ENV 13936:2001
(Main)Workplace atmospheres - Measurement of chemical agents present as mixtures of airborne particles and vapour - Requirements and test methods
Workplace atmospheres - Measurement of chemical agents present as mixtures of airborne particles and vapour - Requirements and test methods
Migrated from Progress Sheet (TC Comment) (2000-07-10): rev. draft BP: BT to approve the change of deliverable from EN to ENV (TA/990706 ++ --> Res BT C 186/1999 (CC/990924)
Arbeitsplatzatmosphäre - Messung chemischer Stoffe, die als Mischung von luftgetragenen Partikeln und Dämpfen vorkommen - Anforderungen und Prüfverfahren
1.1 Allgemeines
Diese Vornorm legt Anforderungen und Prüfverfahren fest für die Messung der Massekonzentration von einatembaren Luftgetragenen Partikeln in Partikel-Dampf-Mischungen von einer einzelnen Verbindung oder von mehreren Verbindungen unter Berücksichtigung zutreffender vorhandener CEN-Normen. Die Vornorm bezieht sich auf die Messung der einatembaren Konzentration von Verbindungen, unabhängig von der Verteilung in Partikeln und Dampf. Es ist nicht erforderlich, dass sich die Probenahmeverfahren zwischen den Phasen unterscheiden.
1.2 Anwendungsgebiet
Diese Vornorm gibt in Anhang B Hinweise auf verschiedene Verfahrensweisen bei der Probenahme von Partikel-Dampf-Mischungen, ihre Vorteile und Grenzen. Die Vornorm bezieht sich nur auf Probenahmesysteme deren Bestandteile von vorhandenen Normen erfasst sind; es können nicht alle möglichen Verfahrensweisen berücksichtigt werden. Üblicherweise werden die Durchführungsanforderungen getrennt für die Probenahme der luftgetragenen Partikeln und für die Probenahme der Dampfbestandteile untersucht, obwohl, wenn es in Abschnitt 4 nicht anders festgelegt ist, das vollständige System für die Untersuchungen benutzt wird. Die Vornorm ist nicht anwendbar, wenn die zu untersuchende Atmosphäre fast vollständig aus Partikeln oder fast vollständig aus Dampf besteht, weil in diesen Fällen die Probenahme von nur Partikeln oder nur Dampf ohne Überschreitung der in EN 482 festgelegten Messunsicherheitsgrenzen vorgenommen werden kann. In dieser Vornorm wird bei der Berechnung der Messunsicherheit von einer Mischung von etwa gleichen Teilen von Partikeln und Dampf ausgegangen. Diese Annahme wird als zutreffend angesehen, wenn die Masse keiner Fraktion - Partikeln oder Dampf - in der Probenahmemischung mehr als etwa 70 % beträgt.
Atmosphères sur les lieux de travail - Mesurage des agents chimiques sous forme de mélanges de particules aériennes et de vapeurs - Exigences et méthodes d'essai
Généralités
La présente Prénorme spécifie des exigences et des méthodes d'essai permettant le mesurage de la concentration en masse atmosphérique inhalable des mélanges de particules/vapeurs, aussi bien de ceux constitués d'un seul composé que de ceux constitués de plusieurs composés, avec référence aux normes CEN existantes si approprié. Elle s'applique au mesurage de la concentration inhalable des composés, indépendamment de leur répartition sous forme de particules et de vapeurs. La différenciation des phases par les méthodes d'échantillonnage n'est pas requise.
Champ d'application
La présente Prénorme donne des recommandations concernant différentes méthodes d'échantillonnage des mélanges de particules/vapeurs en indiquant leurs avantages et limitations en annexe B. Elle n'est applicable qu'aux systèmes d'échantillonnage dont les éléments relèvent de normes déjà existantes et ne traite pas de toutes les méthodes possibles. En principe, les exigences de performance seront contrôlées par des essais séparés selon qu'il s'agit de l'échantillonnage de particules en suspension dans l'air ou de vapeurs, alors que le système complet sera utilisé pour les essais, sauf spécification contraire fixée dans l'article 4. La présente Prénorme n'est pas applicable lorsque l'atmosphère à échantillonner est presque exclusivement composée de particules ou de vapeurs, auquel cas l'échantillonnage des particules seules ou des vapeurs seules, selon le cas, peut être effectué sans dépassement des limites de l'incertitude globale indiquées dans l'EN 482. Dans cette Prénorme, on calcule l'incertitude globale en supposant que le mélange est constitué de proportions approximativement égales de particules et de vapeur. Cette supposition peut être considérée comme valable lorsqu'aucune proportion - de particules ou de vapeurs - n'est supérieure à 70 % environ du mélange échantillonné.
Zrak na delovnem mestu – Merjenje kemičnih agensov v zmesi lebdečih delcev in par – Zahteve in preskusne metode
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
SIST ENV 13936:2002
01-maj-2002
=UDNQDGHORYQHPPHVWX±0HUMHQMHNHPLþQLKDJHQVRYY]PHVLOHEGHþLKGHOFHYLQ
SDU±=DKWHYHLQSUHVNXVQHPHWRGH
Workplace atmospheres - Measurement of chemical agents present as mixtures of
airborne particles and vapour - Requirements and test methods
Arbeitsplatzatmosphäre - Messung chemischer Stoffe, die als Mischung von
luftgetragenen Partikeln und Dämpfen vorkommen - Anforderungen und Prüfverfahren
Atmospheres sur les lieux de travail - Mesurage des agents chimiques sous forme de
mélanges de particules aériennes et de vapeurs - Exigences et méthodes d'essai
Ta slovenski standard je istoveten z: ENV 13936:2001
ICS:
13.040.30 Kakovost zraka na delovnem Workplace atmospheres
mestu
SIST ENV 13936:2002 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST ENV 13936:2002
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SIST ENV 13936:2002
EUROPEAN PRESTANDARD
ENV 13936
PRÉNORME EUROPÉENNE
EUROPÄISCHE VORNORM
May 2001
ICS 13.040.30
English version
Workplace atmospheres - Measurement of chemical agents
present as mixtures of airborne particles and vapour -
Requirements and test methods
Atmosphères sur les lieux de travail - Mesurage des agents Arbeitsplatzatmosphäre - Messung chemischer Stoffe, die
chimiques sous forme de mélanges de particules aériennes als Mischung von luftgetragenen Partikeln und Dämpfen
et de vapeurs - Exigences et méthodes d'essai vorkommen - Anforderungen und Prüfverfahren
This European Prestandard (ENV) was approved by CEN on 20 April 2001 as a prospective standard for provisional application.
The period of validity of this ENV is limited initially to three years. After two years the members of CEN will be requested to submit their
comments, particularly on the question whether the ENV can be converted into a European Standard.
CEN members are required to announce the existence of this ENV in the same way as for an EN and to make the ENV available promptly
at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the ENV) until the final
decision about the possible conversion of the ENV into an EN is reached.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2001 CEN All rights of exploitation in any form and by any means reserved Ref. No. ENV 13936:2001 E
worldwide for CEN national Members.
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Contents
page
Foreword . 4
Introduction. 5
1 Scope. 6
1.1 General. 6
1.2 Field of application. 6
1.3 Object of prestandard . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Requirements . 7
4.1 Requirements for airborne particle sampling. 8
4.2 Requirements for vapour sampling. 8
4.3 Requirements for the sampling device (combined system). 9
4.4 Other requirements. 9
5 Test methods. 9
5.1 Sampled fraction. 9
5.2 Concentration and loading. 10
5.3 Temperature and humidity. 10
5.4 Shelf life . 10
5.5 Maximum capacity of sampler . 10
5.6 Recovery efficiency . 10
5.7 Storage . 10
5.8 Blank value . 10
5.9 Dimension of result. 10
5.10 Air flow stability . 10
5.11 Flow resistance. 11
5.12 Sample identification; methods description; design safety .11
5.13 Electrical safety. 11
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6 Test report . 11
7 Method description (or instructions for use) . 11
Annex A (normative) Calculation of overall uncertainty for sampling a particle / vapour mixture. 13
Annex B (informative) Possible approaches to sampling particle / vapour mixtures. 16
Bibliography. 19
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Foreword
This European Prestandard has been prepared by Technical Committee CEN/TC 137 "Assessment of workplace
exposure", the secretariat of which is held by DIN.
Annex A is normative. Annex B is informative.
This Prestandard includes a Bibliography.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to announce this European Prestandard: Austria, Belgium, Czech Republic, Denmark,
Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain,
Sweden, Switzerland and the United Kingdom.
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Introduction
CEN/TC 137 'Assessment of workplace exposure' has proposed general performance criteria that methods of
determining the concentration of chemical agents in workplace atmospheres should meet (see EN 482). These
performance criteria include maximum values of overall uncertainty (a combination of precision and bias)
achievable under prescribed laboratory conditions for the methods to be used. In addition, the performance criteria
should also be met under a wider variety of environmental influences, representative of workplace conditions.
Chemical agents are often present in workplace air as complex mixtures, distributed in both gaseous and
non-gaseous phases. These mixtures may be comprised of single compounds, e.g. an aerosol of a volatile liquid in
equilibrium with its own vapour, or of multiple compounds, some of which may be entirely in the vapour phase
(including water vapour), and others entirely in the solid or liquid phase.
For health-related sampling, priority should be given to accurate measurement of the inhalable mass concentration
of harmful chemical agents, regardless of whether they are present as airborne particles or vapour. Collected
volatile materials may move between phases due to a change in conditions, during sampling and subsequently, but
the total collected mass remains unchanged. Similar phase changes will also occur during inhalation and will differ
from those occurring in the sample.
In some cases it may also be desirable to measure the distribution of chemical agents between the particulate and
vapour phases as well as the inhalable mass concentration. For example, there may be compounds whose health
effects are known to differ significantly depending on whether they exist as particles or vapour. In addition, control
measures in the workplace may depend on which phase dominates. Exposure limits may be phase-specific.
However the separate quantitation of particle / vapour mixtures according to phase is technically complex, and
subject to error using existing sampling technologies. For this reason this prestandard does not require the
sampling method to differentiate between phases in a particle / vapour mixture.
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1 Scope
1.1 General
This prestandard specifies requirements and test methods for measurement of the inhalable airborne mass
concentration of particle / vapour mixtures of both single and multiple compounds, with reference to existing CEN
standards where relevant. The prestandard applies to the measurement of the inhalable concentration of
compounds, regardless of the distribution into particles and vapour. Sampling methods are not required to
differentiate between phases.
1.2 Field of application
This prestandard gives guidance on various approaches to sampling particle / vapour mixtures, their advantages
and limitations, in annex B. The prestandard only applies to sampling systems whose component elements are
covered by existing standards; not all possible approaches can be covered. Normally, performance requirements
will be tested separately for the airborne particle sampling and for the vapour sampling components whilst using
the complete system for the tests, unless otherwise specified in clause 4. The prestandard does not apply when
the atmosphere to be sampled is composed of almost all particles or almost all vapour, in which case sampling
only particles or vapour as appropriate can be carried out without exceeding the overall uncertainty limits stated in
EN 482. In this prestandard, a mixture of approximately equal proportions of particles and vapour is assumed in the
calculation of overall uncertainty. This assumption may be considered valid when no fraction - particles or vapour -
amounts to more than approximately 70% of the sampled mixture.
1.3 Object of prestandard
This European Prestandard should enable method developers and users of particle / vapour sampling systems to
adopt a consistent approach to method validation and provide a framework for the assessment of method
performance against criteria specified in EN 482. It is the responsibility of the manufacturer or of those who
assemble particle / vapour samplers to ensure that the method complies with the overall uncertainty requirements
under the specified laboratory conditions given in this European Prestandard, including the environmental
influences that may be expected to affect performance.
2 Normative references
This European Prestandard incorporates by dated or undated reference, provisions from other publications. These
normative references are cited at the appropriate places in the text and the publications are listed hereafter. For
dated references, subsequent amendments to or revisions of any of these publications apply to this European
Prestandard only when incorporated in it by amendment or revision. For undated references the latest edition of
the publication referred to applies (including amendments).
EN 481, Workplace atmospheres - Size fraction definitions for measurement of airborne particles.
EN 482, Workplace atmospheres - General requirements for the performance of procedures for the measurement
of chemical agents.
EN 838:1995, Workplace atmospheres - Diffusive samplers for the determination of gases and vapours -
Requirements and test methods.
EN 1076:1997, Workplace atmospheres - Pumped sorbent tubes for the determination of gases and vapours -
Requirements and test methods.
EN 1232:1997, Workplace atmospheres - Pumps for personal sampling of chemical agents - Requirements and
test methods.
EN 1540, Workplace atmospheres - Terminology.
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EN 12919, Workplace atmospheres - Pumps for the sampling of chemical agents with a volume flow rate of over
5 l/min - Requirements and test methods.
prEN 13205:1998, Workplace atmospheres - Assessment of performance of instruments for measurement of
airborne particle concentrations.
prEN 13890:2000, Workplace atmospheres – Procedures for measuring metals and metalloids in airborne particles
– Requirements and test methods.
3 Terms and definitions
For the purposes of this European Prestandard, the terms and definitions given in EN 1540 and the following terms
and definitions apply.
3.1
airborne particles
finely divided matter in solid or liquid form, dispersed in air
3.2
vapour
gaseous phase of a chemical agent
3.3
particle / vapour mixture
an aerosol consisting of airborne particles and vapour
3.4
single component aerosol
an aerosol in which the airborne particles and vapour are composed of the same chemical agent
3.5
multiple component aerosol
an aerosol containing more than one chemical agent, each of which may be present as particles and/or vapour
3.6
recovery efficiency
the ratio of the mass of analyte recovered from a sampling device to the known amount applied
3.7
capacity of sampler
the mass of a specified volatile chemical agent that can be retained within the sampler's collection media without
passing through the system when the pump or pumps operate at the design flow rate, and in the range of
concentrations of interest
3.8
collected sample
the airborne particles and vapour collected on the sampling media (e.g. filter, foam, sorbent) for subsequent
analysis. Sampled deposits in other parts of the sampler such as the inner walls are only included in the collected
sample where the method description includes specific instructions for the recovery of such deposits.
4 Requirements
This clause is divided into the requirements applying to the particle sampling component of the measurement
method, the requirements applying to the vapour sampling component, and the requirements applying to the
combined system. In each case the tests specified shall be conducted on the combined sampling system although
each aspect – i.e. particle sampling, vapour sampling is tested separately. In general it is only practicable to test
using single compounds, which should be chosen appropriately to reflect the intended conditions of use of the
method.
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NOTE The sampling systems for which this prestandard is intended are currently at an early stage of development.
For this reason, the requirements in this clause should be regarded as development objectives. The corresponding test
methods will need to be reviewed in the light of practical experience.
4.1 Requirements for airborne particle sampling
Table 1 – Requirements for airborne particle sampling
Attribute Requirement Test method
4.1.1 Fraction to be Inhalable fraction, according to 5.1
sampled inhalable convention in EN 481
4.1.2 Accuracy 4. 1 of prEN 13205:1998 5.1
4.2 Requirements for vapour sampling
NOTE All tests in this clause shall be carried out for the chemical agent of interest, however, representative or
surrogate compounds may be used if justified in the test report. If relevant data are already available from prior knowledge
these tests are unnecessary.
Table 2 - Requirements for vapour sampling
Attribute Requirement Test method
4.2.1
Concentration and Overall uncertainty 30% to 50% 5.2
loading according to EN 482
4.2.2 Concentration when Overall uncertainty 30% to 50% 5.3
temperatures and humidity according to EN 482
vary
4.2.3 Shelf life Recovery efficiency (see 4.2.1) 5.4
at the beginning and at the end
of stated shelf life do not differ by
more than 10%.
4.2.4 Maximum capacity of Calculate the sampler capacity 5.5
sampler and include value in method
description
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4.3 Requirements for the sampling device (combined system)
Table 3 - Requirements for the sampling device (combined system)
Attribute Requirements Test methods
4.3.1 Overall uncertainty 30% to 50% according to EN Annex A
482
4.3.2 Recovery efficiency Combined recovery from all 5.6
stages is at least 75%, with a
C.V of <10% at each loading.
4.3.3 Storage Recovery after storage is >95% 5.7
of recovery before storage
4.3.4 Blank value Blank value less than one third 5.8
of the mass expected from
sampling for 30 min at 0,1 LV
and at the design flow rate
3
4.3.5 Dimension result Result shall be given in mg/m ; See NOTE under 5.9
under operating conditions
4.4 Other requirements
Table 4 - Other requirements
Attribute Requirements Test Methods
4.4.1 Air flow stability 4.4, 4.6, 4.7, 4.9, 4.10, 4.11, 4.12 5.10
of EN 1232:1997 or EN 12919
4.4.2 Flow resistance Flow resistance not to exceed 5.11
the capacity of the pump or
pumps.
4.4.3 Sample identification Suitable area included for 5.12
marking by the user
4.4.4 Method description To cover the points in clause 7 5.12
4.4.5
Design safety The system shall have no sharp 5.12
or protruding parts
4.4.6 Electrical safety 4.15, 4.16 of EN 1232:1997 5.13
5 Test methods
5.1 Sampled fraction
The airborne particle sampling efficiency and accuracy shall be tested using a suitable, stable material as specified
in prEN 13205:1998, annex A or prEN 13890:2000, annex B. The test material need not be the chemical agent of
interest. Tests may not be necessary where relevant data are already available although it should be checked that
the collected sample is the same as in the previous tests.
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NOTE Some sampling systems may behave differently for solid or liquid particles.
5.2 Concentration and loading
Test method as in 5.6; separate tests for the requirement 4.2.1 are not needed where they have been carried out in
respect of 4.3.2.
5.3 Temperature and humidity
Relevant range given in 5.4 of EN 1076:1997 and 5.4 of EN 838:1995. Test method based on 7.6 of EN 1076:1997
for pumped sorbent tubes, or 7.8 of EN 838:1995 for diffusive samplers.
5.4 Shelf life
Test needed for reagent-impregnated systems only. Repeat test as in 5.6 at the end of the stated shelf life, for one
concentration value only. Limit of shelf life to be stated in the method description.
5.5 Maximum capacity of sampler
The test method for capacity is similar to the test for breakthrough volume for pumped sorbent tubes described in
7.2 of EN 1076:1997. The tests may be omitted if the capacity can be predicted from boiling point or vapour
pressure data (c.f. Brown and Purnell, 1979). The spiking method in 7.2.1 of EN 1076:1997 can be used, although
the back-diffusion test (7.2 of EN 838:1995) is more appropriate for diffusive samplers.
5.6 Recovery efficiency
Test the combined device at the design flow rate, repeating the test three times. Spike at three levels covering the
intended range of use, for example corresponding to between 0,1x and 2x limit value for a nominal 8 h at the
design flow rate. If the vapour spiking method of EN 838 or EN 1076 is used, it will only be possible to generate
atmospheres up to the saturation vapour pressure. Testing with a particle / vapour mixture is preferred, but where
not practicable, application of a liquid or solid spike or use of a vapour atmosphere are acceptable alternatives.
Typical test procedures shall be based on 7.1 of EN 1076:1997 for pumped sorbent tubes, or 7.2 of EN 838:1995
for diffusive samplers, or 8.3 and 8.4 of prEN 13890:2000 for filters.
5.7 Storage
Follow the instructions for use or the method description, for sample handling, transportation and storage
procedures. Use field samples for the test. Compare the results of unstored samples (transported to a laboratory
for analysis if necessary) with those stored for two weeks or as otherwise specified in the method description.
NOTE Some preliminary tests may be necessary to establish optimal conditions for sample handling, transportation
and storage, and to minimise losses (e.g. by leakage in connections or adsorption on surfaces), or gains (e.g. through
revolatisation of collected particles).
5.8 Blank value
Apply the test to all sampling media used in the combined system. Analyse six unexposed samplers to determine
the blank value of the analyte.
5.9 Dimension of result
NOTE If it is necessary to express concentrations reduced to standard conditions, the vapour sampling results may
be recalculated by taking temperature and pressure into account.
5.10 Air flow stability
Test methods based on 6.4, 6.6, 6.7, 6.9, 6.10, 6.11, 6.12 of EN 1232:1997, but modified to reflect the design flow
rate of the combined sampling device. Tests are unnecessary where pumps meeting EN 1232 or EN 12919 at the
design flow rate are used.
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5.11 Flow resistance
Method description to state pressure drop and to recommend a suitable pump or pumps.
5.12 Sample identification; methods description; design safety
Test by visual check.
5.13 Electrical safety
Test method based on 6.15, 6.16 of EN 1232:1997. Tests are only necessary where the sampler has an
independent electricity supply through mains or battery.
6 Test report
The test report shall contain at least the following information:
6.1 A detailed description and identification of the system components tested, including all sampling media. For
commercial devices, identify the manufacturer(s) and the type identification(s);
6.2 Complete identification of test atmospheres used plus details of independent measurement methods where
used;
6.3 Details of the pump(s) used for testing;
6.4 Details of analytical methods used for testing;
6.5 The determined values for recovery efficiency, blank value, sampler capacity and storage losses;
6.6 Statistical analyses of the test results and calculations of overall uncertainty;
6.7 Statement of whether the acceptance criteria are met;
6.8 Any unusual features noted during the determinations;
6.9 Any operations not included in this European Prestandard that may have influence on the results;
6.10 The technical justification for omitting any of the tests.
7 Method description (or instructions for use)
The method description shall contain at least the following information:
7.1 A detailed description and identification of the system components, including all sampling media. For
commercial devices, identify the manufacturer(s) and the type identification(s);
7.2 General description of the principles of the method, the approach followed to sample particle / vapour mixtures
and any relevant assumptions;
7.3 Details of the collection media and substrates to be used, specifying whether and how wall deposits are to be
included in the collected sample;
7.4 The design flow rate or flow rates, sampling times, pressure drop(s) at the design flow rate and recommended
pumps;
7.5
The recovery efficiency for specific analytes, including the effects of concentration, loading, temperature and
humidity;
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7.6 The shelf life of the system;
7.7 The maximum capacity for a specific analyte;
7.8 The levels at which other typical gases and vapours, such as water, are likely to interfere to the extent of
increasing the overall uncertainty above the level specified in this European Prestandard;
7.9 Methods for handling, transportation and storage of samples, including storage times;
7.10 Information on analytical methods to be applied.
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Annex A
(normative)
Calculation of overall uncertainty for sampling a particle / vapour mixture
A.1 Introduction
For comparison of the sampling method for a particle-vapour mixture with the General Performance Requirements
(EN 482), the entire measurement process shall be considered. This requires that the bias and precision
associated with both the sampling and analytical stages are known (or estimated). The true values of these
parameters will probably depend on the actual distribution of the chemical compound(s) between vapour and
particulate phases during sampling. However, as a combined sampler is of most interest when the concentrations
of the two phases are of similar magnitude, the overall uncertainty will be determined for the case where the
vapour concentration equals the particulate concentration in the undisturbed air.
A.2 Definition of relative overall uncertainty
The relative overall uncertainty of a measurement process is expressed, in percentage terms, as a combination of
bias and precision according to the following equation (EN 482):
OU 100bias 2 RSD (A.1)
where:
bias is defined as x x / x ;
ref ref
RSD as s / x ;
n1 ref
x is the average of n repeated measurements;
x is the true or accepted reference value;
ref
s is the standard deviation of n repeated measurements.
n1
A.3 Combination of particle and vapour phase biases
The overall bias of the measuring procedure is given by:
bias0,5bias bias (A.2)
part vap
where:
bias is the bias associated with the particulate phase;
part
bias is the bias associated with the vapour phase.
vap
bias is determined as:
part
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1bias 1 bias 1bias (A.3)
part part.sampl part.re cov
where:
bias is equivalent to the quantity defined in equation (A.3), of annex A of prEN 13205:1998.
part.sampl
The quantity bias is determined from the tests for recovery efficiency (4.3.2), if a test with only particles or a
part.recov
particle / vapour mixture was performed under 5.6. Otherwise it is taken as equal to the value of bias (see
vap.recov
below).
bias is determined as:
vapour
1 bias 1 bias 1 bias 1 bias 1 bias 1 bias (A.4)
vap vap.re cov vap.conc vap.load vap.temp vap.humid
where bias is determined from the test performed under 5.6, with either a particle vapour mixture, a vapour
vap.recov
only, or an evaporated liquid deposit. The quantities bias and bias are the biases depending on vapour
vap.conc vap.load
concentration and vapour loading of deposition medium, both determined from the tests performed in 5.2. and
bias and bias are the biases depending on air temperature and humidity, both determined from the tests
vap.temp vap.humid
performed in 5.3.
Any non-significant bias (Student's t-test) will be considered equal to zero. The standard deviation for bias is
part.sampl
2
equivalent to the square root of the quantity defined in equation (A.5), annex A of prEN 13205:1998, and
standard deviations for the other biases are determined in the analysis of variance of the data from the experiment
for the corresponding attribute. See for example EN 838 or EN 1076 how this is done.
NOTE bias usually depends strongly on the particle size distribution to be sampled, and may depend on other
part.sampl
factors, such as wind speed.
A.4 Combination of particle and vapour phase precisions
Variances are combined by summing squares:
2 2
2
RSD 0,5RSD RSD (A.5)
part vap
where:
RSD is the relative standard deviation associated with the particulate phase;
...
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