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Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative. This standard is drafted in accordance with the rules given in GB/T 1.1-2009. This standard replaces GB/T 6165-2008 Test method of the performance of high efficiency particulate air filter—Efficiency and resistance, and the following main technical changes have been made with respect to GB/T 6165-2008: ——The efficiency test method of filter with MPPS ≤ 0.1 μm is added (see 4.4 hereof); ——The basic performance requirements, maintenance and calibration cycle requirements of the unified high efficiency particulate air filter are added (see 5.1 hereof); ——The efficiency calculation equation by counting method is adjusted (see 5.2.5.1 and 5.2.5.2 hereof; 5.3.6 of Edition 2008); ——The description of aerosol particle size distribution characteristics measured by sodium flame method is defined (see 5.3.1 hereof; 6.2.1 of Edition 2008); ——The requirements for sampling system of filter test device by sodium flame are revised, and the requirements for dilution system are deleted (see 5.3.2.1 hereof; 6.2.2 of Edition 2008); ——Annex G is deleted (see Annex G of Edition 2008). This standard was proposed by the Ministry of Housing and Urban-Rural Development of the People's Republic of China. This standard is under the jurisdiction of the National Technical Committee on HVAC and Purification Equipment of Standardization Administration of China (SAC/TC 143). The previous editions of this standard are as follows: ——GB/T 6165-1996, GB/T 6165-2008; ——GB/T 6166-1985. Test method of the performance of high efficiency particulate air filter— Efficiency and resistance 1 Scope This standard specifies the terms and definitions, symbols and abbreviations of HEPA and ULPA filter mediums and filter efficiency and resistance test, the selection of test methods, the performance test methods of HEPA and ULPA, and the performance test methods of HEPA and ULPA filter mediums. This standard is applicable to the test of HEPA and ULPA filter mediums used to filter aerosols and the efficiency and resistance of filters, and may serve as a reference for the efficiency and resistance test of HEPA and ULPA filter mediums and filters. 2 Normative references The following documents are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. GB/T 1236 Industrial fans—Performance testing using standardized airways GB/T 2624.2 Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full—Part 2: Orifice plates GB/T 2624.3 Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full—Part 3: Nozzles and Venturi nozzles GB 11120 Lubricating oils for turbines GB/T 12564 Generic specification for photomultiplier tubes GB/T 13554 High efficiency particulate air filter GB/T 14295 Air filter GB 50243 Code of acceptance for construction quality of ventilation and air conditioning works JJF 1190 Calibration specification for airborne particle counter JJG 172 Tilting tube micromanometers JJG 875 Digital pressure gauges 3 Terms, definitions and abbreviations 3.1 Terms and definitions For the purposes of this standard, the terms and definitions given in GB/T 13554 and the following apply. 3.1.1 penetration ratio of the aerosol concentration after filtration of the filter element to the aerosol concentration before filtration when the filter element is tested 3.1.2 efficiency ratio of the amount of aerosol filtered by the filter element to the amount of aerosol before filtration when the filter element is tested 3.1.3 rated air flowrate technical parameter identifying the working capacity of a filter, indicating the maximum air volume flow per unit time to ensure the efficiency of the filter Note: It is provided by filter manufacturer. 3.1.4 resistance static pressure difference before and after the filter element under certain test wind speed or air flowrate. For the filter, it is the static pressure difference before and after the filter under rated air flowrate 3.1.5 filter medium unfolded flat filter material for filtering aerosols 3.1.6 high efficiency particulate air filter; HEPA air filter used for air filtration and tested by the counting method specified in this standard, and the filtration efficiency without static elimination treatment and after static elimination treatment under rated air flowrate is not less than 99.95% 3.1.7 ultra low penetration air filter; ULPA air filter used for air filtration and tested by the counting method specified in this standard, and the filtration efficiency without static elimination treatment and after static elimination treatment under rated air flowrate is not less than 99.999% 3.1.8 HEPA filter medium filter medium for making high efficiency particulate air filter 3.1.9 ULPA filter medium filter medium for making ultra low penetration air filter 3.1.10 aerosol generator device for generating standard aerosol for test 3.1.11 particle number concentration number of particles in the measured particle size range per unit volume of gas (air) 3.1.12 particle size nominal diameter of a particle measured by some measurement method (optical or aerodynamic equivalent test) 3.1.13 particle size efficiency filtration efficiency of a filter element for particles of a certain particle size 3.1.14 most penetrating particle size; MPPS particle size corresponding to the lowest point of the sizing efficiency curve of the tested filter element when the test is carried out according to the counting method specified in this standard 3.1.15 minimum filter efficiency filtration efficiency of the tested filter element for the most penetrating particle size under given operating conditions, generally known as MPPS efficiency 3.1.16 median particle diameter corresponding particle size value when the cumulative distribution of aerosol particle size accounts for 50% of the total amount, which is generally expressed by count median particle diameter and mass median particle diameter 3.1.17 sampling flow rate volume flow rate of air sampled by the measuring element of the test instrument when measuring the particle concentration upstream or downstream of the filter element 3.1.18 sampling duration effective time of air sampling upstream or downstream of the tested high efficiency particulate air filter element at the sampling volume flow rate 3.1.19 coincide error error caused by the presence of multiple particles in the scattering cavity of a particle counter at a given time Note: The coincide error will lead to low count concentration and high average particle size in the measurement results. 3.1.20 monodisperse aerosol aerosol with a geometric standard deviation of particle size is less than 1.15 (σg < 1.15) when described by distribution equation 3.1.21 quasi-monodisperse aerosol aerosol with a geometric standard deviation of particle size is not less than 1.15 and not greater than 1.50 (1.15 ≤ σg ≤ 1.50) when described by distribution equation 3.1.22 polydisperse aerosol aerosol with a geometric standard deviation of particle size is greater than 1.50 (σg>1.50) when described by distribution equation 3.1.23 sodium flame method method for calculating the mass efficiency of filter elements by testing the mass concentration upstream and downstream of filter elements with sodium flame photometer in case of polydispersed NaCl aerosol. For filter medium and filter tests, the counting peak diameter of test aerosol particles is (0.09 ± 0.02) μm, and the geometric standard deviation of counting shall not be greater than 1.90 3.1.24 oil mist method method for calculating the mass efficiency of the filter element by testing the mass concentration upstream and downstream of the filter element with an oil mist meter in case of polydispersed liquid aerosols with an average mass diameter of 0.28 μm to 0.34 μm 3.1.25 particle counting method with quasi-monodisperse aerosol method for calculating the counting efficiency of the filter medium by testing the counting concentration upstream and downstream of the filter medium with condensation particle counter (CPC) or optical particle counter (OPC) in case of quasi-monodisperse aerosols (such as solid particle NaCl or liquid particle DEHS, etc.) with counting median diameter of particles of 0.10 μm to 0.30 μm and the geometric standard deviation of not greater than 1.50 3.1.26 particle counting method with monodisperse aerosol method for calculating the counting efficiency of filter elements by testing the counting concentration upstream and downstream of filter elements with condensation particle counter (CPC) in case of monodisperse aerosol. Monodisperse aerosol can be generated by several methods, such as differential mobility analyser (DMA), diffusion battery, evaporation and condensation method, polystyrene latex spheres (PSL), etc. 3.1.27 particle counting method with polydisperse aerosol method for calculating the counting efficiency of filter elements by testing the counting concentration upstream and downstream of filter elements with optical particle counter (OPC) in case of polydisperse aerosol 3.1.28 correlation ratio ratio of particle concentrations in upstream and downstream sampling systems when the test system is not equipped with a tested filter and keeps a stable aerosol concentration Note: When an optical particle counter (OPC) is used in the test system to test the aerosol concentration in the upstream and downstream of the tested filter in sequence, the correlation ratio indicates the difference between the upstream and downstream sampling systems due to the particle loss in the upstream and downstream sampling pipelines, the dilution ratio of the diluent (if the upstream sampling adopts the diluent) and the difference between the upstream and downstream sampling duration; when two optical particle counters (OPC) are used respectively in the test system to test the upstream and downstream aerosol concentration of the tested filter, the correlation ratio indicates the difference caused by the different sampling flow rate and counting efficiency of the upstream and downstream sampling counters. 3.2 Abbreviations For the purposes of this document, the following abbreviations apply. CPC: Condensation particle counter DEHS: [sebacic acid-bis (2-ethyl-) ester (commonly known as di-ethyl-hexyl-sebacate)] DMA: Differential mobility analyser MPPS: Most penetrating particle size OPC: Optical particle counter PAO: Poly alpha olefin PSL: Polystyrene latex spheres HEPA: High efficiency particulate air filter ULPA: Ultra low penetration air filter 4 Selection of test methods 4.1 This standard gives three test methods: counting method, sodium flame method and oil mist method, where counting method is the reference method. 4.2 For high efficiency particulate air filter and its medium, any one of the three methods can be adopted for efficiency test according to requirements, however the test method and test results shall be indicated at the same time. In the production test of HEPA filter medium, rapid test methods such as sodium flame method and particle counting method with quasi-monodisperse aerosol should be adopted under the condition of clear comparison relationship with the reference method. 4.3 For ultra low penetration air filter and its medium, counting method shall be adopted for efficiency test. In the production test of ULPA filter medium, rapid test methods such as particle counting method with quasi-monodisperse aerosol should be adopted under the condition of clear comparison relationship with the reference method. 4.4 For air filters and its medium with MPPS not greater than 0.1 μm, the particle counting method with monodisperse aerosol is adopted as the reference method. In the end-of-manufacturing inspection of this kind of air filter, the counting method can be used to measure the particles in the range of 0.1 μm to 0.2 μm under the condition of clear comparison relationship with the reference method, and the test results shall be corrected according to the comparison relationship with the reference method. 5 Performance device and test method of HEPA and ULPA 5.1 Requirements for test device 5.1.1 Fan 5.1.1.1 Air flowrate The air flowrate shall be calculated as 1.3 times of the maximum air flowrate of the tested air filter. 5.1.1.2 Air pressure Air pressure shall include at least the sum of the following items: a) Duct resistance (1.2 times of calculated resistance); b) Air inlet filter resistance (2 times of its initial resistance); c) Maximum resistance of the tested filter; d) Resistance of air flowrate measuring device; e) For the sodium flame test device, the positive pressure value (not less than 600 Pa) required for sampling after the filter shall be considered. 5.1.1.3 Air flowrate stability During the test, the air flowrate of the test device shall be stable within 2% of the set value. 5.1.2 Air duct 5.1.2.1 Materials PVC plastic or other corrosion-resistant materials should be used in the sodium flame test device from spray box to buffer box; stainless steel air duct should be used for the rest of the sodium flame test device and other test devices. The wall thickness of air duct should not be less than 1 mm. When necessary, the air duct shall be grounded and anticorrosive. 5.1.2.2 Dimensions of front and rear pipe sections of air flowrate measuring device When the standard orifice plate is used, the dimensions of the front and rear pipe sections shall be designed according to the relevant requirements of GB/T 2624.2; when standard nozzles are used, the dimensions of the front and rear pipe sections shall be designed according to the relevant requirements of GB/T 2624.3. 5.1.2.3 Angle of connection pipe of tested filter The included angle of diffusion section and convergence section of the tested filter connection pipe shall not be more than 14° and 30° respectively, and shall meet the relevant requirements of GB/T 1236. 5.1.2.4 Air duct tightness The manufacture, installation and inspection of air ducts in the test device shall meet the relevant requirements of GB 50243 for medium pressure system, and the joints of air ducts shall be welded. For air duct tightness, the duct shall be pressurized under the pressure of 2 kPa for leakage test, and the air leakage shall not be greater than 1.64 m3/(h·m2). 5.1.3 Inlet air filtration 5.1.3.1 Pre-filter The pre-filter shall meet the relevant requirements of GB/T 14295 for medium-effect filter. 5.1.3.2 High efficiency particulate air filter The high efficiency particulate air filter shall meet the relevant requirements of GB/T 13554. When a heater is set upstream of the filter, the temperature resistance of the filter shall not be lower than 60°C. 5.1.4 Air speed uniformity of upstream sampling section Adjust the operating air flowrate of the test device to the maximum test air flowrate, and evenly distribute 9 measuring points on the section of the sampling point upstream of the test air duct according to the cross-sectional area of the air duct as shown in Figure 1 to test the air speed respectively. The deviation between the measured air speed of each measuring point and the average value of each measuring point shall not be more than 10%. a) Square air duct b) Circular air duct Keys: a——Side length of square air duct; D——Diameter of circular air duct. Figure 1 Layout of measuring points for air speed and aerosol concentration uniformity at upstream sampling section 5.1.5 Aerosol concentration uniformity at upstream sampling section Adjust the operating air flowrate of the test device to the maximum test air flowrate, start the aerosol generator and maintain stable operation, and evenly distribute 9 measuring points on the section of the sampling point upstream of the test air duct according to the cross-sectional area of the air duct as shown in Figure 1 to test the aerosol concentration respectively. The deviation between the measured aerosol concentration at each measuring point and the average value at each measuring point shall not be more than 10%. 5.1.6 Upstream aerosol concentration stability Adjust the operating air flowrate of the test device to the maximum test air flowrate, start the aerosol generator and maintain stable operation, and sample at the sampling point upstream of the test air duct. The fluctuation of the measured aerosol mass concentration or the count concentration within the given particle size range within 30 min shall not be greater than 10%. 5.1.7 Requirements for general test apparatus Air flowrate test devices may be designed, installed, used and calibrated in accordance with the relevant requirements of GB/T 2624.2 and GB/T 2624.3 using standard orifice plates or nozzles and shall meet the following requirements: a) Pressure test devices for differential pressure measurements of filter resistance and flow rate shall have an accuracy of not less than 2 Pa and shall be periodically verified and calibrated according to the relevant requirements of JJG 172 or JJG 875 depending on the pressure test device selected. b) Counters shall be periodically verified and calibrated in accordance with the relevant requirements of JJF 1190. The photoelectric measuring instrument in sodium flame photometer shall be tested and calibrated periodically according to the relevant requirements of GB/T 12564. The oil mist meter shall be calibrated according to the requirements of 5.4.3.1.1.4. 5.1.8 Sampling correlation ratio at upstream and downstream When the aerosol generator works stably, the filter is not installed in the test section and the dilution is not installed in the upstream sampling section, the correlation ratio of each particle size block shall be 1.00 ± 0.03. After installing the diluent at the upstream sampling section, the correlation ratio of each particle size block shall be tested and confirmed regularly. 5.1.9 Resistance standard parts 5.1.9.1 Orifice plates (or other resistance standard parts) with known resistance shall be tested regularly according to 5.2.4.2.4. 5.1.9.2 The resistance standard parts shall be properly stored and kept when not in use to prevent damage. 5.1.9.3 The test for resistance standard parts shall meet the following requirements: a) At least 4 air flowrate state points shall be selected for testing within the air flowrate range of the test device. b) During each test, the deviation between the resistance test result and the calibration value at each air flowrate state point shall not be more than 3%. Otherwise, the necessary inspection, maintenance and calibration shall be carried out for the pipeline sealing and the pressure gauge of the flow test device. c) Contrast validation tests can be performed using resistance standard parts and reference test devices. 5.1.10 Reference filter 5.1.10.1 For the test device, a reference filter with known efficiency shall be prepared, and the efficiency test shall be carried out regularly according to the methods specified in 5.2, 5.3 or 5.4. 5.1.10.2 A minimum of two reference filters shall be prepared, of which one is for the primary reference filter and the other one is for standby. The filter mediums selected for reference filters shall not be materials that are difficult to maintain stable filtration efficiency for a long time. The reference filter shall be properly stored and kept when not in use to prevent damage. 5.1.10.3 Reference filters shall be used according to the following requirements: a) The deviation between each efficiency test value of the reference filter and the mantissa of the calibration value (the first non-9 value of the efficiency value) shall not exceed ± 5. b) The primary reference filter shall be selected first during each test. If the deviation between the efficiency test value and the calibration value of the primary reference filter exceeds the requirement of item a), the standby reference filter shall be tested. If the efficiency test value of the standby reference filter meets the requirements of this standard, the primary reference filter shall be replaced. c) If the deviation between the efficiency test value and the calibration value of the primary reference filter and the standby reference filter exceeds the requirements of item a), the sampling system of the test device and the aerosol test device shall be inspected, calibrated and maintained as necessary. 5.1.11 Calibration of test device See Table 1 for the calibration period and requirements of test device. Table 1 Calibration period and requirements of test device Item Calibration period Standard subclauses and requirements referred Air flowrate stability During each test 5.1.1.3 Air duct tightness When the test device is completed and there are major structural adjustments 5.1.2.4 Air speed uniformity at upstream sampling section Every 2 years 5.1.4 Aerosol concentration uniformity at upstream sampling section Every 2 years 5.1.5 Upstream aerosol concentration stability Per year 5.1.6 Test device for flow rate; Per year 5.1.7 Test device for pressure Per year 5.1.7 Counter, sodium flame photometer and oil mist meter Per year 5.1.7 Correlation ratio at upstream and downstream sampling Every test day 5.1.8 Resistance standard parts Every 3 months 5.1.9 Reference filter Every 3 months 5.1.10 5.2 Counting method 5.2.1 Test principle Aerosol generator is used to generate aerosol which meets the test requirements, and OPC is used to test the particles in the range of 0.1 μm to 0.3 μm upstream and downstream of the tested filter, and the diameter counting efficiency is calculated. If the upstream aerosol concentration exceeds the upper limit concentration of OPC, the sampling air shall be diluted to reduce the coincide error of OPC counting. The dilution of sampling air can be achieved by diluent or by the difference of sampling flow rate between OPCs at upstream and downstream. 5.2.2 Test methods Particle counting method with monodisperse aerosol or particle counting method with polydisperse aerosol can be selected for efficiency test. The air duct system of the two methods is the same, but the aerosol generator and the corresponding test device are different. When particle counting method with monodisperse aerosol is used in the test, if the filter medium used in the filter has passed the test by particle counting method with monodisperse aerosol and its MPPS has been obtained, the median particle diameter of monodisperse aerosol count selected in the filter test shall be within 10% of its MPPS. Otherwise, the filter manufacturer shall determine, in consultation with the user, the range of the median diameter of the test aerosol count. 5.2.3 Test devices 5.2.3.1 The filter performance test device by counting method is mainly composed of aerosol generator, air duct system and aerosol sampling and detection device. See Figure 2 for the schematic diagram of the test device. Different test devices are allowed, but the requirements of 5.1 shall be met, and the test results of the same filter shall be consistent with the standard test device. Keys: 1——Fan; 12——Orifice flowmeter; 2——High efficiency particulate air filter; 13——Sampling pipe after filtration; 3——Straight pipe section; 14——Valve; 4——Aerosol inlet; 15——Diluent; 5——Stable section; 16——Particle sampling system; 6——Static pressure ring before filtration; 17——Micromanometer; 7——Sampling pipe before filtration; 18——Thermometer; 8——Tested filter; 19——Hygrometer; 9——Static pressure ring after filtration; D——Diameter of the upstream pipeline of the tested filter; 10——Reducer; d——Diameter of the downstream pipeline of the tested filter; 11——Straight pipe section; X——Dilution ratio. Figure 2 Schematic diagram of filter performance test device by counting method 5.2.3.2 The measuring device shall be OPC, and the test range of OPC particle size shall include at least 0.1 μm, 0.2 μm and 0.3 μm. 5.2.4 Filter detection 5.2.4.1 Operating parameters 5.2.4.1.1 Test air An electric heater shall be set in the air duct system to ensure that the temperature in the system is within (23 ± 5)°C and the relative humidity is not greater than 75%. 5.2.4.1.2 Aerosol testing Oily liquid aerosols such as DEHS and PAO generated by spraying should be used for testing aerosols. When solid aerosols are used for testing, necessary electrostatic neutralization treatment shall be carried out, and the consistency between the test results and oily liquid aerosols shall be verified by reference filters. 5.2.4.1.3 Spray air pressure The pressure of clean compressed air into the sprayer shall meet the requirements of aerosol generator. 5.2.4.1.4 Spray air volume Under the prescribed pressure, the amount of compressed air entering each sprayer shall be constant. 5.2.4.1.5 Upstream aerosol dilution When OPC measures aerosol concentration, the original aerosol shall be diluted in most cases, and the dilution ratio shall be in the range of 10x to 1,000x. The specific value depends on the initial aerosol concentration and the measuring equipment used, and it shall be ensured that the tested aerosol concentration does not exceed the maximum saturation concentration of OPC. 5.2.4.1.6 Aerosol sampling volume The aerosol sampling volume is determined by the sampling volume and sampling duration of OPC, which shall ensure that the downstream aerosol count concentration has statistical significance. 5.2.4.2 Detection steps 5.2.4.2.1 Operation preparation 5.2.4.2.1.1 When the aerosol generator is turned on and there is no tested filter in the test device, the aerosol count concentration of the upstream and downstream shall be measured respectively, and the correlation ratio of the upstream and downstream samples shall be calculated. 5.2.4.2.1.2 Visually inspect the filter medium in the tested filter for defects, cracks and holes; check the joint part of the filter frame corner and whether the frame and filter medium are sealed, whether there is gap and whether there is abnormality in structure. The filter that passes the visual inspection can be used for testing. 5.2.4.2.1.3 Install the tested filter securely on the test section in the direction of the air flow indicated by the arrow. 5.2.4.2.2 System startup 5.2.4.2.2.1 Start the fan, adjust the fan frequency converter and the air duct end valve to make the air flowrate of the air duct system reach the test air flowrate. 5.2.4.2.2.2 Regulate the temperature in the system within the range of (23 ± 5)°C and the relative humidity of not greater than 75%. 5.2.4.2.3 Preliminary test With the aerosol generator turned off and the test filter in place, the downstream aerosol count concentration shall be tested to check the background concentration. 5.2.4.2.4 Resistance detection Use a micromanometer to test the resistance of the filter section under the test air flowrate, and minus the air resistance of the test section to obtain the filter resistance. 5.2.4.2.5 Aerosol generator startup Start the aerosol generator, adjust the parameters of the aerosol generator according to the product instructions and maintain it stable. 5.2.4.2.6 Detection of filter efficiency The filter efficiency shall be detected according to the following requirements: a) Test aerosol shall be uniformly mixed with test air. In order to measure the efficiency of particle size, at least three tests shall be carried out on the particle size ranges of 0.1 μm to 0.2 μm and 0.2 μm to 0.3 μm respectively, and the average value and the lower limit of filtration efficiency with confidence of 95% shall be calculated respectively, and the lower value shall be selected as the counting test efficiency of the tested filter. b) During the efficiency test, two OPCSs can be used to measure at the same time, or one OPC can be used to measure the upstream and downstream of the tested filter successively. When the second measurement method is adopted, the OPC shall be purged before each downstream aerosol concentration test, so that the counting concentration of OPC has dropped to a level that can reliably measure the downstream aerosol concentration before starting to measure the downstream concentration. c) In order to ensure good repeatability and statistical significance of the detection results, the total number of downstream particles detected in each efficiency test cycle shall not be less than 100. 5.2.4.2.7 Detection of other parameters During the detection, the temperature, humidity and static pressure in the air duct where the tested filter is located and the temperature, humidity and atmospheric pressure of the environment shall be measured at the same time. 5.2.5 Calculation of filter efficiency 5.2.5.1 The filtration efficiency E of the tested filter shall be calculated using Equation (1) according to the measurement results of the number of particles before and after the filter by OPC. The first digit after the last 9 is taken as the significant digit for E value, and the second digit shall be rounded off according to the principle of rounding. For example, the measured value E = 99.976%, after rounded off, E = 99.98%. (1) where, E——the filtration efficiency of the tested filter; A2——the concentration of downstream aerosol particles, particles/m3; A0——the background concentration of downstream aerosol particles, particles/m3; A1——the concentration of upstream aerosol particles, particles/m3; R——the correlation ratio. 5.2.5.2 The lower limit efficiency E95%,min of the confidence interval with 95% confidence shall be calculated using Equation (2). (2) where, E95%,min——the lower limit efficiency of confidence interval with 95% confidence; A1,95%min——the lower limit of upstream aerosol concentration with confidence of 95%, in particles/m3; according to Poisson distribution, the lower confidence limit of particle count with confidence of 95% calculated by measured particle concentration is shown in Table 2; A2,95%max——the upper limit of downstream aerosol concentration with confidence of 95%, in particles/m3; according to Poisson distribution, the upper confidence limit of particle count with confidence of 95% calculated by measured particle concentration is shown in Table 2. Table 2 Particle count confidence interval with 95% confidence based on Poisson distribution Particle count Lower confidence limit Upper confidence limit Particle count Lower confidence limit Upper confidence limit 0 0.0 3.7 35 24.4 48.7 1 0.1 5.6 40 28.6 54.5 2 0.2 7.2 45 32.8 60.2 3 0.6 8.8 50 37.1 65.9 4 1.0 10.2 55 41.4 71.6 5 1.6 11.7 60 45.8 77.2 6 2.2 13.1 65 50.2 82.9 8 3.4 15.8 70 54.6 88.4 10 4.7 18.4 75 59.0 94.0 12 6.2 21.0 80 63.4 99.6 14 7.7 23.5 85 67.9 105.1 16 9.4 26.0 90 72.4 110.6 18 10.7 28.4 95 76.9 116.1 20 12.2 30.8 100 81.4 121.6 25 16.2 36.8 n (n > 100) n − 1.96 n + 1.96 30 20.2 42.8 5.3 Sodium flame method 5.3.1 Test principle The atomization drying method is used to test the artificial NaCl aerosol close to the MPPS range of the filter medium. The dried NaCl crystal can be screened by pre-filtration of the medium efficiency filter. The count peak particle size of the test aerosol particles shall be (0.09 ± 0.02)μm, and the geometric standard deviation shall not be greater than 1.90. The NaCl aerosol upstream and downstream of the filter is collected to the burner and burned under the hydrogen flame. The sodium flame light generated by the combustion is transformed into a current signal and detected by the photoelectric measuring instrument. The filtering efficiency of the filter is calculated from the measured current value. 5.3.2 Test device 5.3.2.1 The filter performance test device by sodium flame method is mainly composed of NaCl aerosol generator, air duct system and aerosol sampling and detection device. The schematic diagram of the test device is shown in Figure 3. Keys: 1——Prefilter; 20——Filter detection box; 2——Fan frequency conversion cabinet; 21——Orifice flowmeter; 3——Draught fan; 22——Iris valve; 4——Soft joint; 23——Micromanometer; 5——Air duct; 24——Temperature controller; 6——Electrical heater; 25——Background filter box; 7——High efficiency particulate air filter (HEPA); 26a——Three-way switching valve (background/after filtration); 8——Reducer; 26b——Three-way switching valve (original/after background filtration); 9——Spray box; 27——Vent valve; 10——Sprayer; 28——H2 generator; 11——On/off valve; 29——H2 constant flow valve; 12——Separate cylinder; 30——Burner; 13——Pressure gauge; 31——Photoelectric converter; 14——Spray solenoid valve; 32——Photoelectric measuring instrument; 15——Relief valve; 33——Temperature and humidity meter; 16——Drying pipe section; 34——Spray flowmeter; 17——Buffer tank; 35——Background filtered flowmeter; 18——Fixed blade ring; 36——Original flowmeter; 19a——Front sampling pipe; 37——H2 flowmeter; 19b——Rear sampling pipe; D——Pipe diameter. Figure 3 Schematic diagram of filter performance test device by sodium flame method 5.3.2.2 The NaCl aqueous solution with mass concentration of 2% in the spray box is atomized by a sprayer with clean compressed air to form aerosol mist droplets containing salt and mixed with clean hot air from heating and filtering of fans. In the mixing drying section, the water in the mist droplet evaporates, and when the air flow reaches the buffer tank, the test aerosol has formed a uniform polydispersed solid aerosol. If necessary, a medium efficiency filter can be set at the outlet of the buffer tank to screen the test aerosol closer to the MPPS range of the filter. When setting the medium efficiency filter, the concentration of NaCl aqueous solution can be increased to 10% in order to obtain the test aerosol mass concentration meeting the efficiency test requirements. The length of the downstream pipe section of the buffer tank shall meet the mixing demand of aerosol at the section of the front sampling pipe nozzle (if necessary, a diverter can be set at the outlet of the buffer tank). The air flowrate and static pressure of the air duct system are controlled by the fan frequency converter and the iris valve respectively, and the air flow after the test is discharged from the end of the air duct. 5.3.2.3 Aerosol sampling is pressed into the detection system by the static pressure in the air duct through the front and rear sampling pipes of the tested filter. By changing the position of the valve, the aerosol before and after the filter is sampled alternately, and the original, filtered and background aerosols are sent to the burner respectively. The original aerosol can flow into the burner only after mixing (i.e. dilution) with the clean air filtered by the background filter in the mixer. In the burner, the Na atom in the aerosol is excited by the high temperature of H2 flame and emits a characteristic light with a wavelength of 589 nm, whose intensity is directly proportional to the mass concentration of the aerosol. Sodium light intensity value is changed into photocurrent value through photoelectric converter and detected by photoelectric measuring instrument. The resistance of the filter section is detected by connecting the static-pressure rings on both sides of the tested filter to the micromanometer. The result minus the resistance of the filter detection box is the filter resistance. 5.3.2.4 The construction and maintenance requirements of the filter performance test device by sodium flame method are shown in Annex A, the sprayer and photometer structure are shown in Annex B. Different test devices are allowed, but the requirements of 5.1 shall be met, and the test results of the same filter shall be consistent with the standard test device. 5.3.3 Filter detection 5.3.3.1 Operating parameters 5.3.3.1.1 Test air An electric heater shall be set in the air duct system to ensure that the air inlet temperature of the system is not lower than 5°C, the relative humidity at the inlet of the buffer tank is not higher than 30%, and the relative humidity at the downstream side of the tested filter is not higher than 60%. 5.3.3.1.2 NaCl solution concentration Prepare NaCl solution with mass concentration of (2.0 ± 0.1)% with dry chemical pure NaCl and distilled water (natural water or tap water shall not be used). 5.3.3.1.3 Liquid level The height of NaCl solution in the spray box shall be 90 mm to 110 mm. 5.3.3.1.4 Spray air pressure The pressure of clean compressed air entering the sprayer shall be 0.6 MPa, and the allowable deviation is ±0.02 MPa. 5.3.3.1.5 Spray air volume Under the prescribed pressure, the amount of compressed air entering each sprayer shall meet those specified in Table A.1. 5.3.3.1.6 Original aerosol concentration The original mass concentration range of NaCl shall be 2 mg/m3–8 mg/m3. 5.3.3.1.7 Aerosol sampling volume The amount of sampling air entering the burner shall be 2 L/min. 5.3.3.1.8 H2 volume The volume of H2 entering the burner shall be 200 mL/min and shall be kept constant. 5.3.3.2 Detection steps 5.3.3.2.1 Operation preparation 5.3.3.2.1.1 Turn the turntable on the photoelectric converter to the "OFF" position. Turn on the H2 generator, ignite H2, adjust the flow rate to 200 mL/min, and start the system to start detection after the burner is preheated for 30 min. 5.3.3.2.1.2 Turn on the power switch of the photoelectric measuring instrument and preheat the photoelectric measuring system. 5.3.3.2.1.3 Take out the humidity sensitive probe from the drying vessel, connect it with the signal line led out from the hygrometer and put it into the measuring hole at the inlet of the buffer tank. Turn on the power supply of the hygrometer and press the "measurement" key. The humidity at the entrance of the buffer tank can be displayed on the hygrometer. 5.3.3.2.1.4 Visually inspect the filter medium in the tested filter for defects, cracks and holes; check the joint part of the filter frame corner and whether the frame and filter medium are sealed, whether there is gap and whether there is abnormality in structure. The filter that passes the visual inspection can be used for testing. 5.3.3.2.1.5 Place the tested filter in the box of the air duct system and clamp it. 5.3.3.2.2 System startup 5.3.3.2.2.1 Start the fan, adjust the fan frequency converter and iris valve to make the air flowrate and static pressure of the air duct system meet the detection requirements. Start the air compressor. When the pressure reaches 0.5 MPa, the spray solenoid valve will be opened, the spray pressure will reach 0.6 MPa gradually, maintain the pressure stable, and the air flow meter reading of each sprayer is stable to the design value, and check the test air flowrate again. 5.3.3.2.2.2 Measure the relative humidity of the air at the inlet of the buffer tank. If it is greater than 30%, gradually put the electric heater into operation until the relative humidity reaches the specified value. 5.3.3.2.3 Resistance detection Use a micromanometer to test the resistance of the filter section under the test air flowrate, and minus the air resistance of the test section to obtain the filter resistance. Foreword i 1 Scope 2 Normative references 3 Terms, definitions and abbreviations 4 Selection of test methods 5 Performance device and test method of HEPA and ULPA 6 Performance test method of HEPA and ULPA filter mediums Annex A (Normative) Structure and maintenance of filter performance test device by sodium flame method Annex B (Informative) Structure diagram of components of filter and filter medium test devices by sodium flame method Annex C (Normative) Structure and maintenance of filter test device by oil mist method Annex D (Normative) Correction, calibration and maintenance of filter medium test device by oil mist method Annex E (Normative) Vaporization-condensation oil mist generator in filter test device by oil mist method Annex F (Normative) Oil mist meter Annex G (Normative) Structure and maintenance of filter medium test device by sodium flame method Annex H (Normative) Oil mist generator in the filter medium test device 高效空气过滤器性能试验方法 效率和阻力 1 范围 本标准规定了高效、超高效滤料及过滤器效率和阻力检测的术语、定义、符号与缩略语，试验方法的选择，高效及超高效空气过滤器性能试验方法，高效及超高效滤料性能试验方法等。 本标准适用于过滤气溶胶所使用的高效、超高效滤料及过滤器效率和阻力的检测。亚高效滤料及过滤器的效率和阻力检测可参照执行。 2规范性引用文件 下列文件对于本文件的应用是必不可少的。凡是注日期的引用文件，仅注日期的版本适用于本文件。凡是不注日期的引用文件，其最新版本(包括所有的修改单)适用于本文件。 GB/T 1236工业通风机用标准化风道性能试验 GB/T 2624.2用安装在圆形截面管道中的差压装置测量满管流体流量 第2部分：孔板 GB/T 2624.3用安装在圆形截面管道中的差压装置测量满管流体流量 第3部分：喷嘴和文丘里喷嘴 GB 11120涡轮机油 GB/T 12564光电倍增管总规范 GB/T 13554 高效空气过滤器 GB/T 14295 空气过滤器 GB 50243 通风与空调工程施工质量验收规范 JJF 1190尘埃粒子计数器校准规范 JJG 172倾斜式微压计 JJG 875数字压力计检定规程 3术语和定义、缩略语 3.1术语和定义 GB/T 13554界定的以及下列术语和定义适用于本文件。 3.1.1 透过率penetration 对过滤元件进行试验时，过滤元件过滤后的气溶胶浓度与过滤前的气溶胶浓度之比。 3.1.2 效率 efficiency 对过滤元件进行试验时，过滤元件过滤掉的气溶胶量与过滤前的气溶胶量之比。 3.1.3 额定风量 rated air flowrate 标识过滤器工作能力的技术参数，表示保证过滤器效率的单位时间最大空气体积流量。 注：由过滤器生产厂家提供。 3.1.4 阻力 resistance 在一定试验风速或风量条件下，过滤元件前后的静压差。对过滤器而言，为额定风量下过滤器前后的静压差。 3.1.5 滤料 filter medium 未经折叠、用于过滤气溶胶的平面过滤材料。 3.1.6 高效空气过滤器high efficiency particulate air filter；HEPA 用于空气过滤且使用本标准规定的计数法进行试验，额定风量下未经消静电处理时的过滤效率及经消静电处理后的过滤效率均不低于99.95％的空气过滤器。 3.1.7 超高效空气过滤器ultra low penetration air filter；ULPA 用于空气过滤且使用本标准规定的计数法进行试验，额定风量下未经消静电处理时的过滤效率及经消静电处理后的过滤效率均不低于99.999％的空气过滤器。 3.1.8 高效滤料HEPA filter medium 用于制作高效空气过滤器的滤料。 3.1.9 超高效滤料ULPA filter medium 用于制作超高效空气过滤器的滤料。 3.1.10 气溶胶发生器aerosol generator 用于产生试验用标准气溶胶的装置。 3.1.11 粒子计数浓度particle number concentration 单位体积气体(空气)中，所测量粒径范围内的粒子数量。 3.1.12 粒径particle size 用某种测定方法(光学或空气动力学等效测试)测出的粒子名义直径。 3.1.13 计径效率particle size efficiency 过滤元件对某一粒径粒子的过滤效率。 3.1.14 最易透过粒径most penetrating particle size；MPPS 按本标准所规定的计数法进行试验时，受试过滤元件计径效率曲线最低点对应的粒径。 3.1.15 最易透过效率 minimum filter efficiency 在给定运行条件下，受试过滤元件对最易透过粒径粒子的过滤效率，一般称MPPS效率。 3.1.16 中值直径 median particle diameter 气溶胶粒径累积分布占总量50％时对应的粒径值，常用计数中值直径和质量中值直径表示。 3.1.17 采样流量sampling flow rate 检测仪器在测定过滤元件上游或下游粒子浓度时，其测量元件取样的空气体积流量。 3.1.18 采样时间 sampling duration 在取样体积流量下，受试高效空气过滤元件上游或下游空气采样的有效时间。 3.1.19 重合误差 coincide error 在给定时间内，由于粒子计数器的散射腔中含有多个颗粒而产生的误差。 注：重合误差会导致测量结果中计数浓度偏低、平均粒径偏高。 3.1.20 单分散气溶胶monodisperse aerosol 用分布方程描述时，粒径尺寸几何标准差小于1.15即(σg<1.15)的气溶胶。 3.1.21 准单分散气溶胶quasi-monodisperse aerosol 用分布方程描述时，粒径尺寸几何标准差大于或等于1.15且小于或等于1.50即(1.15≤σg≤1.50)的气溶胶。 3.1.22 多分散气溶胶polydisperse aerosol 用分布方程描述时，粒径尺寸几何标准差大于1.50即(σg>1.50)的气溶胶。 3.1.23 钠焰法 sodium flame method 发生多分散NaCl气溶胶，用钠焰光度计检测过滤元件上、下游的质量浓度，计算过滤元件的质量效率。对于滤料及过滤器试验，发生试验气溶胶颗粒的计数峰值直径为(0.09±0.02)μm，计数几何标准偏差不大于1.90。 3.1.24 油雾法oil mist method 发生多分散液体气溶胶，颗粒的质量平均直径为0.28μm～0.34μm，用油雾仪检测过滤元件上、下游的质量浓度，计算过滤元件的质量效率。 3.1.25 准单分散气溶胶计数法particle counting method with quasi-monodisperse aerosol 发生准单分散气溶胶(如固体颗粒NaCl或液体颗粒DEHS等)，颗粒的计数中值直径在0.10μm～0.30μm之间，几何标准偏差不大于1.50，使用凝结核粒子计数器(CPC)或光学粒子计数器(OPC)检测滤料上、下游的计数浓度，计算滤料的计数效率。 3.1.26 单分散气溶胶计数法particle counting method with monodisperse aerosol 发生单分散气溶胶，使用凝结核粒子计数器(CPC)检测过滤元件上、下游的计数浓度，计算过滤元件的计数效率。单分散气溶胶的发生可以有多种方法，如微分电迁移分析仪(DMA)、扩散电池组、蒸发冷凝法、聚苯乙烯乳胶球(PSL)等。 3.1.27 多分散气溶胶计数法particle counting method with polydisperse aerosol 发生多分散气溶胶(如固体颗粒NaCl或液体颗粒DEHS等)，使用光学粒子计数器(OPC)检测过滤元件上、下游的计数浓度，计算过滤元件的计数效率。 3.1.28 相关系数 corrdation ratio 在试验系统未安装受试过滤器及保持稳定气溶胶浓度的情况下，上、下游采样系统粒子浓度之比。 注：当试验系统采用1台光学粒子计数器(OPC)依次对受试过滤器的上、下游气溶胶浓度进行检测时，相关系数表示由于上、下游采样管路粒子损失、稀释器稀释比(如果上游采样采用稀释器)以及上、下游采样时间的差异所导致的上、下游采样系统差异；当试验系统分别采样2台光学粒子计数器(OPC)对受试过滤器的上、下游气溶胶浓度进行检测时，相关系数表示由于上、下游采样计数器采样流量以及计数效率不同所引起的差异。 3.2 缩略语 下列缩略语适用于本文件。 CPC：凝结核粒子计数器(condensation particle counter) DEHS：癸二酸二辛酯[sebacic acid-bis(2-ethyl-)ester(通用名di-ethyl-hexyl-sebacate)] DMA：微分电迁移分析仪(differential mobility analyser) MPPS：最易透过粒径(most penetrating particle size) OPC：光学粒子计数器(optical particle counter) PAO：聚α烯烃(poly alpha olefin) PSL：聚苯乙烯乳胶球(polystyrene latex spheres) HEPA：高效空气过滤器(high efficiency particulate air filter) ULPA：超高效空气过滤器(ultra low penetration air filter) 4试验方法的选择 4.1 本标准给出计数法、钠焰法、油雾法3种试验方法。基准方法为计数法。 4.2 对于高效空气过滤器及滤料，可根据需求使用3种方法中的任意一种进行效率检测，但应同时注明试验方法及试验结果。在高效滤料的生产检测中，宜在与基准方法明确比对关系的条件下。使用钠焰法和准单分散气溶胶计数法等快速试验方法。 4.3对于超高效空气过滤器及滤料，应使用计数法进行效率检测。在超高效滤料的生产检测中，宜在与基准方法明确比对关系的条件下，使用准单分散气溶胶计数法等快速试验方法。 4.4 对于MPPS不大于0.1μm的过滤器及滤料，基准方法为单分散气溶胶计数法。在该类过滤器出厂检测中，可在与基准方法明确比对关系的条件下，使用计数法对0.1μm～0.2μm区间粒子进行试验。并根据与基准方法的比对关系对试验结果进行修正。 5 高效及超高效空气过滤器性能装置及试验方法 5.1 对于试验装置的要求 5.1.1 风机 5.1.1.1 风量 风量应按受试过滤器最大风量的1.3倍计算。 5.1.1.2风压 风压应至少包括下列各项之和： a)风道阻力(按计算阻力的1.2倍取值)； b)进风过滤器阻力(按其初始阻力的2倍取值)； c)受试过滤器最大阻力； d)风量测量装置阻力； e)对于钠焰法试验装置，应考虑过滤器后取样所需的正压值(不宜小于600 Pa)。 5.1.1.3风量稳定性 测试过程中试验装置风量应稳定在设定值的±2％范围内。 5.1.2风道 5.1.2.1 材料 钠焰法试验装置自喷雾箱至缓冲箱宜采用聚氯乙烯塑料或其他耐腐蚀材料；钠焰法试验装置的其余部分及其他试验装置宜采用不锈钢风道。风道壁厚宜不小于1 mm。必要时，风道应进行接地及防腐处理。 5.1.2.2风量测量装置前、后管段尺寸 当采用标准孔板时，其前、后管段尺寸应按GB/T 2624.2的相关要求进行设计；当采用标准喷嘴时，其前、后管段尺寸应按GB/T 2624.3的相关要求进行设计。 5.1.2.3受试过滤器连接管的角度 受试过滤器连接管扩散段的夹角应不大于14°，收敛段的夹角应不大于30°，且应满足GB/T 1236的相关要求。 5.1.2.4风道密封性 试验装置中风管的制作、安装及检验应满足GB 50243对中压系统的相关要求，风管接缝处应采用焊接。风道密封性应在2 kPa的压力下进行打压检漏，漏风量应不大于1.64 m3/(h·m2)。 5.1.3进风过滤 5.1.3.1 预过滤器 预过滤器应采用满足GB/T 14295中效过滤器相关要求。 5.1.3.2 高效空气过滤器 高效空气过滤器应满足GB/T 13554的相关要求，当过滤器上游设有加热器时，过滤器耐温应不低于60℃。 5.1.4上游采样截面风速均匀性 调整试验装置运行风量至最大测试风量，在试验风道上游采样点所处截面根据风道截面积按图1所示平均分布设置9个测点，分别测试风速，各测点实测风速与各测点平均值之间的偏差应不大于10％。 a)方形风道 b)圆形风道 说明： a——方形风道边长； D——圆形风道直径。 图1 上游采样截面风速和气溶胶浓度均匀性测点布置示意图 5.1.5上游采样截面气溶胶浓度均匀性 调整试验装置运行风量至最大测试风量，启动气溶胶发生器并保持稳定工作，在试验风道上游采样点所处截面根据风道截面积按图1所示平均分布设置9个测点，分别测试气溶胶浓度。各测点实测气溶胶浓度与各测点平均值之间的偏差应不大于10％。 5.1.6上游气溶胶浓度稳定性 调整试验装置运行风量至最大测试风量，启动气溶胶发生器并保持稳定工作，在试验风道上游采样点处进行采样，30 min内所测气溶胶质量浓度或给定粒径范围计数浓度波动应不大于10％。 5.1.7通用测试仪器要求 风量测试装置可采用标准孔板或喷嘴，按GB/T 2624.2及GB/T 2624.3的相关要求进行设计、安装、使用和标定，并应符合以下要求： a)用于过滤器阻力和流量测量装置压差测量的压力测试装置，精度应不低于2 Pa，并应根据所选择压力测试装置的不同，按JJG 172或JJG 875的相关要求定期进行检定及校准。 b)计数器应按JJF 1190的相关要求进行定期进行检定及校准。钠焰光度计中的光电测量仪应按GB/T 12564的相关要求定期进行稳定性测试及校准。油雾仪应按5.4.3.1.1.4要求进行标定。 5.1.8上、下游采样相关系数 在气溶胶发生器稳定工作、测试段未安装过滤器且上游采样段未安装稀释器时，各粒径挡相关系数应为1.00±0.03。在上游采样段安装稀释器后，应定期对各粒径挡相关系数进行测试确认。 5.1.9 阻力标件 5.1.9.1采用已知阻力的孔板(或其他阻力标件)按5.2.4.2.4进行定期测试。 5.1.9.2 阻力标件在不使用时应妥善储存与保管，防止破损。 5.1.9.3阻力标件的测试应满足以下要求： a)应在试验装置风量范围内选择至少4个风量状态点进行测试。 b)每次测试时，每一风量状态点下的阻力测试结果与标定值的偏差应不大于3％。若阻力标件测试阻力值与标定值的偏差大于3％，则应对管道密封性、流量测试装置压力计等进行必要的检查、维护和标定。 c)可使用阻力标件与参比试验装置进行对比验证测试。 5.1.10参考过滤器 5.1.10.1 试验装置应准备效率已知的参考过滤器，按5.2、5.3或5.4规定的方法定期进行效率测试。 5.1.10.2应至少准备2台参考过滤器，其中1台为主参考过滤器，另1台为备用。参考过滤器所选用滤料不应使用难以长期保持稳定过滤效率的材料。参考过滤器在不使用时应妥善储存与保管，防止破损。 5.1.10.3参考过滤器的使用应满足以下要求： a)参考过滤器每次效率测试值与标定值尾数(效率值第一个非9数值)的偏差应不超过±5。 b)每次测试时应首先选择主参考过滤器，若主参考过滤器效率测试值与标定值的偏差超出a)的要求，则应对备用参考过滤器进行测试。若备用参考过滤器效率测试值符合本标准要求时，应更换主参考过滤器。 c)若主参考过滤器及备用参考过滤器效率测试值与标定值的偏差均超过a)的要求，应对试验装置采样系统、气溶胶测试装置等进行必要的检查、标定和维修。 5.1.11试验装置标定 试验装置标定周期及要求见表1。 表1 试验装置标定周期及要求 项目 标定周期 依据标准及要求 风量稳定性 每次试验 5.1.1.3 风道密封性 试验装置建成及有重大结构调整时 5.1.2.4 上游采样截面风速均匀性 每2年 5.1.4 上游采样截面气溶胶浓度均匀性 每2年 5.1.5 上游气溶胶浓度稳定性 每年 5.1.6 流量测试装置 每年 5.1.7 压力测试装置 每年 5.1.7 计数器、钠焰光度计及油雾仪 每年 5.1.7 上、下游采样相关系数 每试验日 5.1.8 阻力标件 每3个月 5.1.9 参考过滤器 每3个月 5.1.10 5.2 计数法 5.2.1 试验原理 用气溶胶发生器发生满足试验要求的气溶胶，使用OPC对受试过滤器上、下游0.1μm～0.3μm粒径范围内的粒子进行检测，并计算计径效率。测量上游气溶胶浓度时，若上游气溶胶浓度超过OPC上限浓度。采样空气应经过稀释，以降低OPC计数的重合误差。采样空气的稀释可通过稀释器实现，也可通过上、下游OPC取样流量的差异实现。 5.2.2试验方法 可选择单分散气溶胶计数法或多分散气溶胶计数法进行效率测试。两种方法的风道系统一致，仅气溶胶发生器及所对应的检测装置有所区别。当采用单分散气溶胶计数法进行试验时，如过滤器所采用滤料已经过单分散气溶胶计数法试验，并已获得其MPPS，则过滤器试验中所选择的单分散气溶胶计数中值直径应在其MPPS的±10％以内。否则，过滤器制造商应与用户协商确定试验气溶胶的计数中值直径范围。 5.2.3试验装置 5.2.3.1 计数法过滤器件能检测试验装置主要由气溶胶发生器、风道系统、气溶胶取样与检测装置组成，试验装置示意图见图2。试验装置允许有所不同，但应满足5.1的要求，且对同一过滤器的试验结果应与标准试验装置一致。 说明： 1——风机： 2——高效空气过滤器； 3——直管段； 4——气溶胶入口； 5——稳定段； 6——过滤前静压环； 7——过滤前采样管； 8——受试过滤器； 9——过滤后静压环； 10——变径管； 11——直管段； 12——孔板流量计； 13——过滤后采样管； 14——阀门； 15——稀释器； 16——粒子采样系统； 17——微压计； 18——温度计； 19——湿度计； D——被测过滤器上游管道直径； d——被测过滤器下游管道直径； x——稀释倍数。 图2计数法过滤器性能检测试验装置示意图 5.2.3.2测量装置应使用OPC，OPC粒径测试范围内应至少包括0.1μm、0.2μm、0.3μm三挡。 5.2.4过滤器检测 5.2.4.1运行参数 5.2.4.1.1试验空气 风道系统中应设置电加热器，以保证系统内的温度在(23±5)℃范围内、相对湿度不大于75％。 5.2.4.1.2测试气溶胶 测试气溶胶宜采用喷雾方式发生的DEHS、PAO等油性液态气溶胶，当采用固态气溶胶进行测试时，应进行必要的静电中和处理，并利用参考过滤器验证其与油性液态气溶胶测试结果的一致性。 5.2.4.1.3喷雾空气压力 进入喷雾器的洁净压缩空气的压力应满足气溶胶发生器的要求。 5.2.4.1.4喷雾空气量 在规定的压力下，进入每个喷雾器的压缩空气量应恒定。 5.2.4.1.5上游气溶胶稀释 OPC在测量气溶胶浓度时，大多数情况下应对原始气溶胶进行稀释，稀释倍数应在10倍～1 000倍范围内，具体数值取决于最初的气溶胶浓度和使用的测量设备，应保证测试气溶胶浓度不超过OPC的最大饱和浓度。 5.2.4.1.6气溶胶取样量 气溶胶取样量由OPC的取样量及采样时间决定，应保证下游气溶胶计数浓度具有统计意义。 5.2.4.2检测步骤 5.2.4.2.1 运行准备 5.2.4.2.1.1 应在开启气溶胶发生器、试验装置中无受试过滤器的情况下，分别测量上、下游的气溶胶计数浓度，并计算上、下游采样的相关系数。 5.2.4.2.1.2 目测检查受试过滤器中的滤料有无缺损、裂缝和孔洞；检查过滤器边框角的结合部位以及边框与滤料之间是否密封、有无间隙、构造上有无异常。经外观检查合格的过滤器方可作为检测用。 5.2.4.2.1.3将受试过滤器按箭头指示的气流方向紧固安装于测试段上。 5.2.4.2.2 系统启动 5.2.4.2.2.1 启动风机，调节风机变频器和风道末端阀门，使风道系统的风量达到试验风量。 5.2.4.2.2.2调节系统内的温度在(23±5)℃范围内、相对湿度不大于75％。 5.2.4.2.3预备性检验 应在关闭气溶胶发生器和受试过滤器就位的情况下，测试下游气溶胶计数浓度，检查背景浓度。 5.2.4.2.4 阻力检测 使用微压计测试试验风量下的过滤段阻力，减去测试段的空阻力，即为过滤器阻力。 5.2.4.2.5 启动气溶胶发生器 启动气溶胶发生器。依据产品说明书调节气溶胶发生器各项参数并保持稳定。 5.2.4.2.6过滤器过滤效率检测 过滤器效率检测应满足以下要求： a)试验气溶胶应与试验空气均匀混合。为了测定粒径效率，应分别对0.1μm～0.2μm及0.2μm～0.3μm两挡粒径范围进行至少3次测试，分别计算平均值及置信度为95％的过滤效率下限，选择其较低值作为受试过滤器的计数法测试效率。 b)进行效率测试时，可用2台OPC同时测量，也可用1台OPC先后在受试过滤器的上、下游分别测量。采用第2种测量方式时，应在每次下游气溶胶浓度检测前对OPC进行净吹，以便在开始测量下游浓度之前，OPC的计数浓度已经下降到能可靠测定下游气溶胶浓度的水平。 c)为保证检测结果具有良好的重复性及统计意义，每个效率测试周期内，检测到的下游粒子总数应不少于100粒。 5.2.4.2.7其他参数检测 在检测期间，应同时测出受试过滤器所处风道内的温度、湿度、静压和环境的温度、湿度、大气压。 5.2.5过滤器过滤效率计算 5.2.5.1 根据OPC对过滤器前后的粒子数测量结果，受试过滤器的过滤效率E应按式(1)进行计算。E取最后一个9之后的第一位数字为有效数字，第二位数字按四舍五入进行修约。例如，实测值E=99.976％，修约后E=99.98％。 (1) 式中： E——受试过滤器过滤效率； A2——下游气溶胶粒子浓度，单位为粒每立方米(粒/m3)； A0——下游气溶胶粒子背景浓度，单位为粒每立方米(粒/m3)； A1——上游气溶胶粒子浓度。单位为粒每立方米(粒/m3)； R——相关系数。 5.2.5.2置信度为95％的置信区间下限效率E95％,min应按式(2)进行计算。 (2) 式中： E95％,min——置信度为95％的置信区间下限效率； A1,95％min——置信度为95％的上游气溶胶浓度下限，单位为粒每立方米(粒/m3)，依据泊松分布，实测粒子浓度计算置信度为95％的粒子计数置信下限见表2； A2,95％max——置信度为95％的下游气溶胶浓度上限，单位为粒每立方米(粒/m3)，依据泊松分布，实测粒子浓度计算置信度为95％的粒子计数置信上限见表2。 表2依据泊松分布。置信度为95％的粒子计数置信区间 粒子数 置信下限 置信上限 粒子数 置信下限 置信上限 0 0.0 3.7 35 24.4 48.7 1 0.1 5.6 40 28.6 54.5 2 0.2 7.2 45 32.8 60.2 3 0.6 8.8 50 37.1 65.9 4 1.0 10.2 55 41.4 71.6 5 1.6 11.7 60 45.8 77.2 6 2.2 13.1 65 50.2 82.9 8 3.4 15.8 70 54.6 88.4 10 4.7 18.4 75 59.o 94.0 12 6.2 21.0 80 63.4 99.6 14 7.7 23.5 85 67.9 105.1 16 9.4 26.0 90 72.4 110.6 18 10.7 28.4 95 76.9 116.1 20 12.2 30.8 100 81.4 121.6 25 16.2 36.8 n(n>100) n-1.96 n+1.96 30 20.2 42.8 5.3 钠焰法 5.3.1 试验原理 用雾化干燥的方法人工发生接近过滤材料MPPS范围的NaCl气溶胶进行测试，可采用中效过滤器预过滤筛选的方式对干燥后的NaCl晶体进行筛选。测试气溶胶颗粒的计数峰值粒径应为(0.09±0.02)μm，几何标准偏差应不大于1.90。将过滤器上、下游的NaCl气溶胶采集到燃烧器并在氢火焰下燃烧，将燃烧产生的钠焰光转变为电流信号并由光电测量仪检测，用测定的电流值求出过滤器的过滤效率。 5.3.2 试验装置 5.3.2.1 钠焰法过滤器性能检测试验装置主要由NaCl气溶胶发生装置、风道系统、气溶胶取样与检测装置组成，试验装置示意图见图3。 洁净压缩空气 说明： 1——预过滤器； 2——风机变频柜； 3——风机； 4——软接头； 5——风管； 6——电加热器； 7——高效空气过滤器； 8——变径管； 9——喷雾箱； 10——喷雾器； 11——通断阀； 12——分气缸； 13——压力表； 14——喷雾电磁阀： 15——减压阀； 16——干燥管段； 17——缓冲箱； 18——静压环； 19a——前取样管； 19b——后取样管； 20——过滤器检测箱体； 21——孔板流量计； 22——光圈阀； 23——微压计； 24——温控仪； 25——本底过滤盒； 26a——三通切换阀(本底/滤后)； 26b——三通切换阀(原始/本底滤后)； 27——放气阀； 28——H2发生器： 29——H2恒流阀； 30——燃烧器； 31——光电转换器； 32——光电测量仪； 33——温湿度仪； 34——喷雾流量计； 35——本底滤后流量计； 36——原始流量计； 37——H2流量计； D——管道直径。 图3钠焰法过滤器性能检测试验装置示意图 5.3.2.2用洁净压缩空气将喷雾箱中质量浓度为2％的NaCl水溶液经喷雾器雾化。形成含盐雾滴气溶胶，并与来自风机经过加热与过滤的洁净热空气相混合。在混合干燥段，雾滴中的水分蒸发，气流到达缓冲箱时，试验气溶胶已形成均匀的多分散相固体气溶胶。必要时，可在缓冲箱出口处设一道中效过滤器，筛选出更接近过滤器MPPS范围的测试气溶胶。设置中效过滤器时，可将NaCl水溶液浓度提高到10％，以获取满足效率测试需求的测试气溶胶质量浓度。缓冲箱下游管段长度应能满足气溶胶在前取样管口截面处的混匀需求(必要时，可在缓冲箱出口处设分流器)。风道系统的风量和静压分别由风机变频器及光圈阀控制，试验后的气流由风道末端排出。 5.3.2.3气溶胶取样靠风道内的静压通过受试过滤器前、后取样管压入检测系统，通过改变阀门的位置，交替对过滤器前、后气溶胶进行取样，并将原始、滤后和本底气溶胶分别送入燃烧器。原始气溶胶在混合器中与经过本底过滤器过滤的洁净空气相混合(即稀释)后，方可进入燃烧器。在燃烧器内，气溶胶中的Na原子被H2火焰高温所激发，发出波长为589 nm的特征光，其强度与气溶胶质量浓度成正比。钠光强值通过光电转换器变为光电流值，由光电测量仪进行检测。过滤段阻力由受试过滤器两侧的静压环连接至微压计检测，其结果减去过滤器检测箱体的阻力即为过滤器阻力。 5.3.2.4 钠焰法过滤器性能检测试验装置的构造与维护要求见附录A、喷雾器及光度计构造参见附录B。试验装置允许有所不同，但应满足5.1的要求，且对同一过滤器的试验结果应与标准试验装置一致。 5.3.3过滤器检测 5.3.3.1 运行参数 5.3.3.1.1 试验空气 风道系统中应设置电加热器，以保证系统的进风温度不低于5℃、缓冲箱入口处的相对湿度不高于30％、受试过滤器下游侧相对湿度不高于60％。 5.3.3.1.2 NaCl溶液浓度 用干燥的化学纯NaCl和蒸馏水(不应使用天然水或自来水)配制成质量浓度为(2.0±0.1)％的NaCl溶液。 5.3.3.1.3液面高度 喷雾箱内NaCl溶液液面距喷雾器喷孔高度应为90 mm～110 mm。 5.3.3.1.4喷雾空气压力 进入喷雾器的洁净压缩空气的压力应为0.6 MPa，允许偏差为±0.02 MPa。 5.3.3.1.5喷雾空气量 在规定的压力下，进入每个喷雾器的压缩空气量应满足表A.1的要求。 5.3.3.1.6气溶胶原始浓度 NaCl原始质量浓度范围应为2 mg/m3～8 mg/m3。 5.3.3.1.7气溶胶取样量 进入燃烧器的采样空气量应为2 L/min。 5.3.3.1.8 H2量 进入燃烧器的H2量应为200 mL/min，并应保持恒定。 5.3.3.2 检测步骤 5.3.3.2.1 运行准备 5.3.3.2.1.1 将光电转换器上的转盘转到“全闭”位置。打开H2发生器，点燃H2，调节流量为200 mL/min，燃烧器预热30 min后可启动系统开始检测。 5.3.3.2.1.2打开光电测量仪电源开关，预热光电测量系统。 5.3.3.2.1.3将湿敏探头从干燥器皿中取出，与湿度计上引出的信号线连接并放入缓冲箱入口处的测孔中。打开湿度计的电源，按下“测量”键，湿度计上即可显示缓冲箱入口处的湿度。 5.3.3.2.1.4 目测检查受试过滤器中的滤料有无缺损、裂缝和孔洞；检查过滤器边框角的接合部位以及边框与滤料之间是否密封、有无间隙、构造上有否异常。经外观检查合格的过滤器方可作为检测用。 5.3.3.2.1.5将受试过滤器置于风道系统的箱体中并夹紧。 5.3.3.2.2 系统启动 5.3.3.2.2.1 启动风机，调节风机变频器和光圈阀阀门使风道系统的风量和静压达到检测要求。启动空气压缩机，待压力达到0.5 MPa时，开启喷雾电磁阀，喷雾压力逐渐达到0.6 MPa，维持压力稳定，且每个喷雾器的空气流量计读数稳定至设计值，同时再次校核试验风量。 5.3.3.2.2.2测量缓冲箱入口处的空气相对湿度，如大于30％，应逐步投入电加热器，直至相对湿度达到规定值。 5.3.3.2.3 阻力检测 使用微压计测试试验风量下的过滤段阻力，减去过滤器检测箱体的空阻力，即为过滤器阻力。 5.3.3.2.4过滤器过滤效率检测 5.3.3.2.4.1 将三通切换阀(图3中26a、26b)转至“本底”，用放气阀调节本底滤后流量计(图3中35)的流量为120 L/h，将光电转换器上的滤光转盘转至“全通”位置(此时减光倍数N=1)，打开光窗，用钠焰光度计测量本底洁净空气光电流值，测量结束后关闭光窗。 5.3.3.2.4.2将三通切换阀(图3中26b)转至“原始”，用放气阀调节原始流量计(图3中36)流量为120 L/h，将滤光转盘转至Ⅱ，打开光窗，用钠焰光度计测量过滤前气溶胶光电流值，测量结束后关闭光窗。 5.3.3.2.4.3将三通切换阀(图3中26a、26b)转至“滤后”，用放气阀调节本底滤后流量计(图3中35)的流量为120 L/h，将滤光转盘转至Ⅱ(由于过滤器效率的不同，转盘有可能需要转至I或全通)，打开光窗，用钠焰光度计测量过滤后气溶胶光电流值，测量结束后关闭光窗。 5.3.3.2.5其他参数检测 在检测期间，应同时测出受试过滤器所处风道内的温度、湿度、静压和环境的温度、湿度、大气压。 5.3.3.3过滤器过滤效率计算 受试过滤器过滤效率E(％)可按式(3)进行计算。E取最后一个9之后的第一位数字为有效数字，第二位数字按四舍五入原则进行修约。例如，实测值E=99.976％，修约后E=99.98％。 (3) 式中： E——受试过滤器过滤效率； P——受试过滤器透过率； A′1——过滤前气溶胶光电流值，单位为微安(μA)； A′2——过滤后气溶胶光电流值，单位为微安(μA)； A′0——本底洁净空气光电流值，单位为微安(μA)； φ——白吸收修正系数。由试验求得，在本标准的设备和运行参数条件下φ=2。 当A′1/>>A′0时，A′0可以忽略不计，式(3)可简化为式(4)。 (4) 5.4油雾法 5.4.1 试验原理 在规定的试验条件下，用涡轮机油通过汽化—冷凝式油汽发生炉人工发生油雾气溶胶，气溶胶粒子的质量平均直径范围为0.28μm～0.34μm。使与空气充分混合的油雾气溶胶通过受试过滤器，分别采集过滤器上、下游的气溶胶，通过油雾仪(或浊度计)测量其散射光强度。散射光强度的大小与气溶胶浓度成正比，由此即可求出受试过滤器的过滤效率。 5.4.2试验装置 5.4.2.1 油雾法过滤器性能检测试验装置主要由油雾气溶胶发生装置、风道系统、气溶胶取样与检测装置组成，试验装置示意图见图4，宜采用负压系统。 说明： 1——光电雾室； 2——透过率测定仪； 3——油雾发生炉； 4——缓冲分离器； 5——贮油器； 6——分油罐； 7——玻璃毛细管； 8——液压计； 9——玻璃孔板流量计； 10——真空泵； 11——气压计； 12——空气除尘器； 13——高效空气过滤器； 14——滤尘罐； 15——微压计； 16——U型压力计； 17——液体转子流量计； 18——玻璃旋塞。 图4油雾法过滤器性能检测试验装置示意图 5.4.2.2油雾法过滤器试验装置的构造与维护要求见附录C，其标定、校对与维护要求见附录D。试验装置允许有所不同，但应满足5.1的要求，且对同一过滤器的试验结果应与标准试验装置一致。 5.4.3过滤器检测 5.4.3.1 运行准备 5.4.3.1.1过滤器外观检查 目测检查受试过滤器中的滤料有无缺损、裂缝和孔洞；检查过滤器边框角的接合部位以及边框与滤料之间是否密封、有无间隙、构造上是否异常。经外观检查合格的过滤器方可作为检测用。 5.4.3.1.2风道部件调节和阻力测试 按箭头指示方向确定受试过滤器的气流方向及上、下位置，加上密封圈后，将其均匀地夹紧在主风道上。关闭旁风道电动阀，打开主风道电动阀，启动风机，用风量调节阀将风量调到受试过滤器的额定风量，测试受试过滤器在额定风量下的阻力。打开旁风道电动阀，关闭主风道电动阀，调节旁风道上的阻力模拟器的阻力，使之与受试过滤器的阻力相同。 5.4.3.1.3试验油雾发生 向贮油器内添加经预先过滤的涡轮机油。接通油雾发生炉电源，加热炉膛。当温度升高到适当温度后(视工作风量及试验油雾浓度而定)，向油雾发生炉供给压缩空气。按附录E要求的发雾参数调节油管数、稀释空气量、加油量等，并保持稳定。 5.4.3.2油雾仪调校 油雾仪的构造见附录F。按油雾仪使用说明书的要求接通电源并进行仪器自校。将浓度为1 000 mg/m3、油雾质量平均粒径为0.28 μm～0.34μm的油雾气溶胶和洁净空气送入雾室。按油雾仪使用说明书的要求调满度并测自身散光值K0，K0应小于0.000 20％。 5.4.3.3 油雾浓度和分散度测量 5.4.3.3.1 油雾浓度测量 仪器调零，启动真空泵，关闭主风道，开启旁风道，将洁净空气和油雾气溶胶取样通入光电雾室。开启光源，由光电雾室测得油雾浓度。 5.4.3.3.2分散度测量 转动专门用于分散度测量的偏振旋钮分别于⊥和∥位置上，得到相应的光电雾室测量值，并按式(5)计算偏光故障值。 |
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