1、UDC628.511 : 331.1 : 620.113 DEUTSCHE NORM September 199 Workplace atmospheres Size fraction definitions for measurement of airborne particles English version of DIN EN 481 Eeuth Verlag GmbH Berlin, has the exclusive right of sale for German Standards (DIN-Normen). 02.94 DIN EN 481 DINEN481 Eng/. Pr
2、ice group Sales No. 11 07 Arbeitsplatzatmosphre; Festlegung der Teilchengrenverteilung zur Messung luftgetragener Partikel European Standard EN 481 : 1993 has the status of a DIN Standard. A comma is used as the decimal marker. National foreword This standard has been prepared by CEN/TC 137. The res
3、ponsible German body involved in the preparation of this standard was the Normenausschu Gefahrstoffel Arbeitsschutz (Hazardous Substances and Occupational Safety Standards Committee). EN comprises 14 pages. EUROPEAN STANDARD NORME EUROPENNE EUROPAISCHE NORM EN 481 July 1993 UDC 628.511 : 331 .I : 62
4、0.1 13 Descriptors: Air, quality, air pollution, workroom, accident prevention, aerosols, sampling, suspended matter, measure- ments, particle density, specifications. English version Workplace atmospheres Size fraction definitions for measurement of airborne particles Atmosphres des lieux de travai
5、l; dfini- tion des fractions de taille pour le mesu- rage des particules en suspensions dans lair Arbeitsplatzatmosphre; Festlegung der Teilchengrenverteilung zur Messung luftgetragener Partikel This European Standard was approved by CEN on 1993-07-27. CEN members are bound to comply with the CENEEN
6、ELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any
7、CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN
8、 members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Euro
9、pisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels O 1993. Copyright reserved io all CEN members. Ref. No. EN 481 : 1993 E Page 2 EN 481 : 1993 Foreword This European Standard was prepared by Technical Committee CEN/TC 137 Assessment of workplace exposure, the Secret
10、ariat of which is held by DIN. This standard was submitted to Formal Vote, and the result was positive. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, and conflicting national standards withdrawn, by January 1994
11、 at the latest. In accordance with the CENKENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland a
12、nd United Kingdom. Page 3 EN 481 : 1993 O Introduction The proportion of total particulate matter which is inhaled into a human body depends on properties of the particlec, on the speed and direction of air movement near the body, on breathing rate, and whether breathing is through nose or mouth. In
13、haled particles can then deposit somewhere in the respiratory tract, or can be exhaled. The site of deposition, or probability of exhalation, depends on properties of the particle, respiratory tract, breathing pattern, and other factors. Liquid particles or soluble components of solid particles can
14、be absorbed by the tissues wherever they deposit. Particles can cause damage close to the deposition site if they are corrosive, radioactive, or capable of initiating some other type of damage. Insoluble particles can be transported to another part of the respiratory tract or body, where they can be
15、 absorbed or cause a biological effect. There is a wide variation from one person to another in the probability of particle inhalation, deposition, reaction to deposition, and clearance. Nevertheless, it is possible to define conventions for size selective sampling of airborne particles when the pur
16、pose of sampling is health-related. These conventions are relationships between aerodynamic diameter and the fractions to be collected or measured, which approximate to the fractions penetrating to regions of the respiratory tract under average conditions. Measurement conducted according to these co
17、nventions will probably yield a better relationship between measured concentration and risk of disease. Note: For further information on the factors affecting inhalation and deposition, and their application in standards, see 81, 191, IO, 11 11, I121 and 131. 1 Scope This standard defines sampling c
18、onventions for particle site fractions which are to be used in assessing the possible health effects resulting from inhalation of airborne particles in the workplace. They are derived from experimental data for healthy adults. Conventions are defined for the inhalable, thoracic and respirable fracti
19、ons; extrathoracic and tracheobronchial conventions may be calculated from the defined conventions. (The inhalable fraction is sometimes called inspirable - the terms are equivalent. The nomenclature of the fractions is discussed in annex A). Assumptions are given in clause 4. The convention chosen
20、will depend on the region of effect of the component of interest in the airborne particles (see clause 3). Conventions are stated in terms of mass fractions, but they may also be used when the intention is to evaluate the total surface area or the number of particles in the collected material. $ _.
21、In practice, the conventions will often be used to specify instruments to sample airborne particles for the purpose of measuring concentrations corresponding to Page 4 EN 481 : 1993 the defined fractions. It should be noted that experimental error in the testing of instruments, and possible dependen
22、ce on factors other than aerodynamic diameter, mean that it is only possible to make a statement of probability that an instruments performance falls within a certain range, and that different instruments will fall within an acceptable range. Note: The problem of comparing instruments with the conve
23、ntions is to be dealt with in another standard. One application is the comparison of mass concentration of airborne size fractions with limit values. It should be noted with respect to relevant European Directives that the use of other methods is allowed provided that they yield the same or stricter
24、 conclusion. One important example is the respirable convention in relation to compliance with the limit value. Equipment matching the Johannesburg convention ZI will in practical circumstances give the same or a higher mass concentration (by up to about 20 30) than equipment matching the respirable
25、 convention given in 5.3, so the use of equipment matching the Johannesburg convention will be consistent with the European Directive. The conventions should not be used in association with limit values defined in completely different terms, for example for fibre limit values defined in terms of the
26、 length and diameter of fibres. 2 Definitions For the purposes of this standard, the following definitions apply. 2.1 Sampling convention A target specification for sampling instruments which approximates to, for each particle aerodynamic diameter: - in the case of inhalable convention, the ratio of
27、 the mass concentration of particles entering the respiratory tract to the corresponding mass concentration in the air before the particies are affected by the presence of the exposed individual and inhalation; - in the case of the other conventions, the ratio of the mass concentration of particles
28、entering the specified region of the respiratory tract to the mass concentration of particles entering the respiratory tract. (These other conventions can also be expressed as ratios to the mass concentration of total airborne particles). Page 5 EN 481 : 1993 2.2 Particle aerodynamic diameter The di
29、ameter of a sphere of density 1 g cm-3 with the same terminal velocity due to gravitational force in calm air, as the particle, under the prevailing conditions of temperature, pressure and relative humidity (see clause 4). Note: For particles of aerodynamic diameter less than 0,5 pm, the particle di
30、ffusion diameter should be used instead of the particle aerodynamic diameter. The particle diffusion diameter means the diameter of a sphere with the same diffusion coefficient as the particle under the prevailing conditions of temperature, pressure and relative humidity. 2.3 Inhalable fraction The
31、mass fraction of total airborne.particles which is inhaled through the nose and mouth. Note: The inhalable fraction depends on the speed and direction of the air movement, on breathing rate and other factors. 2.4 Inhalable convention A target specification for sampling instruments when the inhalable
32、 fraction is the fraction of interest. 2.5 Extrathoracic fraction The mass fraction of inhaled particles failing to penetrate beyond the larynx. 2.6 Extrathoracic convention A target specification for sampling instruments when the extrathoracic fraction is of interest. 2.7 Thoracic fraction The mass
33、 fraction of inhaled particles penetrating beyond the larynx. Page 6 EN 481 : 1993 2.8 Thoracic convention A target specification for sampling instruments when the thoracic fraction is of interest. 2.9 Tracheobronchial fraction The mass fraction of inhaled particles penetrating beyond the larynx, bu
34、t failing to penetrate to the unciliated airways. 2.1 O Tracheobronchiai convention A target specification for sampling instruments when the tracheobronchial fraction is of interest. 2.1 1 Respirable fraction The mass fraction of inhaled particles penetrating to the unciliated airways. 2.12 Respirab
35、le convention A target specification for sampling instruments when the respirable fraction is of interest. 2.13 Total airborne particles All particles surrounded by air in a given volume of air. Note: Because all measuring instruments are size-selective to some extent, it is often impossible to meas
36、ure the total airborne particle concentration. 3 Principle of conventions The sampling conventions recognise that only a fraction of the airborne particles which are near to the nose and mouth is inhaled. This fraction is called the inhalable fraction (see 2.3). For some substances, the sub-fraction
37、s of this which penetrate beyond the larynx, or to the unciliated airways are of special significance for health. This standard presents conventionalised curves approximating to the fraction inhaled and the sub-fractions reaching beyond the larynx or to the unciliated airways. These curves are calle
38、d the inhalable convention (see 2.41, the thoracic convention (see 2.8) and the respirable convention (see 2.1 2). Page 7 EN 481 : 1993 Extrathoracic (see 2.6) and tracheobronchial (see 2.1 O) conventions may be calculated from these. Instruments used for sampling need to conform with the sampling c
39、onvention appropriate to the region of the respiratory tract where deposition of the substance being measured might lead to biological effect. For example, the inhalable convention would be chosen if the substance might lead to a biological effect wherever it deposited, the thoracic convention would
40、 be chosen if the region was the bronchi, and the respirable convention if the region was the a lveo I i. Instruments can be used to collect individual fractions according to the conventions, or to collect several fractions simultaneously. For example, an instrument could collect particles from the
41、air according to the inhalable convention, and then separate this material into portions according to thoracic, tracheobronchial and respirable conventions. Alternatively, an instrument might just collect the respirable fraction from the air. In this case, the design would have to ensure that select
42、ion at the entry due to aerodynamic effects, and subsequently within the instrument, was such that the overall selection was in accordance with the conventions. 4 Assumptions and approximations Approximations and assumptions are unavoidable in simulating by sampling conventions the very complex inte
43、raction of variables that governs respiratory tract entry and penetration. The conventions are necessarily only approximations to respiratory tract behaviour, and the following assumptions are particularly important: The inhalable fraction depends on air movement - speed and direction - on breathing
44、 rate, and on whether breathing is by nose or mouth. The values given in the inhalable convention are for representative values of breathing. rate, and averaged for all wind directions. This is appropriate for an individual uniformly exposed to all wind directions or predominantly to wind from the s
45、ide or from behind. The convention usually under-estimates the inhalable fraction of larger particles for an individual who usually faced the wind, particularly in windspeeds greater than 4 m s-. The respirable and thoracic fractions vary from individual to individual and with breathing pattern, and
46、 the conventions are necessarily approximations to the average case. Each convention approximates to the fraction penetrating to a region, not to the fraction depositing there. In general, particles must deposit to have a biological effect. In this respect, the conventions will lead to an over- esti
47、mate of the potential biological effect. The most important example is that the respirable convention over-estimates the fraction of very small Page 8 EN 481 : 1993 particles which are deposited in the unciliated airways, because a fraction of these particles is exhaled without being deposited. In m
48、any workplaces, these very small particles do not contribute much to the sampled mass. The thoracic convention approximates to the thoracic fraction during mouth breathing, which is greater than the thoracic fraction during nose breathing. The extrathoracic convention can therefore under-estimate th
49、e worst case extrathoracic fraction, which occurs during nose breathing. 5 Specifications for conventions 5.1 Inhalable convention Sampling of the inhalable fraction shall conform with the following convention: the percentage E, of airborne particles of aerodynamic diameter D in micrometres which are to be collected shall be given by given by E, = 50 (1 + exp - 0,06 DI) (1) Some values given by this equation are given in table 1 and illustrated in figure 1. Note: Experimental data on the inhalable fraction do not yet exist for D 100 pm, and the convention should
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