1、June 2008DEUTSCHE NORM English price group 11No part of this standard may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 11.040.10!$O 90 % RH and
2、place the BSF at position A. A.4.2.2 To simulate use with a hot water humidifier, set the mean temperature at the inlet to the Y-piece to (38 1) C and the relative humidity to 90 % RH and place the BSF at position B. A.4.3 With the inspiratory limb humidity generator removed from the breathing syste
3、m A.4.3.1 To simulate use in a non-rebreathing system, place the BSF at position A. A.4.3.2 To simulate use in the expiratory limb of a breathing system, place the BSF at position C. A.5 Procedure A.5.1 Set up the apparatus and operate the humidity-generating patient model, ensuring that the water b
4、ath temperature has stabilized at (37 1) C. For the conditioning requirements specified in A.4.2, operate the inspiratory limb humidity generator until the temperature and humidity measured at position 1 of Figure A.1 have reached the specified values. Set the patient model parameters according to t
5、he intended use of the BSF, as given in Table A.1. A.5.2 Fit the BSF in the breathing system at the position required to simulate its intended use, as given in A.4 and Figure A.1. A.5.3 Operate the apparatus to condition the BSF for the maximum period recommended by the manufacturer for clinical use
6、, or for (25 1) h if this is not stated. A.5.4 Within 5 min of the end of the conditioning period, remove the conditioned BSF and test the BSF in accordance with Clause 3. Table A.1 Patient model parameters for conditioning BSF Tidal volume Frequency Ventilation rate Vtaf lmin1BSF intended use ml mi
7、n1I:E ratio (inspiration: expiration) Paediatric 250 20 5 1:1 Adult 500 15 7,5 1:1 a Tidal volume is the volume of gas entering or leaving the lungs of the patient in a breath.10 DIN EN ISO 23328-1:2008-06 EN ISO 23328-1:2008 (E) Key 1 position of temperature and humidity sensor for use with inspira
8、tory limb humidity generator 2 insulated enclosure 3 rigid reservoir 4 pump A, B, C Positions of BSF for testing (see A.4) NOTE Symbols are in accordance with ISO 8835-2. Figure A.1 Conditioning apparatus for BSF 11 DIN EN ISO 23328-1:2008-06 EN ISO 23328-1:2008 (E) Annex B (informative) Aerosol par
9、ticle size distribution B.1 The test apparatus described in 3.3 detects the mass of aerosol particles. Hence, aerosol particle size distribution is defined in terms of the mass median aerodynamic diameter (MMAD) and the geometric standard deviation (GSD). B.2 A typical particle size distribution is
10、shown in Figure B.1. B.3 It can be seen that at 50 % of the total mass (m), the median particle size (dm) is 0,26 m. One standard deviation from 50 % of the total mass is at 84,13 % and 15,87 % cumulative mass distribution on the Y-axis. GSD is calculated by noting the particle sizes drand dsat thes
11、e points and using the expression: rsGSD /dd= NOTE This calculation can be made provided the curve is effectively straight between 90 % and 10 % cumulative mass distribution. The GSD should have a maximum value of 1,86, for the purposes of this part of ISO 23328. Key Y cumulative mass distribution,
12、% X aerodynamic particle size, m (logarithmic scale) Figure B.1 Typical aerosol particle size distribution 12 DIN EN ISO 23328-1:2008-06 EN ISO 23328-1:2008 (E) Annex C (informative) Rationale for chosen test method C.1 NIOSH test method (42 CFR Part 84) During the development of this part of ISO 23
13、328, the committee considered a variety of test methods specified in European and other standards for particulate filters for respiratory protective devices and other applications. Currently, there are no national or international standards that challenge a BSF with microorganisms. Whilst tests have
14、 been described using a microbiological challenge, it was the view of the committee that these methods neither offered any advantages over, nor had any greater clinical relevance than, the already well established particulate methods. However, the committee decided that the EN 1822 series was unsuit
15、able, as it is intended for HEPA and ULPA filters for cleanroom and other similar applications. EN 143, intended for testing respiratory protective devices, was considered but the particulate range used (0,4 m to 0,6 m) is somewhat larger than the currently recognized most penetrating particle size
16、(MPPS) range for typical BSF of 0,1 m to 0,3 m. It was decided to use the NIOSH test method as the basis for testing because: it uses particles with a mass median diameter of 0,3 m, which is closer to the MPPS for typical breathing system filters; it has a greater sensitivity than EN 143; minimum ch
17、anges are needed for the method to be used to test BSF; test equipment suitable for carrying out the NIOSH test is commercially available. C.2 Aerosol test material NIOSH 42 CFR Part 84 specifies two types of aerosol for testing filters, namely a mildly degrading particulate, sodium chloride, and a
18、highly degrading one, dioctyl phthalate (DOP). Testing with DOP is intended to simulate conditions in which the filter would be required to function in an atmosphere contaminated with oils or other toxic and degenerative particles. Clearly, this is not the case for BSF and therefore the Committee ag
19、reed that testing would only be with sodium chloride. C.3 Electrostatically neutral aerosol There are two fundamental types of particulate filter, mechanical and electrostatic. The efficiency of a mechanical filter is determined by its physical features, for example diameter, orientation and arrange
20、ment of fibers. The efficiency of an electrostatic filter is enhanced by its ability to retain charged particles. However, the efficiency is reduced for uncharged particles. 13 DIN EN ISO 23328-1:2008-06 EN ISO 23328-1:2008 (E) Although in reality many particles challenging a BSF have a charge, the
21、test conditions specify an aerosol neutralized to the Boltzmann equilibrium state in order to provide a reproducible challenge to all types of BSF. C.4 Flowrate The efficiency of a filter increases with decreased flowrate. Flowrates typically encountered in the clinical environment have been chosen
22、for the test, taking into account both spontaneously breathing and ventilated patients. C.5 BSF occlusion Other standards for respiratory protection equipment included tests to determine the performance following loading with a quantity of dust or other material. As the loading of BSF increases, the
23、 filtration efficiency changes. It is important to choose a challenge concentration which differentiates between, but does not unreasonably overchallenge, the BSF. In clinical use, there would not normally be an excessive load of particles or microorganisms on the BSF. Therefore, it would be unreaso
24、nable to test the BSF when loaded with a large mass of sodium chloride. The commercially available test apparatus that has been used during the development of this part of ISO 23328 has set challenge concentrations and it has been possible to demonstrate differences between BSF with a load in the ra
25、nge of 0,05 mg to 0,3 mg. However, the effect of moisture on the resistance to airflow of the BSF is an important aspect, and is covered in ISO 23328-2. 14 DIN EN ISO 23328-1:2008-06 EN ISO 23328-1:2008 (E) Annex D (informative) Clauses of this part of ISO 23328 addressing the essential principles o
26、f ISO/TR 16142 This part of ISO 23328 supports the essential principles of ISO/TR 16142 as given in the clauses listed in Table D.1. Other requirements and other standards may be applicable to the product(s) falling within the scope of this part of ISO 23328. Compliance with the clauses of this part
27、 of ISO 23328 provides one means of conforming with the specific essential principles of ISO/TR 16142:1999. Table D.1 Correspondence between this part of ISO 23328 and ISO/TR 16142:1999 Clause/subclause of this part of ISO 23328 Corresponding essential principle of ISO/TR 16142:1999 All 1, 8.1 15 DI
28、N EN ISO 23328-1:2008-06 EN ISO 23328-1:2008 (E) Annex ZA (informative) Relationship between this European Standard and the Essential Requirements of EU Directive 93/42/EEC Medical devices This European Standard has been prepared under a mandate given to CEN by the European Commission and the Europe
29、an Free Trade Association to provide a means of conforming to Essential Requirements of the New Approach Directive 93/42/EEC Medical devices. Once this standard is cited in the Official Journal of the European Communities under that Directive and has been implemented as a national standard in at lea
30、st one Member State, compliance with the clauses of this standard given in table ZA confers, within the limits of the scope of this standard, a presumption of conformity with the corresponding Essential Requirements of that Directive and associated EFTA regulations. Table ZA Correspondence between t
31、his European Standard and Directive (Add the reference and title of the Directive) Clause(s)/sub-clause(s) of this EN Essential Requirements (ERs) of Directive 93/42/EEC Medical devices Qualifying remarks/Notes All This standard is intended to provide a test method that will allow evaluation of the
32、performance of filters intended for use within clinical breathing systems and will improve comparability of results WARNING Other requirements and other EU Directives may be applicable to the product(s) falling within the scope of this standard. 16 DIN EN ISO 23328-1:2008-06 EN ISO 23328-1:2008 (E)
33、Bibliography 1 ISO 8835-2, Inhalational anaesthesia systems Part 2: Anaesthetic breathing systems for adults 2 ISO/TR 16142:1999, Medical devices Guidance on the selection of standards in support of recognized essential principles of safety and performance of medical devices 3 ISO 23328-2, Breathing
34、 system filters for anaesthetic and respiratory use Part 2: Non-filtration aspects 4 EN 143, Respiratory protective devices Particle filters Requirements, testing, marking 5 EN 1822, High efficiency air filters (HEPA and ULPA) 6 National Institute for Occupational Safety and Health (NIOSH). Respirat
35、ory Protective Devices. Code of Federal Regulations, Title 42, Part 844)7 WILKES A.R. Assessing the filtration performance of breathing system filters using salt particles (Abstract). British J. Anaesthesia 2000; 84, p. 279 8 WILKES A.R. Comparison of two techniques for measuring penetration of sodi
36、um chloride particles through breathing system filters. British J. Anaesthesia 2002; 89, pp. 541-545 9 WILKES A.R. Factors affecting the filtration performance of breathing system filters (Abstract). British J. Anaesthesia 2000; 84, p. 280 10 WILKES A.R. Measuring the filtration performance of breat
37、hing system filters using sodium chloride particles. Anaesthesia 2002; 57, pp. 162-168 4) Available from National Institute for Occupational Safety and Health (NIOSH), 1095 Willowdale Road, Morgantown, West Virginia 26505-2888, USA http:/www.cdc.gov/niosh/homepage.html. 17 DIN EN ISO 23328-1:2008-06 EN ISO 23328-1:2008 (E)
