Workplace atmospheres - Guidance for sampling of inhalable, thoracic and respirable aerosol fractions

This Technical Report describes methods that are suitable for the determination of the health-related fractions of most aerosols in the workplace.
For more complex aerosols such as bioaerosols, fibres, radioactive aerosols and particle-vapour mixtures further considerations are necessary (see e.g. relevant standards).
This Technical Report is not applicable to the monitoring of airborne particle concentrations using direct-reading instruments.

Arbeitsplatzatmosphäre - Leitfaden zur Probenahme der einatembaren, thorakalen und alveolengängigen Aerosolfraktion

Atmosphères de lieux de travail - Guide pour l'échantillonnage des fractions d'aérosols inhalables, thoraciques et alvéolaires

Le présent Rapport technique décrit les méthodes adaptées à la détermination des fractions liées à la santé de la plupart des aérosols présents sur les lieux de travail.
Dans le cas d'aérosols plus complexes, tels que les bioaérosols, les fibres, les aérosols radioactifs et les mélanges de particules et de vapeur, d'autres considérations sont nécessaires (voir, par exemple, les normes appropriées).
Le présent Rapport Technique ne s'applique pas au contrôle des concentrations de particules en suspension dans l'air à l'aide d'instruments à lecture directe.

Zrak na delovnem mestu - Navodilo za vzorčenje inhalabilnih, torakalnih in respirabilnih frakcij aerosolov

General Information

Status
Published
Publication Date
23-Aug-2005
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
24-Aug-2005
Completion Date
24-Aug-2005

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SLOVENSKI STANDARD
SIST-TP CEN/TR 15230:2005
01-december-2005
=UDNQDGHORYQHPPHVWX1DYRGLOR]DY]RUþHQMHLQKDODELOQLKWRUDNDOQLKLQ
UHVSLUDELOQLKIUDNFLMDHURVRORY

Workplace atmospheres - Guidance for sampling of inhalable, thoracic and respirable

aerosol fractions

Arbeitsplatzatmosphäre - Leitfaden zur Probenahme der einatembaren, thorakalen und

alveolengängigen Aerosolfraktion

Atmospheres de lieux de travail - Guide pour l'échantillonnage des fractions d'aérosols

inhalables, thoraciques et alvéolaires
Ta slovenski standard je istoveten z: CEN/TR 15230:2005
ICS:
13.040.30 Kakovost zraka na delovnem Workplace atmospheres
mestu
SIST-TP CEN/TR 15230:2005 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TP CEN/TR 15230:2005
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SIST-TP CEN/TR 15230:2005
TECHNICAL REPORT
CEN/TR 15230
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
August 2005
ICS 13.040.30
English Version
Workplace atmospheres - Guidance for sampling of inhalable,
thoracic and respirable aerosol fractions

Atmosphères de lieux de travail - Guide pour Arbeitsplatzatmosphäre - Leitfaden zur Probenahme der

l'échantillonnage des fractions d'aérosols inhalables, einatembaren, thorakalen und alveolengängigen

thoraciques et alvéolaires Aerosolfraktion

This Technical Report was approved by CEN on 10 July 2005. It has been drawn up by the Technical Committee CEN/TC 137.

CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,

Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,

Slovenia, 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

© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 15230:2005: E

worldwide for CEN national Members.
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Contents Page

Foreword ..........................................................................................................................................................3

0 Introduction.........................................................................................................................................4

1 Scope ...................................................................................................................................................6

2 Normative references .........................................................................................................................6

3 Terms and definitions.........................................................................................................................6

4 Sampling strategy...............................................................................................................................6

5 Method performance...........................................................................................................................8

6 Sampling instruments ........................................................................................................................9

7 Ancillary equipment required for field use......................................................................................11

8 Sampling procedure .........................................................................................................................12

9 Analysis of samples..........................................................................................................................14

Annex A (informative) Basic information to be recorded when sampling and afterwards .....................17

Annex B (informative) Examples of samplers for the inhalable, thoracic and respirable aerosol

fraction, which are or have been available on the market up to 2004, and published

reports on their performance...........................................................................................................19

Bibliography...................................................................................................................................................26

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Foreword

This Technical Report (CEN/TR 15230:2005) 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 the elements of this document may be the subject of patent

rights. CEN shall not be held responsible for identifying any or all such patent rights.

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0 Introduction
0.1 Background

A number of materials hazardous to health occur in the workplace in the form of aerosols, i.e. suspensions of

solid or liquid particles in air. Dust is generally understood to be an aerosol of solid particles, mechanically

produced, with individual particle diameters of 0,1 µm upwards. Dust particles can be compact in shape, or

can have extreme shapes, as for example in the case of airborne fibres. Fume is an aerosol of solid particles

generated by condensation from the vapour state usually following the evaporation of molten metals. Smoke

is an aerosol of solid and or liquid particles generated by condensation or nucleation of vapours after burning

of carbonaceous material. In both fumes and smokes the primary particle diameters are typically less than

0,1 µm which form larger aggregated particles. Mists are aerosols formed from liquid droplets. In this

document the term ‘‘aerosol’ is used to describe any suspension of particles in air, whether the airborne

particles constitute a solid dust, airborne fibres or droplets, a fume, a smoke or a mist.

Aerosol sampling at workplaces can be performed for many reasons using different sampling strategies:

These include comparison of the measured concentration with the occupational exposure Limit Value (LV),

exposure assessment for epidemiological studies and evaluation of control measures. Occupational Exposure

Limits have been defined for many types of aerosol. In order to demonstrate that personal exposure is

adequately controlled it is usually necessary to determine the concentration of the aerosol by means of

personal sampling. In some cases a direct determination of the aerosol concentration is all that is needed. In

other cases a subsequent analytical technique is applied for the determination of a particular harmful element

or compound present in the aerosol.
0.2 Sampling instruments

Many instruments have been developed over the years for sampling airborne particles for the purpose of

assessing exposure or for determining the efficacy of dust control measures (see [6]). In the past, sampling

instruments were often inadequately standardised in terms of their collection characteristics. Modern

standards for monitoring exposure to airborne particles are performance based, i.e. they require that the

instruments used meet agreed performance criteria with respect to target specifications. This document is

intended to help those responsible for making measurements to select and use instruments that meet these

modern performance standards.
0.3 Inhalable, thoracic and respirable fractions of airborne particles

Most industrial aerosols contain particles of a wide range of sizes. The behaviour, deposition and fate of any

particle after entry into the human respiratory system, and the response that it elicits, depends on the nature

and size of the particle. For the purposes of occupational hygiene it is important to consider the concentrations

of particles present in different size fractions.

Inhalable dust corresponds to the fraction of airborne material that enters the nose and mouth during

breathing, and is therefore available for deposition anywhere in the respiratory tract. The target specification

for sampling the inhalable fraction is given in EN 481. In reality the inhalable fraction depends on the

prevailing air movement around the exposed person (wind speed and direction), and on whether breathing is

by nose or mouth. It has, however, been possible to define a target specification for sampling instruments that

approximates to the inhalable fraction, for representative values of breathing rate, and for a person exposed

equally to all wind directions.

Thoracic dust corresponds to the fraction of airborne material that passes through the nose or mouth of the

exposed person, and enters the branching airways of the lungs. The target specification for sampling the

thoracic fraction is given in EN 481. In reality the thoracic fraction depends on breathing rate and varies for

different individuals, however it has been possible to define a target specification for sampling instruments

which approximates to the thoracic fraction for an average person.
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Respirable dust corresponds to the fraction of airborne material that penetrates to the gas exchange region of

the lung. The target specification for sampling the respirable fraction is given in EN 481. The respirable

fraction varies for different individuals, however it has been possible to define a target specification for

sampling instruments, which approximates to the respirable fraction for an average person.

NOTE 1 The PM 10 fraction is defined by US Environmental Protection Agency (and adopted in EN 12341). It also

corresponds to the fraction of material that passes through the nose or mouth of the exposed person, and passes the

larynx. However, it is based on other experimental data than the scientific basis for the thoracic fraction, and is therefore

slightly different. The main difference between the PM 10 and thoracic sampling conventions is that at 15 µm the sampling

efficiency for a sampler for PM 10 should be zero whereas it for a sampler for the thoracic fraction should be 19 %.

NOTE 2 The PM 2,5 fraction sampler is defined by US Environmental Protection Agency (see also EN 14907). It

corresponds to the fraction of material in the accumulation and nuclei modes of the ambient particle size distribution.

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1 Scope

This Technical Report describes methods that are suitable for the determination of the health-related fractions

of most aerosols in the workplace.

For more complex aerosols such as bioaerosols, fibres, radioactive aerosols and particle-vapour mixtures

further considerations are necessary (see e.g. relevant standards).

This Technical Report is not applicable to the monitoring of airborne particle concentrations using direct-

reading instruments.
2 Normative references

The following referenced documents are indispensable for the application of this document. For dated

references, only the edition cited applies. For undated references, the latest edition of the referenced

document (including any amendments) applies.

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 689, Workplace atmospheres – Guidance for the assessment of exposure by inhalation to chemical

agents for comparison with limit values and measurement strategy

EN 1232, Workplace atmospheres – Pumps for personal sampling of chemical agents – Requirements and

test methods
EN 1540, Workplace atmospheres – Terminology

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

EN 13098, Workplace atmospheres – Guidelines for measurement of airborne micro-organisms and endotoxin

EN 13205, Workplace atmospheres – Assessment of performance of instruments for measurement of

airborne particle concentrations

ISO 15767, Workplace atmosphere – Controlling and characterizing errors in weighing collected aerosols

3 Terms and definitions

For the purposes of this document, the terms and definitions given in the standards listed above, if applicable,

apply.
4 Sampling strategy

No sampling strategy can provide comprehensive information for all objectives. The sampling strategy should

be carefully tailored to meet the required objectives. Before a measurement survey is started in the workplace

a number of fundamental questions like these have to be answered:
 why sample?
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 how to sample?
 whose exposure should be measured?
 where to sample?
 when to measure?
 how long to sample for?
 how many measurements?
 how often to sample?

The reason being that time, money and sampling technology constraints are such that not every worker’s dust

exposure can be measured on every single day of his working career. An optimal sampling strategy will have

to be designed given the limited budget available. The actual sampling strategy used will be largely

determined by the reasons for the measurement survey. Several objectives can be mentioned:

 to provide information on personal exposure to evaluate compliance with limit values;

 to provide information on personal exposure in the framework of an epidemiological study;

 to provide information on the location and intensity of a source;

 to provide information on prevailing concentrations and trends in the general workplace atmosphere;

 to provide information on the effectiveness of control measures;

 to provide samples of airborne particles for subsequent analytical or toxicological investigations.

For the first two objectives personal sampling is well suited to measure or to monitor individual exposure of

workers to airborne particles. The aerosol is sampled in the breathing zone of individual workers. The other

objectives on the other hand are often met through static sampling. The aim of static sampling is usually to

measure and to analyse the workplace atmosphere in terms of aerosol concentration, particle size-distribution

and chemical or mineralogical composition. Another purpose of static sampling is monitoring of time-variations

in aerosol concentration at fixed locations. There can be special situations which need the application of a

static-sampling strategy, for example, when higher air volume flow rates are needed, or when the system of

compliance control measurements depends on that approach. All deviations from a personal sampling

strategy should be specifically justified.

When checking compliance often so-called “worst-case” sampling is performed, but these measurements are

of limited use for assessing exposure epidemiological purposes. Strategies like “worst-case” sampling can be

cost-effective for compliance testing. However, special care should be taken when measurement results

coming from a “worst-case” strategy have to be used for epidemiological purposes. Nevertheless this is done

in many cases.

Studies focusing on temporal and personal patterns of occupational exposure concentrations, have shown

that assumptions of homogeneous or similar exposure groups made up of workers performing the same tasks

in one location are often not met. Efficient and effective measurement strategies therefore should take into

account temporal and personal variations in exposure concentrations.

Guidance for the assessment of exposure to inhalation to chemical agents for comparison with limit values

can be found in EN 689. The strategies described in EN 689 assume that homogeneous exposure groups

exist. Rappaport et al. (see [4]) have described more recently a measurement strategy taking into account

between-worker variability in long-term exposure. This strategy uses an observational group approach, but

recognises that exposure varies both within and between workers. The strategy proposed by Rappaport et.al.

is only suitable for situations where we seek to evaluate and control long-term exposures, which can give rise

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to chronic health effects. It would be inappropriate to employ this approach to evaluate and control short-term

exposures or scenarios where acute effects are likely. Additionally, in short-term sampling the limit of

quantitation has to be considered.
5 Method performance
5.1 Limit of detection and limit of quantitation

Both the limit of detection and the limit of quantitation of the methods described in this document depend on

the volume of air sampled, and on the analytical method used to quantify the dust collected on the sampling

substrates used within the sampling instruments described. Further information on the determination of the

limits of detection and quantitation for gravimetric analysis of airborne dust samples is given in ISO 15767.

5.2 Sampling bias
Sampling bias arises primarily from two sources:

a) Concentration bias is minimised by carefully siting the sampler within the breathing zone of the worker,

close to the nose and mouth (see 8.2). The concentration to which the sampler is exposed is not

necessarily the same as the concentration to which the person is exposed. This is a particularly difficult

problem for sampling the inhalable fraction, as larger dust particles are very non-uniformly distributed and

are typically produced by localised sources in the workplace.

b) The samplers listed in this Technical Report have been demonstrated to match the target specifications

over a reasonable range of conditions, as laid down by the test procedures and requirements of

EN 13205. There are no sampling instruments in existence that closely match the target specifications

given in EN 481 under all possible workplace conditions.
5.3 Sampling precision

The main source of lack of precision in the measurement of workplace dust concentrations is the non-

uniformity (in time and space) of the aerosol cloud surrounding the worker. Analytical and sampling precisions

are generally better in comparison. Workplace-based studies using pairs of samplers on each worker have

been used to determine the real precision in dust sampling results. For sampling of the inhalable aerosol

fraction for example, a second contemporaneous sample on a worker was found to lie within a factor of two of

the first sample, on 95 % of occasions (see [5]). Precision in the measurement of thoracic or respirable dust is

lower than this figure as smaller particles become more uniformly mixed in workplace air.

Lack of precision caused by the sampling instrument itself is limited by the requirements of EN 13205. See 5.5

of this document.
5.4 Analytical bias and precision

Relevant standards, for example ISO 15767 for gravimetric analysis, should be consulted for details of the

analytical bias and precision. Compared to the variability of the workplace aerosol itself, analytical bias and

lack of precision generally have (with adequate laboratory quality control) minor impact on the error in the

measurement of airborne particle concentrations.
5.5 Expanded uncertainty

Sampling instruments meeting the requirements of EN 13205 will have an accuracy better than or equal to

30 %. Note however, for complete measurement procedures for airborne particles, the expanded uncertainty

(see EN 482) is a combination of the uncertainty of the sampled volume, the uncertainty of the sampled

fraction, the uncertainty of the transportation, storage, sample preparation, etc. and the uncertainty of the

analytical method employed.
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The measured concentration will be a good approximation of the concentration to which the worker is exposed,

only, if the sampler meets the requirements of EN 13205, if it has been correctly sited (see 8.2), if the

sampling time corresponds to or is representative of the exposure time and if the transportation, storage and

analytical methods used are appropriate. The temporal, spatial and personal variability of the workplace

aerosol concentration often far exceeds the variability of sampling and analysis procedures. The sampling

strategy used needs to accommodate the large variability of workplace concentrations.

6 Sampling instruments
6.1 Personal and static samplers

Workplace aerosols can be sampled for different purposes, which determine the choice of an appropriate

sampler (personal or static).

Static samplers often use high flow rates (> 10 l min ) in order to collect a high amount of particulate matter,

sufficient for further analysis.

A high flow rate pump shall not be allowed to exhaust more than a small fraction of the air flow through a room.

Personal sampling systems are worn by the persons themselves, and for this reason a personal sampler

should be small and light and therefore its flow rate is usually also small.

In practice, it is also possible to use personal samplers for static sampling but a personal sampler might not be

a validated static sampler. Static samplers are usually not suitable for personal sampling because of their

weight, except for special cases, e.g. samplers mounted in a driving cabin for sampling the exposure of the

driver.

NOTE Static samplers are sometimes called stationary samplers, area samplers or fixed-point samplers.

Personal and static samplers should meet the same sampling performance criteria as given in EN 13205. See

5.2 b).
6.2 Personal and static samplers for the inhalable aerosol fraction

Samplers for the inhalable aerosol fraction with the potential to meet the requirements of EN 481 and

EN 13205 for several environmental conditions are listed in Table B.1. With each sampler name, references

are given to reports and papers that demonstrate the performance of the sampler. These references should

be consulted for detailed information on the field conditions for which satisfactory performance is obtained.

For samplers of the inhalable aerosol fraction, the instruments listed have most difficulty to meet the

requirements in field situations where there are
• high external winds, e.g. in underground mines or out doors;

• large particles generated with high momentum (“projectiles”), e.g. as produced in woodworking or textile

manufacture;

• losses during transportation of samples, e.g. when samples are taken remotely from the analytical

laboratory and shipped by mail.

In general these problematic situations lead to undersampling of the inhalable aerosol fraction, except for

“projectiles”.

NOTE The concentration of the inhalable aerosol fraction is usually very localised and therefore static samplers are

unlikely to give a valid indication of personal exposure.
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6.3 Personal and static samplers for the thoracic aerosol fraction

Samplers for the thoracic aerosol fraction with the potential to meet the requirements of EN 481 and

EN 13205 for several environmental conditions are listed in Table B.2. With each sampler name, references

are given to reports and papers that demonstrate the performance of the sampler. These references should

be consulted for detailed information on the field conditions for which satisfactory performance is obtained.

For samplers of the thoracic aerosol fraction, the instruments listed have most difficulty to meet the

requirements in field situations where there are
• high external winds;

• high concentrations, i.e. some samplers have a tendency to become overloaded, either at the separation

stage or the collection stage;

• pulsating flow, i.e. some samplers are sensitive to flow pulsation in older models of sampling pumps (i.e.

pumps not specified according to EN 1232).

• losses during transportation of samples, e.g. when samples are taken remotely from the analytical

laboratory and shipped by mail;

In general these problematic situations lead to undersampling of the thoracic aerosol fraction of airborne dust.

NOTE 1 The concentration of thoracic dust is usually localised and therefore static samplers are less likely to give a

valid indication of personal exposure.

NOTE 2 In many cases a sampler for the PM 10 aerosol fraction will only give a minor bias relative to the thoracic

aerosol fraction.
6.4 Personal and static samplers for the respirable aerosol fraction

Samplers for the respirable aerosol fraction with the potential to meet the requirements of EN 481 and

EN 13205 for several environmental conditions are listed Table B.3. With each sampler name, references are

given to reports and papers that demonstrate the performance of the sampler. These references should be

consulted for detailed information on the field conditions for which satisfactory performance is obtained.

For samplers of the respirable aerosol fraction, the instruments listed have most difficulty to meet the

requirements in field situations where there are:

• high concentrations, i.e. some samplers can become overloaded, either at the separation stage or the

collection stage;

• pulsating flow, i.e. some samplers are sensitive to flow pulsation in older models of sampling pumps (i.e.

pumps not specified according to EN 1232);

• losses during transportation of samples, e.g. when samples are taken remotely from the analytical

laboratory and shipped by mail.

In general these problematic situations lead to undersampling of the respirable aerosol fraction of airborne

dust.

6.5 Personal samplers simultaneously collecting the inhalable, thoracic and respirable

aerosol fractions

Samplers for two or all three aerosol fractions with the potential to meet the requirements of EN 481 and

EN 13205 for several environmental conditions are listed in Table B.4. With each sampler name, references

are given to reports and papers that demonstrate the performance of the sampler. These references should

be consulted for detailed information on the field conditions for which satisfactory performance is obtained.

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Multifraction samplers have most difficulty to meet the requirements in field situations where there are

• high external winds, e.g. in underground mines or out doors;

• large particles generated with high momentum (“projectiles”), e.g. as produced in woodworking or textile

manufacture;

• high concentrations or narrow size distributions, i.e. parts of the samplers have a tendency to become

overloaded and this can distort the separation characteristics of the sampler;

• low concentrations, for one or two fractions the deposit might be below the limit of quantitation;

• losses during transportation, e.g. migration of deposit from one aerosol fraction to another, which can

occur when samples are taken remotely from the analytical laboratory.

In general these problematic situations lead to incorrect collection of the inhalable aerosol fraction, or to

incorrect subdivision of the airborne dust between aerosol fractions, typically manifested as overestimation of

the respirable aerosol fraction and underestimation of the inhalable aerosol fraction.

7 Ancillary equipment required for field use
7.1 Sampling pumps

Sampling pumps used for dust sampling should comply with the requirements of EN 1232 and EN 12919, and

should have as a minimum the following features:

 an automatic flow control which keeps the volumetric flow rate constant (within ± 5 % of the initial flow

rate)in the case of changing back pressure;

 either a malfunction indicator, which following the completion of sampling indicates that the air flow has

been reduced or interrupted during sampling; or an automatic cut-out, which stops if the pump flow is

reduced or interrupted;

 a facility for adjustment of the flow rate such that it can only be actuated with the aid of a tool (e.g. a

screw driver) or requires special knowledge for operation (e.g. software), so as to prevent inadvertent

adjustment of the flow rate during use.

 For some samplers, e.g. cyclones, pulsation damped flow is particularly important and an external

pulsation damper must be used if the pump does not contain an integral damper.
7.2 Other equipment required

 A portable flow meter, capable of measuring the desired volumetric flow rate to within 2,5 % of the

nominal flow rate of the sampler, and calibrated against a flow meter whose accuracy is traceable to

national standards. Bubble flow meters are preferred for measuring the volumetric flow rate because the

readings they give are independent of temperature and pressure. For other flow meters, it can be

necessary to measure the temperature and pressure at the time of use and apply corrections if these

differ from the conditions under which the flow meter was calibrated.

A special adapter between the sampler and the flow meter are in some cases required in order to

measure the flow rate correctly. The flow rate shall always be determined as the volumetric flow of air (of

local ambient temperature and pressure) into the sampler inl
...

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