BS PD CEN TR 16013-1-2010 Workplace exposure — Guide nfor the use of direct-reading ninstruments for aerosol nmonitoring nPart 1 Choice of monitor for specific napplicati.pdf

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1、raising standards worldwide NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BSI Standards Publication PD CEN/TR 16013-1:2010 Workplace exposure Guide for the use of direct-reading instruments for aerosol monitoring Part 1: Choice of monitor for specific applicationsPD CEN/TR 1

2、6013-1:2010 PUBLISHED DOCUMENT National foreword This Published Document is the UK implementation of CEN/TR 16013-1:2010. The UK participation in its preparation was entrusted to Technical Committee EH/2/2, Work place atmospheres. A list of organizations represented on this committee can be obtained

3、 on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. BSI 2010 ISBN 978 0 580 69045 7 ICS 13.040.30 Compliance with a British Standard cannot confer immunity from legal obligations. Th

4、is Published Document was published under the authority of the Standards Policy and Strategy Committee on 31 July 2010 Amendments issued since publication Date Text affectedPD CEN/TR 16013-1:2010TECHNICAL REPORT RAPPORT TECHNIQUE TECHNISCHER BERICHT CEN/TR 16013-1 May 2010 ICS 13.040.30 English Vers

5、ion Workplace exposure - Guide for the use of direct-reading instruments for aerosol monitoring - Part 1: Choice of monitor for specific applications Exposition au poste de travail - Guide dutilisation des instruments lecture directe pour la surveillance des arosols - Partie 1: Choix du moniteur pou

6、r des applications spcifiques Exposition am Arbeitsplatz - Leitfaden fr die Anwendung direkt anzeigender Gerte zur berwachung von Aerosolen - Teil 1: Auswahl des Monitors fr besondere Anwendungsflle This Technical Report was approved by CEN on 13 March 2010. It has been drawn up by the Technical Com

7、mittee CEN/TC 137. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,

8、 Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2010 CEN All rights of exploitation in any form and by any means reserved worl

9、dwide for CEN national Members. Ref. No. CEN/TR 16013-1:2010: EPD CEN/TR 16013-1:2010 CEN/TR 16013-1:2010 (E) 2 Contents Page Foreword 3 Introduction .4 1 Scope 6 2 Abbreviations .6 3 Principles of direct-reading aerosol monitoring methods 6 3.1 General 6 3.2 Vibrational mass methods 7 3.2.1 Piezoel

10、ectric mass monitors 7 3.2.2 TEOM Tapered Element Oscillating Microbalance 9 3.3 Beta mass monitors . 12 3.3.1 Operating principle . 12 3.3.2 Determination of mass concentration of health-related fractions . 14 3.3.3 Calibration of beta mass monitors 14 3.3.4 Advantages and disadvantages 14 3.3.5 Cu

11、rrently available beta mass monitors 15 3.4 Methods of optical measurement of aerosols . 16 3.4.1 General . 16 3.4.2 Photometers 16 3.4.3 Optical particle counters 20 4 Requirements for different applications of direct-reading dust monitors 23 4.1 General . 23 4.2 Walk through surveys 23 4.3 Identif

12、ication of main process or source emitting aerosols 23 4.4 Use with video visual techniques . 23 4.5 Assessing efficiency of control systems . 24 4.6 Watchdogs to monitor levels in workplaces and ensure controls are working . 24 4.7 Surrogate personal exposure assessment 24 Bibliography . 25 PD CEN/

13、TR 16013-1:2010 CEN/TR 16013-1:2010 (E) 3 Foreword This document (CEN/TR 16013-1:2010) has been prepared by Technical Committee CEN/TC 137 “Assessment of workplace exposure to chemical and biological agents”, the secretariat of which is held by DIN. Attention is drawn to the possibility that some of

14、 the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. CEN/TR 16013, Workplace exposure Guide for the use of direct-reading instruments for aerosol monitoring, consists of the following parts

15、: Part 1: Choice of monitor for specific applications Part 2: Evaluation of airborne particle concentrations using Optical Particle Counters Part 3: Evaluation of airborne particle concentrations using photometers (in preparation) PD CEN/TR 16013-1:2010 CEN/TR 16013-1:2010 (E) 4 Introduction The ass

16、essment of aerosols in the workplace can have several aims, including: a) estimation of the mean concentration of health-related aerosol particles (see EN 481) during a working shift period (workplace characteristics or personal exposure by static or personal sampling); b) sampling to provide a samp

17、le of airborne particles for later analysis (gravimetric, morphological, chemical, physical, mineralogical, etc., see EN 482); c) evaluation of almost instantaneous concentrations produced by various work activities using automatic instruments (photometers, -attenuation instruments, vibrational mass

18、 balance instruments); d) evaluation of almost instantaneous concentrations and particle size distributions (optical particle counters OPC). This Technical Report concerns items c) and d), gives the principles, and details the general conditions to be satisfied. In occupational hygiene, no measureme

19、nt procedure recommends exposure monitoring using direct- reading aerosol monitors. These instruments should instead be considered as permitting a complementary approach to the conventional filter-based gravimetric method. The different types of information obtained are explained in Figure 1. a ) b

20、) Key X sample number (time) Y concentration (arb units) Figure 1 Information from integrated filter sampling vs. continuous monitoring There is a wide range of portable and personal direct-reading aerosol monitors available. Recent advances in modern electronics and battery technology means direct-

21、reading dust monitors are becoming smaller and lighter and of relatively low price. In addition to reliance on compliance with Occupational Exposure Limits, emphasis is now also being placed on control banding and advice on suitable control systems. This has led to new roles being identified for dir

22、ect-reading aerosol monitors in ensuring that systems deployed to control exposure to airborne dusts actually work. Some types of direct-reading aerosol monitors appear to be well suited to evaluate prevention action efficiency and to space- and time-related monitoring of concentration. PD CEN/TR 16

23、013-1:2010 CEN/TR 16013-1:2010 (E) 5 All instruments mentioned in this document (see, in particular, Tables 2, 4, 6, 8 and 10) are examples of suitable products available commercially. This information is given for the convenience of users of this Technical Report only and does not constitute an end

24、orsement by CEN of these products. PD CEN/TR 16013-1:2010 CEN/TR 16013-1:2010 (E) 6 1 Scope This Technical Report describes the principles underlying the evaluation of one or more aerosol fractions using direct-reading aerosol monitors. The currently available methods for monitoring levels of aeroso

25、ls in workplaces for a range of different purposes are described and details are given of their limits and possibilities in the field of occupational hygiene. The document does not cover the sampling of aerosols for compliance with occupational exposure limits or the collection of aerosol particles

26、for subsequent analysis. 2 Abbreviations For the purposes of this document, the following abbreviations apply. DRAM direct-reading aerosol monitor LOD limit of detection OEL occupational exposure limit OPC optical particle counter PM particulate matter TEOM tapered element oscillating microbalance T

27、SP total suspended particulate 3 Principles of direct-reading aerosol monitoring methods 3.1 General There are many methods, based on different physical principles, for the instantaneous measurement of aerosols. Instruments used are generally called direct-reading or continuous monitoring instrument

28、s. Depending on their design, they can give the instantaneous or sequential concentration and can sometimes even measure particle size distribution. Instantaneous measurement has several advantages: a) immediate knowledge of the result without going through the laboratory, whence the possibility of

29、rapid intervention (e.g. implementation of a ventilation system); b) continuous measurement, long-distance surveillance, concentration record over time, mean concentration integration and calculation in selected periods, maxima and minima determination, source location, etc.; c) measurement of conce

30、ntration for particles of unstable composition (e.g. volatile substances); d) monitoring and control of aerosol concentration. Depending on the principles used, automatic methods can be classed into the following three main groups: vibrational mass method (see 3.2); beta attenuation method (see 3.3)

31、; optical methods (see 3.4). PD CEN/TR 16013-1:2010 CEN/TR 16013-1:2010 (E) 7 3.2 Vibrational mass methods 3.2.1 Piezoelectric mass monitors 3.2.1.1 Operating principle Particles drawn into the instrument are collected on the surface of a piezoelectric crystal, forming part of a quartz crystal-based

32、 oscillating circuit (see Figure 2). Key 1 piezoelectric crystal 2 frequency Figure 2 Schematic of piezoelectric mass monitor The mass of deposited particles causes a reduction in the oscillation frequency f. The changed frequency is compared with the previous recorded initial frequency or a control

33、 circuit frequency. The frequency reduction is directly proportional to the particle mass (see 8). The proportionality factor k fexpresses the crystal sensitivity with respect to the deposited weight. It is constant for each crystal (see 7) and its value varies, in most cases, by approximately 200 H

34、z/g. If the frequency change during sampling, for a time t, is f, the weight of collected dust will be f k f and the aerosol mean concentration can be calculated according to Equation (1): f s k t Q f C = (1) where C is the aerosol mean concentration, in milligrams per cubic metre;f is the change re

35、sonance frequency, in Hertz; Q is the sampling flow rate, in litres per minute; t s is the sampling time, in minutes; k f is the crystal mass sensitivity, in Hertz per microgram The method is very sensitive and allows low concentrations of the order of several tens of micrograms per cubic metre to b

36、e measured. However, it is limited to fine particles (usually smaller than 10 m) because of the small mechanical force between the particle and the crystal surface: if its mass is high, the particle cannot follow the vibration frequency. This is also a problem for high loads when there is lack of co

37、upling between the PD CEN/TR 16013-1:2010 CEN/TR 16013-1:2010 (E) 8 outermost layers of particles and the crystal. This requires the crystal to be regularly cleaned and may limit the monitoring duration. 3.2.1.2 Determination of mass concentration of health-related fractions The change in frequency

38、of crystal is directly proportional to the mass of particles deposited and is therefore largely independent of the physical and chemical properties of the particles. There is no need therefore to use on-site calibration factors, providing that the crystal is not overloaded. Because of particle size

39、limitations on particle/sensor coupling (mentioned above) only the mass concentration of the respirable fraction is measurable. Respirable size selection can be achieved using any suitable size selector; one instrument uses a single stage impactor with the respirable particles deposited on the cryst

40、al by electrostatic precipitation. Another instrument uses multiple crystals as the collection substrate for size separated particles in a 10-stage cascade impactor. 3.2.1.3 Calibration of piezoelectric instruments Each crystal sensor has its own frequency response and so the instrument incorporatin

41、g the crystal will be calibrated in the factory to give the required mass response. Provided that the crystal is not damaged, no further calibration is required. 3.2.1.4 Advantages/disadvantages of piezoelectric instruments Table 1 gives advantages and disadvantages of piezoelectric instruments. Tab

42、le 1 Advantages/disadvantages of piezoelectric instruments Advantages Disadvantages direct measurement of dust mass usage limited by dust loading on crystal no on-site calibration required regular cleaning of crystal required response independent of chemical composition and particle size (below 10 m

43、) only suitable for respirable particles relatively easy to use PD CEN/TR 16013-1:2010 CEN/TR 16013-1:2010 (E) 9 3.2.1.5 Currently available piezobalance instruments Table 2 gives an overview on currently available piezobalance instruments. Table 2 Currently available piezobalance instruments Name a

44、Portable/ personal Size Weight Size selection Flow rate Response time Accuracy Measure- ment range mm kg l/min s mg/m 3Kanomax Piezo- balance dust monitor Model 3511 portable 311 170 130 2 respirable fraction by impactor 1 from 0 mg/m 3 to 1 mg/m 3 : 24 s from 1 mg/m 3 to 10 mg/m 3 : 120 s 10 % of r

45、eading 0,02 to 10 California Measure- ments Inc, PC- 2HX QCM real-time cascade impactor portable, but mains- operated (battery- powered version by special order) cascade impactor: 35 12,5 32 control unit: 18 43 32 5,4 10 10 stages (0,1 m to 14 m) 2 for average concentration 0,05 mg/m 3 : 30 s not gi

46、ven 0,005 to 1 NOTE “Accuracy“ is defined by the manufacturers. aKanomax Piezo-balance dust monitor Model 3511 and California Measurements Inc, PC-2HX QCM real-time cascade impactor are examples of suitable products available commercially. This information is given for the convenience of users of th

47、is Technical Report and does not constitute an endorsement by CEN of these products. 3.2.2 TEOM Tapered Element Oscillating Microbalance 3.2.2.1 Operating principle This device is similar in principal to the piezoelectric microbalance but the oscillating frequency is applied to a tapered glass tube

48、equipped with sampling filter at its narrow end (see Figure 3). PD CEN/TR 16013-1:2010 CEN/TR 16013-1:2010 (E) 10 Key 1 filter 2 tapered glass tube f frequency Figure 3 Schematic of the TEOM device The 13 mm diameter filter responsible for collecting the sampled aerosol particles is held inside a pl

49、astic cassette that is a close push-fit to the glass tube. The top part of the tapered tube is coated with an electrically conducting layer and it is placed between two flat electrodes, which maintain a continuous electric field. An oscillating current flows through the conducting layer, prompting vibration of the tapered tube. The vibration frequency is measured by an optical system comprising an LED