 or 37 0.5℃ for 65438 00 days. Pay attention to moisturizing.
B6.5 Observation results: Legionella grows slowly and is easily covered by other bacteria, so it needs to be observed under a stereomicroscope every day. Legionella colonies have various colors, usually white, gray, blue or purple, but there are also dark brown, grayish green and crimson. The colony is neat and the surface is smooth, which is a typical ground glass and has fluorescence under ultraviolet light.
B6.6？ Colony verification: Two suspicious colonies were selected from each plate, inoculated on BCYE agar plate lacking BCYE and L- amino acid for subculture, and cultured at 35 or 37 0.5℃ for 2 days. Any colony that grows on BCYE medium but does not grow on BCYE agar plate without L- amino acid is Legionella colony.
14 appendix c:? Detection method of inhalable particulate matter in air supply of air conditioning system This appendix specifies the detection method of inhalable particulate matter (PM 10) concentration in air supply of building air conditioning system.
C 1？ tool
C 1. 1？ PM 10 detector is a portable direct reading instrument.
C 1.2？ The particle trapping characteristics of the test instrument should meet the requirements of DA501010 mm and SG10.501.
When the collection efficiency is 50%, it corresponds to the particle aerodynamic diameter of Da50 instrument.
sg？ –? Geometric standard deviation of instrument collection efficiency
C 1.3？ The measuring precision error of this measuring instrument is less than 65438 00%.
C 1.4？ The total precision error of the testing instrument is less than 25%.
OSA∣b∣+∣MVC∣
b？ –? The arithmetic mean of relative error of PM 10 is measured by gravimetric method and instrumental method in pairs.
MVC？ –? Geometric average of relative error of PM 10 instrument.
C 1.5？ The measuring range of the instrument is better than 0.0 1 10 mg/m3.
C 1.6？ The indicated value of testing instrument is not mass concentration, and the conversion coefficient (K) value of mass concentration that meets the requirements must be given.
C 1.7？ Before the instrument is used, it should be checked and calibrated according to the requirements of the instrument manual.
C2？ Detection point arrangement
C2. 1？ The inspection points are located at the downwind direction 1520cm of the diffuser of the air supply outlet, and are uniformly arranged diagonally or quincunx according to the number of inspection points.
C2.2？ Three inspection points shall be set when the air outlet area is less than 0. 1m2, and five inspection points shall be set when the air outlet area is greater than 0. 1m2.
C2.3？ If each air conditioning and ventilation system is responsible for supplying air to three or less rooms, all rooms should be tested; The air conditioning system is responsible for supplying air to more than 3 rooms, sampling inspection 10% inspection, but not less than 3 rooms.
C2.4？ There are less than or equal to 2 air outlets in each test room, and all air outlets should be tested; 50% samples shall be taken from more than two air outlets for testing, but not less than two.
C3？ Detection time and frequency
C3. 1？ The test shall be carried out under the normal working conditions of air conditioning and ventilation system.
C3.2？ Check each checkpoint 3 times.
C3.3？ The measurement time of each data is determined according to the concentration of PM 10 in the gas source, instrument sensitivity and instrument measurement range.
C4？ Detection data processing
C4. 1？ For the measured value of non-mass concentration indication, the indication of each test should be converted into mass concentration according to the requirements of the instrument manual.
CR*K
c？ –? Mass concentration, mg/m3
r？ –? Effective indication of the instrument (after deducting background value and base value, etc.). )
k？ –? Mass concentration conversion coefficient of instrument
C4.2？ Calculation of PM 10 concentration (Ca) in air supply
Cijkl？ –? Room l, tuyere k, measuring point j, test value I;
N number of measuring points;
M number of tuyeres measured;