continuous emission monitoring systems

8/10/2019 Continuous Emission Monitoring Systems

http://slidepdf.com/reader/full/continuous-emission-monitoring-systems 1/31

Procedures and General Requirements

for the Compliance Testing of

Continuous Emission Monitoring Systems

Environment Agency

Version 2, Revision 1

April 2003



MCERTS Procedures and General Requirements for CEMs, V2, Rev 1, April 2003 i

Foreword

The Environment Agency (the Agency) has established its Monitoring Certification Scheme,

MCERTS, to deliver quality environmental measurements. The scheme provides for the

product certification of instruments, the competency certification of personnel and the

accreditation of laboratories based on international standards. MCERTS is progressively being extended to cover all regulatory monitoring activities.

MCERTS operates under the requirements of European and international standards. The

Agency has appointed Sira Certification Service (SCS) as the Certification Body to operate

MCERTS on the Agency’s behalf. SCS is independent of all the interested groups, such as

the instrument manufacturers, monitoring personnel, test-house laboratories and end-users.

The Agency has published MCERTS performance standards for continuous emission

monitoring systems (CEMs). This document specifies the procedures and describes the

general requirements for the testing of CEMs for compliance with the performance standards.All testing under MCERTS must be carried out by laboratories and test organisations that

comply with the requirements of BS EN ISO/IEC 17025 for these procedures.

Both the performance standards and the test procedures are based on relevant CEN, ISO and

national standards. Testing comprises a combination of laboratory and field tests to ensure

that instruments perform to the technical requirements and work in real applications. The

scope of the test programme and evaluation of the results is carried out by SCS, using a group

of independent experts known as the Certification Committee.

If you have any questions regarding the testing of CEMs under MCERTS, please contact:

Sira Certification Service Tel: +44 (0)208 467 2636

South Hill Fax: +44 (0)208 295 1990

Chislehurst

Kent BR7 5EH

If you have any general questions about MCERTS, please contact:

Environment Agency Tel: +44 (0)1772 714362

Monitoring & Assessment Process Fax: +44 (0)1772 714360

Lutra House

off Seedlee Road

Walton Summit

Preston PR5 8BX

or visit the MCERTS website at www.environment-agency.gov.uk/mcerts/

Dr Mick Pearson

Head: Monitoring & Assessment Process

March 2003



MCERTS Procedures and General Requirements for CEMs, V2, Rev 1, April 2003 ii



MCERTS Procedures and General Requirements for CEMs, V2, Rev 1, April 2003 iii

Contents

1. Introduction........................................................................................................................1

2. Scope....................................................................................................................................1

3. References ...........................................................................................................................1

4. Definitions ...........................................................................................................................2

5. Provisions for test organisations.......................................................................................5

5.1 General requirements for test-houses and testing ......................................................5

5.2 Procedures and documentation...................................................................................6

5.3 Measurement equipment and calibration gases..........................................................6

5.4 Performance evaluation..............................................................................................6

5.5 Paired testing of instruments......................................................................................6

5.6 Reporting....................................................................................................................6

6. Laboratory test procedures...............................................................................................7

6.1 Screening checks – all CEMs.....................................................................................7

6.2 Operating environments – all CEMs..........................................................................86.3 Specific tests for gas monitoring CEMs...................................................................10

6.4 Specific tests for TOC monitoring CEMs ................................................................14

6.5 Specific tests required for particulate measuring instruments .................................16

6.6 Specific requirements for CEMs monitoring temperature, pressure and flow.........16

7. Field test requirements ....................................................................................................17

7.1 General requirements for all CEMs .........................................................................17

8. Status of this document....................................................................................................21

Appendix 1: Required format for reports on performance evaluation of CEMs.......22

Appendix 2: Interfering compounds...............................................................................24

Appendix 3: Standard reference methods......................................................................25



MCERTS Procedures and General Requirements for CEMs, V2, Rev 1, April 2003 iv



MCERTS Procedures and General Requirements for CEMs, V2, Rev 1, April 2003 Page 1 of 25

Procedures and General Requirements for the Compliance Testing of

Continuous Emission Monitoring Systems

1. Introduction

1.1.1 This document describes the test procedures and general requirements for the testingof continuous emission monitoring systems (CEMs) for compliance with the

MCERTS performance standards. It also describes the specific, supplementary

provisions for MCERTS-certified CEMs to be accepted by the Umweltbundesamt

(UBA) for inclusion on the German Federal Register of approved equipment.

2. Scope

2.1.1 The procedures and requirements in this document cover both laboratory and field

compliance testing of CEMs under MCERTS.

3. References

3.1 Normative references

a) BS EN 45001 (1998). General criteria for the operation of testing laboratories.

b) BS EN ISO/IEC 17025 (2000). General requirements for the competence of

testing and calibration laboratories.

c) Performance Standards for Continuous Emission Monitoring Systems – The

Environment Agency’s Monitoring Certification Scheme (MCERTS),

Version 2, Revision 1, April 2003.

3.2 General references

d)

BS 6069 Section 4.4 (1993). Stationary source emissions – Determination of

the mass concentration of sulphur dioxide – Performance characteristics of

automated measuring methods. Also known as ISO 7935.

e) BS EN 12619 (1999). Determination of the mass concentration of TOC at low

concentrations in flue gases.

f) BS EN 13526 (2002). Determination of the mass concentration of TOC at high

concentrations in flue gases.

g) BS EN 50081-1 (1992). Electromagnetic compatibility. Generic emission

standard. Residential, commercial and light industry.h) BS EN 50081-2 (1994). Electromagnetic compatibility. Generic emission

standard. Industrial environment.

i) BS ISO 6879 (1995). Air quality – Performance characteristics and related

concepts for air quality measurements.

j) BS ISO 10155 (1995). Stationary source emissions – Automated monitoring

of mass concentrations of particles – Performance characteristics, test methods

and specifications.

k) BS ISO 14164 (1999). Stationary source emissions – Determination of volume

flow rate of gas streams in duct – automated method.

l) ISO 9169 (1994). Air quality – Determination of performance characteristics

of measurement methods. Also Amendment 1 (CD) (1998).m) ISO 10396 (1993). Stationary source emissions – Sampling for the automated




determination of gas concentrations.

n) ISO 10849 (1996). Stationary source emissions – Determination of mass

concentration of nitrogen oxides – Performance characteristics of automated

measuring systems.

o)

ISO 12039 (2001). Stationary source emissions – Determination of the

volumetric concentration of CO, CO2 and oxygen – Performancecharacteristics and calibration of an automated measuring system.

p)

BS EN 60359 (2002). Electrical and electronic measurement equipment.

Expression of performance

q) MCERTS – Guidance on the Acceptance of German Type Approval Test

Reports for CEMs, Environment Agency, 2001.

r) VDI 4203, Part 1 (2001). Testing of automated measuring systems. General

concepts.

s) VDI 4203, Part 2 (2001). Testing of automated measuring systems. Test

procedures for measuring systems of gaseous and particulate emissions.

t) IEC 60068-1 (1988-06)

u)

Environmental testing. Part 1: General and guidance

v) IEC 60068-2, Parts 1 to 81, Environmental testing, specific requirements..

4. Definitions

4.1 Accuracy: The closeness of agreement between a single measured value of the

determinand and the true value (or an accepted reference value).

4.2 Analysis function: Statistical relationship between the starting variable (signal

measured) of the measuring system and the associated measurement result

(measured value) simultaneously determined at the same point of measurementusing a standard method of reference measurement.

NOTE 1: The analysis function is normally calculated using linear regression.

NOTE 2: ISO 10155 uses the term “calibration function” to refer to this function. This use of the term conflicts

with other ISO standards (for example, ISO 6879) and VDI. Within MCERTS, the term “analysis

function” is used to avoid such inconsistencies.

4.3 Availability: The fraction of the total monitoring time for which data of acceptable

quality have been collected.

4.4 Averaging time: The period of time over which an arithmetic or time-weighted

average of concentrations is calculated. [T a is the averaging time used by the CEM.T ra is the required data averaging period, e.g. prescribed by legislation.]

4.5 CEM: Acronym for a continuous emission monitoring system. Entirety of all

measuring instruments and additional devices for obtaining a measurement result.

NOTE 1: Apart from the actual measuring device (the analyser), a CEM includes facilities for taking samples

(e.g. probe, sample gas lines, flow meters and regulator, delivery pump), for sample conditioning (e.g.

dust filter, pre-separator for disturbing components, cooler, converter) and for recording. This

definition also includes testing and adjusting devices that are required for functional checks and, if

applicable, for commissioning.

NOTE 2: CEM is an alternative term for “automatic measuring system” (AMS), which is the term used

elsewhere in Europe.




4.6 Certification range: The determinand values over which the instrument is to be

tested, bounded by specified upper and lower limits. Testing takes place within the

certification range.

4.7 Converter efficiency: The efficiency with which the internal converter unit of a

NO x analyser reduces NO2 to NO.

4.8 Cross-sensitivity: Response of the CEM to determinands other than those it is

designed to measure. See Interference.

4.9 Detection limit: This is the concentration value of the determinand below which

there is at least a 95% level of confidence that the measured value corresponds to a

sample free of that determinand.

4.10 Delay time, T 10: The time taken for the output reading of the CEM to reach 10% of

the total change in instrument response.

4.11 Expanded uncertainty: Quantity defining a level of confidence about the result of

a measurement that may be expected to encompass a specific fraction of the

distribution of values that could reasonably be attributed to a determinand.

NOTE: The level of confidence would typically be 95%.

4.12 Field repeatability: A measure of the 95% level of confidence interval of the

difference of measuring results from two CEMs used under identical conditions.

NOTE 1: The term “reproducibility” is sometimes used instead of “field repeatability”.

4.13 Gas analyser: An analytical instrument that provides an output signal that is a

function of the concentration, partial pressure, flow or temperature of one or morecomponents of a gas mixture.

4.14 Integral performance: The integral performance is defined as a measure of the

working accuracy of the CEM. The integral performance is derived from the

differences in pairs of measured values of the determinand by the CEM and

reference method. There must be a sufficient number of paired measurements spread

over the period of unattended operation. It is calculated according to the formula for

standard deviation.

The difference in uncertainties between the measurements from the CEM and the

reference methods is defined in equation (1):

2

C

2

DF S S I −= (1)

where S D is derived from the uncertainty in the differences between the CEM and

SRM measurements using equation (2):

−

−= ∑∑

==

2

11

2

D

1

1

1 n

i

i

n

i

i Z n

Z n

S (2)




where

Z i = X i – Y i;

X i = individual result obtained by the SRM;

Y i = mean result obtained by the CEM over the same time period as that taken to

perform SRM measurement;

n = number of measurement pairs;S C = known standard deviation in the results obtained by the SRM. (It is generally

given in CEN/ISO standards describing the appropriate methods – for

example, ISO 7934.)

4.15 Interference: A negative or positive effect that a substance has upon the output of

the instrument when that substance is not the target determinand.

4.16 Interferent: Component of the sample, excluding the measured constituent, that

affects the output signal.

4.17 Limiting conditions: The extreme conditions that an instrument can withstand

without damage and any decrease in its abilities to perform reliable measurements

when it is working under its rated operating conditions.

4.18 Linearity: Measure of fit of the instrument’s response to a straight line using a

number of samples of approximately equally distributed concentrations of a

pollutant and a zero concentration.

4.19 Linearity error: The maximum deviation between the actual analyser readings and

the best-fit line (linear regression line).

4.20 Maintenance interval: Maximum admissible interval of time for which the

performance characteristics will remain within a predefined range without servicing,

e.g. refill, calibration, or adjustment.

4.21 Output: A reading, or a digital or analogue electrical signal, generated by an

instrument in response to a determinand.

4.22 Performance characteristic: One of the quantities (described by values, tolerances,

range) assigned to equipment in order to define its performance.

4.23 Reference conditions: A specified set of values (including tolerances) of influencevariables delivering representative values of performance characteristics.

4.24 Reference material: A substance or mixture of substances, with a known

composition within specified limits. One or more of the properties of the reference

material are sufficiently well established over a stated period of time to be used for

the calibration of an apparatus, for the assessment of a measuring method or for

assigning values to materials.

4.25 Repeatability: The ability of a CEM to provide closely similar indications for

repeated applications of the same determinand under the same conditions of measurement.




4.26 Response time, T 90: The time taken for the output indicator reading of the CEM to

reach 90% of the total change in CEM response.

4.27 Span: Difference of the instrument readings between zero and a stated determinand

value. By convention, this determinand value is chosen to be 70% to 80% of the

upper limit of the measurement.

4.28 Span drift: The change in instrument reading in response to a specified value of a

determinand over a stated period of unattended operation.

4.29 Stable test gas mixture: A mixture of gases where the component to be measured is

known and neither reacts with the containment system, nor is adsorbed on to it (e.g.

a cylinder).

4.30 Standard uncertainty: Uncertainty of the result of a measurement expressed as a

standard deviation.

4.31 Uncertainty: The parameter associated with the result of a measurement that

characterises the dispersion of the values that could reasonably be attributed to the

determinand.

4.32 Zero gas: A gas mixture used to establish the zero point of a calibration curve when

used with a given analytical procedure within a given calibration range.

4.33 Zero drift: The change in instrument reading in response to a zero value of the

determinand over a stated period of unattended operation.

5. Provisions for test organisations

5.1 General requirements for test-houses and testing

5.1.1 Test organisations shall comply with the requirements of BS EN ISO/IEC 17025 for

testing of CEMs under MCERTS and possess the necessary equipment and

capabilities to perform the tests specified in this document.

NOTE 1: Demonstration of compliance shall be either through accreditation by a national accreditation body, or

by a successful audit to EN ISO/IEC 17025 by the MCERTS Certification Body.

NOTE 2: Prior to March 2002, test organisations had to comply with the requirements of BS EN 45001.

5.1.2 Instrument testing would normally begin in the laboratory. If the instrumentsuccessfully passes the laboratory tests, then it proceeds to the three-month field

tests.

5.1.3 When performing the tests, the test-house must consider each performance

characteristic on its own. In the case of multiple-component CEMs, the evaluation

must cover the influence of intended combinations of measurement components on

the performance of the CEM.

5.1.4 If a CEM does not meet any of the requirements in the performance standards, then

the test-house must inform the Certification Body without delay.




5.2 Procedures and documentation

5.2.1 The test-house shall have documented procedures to provide for the applicable test

requirements in Sections 6 and 7 of this document.

5.2.2 The test-house shall retain the test records and reports, as well as all documents of

importance for at least five years.

5.3 Measurement equipment and calibration gases

5.3.1 All equipment and calibration gases used for evaluating the performance of CEMs

shall be verified as fit for purpose. This shall include certificates of calibration

traceable to national standards.

NOTE: Any combination of cylinders, gas blenders, dilution systems and permeation tubes may be used to

generate test and calibration gases.

5.4 Performance evaluation

5.4.1 The test-house shall evaluate the performance of the CEM for compliance with therelevant MCERTS performance standards. The requirements of the appropriate tests

are described in Sections 6 and 7.

5.5 Paired testing of instruments

5.5.1 Testing for MCERTS certification shall be performed on a minimum of one

instrument for gas monitoring CEMs and one instrument for the laboratory tests for

particulate monitoring CEMs. Two instruments are required for the field test for

particulate monitoring CEMs to determine field repeatability.

5.5.2 Two instruments shall be tested in all cases where the manufacturer requires theMCERTS-certified CEM to be accepted by the Umweltbundesamt (UBA) for

inclusion on the German Federal Register of approved equipment. Both instruments

are required to pass all the laboratory and field tests.

5.6 Reporting

5.6.1 The test-house shall produce a report describing the test programme and the results

of the evaluation. This test report shall contain at least the following:

• a description of the CEM under test, including the manufacturer, type and

unique identity;• a description of the test programme;

• a description of the methods and reference tests employed in the

programme;

• any deviations from the standard methods;

• the results of the test;

• details of necessary maintenance work and remedial actions required to

ensure that the equipment meets the performance standards;

• a proposed scope of capabilities to be included on the certificate;

• a summary table stating the required performance characteristics for each

parameter, a statement of pass or fail, and a reference to the relevant section

of the test report.




5.6.2 The operating instructions, the manufacturer’s description of the equipment as well

as other relevant information shall be attached to the test report.

5.6.3 Appendix 1 describes the required format for the report.

6. Laboratory test procedures

6.1 Screening checks – all CEMs

(i) Instrument receipt, set-up and adjustment

6.1.1 Upon receipt of the CEM, the test-house shall check that the manufacturer has sent

an appropriate and complete CEM, plus instructions for use.

6.1.2 The test-house shall ensure that the CEM is set up, calibrated and adjusted in

accordance with the manufacturer’s instructions.

NOTE: The manufacturer is normally expected to install and set up the CEM.

(ii) Short-term drift and repeatability

6.1.3 The test-house shall have procedures to screen the stability and response of the

CEM. Such procedures can include an evaluation of short-term drift and

repeatability. Typically, a CEM shall be allowed to warm up, after which it is

supplied with a zero or span gas. If the reading drifts significantly or the signal is

unacceptably noisy, then the tests shall be terminated until the Certification Body

decides on the appropriate course of action.

NOTE: As a guideline, the instrument’s response should not drift more than 2% of the certification range over

24 hours and have a noise level that is less than 2% over the same period.

(iii) Prevention of unauthorised adjustment

6.1.4 The test-house shall evaluate the effectiveness of the mechanism that prevents

inadvertent and unauthorised adjustment.

(iv) Position of zero point and reference point on the device display

6.1.5 The test-house shall use a zero gas and a reference gas to determine whether the zero

point is between 10% and 20% of the full-scale deflection (FSD) and whether the

span point is between 70% and 80% of the range.

(v) Indicating range

6.1.6 The test-house shall determine whether the indicating ranges are appropriate and can

be adjusted for the required tasks.

(vi) Supplementary data outputs

6.1.7 The test-house shall verify by inspection that the CEM has a supplementary output

for an external data recording device, and whether the measurement signals

displayed on an external device are the same as those on the CEM.




(vii) Status signals

6.1.8 The test-house shall verify by inspection whether the CEM has provisions for

displaying its operational status, whether the mechanisms are effective and the

displayed status is correct.

NOTE: Status signals include indication of normal operation, calibration and faults. Not all fault conditions

require evaluation.

(viii) Automatic corrections for zero and span drift

6.1.9 If CEMs are equipped with an automatic function to correct zero and span drift, then

the test-house shall determine the maximum permissible correction range in which

readjustment is possible.

6.1.10 Initially, the test-house shall admit a test gas or other test media at the zero and

reference point and repeat this exercise three times. Then the test-house shall alter

the settings of the analyser so that such an adjustment simulates a zero and span

drift. The test-house shall then determine whether the automatic correction functionseffectively and corrects the simulated drift.

NOTE: This test is also repeated during the field test.

6.2 Operating environments – all CEMs

6.2.1 The CEM shall be tested to show whether it is influenced by changes in operating

environments as specified in this section.

6.2.2 The extent of the environmental testing will be agreed between the manufacturer

and the Certification Body, taking into account the environment likely to be

encountered in the industrial process(es) for which product certification is sought.

NOTE: The Certification Body will consider whether different components of CEMs should be subjected to

different levels of environmental testing (for example, the stack-mounted components will in general

require more rigorous tests than components mounted off-stack).

6.2.3 During the tests, the CEM shall be subjected to the specified range of environmental

conditions and the changes in its zero and span values determined. The range of

conditions tested will be reported on the certificate.

(i) Mains voltage

6.2.4 Using an isolating transformer, the test-house shall vary the voltage to the CEM in

10 V increments, varying the voltage from 230 V to 190 V and then from 230 V to250 V. The test shall be performed at the zero point and at the span point. The

measurement signals shall be recorded in each case and the test shall be repeated at

least three times.

(ii) Vibration

6.2.5 When required by the Certification committee, this test shall be applied to stack-

mounted components of the CEM only and shall be made with reference to IEC 68-

1/2 ( Basic Environmental Testing Procedures) recommendations. The instrument

shall be subjected to vibration on three perpendicular axes in turn, with a swept

range of frequencies from 10 Hz to 150 Hz at one octave per minute and at an RMS

acceleration of 19.6 m s –2.




6.2.6 If any resonant frequencies are observed, a vibration test shall be carried out at each

observed frequency for a period of two minutes. This shall be followed by a

functional test.

6.2.7 If no resonant frequencies are observed, a vibration test shall be made at a frequency

of 50 Hz for a period of two minutes. This shall be followed by a functional test.

(iii) Effects of variations in ambient temperature

6.2.8 The test-house shall carry out these tests by using a climatic chamber, which can

vary the temperature from at least –20 °C to +50 °C.

6.2.9 The CEM is placed in a climatic chamber, whose temperature is then set to 20 °C.

The CEM must be allowed to warm up and adjusted for zero and span settings if

required.

6.2.10 In the case of assemblies for use outdoors, the following temperatures must be set inthe climatic chamber in this order of sequence:

20 °C → 10 °C → 0 °C → –10 °C → –20 °C → –10 °C → 0 °C → 10 °C

→ 20 °C → 30 °C → 40 °C→ 50 °C → 40 °C → 30 °C → 20 °C

6.2.11 In the case of assemblies for use at temperature-controlled locations, the following

temperatures must be set in this order of sequence:

20 °C → 10 °C → 5 °C → 10 °C → 20 °C → 30 °C → 40 °C → 30 °C → 20 °C

6.2.12 After a sufficient equilibration period, the CEM is injected with zero and span gases.Zero and span checks are performed at each temperature, and the procedure is

repeated three times. If the test-house performs fewer tests, then it must have data to

justify its approach, e.g. by demonstrating a pattern of low variability, where the

assessment of low variability is supported by statistical analyses.

(iv) Content of condensing water vapour in air

6.2.13 The effect of liquid water on the measuring system must be examined by visual

inspection in relation to the CEM’s protection class. This requirement is only

significant if the CEM is to be used outdoors. If it is to be expected that the

condensing water vapour in the air will influence the measurement signals, thisinfluence must be described.

(v) Effect of sample gas temperature and pressure

6.2.14 If the Certification Body decides that the CEM’s response to sample gas temperature

and pressure needs to be evaluated, then the test-house shall perform the following

tests described in paragraphs 6.2.15 –6.2.17.

6.2.15 The sample gas will be air or nitrogen containing the determinand gas at a

concentration of between 70% and 95% of the maximum of the certification range.

6.2.16 The output signal of the CEM will be measured with the sample gas at a temperature




that is successively at the bottom and top of the specified temperature range and at

the middle of the range. The middle temperature will be omitted if the specified

range is less than 30 °C. The results will be used to calculate the CEM response

change per unit temperature.

6.2.17 The output signal of the CEM shall be measured with the sample gas at ambientatmospheric pressure and again with the same gas at a pressure approximately 3 kPa

above this. The difference in indicated CEM readings at the two pressures is be used

to calculate the response change per unit sample gas pressure.

6.3 Specific tests for gas monitoring CEMs

(i) Response time

6.3.1 The response time is measured by introducing step changes in the concentration of

determinand gas at the input of the CEM system. The size of each step shall be

between 10% and 90% of the certification range and need not begin or end at zeroconcentration. This test shall be repeated at least eight times, unless the test-house

can demonstrate that fewer repetitions are statistically justified.

6.3.2 For extractive CEM systems, whose delay and response times depend partially upon

the length of their associated sample lines, the sample line supplied shall be

nominally 10 m in length. The gas flow rate in the sample line during the tests shall

be noted, as this also will influence the delay times.

NOTE: To assess the effect of the sample line on the delay time, it is necessary to know the sample line’s

length, internal diameter and flow rate.

(ii) Linearity6.3.3 The linearity of the response of the CEM to changes in the concentration of the

determinand shall be tested over a range from approximately 10% to 90% of the

maximum of the agreed certification range of the instrument, using at least five

concentrations and an additional certified zero gas. The test-house shall determine

the greatest deviation of the CEM’s response from the linear regression line fitted to

the observed values, and this will be expressed as a percentage of the maximum of

the certification range. Statistical tests shall be carried out to ensure that the

maximum deviation observed is not due to a single unrepresentative outlier value.

(iii) Cross-sensitivity to interfering substances

6.3.4 The test-house shall establish the sensitivity of the CEM to gases other than its

determinand gas, expected to be present in its measurement environment and where

there is a potential response. The gases and their concentrations in these tests will be

agreed with the Certification Body before testing. They will be related to the

industrial processes that the CEM is intended to monitor and to the type of gas

detection system that is employed by the CEM. Appendix 2 is used by the

Certification Body as a guide to the gases and concentrations that will be required.

NOTE: The German requirements specify that all the gases in Appendix 2 must be examined.




6.3.5 Test gases shall be introduced individually at the agreed concentrations into the

CEM and its responses recorded. Additional tests may be carried out where

appropriate on other species, such as particulates. The response to each of the

interfering substances shall be expressed as a percentage of the maximum of the

CEM’s certification range. The response shall be tested with zero and span gases.

6.3.6 The CEM’s combined response, S , to all of the interfering substances will then be

calculated using equation (3):

R M =S

n

i

i∑=1r

100(3)

where

Ri = response to the specified concentration of each interfering substance, inclusive

of the sign of that response;

M r = maximum of the instrument’s certification range;n = number of interfering substances tested.

6.3.7 The purpose of the S factor is to give an indication of the combined effect of the

likely interferents.

6.3.8 In addition to the individual application of interferent gases, the response of the

CEM shall be measured using a mixture of all of the gases, at the same

concentrations used in the individual interferent tests. This will test the hypothesis

of additivity made in equation (3).

6.3.9 The combined effect of all the interferent gases (represented by the S factor) shouldnot exceed the performance characteristics expressed as a percentage of the

maximum of the certification range given in MCERTS performance standards.

Similarly, the effect of the interferent mixture should not exceed this limit.

(iv) Detection limit

6.3.10 This is the concentration value of the determinand below which there is at least a

95% level of confidence that the measured value corresponds to a sample free of

that determinand. It is defined by equation (4):

C D = t f (0.95)S 0 (4)

where

C D = detection limit (expressed in determinand concentration units);

S 0 = standard deviation of the measurements;

( f + 1) = number of measurement values obtained during the test for detection limit;

t f (0.95)= statistical Student t -factor for a 95% confidence level with f degrees of

freedom.

6.3.11 To determine the detection limit, the response of the CEM to a zero gas is measured.

The measurement period shall be at least three times the response time, and this test

is repeated at least 30 times. The most sensitive measuring range must be selected

for this purpose, and the standard deviation, S 0, is calculated from the readings.6.3.12 The detection limit value determined by this test shall be expressed as a percentage




of the certification range.

(v) Influence of test gas flow on the measurement signal

6.3.13 This test requires a control unit that can adjust the flow of sampled exhaust gas

through the CEM.

6.3.14 The CEM is initially operated at the flow rate prescribed by the manufacturer. This

flow rate is then varied upwards and downwards in steps of 10% until the

measurement signal changes by more than 1% of the certification range. The test-

house shall also check whether the manufacturer has stated the test gas flow in the

equipment’s operating instructions.

6.3.15 This test must be repeated three times at the zero and reference point, respectively.

Furthermore, status signals must indicate that the instrument is giving erroneous

readings once the instrument reading changes by more than 1% of the certification

range due to flow rate changes.

(vi) Test of the converter in NO x analysers

NOTE: Before calibrating a NO x analyser that uses a converter, it is essential to ensure that the converter

efficiency lies as close to unity as possible. The determination of the efficiency is based on the

principle that the response of the apparatus to the total amount of nitrogen oxides (NO x) does not

change if analyses are made of varying mixtures of nitrogen monoxide and nitrogen dioxide, but for

which the total concentration of nitrogen oxides is constant.

6.3.16 The following equipment is required:

• A source of nitrogen monoxide, such as a compressed gas cylinder containing

nitrogen monoxide in nitrogen at a concentration of the order of 80% of the

certification range. The actual concentration need not be known provided that it

remains constant throughout the test.

• A source of oxygen, such as a compressed gas cylinder containing air or

oxygen.

• An ozone generator, capable of producing varying amounts of ozone from

oxygen.

6.3.17 Ensure that the total flow rate of nitrogen monoxide and air (or oxygen) is at leastequal to the flow rate of gas through the analyser.

NOTE: If the flow rate of nitrogen oxide is greater than the flow rate through the analyser, then a by-pass will

be required for the excess.

6.3.18 In all of the following steps, determine the responses of the analyser to both the

nitrogen monoxide and total NO x.

NOTE: This procedure evaluates the concentration of nitrogen dioxide being produced, which should be in the

range 10% to 90% of the NO x.

a) Turn off the ozone generator. Then note the concentration of total NO x ( R1)

and the concentration of nitrogen monoxide ( P 1). b) Turn on the ozone generator. Record the concentration of total NO x ( R2) and




the concentration of nitrogen monoxide ( P 2).

NOTE: Ozone is formed, which reacts with the nitrogen monoxide to produce nitrogen dioxide before the

gases enter the analyser.

c) Vary the output of the ozone generator and record the displayed

concentrations of total NO x ( R2, R3, R4, …, Rn) and nitrogen monoxide ( P 2,

P 3, P 4, …, P n). NOTE: The ratios R2/ R1, R3/ R1, R4/ R1, …, Rn/ R1 should be as close to unity as possible. Therefore, the

concentration of total NO x should be constant in each case and independent of the ratio of the

concentrations of nitrogen dioxide to nitrogen monoxide.

d) Calculate the converter efficiency, expressed as a percentage, using equation

(5), where Rn and P n are the recorded concentrations of total NO x and

nitrogen monoxide for each setting of the ozone generator.

100)()(

1

11E ×

−

−−−=

n

nn

P P

P R P RC (5)

whereC E = converter efficiency;

R1,n = concentrations of total NO x;

P 1,n = concentrations of NO.

6.4 Specific tests for TOC monitoring CEMs

NOTE: These tests are additional to those required in Section 6.3 and specifically for flame ionisation

detectors (FIDs) for monitoring total organic carbon (TOC).

(i) Range of response factors

6.4.1 The test-house shall determine the response factors of the CEM to the individualcompounds listed in Table 1 (low concentrations of TOC) and Table 2 (high

concentrations of TOC), relative to propane. Alternative gases in each hydrocarbon

group are acceptable provided that the test-house can justify their inclusion.

Table 1 Groups and compounds for testing response factors

- at low concentrations of TOC

Hydrocarbon group Compounds

Alkanes Methane and ethane

Aromatic Benzene and toluene

Chlorinated Dichloromethane

Table 2 Groups and compounds for testing response factors

- at high concentrations of TOC

Hydrocarbon group Compounds

Alkanes Methane, ethane, butane, hexane, heptane, octane and cyclohexane

Aromatic Benzene and toluene

Alcohols Methanol, ethanol and propanol

Esters Methyl acetate, ethyl acetate and isobutyl acetate

Ketones Acetone

Organic acids Acetic acid




6.4.2 Equation (6) shall be used to calculate the carbon-related response factor, f c.

÷

=

ref c,

ref

,c

cC

S

C

S f

i

i (6)

where

f c = carbon-related response factor;

S i = reading of the FID (measurement signal) for substance i;

S ref = reading of the FID (measurement signal) for propane;

C c,i = carbon concentration of substance i in milligrams per cubic metre (273 K;

101.3 kPa);

C c,ref = carbon concentration of propane in milligrams per cubic metre (273 K;

101.3 kPa).

(ii) Control gas mixture – low levels of TOC

6.4.3 The test-house shall determine the response of the FID to a control gas mixture asdefined in Table 3. This test may be incorporated as part of the tests for cross-

sensitivity responses.

Table 3 Composition of the control gas mixture, concentrations as carbon

Component Concentration (% or mg m –3

as C)

Methane 2.0 mg m –3

Ethane 1.5 mg m –3

Toluene 0.5 mg m –3

Benzene 0.5 mg m –3

Dichloromethane 0.5 mg m –3

Oxygen 11%

Carbon dioxide 10%

Carbon monoxide 50 mg m –3

(iii) Determination of the effect of oxygen synergism

6.4.4 Oxygen can affect both the zero point and the span value. To determine the effects

of oxygen, the following test gases shall be used.

Zero gases:a) 100% nitrogen;

b) 90% nitrogen and 10% oxygen (by volume);

c) 80% nitrogen and 20% oxygen (by volume).

Span gases:

a) 100% nitrogen plus propane X mg m –3;

b) 90% nitrogen and 10% oxygen (by volume) plus propane X mg m –3;

c) 80% nitrogen and 20% oxygen (by volume) plus propane X mg m –3;

where X is 16 mg m –3 for FIDs measuring low concentrations of TOC and 75% of

the respective emission limit for FIDs measuring high concentrations of TOC.




NOTE: The effect of oxygen interference can be reduced by using zero and span gases with the same oxygen

concentration as the flue gas.

6.5 Specific tests required for particulate measuring instruments

NOTE: The laboratory testing of particulate monitors may be carried out either using a form of simulated

particulate, such as a filter, or in a wind tunnel test facility. The latter should be able to provide a well-characterised and reproducible particulate size distribution with a mass concentration variable from 0

to 500 mg m –3 at a gas flow velocity of 0.5 to 15 m s –1.

(i) Response time

6.5.1 Either using a simulated particulate, or a particulate reference material within a wind

tunnel, the time is recorded for the CEM to reach 90% of the particulate

concentration. This test shall be repeated at least eight times, unless the test-house

can demonstrate that fewer repetitions are statistically acceptable.

NOTE 1: Simulated particulate includes filters, which are typically used to adjust particulate monitoring CEMs

which use optical principles.

NOTE 2: The test for linearity may be tested as part of the field-test, provided that there is a suitably wide range

of particulate concentrations.

(ii) Linearity

6.5.2 The instrument shall be calibrated according to the manufacturer’s instructions,

using a reproducible particulate mass concentration or a simulation.

NOTE: When using a wind tunnel, this procedure will normally require the particulate flow or simulation to

be maintained continuously for at least half an hour.

6.5.3 For instruments used for quantitative purposes, the linearity of the CEM’s response

to changes in particulate concentration shall be tested over at least five levels in the

range 10% to 90% at a typical air flow velocity of about 7 m s

–1

when performingthis test in a wind tunnel.

6.5.4 The instrument response will be assessed using the correlation coefficient specified

in the standard ISO 10155. For indicative monitors, the linearity test will be a test of

continuous output only. Four instrument output readings evenly distributed across

the range will be reported.

NOTE 1: The test-house may perform this test in the field, using agreed procedures, if the process parameters

can be altered to produce a sufficient range of particulate concentrations.

NOTE 2: The test-house may use filters to provide additional information on the linearity response of optical,

cross-stack instruments.

(iii) Cross-sensitivity to interference

6.5.5 The sensitivity of the CEM to the following potential types of interferent will be

tested, when required by the Certification Body:

a) Interfering gases. A gas test chamber will be used to test the zero response to

selected interfering gases, for example, for instruments using broad-band

optical radiation.

b) Effect of velocity changes. A wind tunnel will be used to measure the effect

of velocity changes at a fixed particulate concentration, using up to 10

different velocities at equal steps between 2.5 m s –1 and 15 m s –1.

c) Effect of particle size. The effect of changing the size of the particulate




employed in the wind tunnel will be measured.

6.5.6 The Certification Body will define which of the above interferent tests should be

conducted on each CEM, in consultation with the manufacturer and the test-house.

This decision will be based on an expert understanding of the measurement

methodology adopted by the CEM. There is no CEM performance standard for thesetests; however, the results of the tests will be reported on the MCERTS certificate.

(iv) Detection limit

6.5.7 The detection limit of the CEM shall be measured by determining the instrumental

noise, using a flow of clean air and measuring the instrument’s response to this. The

procedure is then the same as that for gas monitoring CEMs, as described in

paragraphs 6.3.10–6.3.12.

6.6 Specific requirements for CEMs monitoring temperature, pressure and flow

velocity

6.6.1 Monitors measuring temperature (T ), pressure ( P ) or flow velocity ( F ) will be

referred to generically in this section as TPF monitors.

6.6.2 For each TPF monitor, the test-house shall agree with the Certification Body a

maximum and minimum of the determinand scale, where the minimum will not

usually be zero.

6.6.3 Flow monitoring CEMs will generally be tested in a duct that conforms to the

requirements of international standard ISO 10780. Some flow CEMs may require

special testing techniques, which will be agreed between the Certification Body, the

manufacturer and the testing organisation.

(i) Response time

6.6.4 The tests outlined in paragraphs 6.3.1 and 6.3.2 for gaseous CEMs also apply in

general to TPF monitors. This test is performed by increasing the parameter value

from near its minimum value up to a value of 90% of the certification range.

(ii) Accuracy

6.6.5 The instrument shall be calibrated according to the manufacturer’s instructions. The

CEM’s accuracy shall be evaluated relative to a reference instrument (reference

Pitot tube(s) for flow monitors, traceability to ITS-90 for temperature monitors)

whose own calibration is traceable, where possible, to national standards.

(iii) Linearity

6.6.6 The linearity of the response of the TPF monitor shall be tested over 10% to 90% of

the certification range, using at least five determinand values approximately equally

spaced across this range. The maximum difference between any measured point and

the linear regression fit to all the points will be taken as the deviation from linearity.

(iv) Detection limit6.6.7 The detection limit of TPF monitors shall be determined in a similar fashion to that




for gaseous CEMs, outlined in paragraphs 6.3.10–6.3.12.

NOTE: The test-house may use a determinand value near the agreed minimum of the certification range,

subject to confirmation by the Certification Body.

7. Field test requirements

7.1 General requirements for all CEMs

(i) Provisions for field tests

7.1.1 The field test requires the provision of a complete CEM and a data recording

system. The test-house shall ensure that the CEM is installed and set up correctly.

NOTE: The CEM will normally be set up by the manufacturer, under the supervision of the test-house.

7.1.2 Two identical CEMs shall be tested where the manufacturer requires the MCERTS-

certified CEM to be accepted by the UBA for inclusion on the German Federal

Register of approved equipment.

7.1.3 The field test is a performance evaluation on an industrial facility appropriate to the

CEM’s area of application.

7.1.4 The field test shall be at least of three months duration and shall be expected to be

carried out over a continuous period. Only in exceptional cases, which must be fully

justified (for example, in the case of operation-related interruptions or process

breakdown), will it be possible to count shorter testing periods towards the three-

month period.

7.1.5 During the field test, the performance characteristics of the CEM shall bedetermined under representative operational conditions. This means that the tests

shall be performed when the processes are operating normally.

NOTE: The main performance characteristics determined during the field test include field repeatability, drift

behaviour, maintenance interval and reading accuracy.

(ii) Accuracy

7.1.6 The accuracy of a CEM is determined under field conditions by comparing the

CEM’s responses with those of either a specified SRM or a suitable CEM that has

been previously certified under the MCERTS scheme. The SRMs allowed for each

determinand within MCERTS are given in Appendix 3. If a gas monitoring CEM is

being used for the reference testing, then both the test CEM and the reference CEMshall be calibrated with the same calibration gases, which must be traceable to

national standards.

NOTE: This provision does not apply to CEMs monitoring TOC.

7.1.7 One of two statistical tests shall be performed in order to determine accuracy. These

are related to the (i) analysis function and (ii) integral performance. The analysis

function shall ordinarily be used when the measurements span at least 50% of the

certification range, while the test for integral performance shall ordinarily be used

when the measurements span less than 50% of the certification range.

7.1.8 For indicative particulate monitors, the accuracy test will be a test of the continuousoutput only. Four output readings across the range will be reported. For other CEMs,




two different test methods will be used, depending on the CEM that is to be

evaluated. These will involve either defining an analysis function or determining the

integral performance of the CEM. Integral performance is specified in the relevant

ISO standards (with the exception of the ISO standard relating to the measurement

of particulates).

7.1.9 The analysis function shall be determined in all cases where the manufacturer

requires the MCERTS-certified CEM to be accepted by the UBA for inclusion on

the German Federal Register of approved equipment.

a) Analysis function

7.1.10 The analysis function (or curve), as specified in ISO 10155, relates each

measurement of the actual stack or flue gas concentration obtained by the CEM to a

known concentration of the determinand. This known concentration value is derived

from measurements carried out simultaneously using a specified, appropriately co-

located, SRM.

NOTE: ISO 10155 uses the term “calibration function” instead of “analysis function”. This use of the term

“calibration function” conflicts with other ISO standards (for example, ISO 6879) and VDI. Within

MCERTS, the term “analysis function” is used to avoid such inconsistencies.

7.1.11 The analysis function is calculated from a number of simultaneous paired

determinations of the determinand concentration obtained using the CEM and the

SRM. At least 20 measurement points are required across a significant portion of the

certification range of the CEM, and a linear regression calculation is performed

according to the requirements of ISO 10155.

b) Integral performance

7.1.12 The integral performance ( I F) is derived from approximately 20 paired

measurements of the stack gas conditions using the CEM and a collocated SRM, but

generally only a limited portion of the certification range is covered (for practical

reasons). The sampling period of the CEM is chosen to be long enough for a value

for the SRM output to be determined over the same period. The integral

performance is then calculated using equations (1) and (2).

(iii) Field repeatability

7.1.13 This test is required for all particulate monitoring CEMs and for gaseous monitoringCEMs where the manufacturer requires the MCERTS-certified CEM to be accepted

by the UBA for inclusion on the German Federal Register of approved equipment.

7.1.14 The field repeatability quotient ( RD) is determined by means of two identical CEMs

operated side by side. The quotient is determined using equation (7):

D

DU

B R = (7)




where

RD = reproducibility quotient;

U D = expanded measurement uncertainty obtained from paired measurements;

B = readings from the reference tests.

U D is calculated using equation (8):

2

D0.95;1

D

S t U

n−= (8)

where

t f ; 0.95 = Student factor for a statistical certainty of 95% and degree of freedom f = n

(when n > 200, t = 1.96);

n = number of paired tests;

S D = standard deviation derived from measurements performed simultaneously

with two measuring systems of identical design at the same point of

measurement.

S D is calculated using equation (9), which is the standard deviation of paired

samples:

1

)(1

2

21

D−

−

= ∑ =

n

x x

S

n

i ii

(9)

where

x1i, x2i = ith measurement signal from the first or second measuring system.

(iv) Time-dependent zero and span drift

7.1.15 The test-house shall assess the CEM’s zero and span drifts over the field test period.

The zero and span values of each CEM will be assessed weekly and the average drift

per day, week or month will be calculated from these.

7.1.16 In addition, if the CEM is equipped with an automatic calibration and readjustment

facility, then the test-house shall check the data before and after automatic

calibrations to determine the shift caused by the application of the internal

correction. This correction should not be greater than the allowed zero and span

drift. The automatic calibrations should occur within the maintenance interval.

(v) Instrument availability and maintenance interval

7.1.17 The overall availability of the CEM and the maintenance interval (as defined in ISOstandards) are recorded during the field test period. The CEM’s availability is




defined as the fraction of the total time for which usable measuring data are

available. The maintenance interval is defined as the time in the operating

environment over which the instrument’s zero and span drifts remain within the

limits specified in this document. The maintenance interval will be recorded for the

CEM under test, and the results reported on the test certificate. This will provide an

estimate of the level of maintenance required operationally. NOTE: The automatic correction for zero and span drift is ordinarily switched on during this test.

7.1.18 Where a CEM cannot be tested on-line for zero and span drifts, the test-house shall

use an alternative procedure for measuring the maintenance interval. The

alternatives will be agreed between the Certification Body and the manufacturer.

7.1.19 The test-house shall determine the availability of the CEM by recording when the

field test begins and ends, as well as all interruptions to the test that result in the

CEM being unavailable. Such interruptions include malfunctions, servicing work

and automatic adjustments. The results must be summarised in a table using theformat in Table 4, and the availability shall be calculated using equation (10).

−=

G

AG100t

t t V (10)

where

V = availability;

t G = total operating time;

t A = total outage time.

Table 4 Summary of availability test results

Time CEM

Total operating time min

Outage time

device internal setting times

device malfunction and repairs

servicing, adjustment

min

min

min

Availability 95%

(vi) Relative humidity

7.1.20 The test-house shall note any visible effects of relative humidity. If it is to be

expected that changes in relative air humidity will influence the measurement

signals, then the test-house must describe this influence.




8. Status of this document

8.1 The MCERTS test procedures and general requirements in this document may be

subject to review and amendment following publication. The latest version of the

document, together with the performance standards for CEMs and guidance on thescheme, is available on the Agency’s website at:

www.environment-agency.gov.uk/mcerts/

8.2 If you have any questions regarding the certification process, or would like to offer

testing services under MCERTS, please contact the Certification Body at the address

given in the foreword.




Appendix 1: Required format for reports on performance evaluation of

CEMs

Table A1 Format for test reports

Report format for MCERTS performance evaluations of CEMs

Name of Test Organisation Comments

Report type:

CEM tested:

Type of instrument:

Manufacturer:

Test period, from to

Date of report:

Report number:

Scope of report:

Contents

1 Synopsis with proposed scope of certification

1.1 Summary of test results •

The report will include a brief summary of the performance of the CEM, stating the capabilities of the CEM with respect to the

certification ranges

1.2 Suggested scope certification The report shall include a proposed scope of certification for the

Certification Body’s consideration. The following information shall be

included:

• Specific CEM identity

• Measurement component(s)

• Equipment manufacturer together with full address

• Field of application

• Measuring range for suitability test

•

Any restrictions. Such limitations shall be recorded if testing

shows that the CEM does not cover the full scope of possible

application fields

• Previous test reports:

– In cases of supplementary or extended testing, reference must

be made to all preceding test reports

– Test organisation

– Test report number and date of compilation

• Attention must be drawn to any equipment peculiarities.

2 Task definition

2.1 Nature of the tests •

First test or supplementary testing

2.2 Objectives • Specification of which performance specifications were tested

• Bibliography

• Scope of any supplementary tests

3 Description of CEM tested

3.1 Measuring principle • Description of metrological and scientific relationships

3.2 Measuring system scope and set-up • Description of all measuring system components covered in the

scope of testing, if possible including a copy of an illustration or

flow diagram showing the measuring system

• Statement of technical specifications, if appropriate in tabular

form




4 Test programme

4.1 Laboraty test / laboratory inspection • Details must be provided on the test programme, in relation to

the measuring system under test

• In the case of supplementary or extended testing, the additional

scope of testing must be detailed and substantiated

•

Statement of all test steps involved

4.2 Field test • All test steps involved

• Plant type on which the field test examinations were carried out

• CEM’s measuring range to be covered in the test

• Installation conditions and operating conditions for the

measuring system under test

5 Methods of reference measurements

5.1 Method of measurement • The test-house shall state the reference method used. Reference

methods shall be chosen from the most appropriate European,

national or international standards and guides

•

Only validated methods may be used

• If CEMs are used for reference testing, details must be provided

on the analyser type, manufacturer, measuring range selected,

certification and suitability

5.2 Test rig set-up • The report shall include a description of the sampling probe, any

dust filters used for particle separation in the measurement of

gaseous substances, details on the sample gas line (length,

material, size) and on sample gas conditioning system

• The certified test gases used for this purpose must be describedin respect of their specifications

6 Test results

6.1 Citation of MCERTS performance

specifications

For each parameter tested, the report shall state the MCERTS standards

6.2 Equipment The report shall outline the type of equipment used for the test

6.3 Method There shall be a brief description of the test

6.4 Evaluation and assessment

6.5 A presentation of the test results

7 Tabular summary of test results

7.1 Summary table of test results The test results shall be summarised in a table and include the following

information:

•

Statement, as table footer, of the minimum requirements applied

• Reference of the performance specification

• The performance specification in abbreviated form

• The test result

• Compliance with the specification (yes/no)

• A reference to the relevant page of the test report

Appendices

A Appendix A: Raw data from the tests

B Appendix B: Operating instructions Instructions and manuals for the CEM shall be appended to the report




Appendix 2: Interfering compounds

Table A2 Recommended minimum concentrations of interferents

Components Concentration orvolume concentration

Unit

O2 3 and 21 %

H2O 20 %

CO 300 mg m –3

CO2 15 %

CH4 50 mg m –3

N2O 20 mg m –3

N2O (fluidised-bed firing) 100 mg m –3

NO 300 mg m –3

NO2 30 mg m –3

NH3 20 mg m –3

SO2 200 mg m –3

SO2 (coal-fired power stations

without desulphurisation)

1000 mg m –3

HCl 50 mg m –3

HCl (coal-fired power stations) 200 mg m –3



Appendix 3: Standard reference methods

Table A3 Standard reference methods for each determinand. Equivalent national

standards and reference methods may be used as an alternative

Determinand Standard reference method

SO2 ISO 7934 (BS6069 Section 4.1) – Method for the determination of

the mass concentration of sulphur dioxide – hydrogen peroxide/

barium perchlorate/thorium method

BS ISO 11632 – Stationary source emissions – Determination of the

mass concentration of SO2 – Ion chromatography method

USEPA Method 6c, using instruments that meet the MCERTS

performance standards

CO USEPA Method 10, using instruments that meet the MCERTS performance standards

O2 USEPA Method 3a, using instruments that meet the MCERTS

performance standards

NO x BS ISO 11564 – Determination of mass concentration of nitrogen

oxides – Naphthylethylene-diamine photometric method

USEPA Method 7E, using instruments that meet the MCERTS

standards

HCl BSEN 1911-1/2/3 – Manual method for determination of HCl

Particulates ISO 9096 (BS6069 Section 4.3) –

Determination of concentrationand flow rate of particulates material in gas-carrying ducts – manual

gravimetric method

BS EN 13284-1 - Stationary source emissions - Determination of

low range mass concentration of dust - Part 1: Manual gravimetric

method

Flow ISO10780 – Measurement of velocity and volume flow rate of gas

streams in ducts

BS 1042-2.1 – Measurement of fluid flow in closed conduits

Temperature Traceable to the national primary standard

Pressure Traceable to the national primary standard

Water vapour Traceable to the national primary standard

continuous emission monitoring systems

Documents