Solid recovered fuels - Methods for the determination of biomass content (ISO 21644:2021)

This International Standard specifies two methods for the determination of the biomass content in solid
recovered fuels: the selective dissolution and the 14C content method. The standard provides the
criteria for choosing the more appropriate method and some examples of application.

Feste Sekundärbrennstoffe - Verfahren zur Bestimmung des Gehaltes an Biomasse (ISO 21644:2021)

Dieses Dokument legt drei Verfahren zur Bestimmung des Biomassegehalts in festen Sekundärbrennstoffen fest: das Verfahren der Bestimmung des 14C-Gehalts, das Verfahren der selektiven Auflösung und das Verfahren der manuellen Sortierung.

Combustibles solides de récupération - Méthode de détermination de la teneur en biomasse (ISO 21644:2021)

Trdna alternativna goriva - Metode za določevanje biomase (ISO 21644:2021)

General Information

Status
Published
Public Enquiry End Date
30-Mar-2020
Publication Date
11-Feb-2021
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
03-Feb-2021
Due Date
10-Apr-2021
Completion Date
12-Feb-2021

RELATIONS

Buy Standard

Standard
SIST EN ISO 21644:2021
English language
53 pages
sale 10% off
Preview
sale 10% off
Preview

e-Library read for
1 day

Standards Content (sample)

SLOVENSKI STANDARD
SIST EN ISO 21644:2021
01-marec-2021
Nadomešča:
SIST EN 15440:2011
SIST EN 15440:2011/AC:2011
Trdna alternativna goriva - Metode za določevanje biomase (ISO 21644:2021)
Solid recovered fuels - Methods for the determination of biomass content (ISO
21644:2021)

Feste Sekundärbrennstoffe - Verfahren zur Bestimmung des Gehaltes an Biomasse (ISO

21644:2021)
Combustibles solides de récupération - Méthode de détermination de la teneur en
biomasse (ISO 21644:2021)
Ta slovenski standard je istoveten z: EN ISO 21644:2021
ICS:
27.190 Biološki viri in drugi Biological sources and
alternativni viri energije alternative sources of energy
75.160.10 Trda goriva Solid fuels
SIST EN ISO 21644:2021 en,fr,de

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

---------------------- Page: 1 ----------------------
SIST EN ISO 21644:2021
---------------------- Page: 2 ----------------------
SIST EN ISO 21644:2021
EN ISO 21644
EUROPEAN STANDARD
NORME EUROPÉENNE
January 2021
EUROPÄISCHE NORM
ICS 75.160.10 Supersedes EN 15440:2011
English Version
Solid recovered fuels - Methods for the determination of
biomass content (ISO 21644:2021)

Combustibles solides de récupération - Méthode de Feste Sekundärbrennstoffe - Verfahren zur

détermination de la teneur en biomasse (ISO Bestimmung des Gehaltes an Biomasse (ISO

21644:2021) 21644:2021)
This European Standard was approved by CEN on 22 November 2020.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this

European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references

concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN

member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by

translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management

Centre has the same status as the official versions.

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

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 21644:2021 E

worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN ISO 21644:2021
EN ISO 21644:2021 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

---------------------- Page: 4 ----------------------
SIST EN ISO 21644:2021
EN ISO 21644:2021 (E)
European foreword

This document (EN ISO 21644:2021) has been prepared by Technical Committee ISO/TC 300 "Solid

recovered materials, including solid recovered fuels" in collaboration with Technical Committee

CEN/TC 343 “Solid Recovered Fuels” the secretariat of which is held by SFS.

This European Standard shall be given the status of a national standard, either by publication of an

identical text or by endorsement, at the latest by July 2021, and conflicting national standards shall be

withdrawn at the latest by July 2021.

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.

This document supersedes EN 15440:2011.

According to the CEN-CENELEC Internal Regulations, the national standards organizations of the

following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,

Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,

Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of

North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the

United Kingdom.
Endorsement notice

The text of ISO 21644:2021 has been approved by CEN as EN ISO 21644:2021 without any modification.

---------------------- Page: 5 ----------------------
SIST EN ISO 21644:2021
---------------------- Page: 6 ----------------------
SIST EN ISO 21644:2021
INTERNATIONAL ISO
STANDARD 21644
First edition
2021-01
Solid recovered fuels — Methods for
the determination of biomass content
Combustibles solides de récupération – Méthode de détermination de
la teneur en biomasse
Reference number
ISO 21644:2021(E)
ISO 2021
---------------------- Page: 7 ----------------------
SIST EN ISO 21644:2021
ISO 21644:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 21644:2021
ISO 21644:2021(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Symbols and abbreviations ....................................................................................................................................................................... 3

5 Principle ........................................................................................................................................................................................................................ 4

6 Determination of biomass content .................................................................................................................................................... 4

6.1 Sampling ....................................................................................................................................................................................................... 4

6.2 Sample preparation ............................................................................................................................................................................ 4

6.3 Applicable methods ............................................................................................................................................................................ 4

7 Expression of results ........................................................................................................................................................................................ 5

8 Performance characteristics .................................................................................................................................................................... 5

9 Test report ................................................................................................................................................................................................................... 6

Annex A (normative) Determination of the biomass content based on the C method ................................7

Annex B (normative) Determination of biomass content using the selective dissolution

method (SDM) ......................................................................................................................................................................................................25

Annex C (normative) Determination of biomass content using the manual sorting method

(Msort) .........................................................................................................................................................................................................................34

Annex D (informative) Limitations of the determination methods ..................................................................................39

Annex E (informative) Performance data .....................................................................................................................................................42

Bibliography .............................................................................................................................................................................................................................45

© ISO 2021 – All rights reserved iii
---------------------- Page: 9 ----------------------
SIST EN ISO 21644:2021
ISO 21644:2021(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to

the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see

www .iso .org/ iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 300, Solid recovered fuels.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2021 – All rights reserved
---------------------- Page: 10 ----------------------
SIST EN ISO 21644:2021
ISO 21644:2021(E)
Introduction

The biomass content of solid recovered fuels is relevant for the evaluation of the impact of energy

production on greenhouse gas emission. Instrumental methods, wet chemical and manual procedures

are available for the calculation of the renewable energy fraction. Instrumental methods are based on

the determination of C content while manual procedures are based on separation of different fractions

by visual inspection. The wet chemical procedure differentiate biomass from non-biomass materials as

function of the acid dissolution behaviour.
The fraction of biomass is expressed:
— by mass;
— by energy content (gross or net calorific value);
— by carbon content.

This document is primarily intended for laboratories, producers, suppliers and purchasers of solid

recovered fuels, but is also useful for the authorities and inspection organizations.

© ISO 2021 – All rights reserved v
---------------------- Page: 11 ----------------------
SIST EN ISO 21644:2021
---------------------- Page: 12 ----------------------
SIST EN ISO 21644:2021
INTERNATIONAL STANDARD ISO 21644:2021(E)
Solid recovered fuels — Methods for the determination of
biomass content
1 Scope

This document specifies three methods for the determination of the biomass content in solid recovered

fuels: the C content method, the selective dissolution and the manual sorting methods.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements 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.

ISO 21637:2020, Solid recovered fuels — Terminology, definitions and descriptions

ISO 21645 , Solid recovered fuels — Methods for sampling
ISO 21646 , Combustibles solides de récupération — Préparation des échantillons
ISO 21654 , Solid recovered fuels — Determination of calorific value
ISO 21656 , Solid recovered fuels — Determination of ash content

ISO 21663, Solid recovered fuels — Methods for the determination of total carbon (C), hydrogen (H),

nitrogen (N) and sulphur (S) by the instrumental method
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 21637:2020 and the

following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
ash content on dry basis

mass of inorganic residue remaining after ignition of a fuel under specified conditions, expressed as

mass fraction in percent of the dry matter in the fuel, also includes removed ash contributors

Note 1 to entry: This is typically expressed as a percentage of the mass of dry matter in the fuel source.

Note 2 to entry: Depending on the combustion efficiency the ash may contain combustibles.

Note 3 to entry: If a complete combustion is realized, ash contains only inorganic, non-combustible components.

[SOURCE: ISO 21637:2020, 3.3]
1) Under preparation. Stage at the time of publication ISO/FDIS 21645.
2) Under preparation. Stage at the time of publication ISO/DIS 21646.
3) Under preparation. Stage at the time of publication ISO/FDIS 21654.
4) Under preparation. Stage at the time of publication ISO/FDIS 21656.
© ISO 2021 – All rights reserved 1
---------------------- Page: 13 ----------------------
SIST EN ISO 21644:2021
ISO 21644:2021(E)
3.2
biogenic

produced in natural processes by living organisms but not fossilized or derived from fossil resources

3.3
biomass

material of biological origin excluding material embedded in geological formations and/or fossilized

[SOURCE: ISO 16559:2014, 4.32, modified — Notes 1 and 2 to entry have been removed.]

3.4
calorific value

quantity of heat produced by the complete combustion, at a constant pressure equal to 1 013,25 mbar,

of a unit volume or mass of gas, the constituents of the combustible mixture being taken at reference

conditions and the products of combustion being brought back to the same conditions

[SOURCE: EN 437: 2018, modified — Second paragraph (the list) has been removed.]
3.5
gross calorific value

calorific value where the water produced by combustion is assumed to be condensed

[SOURCE: ISO 21637:2020, 3.34]
3.6
isotope abundance
fraction of atoms of a particular isotope of an element
3.7
laboratory sample
part of the sample (3.13) sent to or received by the laboratory

Note 1 to entry: When the laboratory sample is further prepared (reduced) by subdividing, mixing, grinding, or

by combinations of these operations, the result is the test sample. When no preparation of the laboratory sample

is required, the laboratory sample is the test sample. A test portion is removed from the test sample for the

performance of the test or for analysis.

Note 2 to entry: The laboratory sample is the final sample from the point of view of sample collection, but it is the

initial sample from the point of view of the laboratory.

Note 3 to entry: Several laboratory samples may be prepared and sent to different laboratories or to the same

laboratory for different purposes. When sent to the same laboratory, the set is generally considered as a single

laboratory sample and is documented as a single sample.
3.8
moisture
water removable under specific conditions
[SOURCE: ISO 21637:2020, 3.46]
3.9
net calorific value at constant volume

calorific value where the water produced by combustion is assumed to be in the vapour state

[SOURCE: ISO 21637:2020, 3.47]
3.10
nominal minimum particle size

aperture size of the sieve used for determining the particle size distribution of solid recovered fuels

through which no more than 5 % by mass of the material passes
2 © ISO 2021 – All rights reserved
---------------------- Page: 14 ----------------------
SIST EN ISO 21644:2021
ISO 21644:2021(E)
3.11
nominal top size

smallest aperture size of the sieve used for determining the particle size distribution of solid recovered

fuels through which at least 95 % by mass of the total material passes through the sieve

[SOURCE: ISO 21637:2020, 3.48]
3.12
percentage modern Carbon
pmC
carbon mass fraction from biogenic origin

Note 1 to entry: The internationally accepted radiocarbon dating reference value is 95 percent of the activity, in

AD 1950, of this NBS oxalic acid SRM4990B.
Note 2 to entry: In 2015, the value of 100 % biogenic carbon was set at 102 pmC.
Note 3 to entry: The biogenic origin is expressed in percentage.
3.13
sample

quantity of material, from a larger amount for which the quality is to be determined

[SOURCE: ISO 21637:2020, 3.63, modified — Notes 1–3 to entry have been removed.]
3.14
sample preparation

actions taken to obtain representative laboratory samples (3.7) or test portions from the original sample

(3.13) as received
[SOURCE: ISO 21637:2020, 3.66]
4 Symbols and abbreviations

For the purposes of this document, the following symbols and abbreviations apply.

C symbol for element carbon
D diameter (mm)
C carbon isotope with an atomic mass of 14 u
LSC Liquid Scintillation Counter or Liquid Scintillation Counting
Msort manual sorting method
RSD relative standard deviation
SDM selective dissolution method
SRF solid recovered fuel
TC total carbon content
u atomic mass unit
w mass fraction expressed as a percentage by mass
w content expressed as a percentage of the energy content
cal
w content expressed as a percentage of the total carbon content
© ISO 2021 – All rights reserved 3
---------------------- Page: 15 ----------------------
SIST EN ISO 21644:2021
ISO 21644:2021(E)

The different references used in this document are indicated by the following indices:

— for air dried (dried at room temperature 20–25 °C for 24 hours)
(ad)
— for as received
(ar)
— for dry
(d)
— for dry and ash free, where appropriate.
(daf)

EXAMPLE w means the fraction of energy content in the non-biomass fraction by calorific value, on

cal,NB()d
dry basis.
5 Principle

The determination of the biomass content is based on selective dissolution, manual sorting or C

measurement of biomass in solid recovered fuel. The choice for the method to be used is described

in Clause 6. The biomass content gives an estimation of the content of the biogenic fraction in solid

recovered fuel.
6 Determination of biomass content
6.1 Sampling

Sampling, transport, storage of the solid recovered fuel and sample preparation in the field shall be

conducted according to ISO 21645 and ISO 21646.
6.2 Sample preparation

Preparation of the test sample for the C or SDM shall be conducted according to ISO 21646. For the

Msort, no sample preparation is performed.

Since SRF is considered as a heterogeneous material, the minimum sample amount to be used for each

test shall be:

— C method: a quantity between 0,4 and 2 g of the material with a nominal top size of 1 mm or

less, depending on the device used for combustion (bomb, combustion tube furnace or elemental

analyser) or the quantity indicated by the constructor in the case of the use of a laboratory scale

combustion apparatus;

— selective dissolution method (SDM): at least 5 g of the material with a nominal top size of 1 mm or less;

— manual sorting method (Msort): at least as big as the minimum sample size according to ISO 21645

(as received), as calculated in ISO 21646.
6.3 Applicable methods
For the determination of biomass content three methods are available:

1) the instrumental C method shall be according to Annex A. This method is based on the

14 14

determination of the ratio of C to the total carbon content; the C is proportional to the biomass

content of the SRF. This method is suitable for samples of all types of fuel and shall be according to

Annex A. A value of 10 % biogenic carbon can be considered as the lower range of application of C

method by liquid scintillation counter (LSC);

2) the selective dissolution method (SDM) shall be according to Annex B. The determination of the

biomass content by the SDM is based on the property of biomass that it can be dissolved in a

sulphuric acid / hydrogen peroxide mixture. This method has limitations that makes it less suitable

4 © ISO 2021 – All rights reserved
---------------------- Page: 16 ----------------------
SIST EN ISO 21644:2021
ISO 21644:2021(E)

if the content of natural and/or synthetic rubber in the SRF is more than 10 %, or if the sum of the

content of hard coal, coke, brown coal, lignite, degradable plastics of fossil origin, non-degradable

plastic of biogenic origin, oil or fat present as a constituent of biomass, wool, viscose, nylon,

polyurethane or other polymers containing molecular amino groups and silicon rubber exceeds

5 %. Additional information about these limitations is found in Annex D. The selective dissolution

method (SDM) is applicable for the biomass percentage content between 10 % and 90 %;

3) the manual sorting method (Msort) shall be according to Annex C. The determination of the

biomass content by the manual sorting method is based on the visual examination of fractions and

their separation on the basis of their nature and origin. The method is suitable for samples with a

particle size >10 mm.
For the limitations of the three methods see Annex D.
7 Expression of results

Depending on the use of the results, three different dimensions are used to express the biomass content:

a) biomass in percent by mass w ;
b) biomass in percent by calorific value w ;
B,cal
c) biomass in percent by carbon content w .
B,TC
The expression of results by C method shall be according to Annex A.
The expression of results by SDS method shall be according to Annex B.
The expression of results by Msort method shall be according to Annex C.
8 Performance characteristics

External data for the calculation of the expanded uncertainty of measurements are presented in

Annex E where results of round robin and validation studies are summarized. These values should be

used in combination with individual laboratory performance characteristics and a desired coverage

factor to get the overall uncertainty.
Practical examples of use of the data from Annex E:
EXAMPLE 1

A laboratory wants to determine the expanded uncertainty of measurement of SDM method (% by mass).

The intra-laboratory reproducibility for the laboratory calculated from internal validations studies and control

charts was determined to be 2,5 % (RSD).
[3]

The round robin results from the QUOVADIS study (Table E.2) give a RSD value of 3,43 % (at 67,79 % level).

2 2
u c,rel = √(2,5 +3,43 ) = 4,24 %
U rel = 2 × u c,rel = 8,48 %

where u c,rel is the combined uncertainty of measurement and U rel is the expanded uncertainty of measurement

using a coverage factor of 2 (~95 % confidence interval).
© ISO 2021 – All rights reserved 5
---------------------- Page: 17 ----------------------
SIST EN ISO 21644:2021
ISO 21644:2021(E)
EXAMPLE 2
A laboratory measures the biomass content by C method – LSC B (% by TC).

The intra-laboratory reproducibility for the laboratory calculated from internal validations studies and control

charts was determined to be 2,4 % (RSD).
[3]

The round robin results from the QUOVADIS study (Table E.6) give a RSD value of 2,5 % (at 55,5 % level).

2 2
u c,rel = √(2,4 +2,5 ) = 3,5 %
U rel = 2 × u c,rel = 7,0 %

where u c,rel is the combined uncertainty of measurement and U rel is the expanded uncertainty of measurement

using a coverage factor of 2 (~ 95 % confidence interval).
9 Test report
The test report shall contain at least the following information:
a) identification of the laboratory performing the test;
b) date of the test;
c) identification of product (sample) tested;
d) sample preparation (e.g. method of size reduction, drying, subdivision);
e) storage conditions;

f) date of receipt of laboratory sample and dates of the test (beginning and end);

g) a reference to this document (ISO 21644:2020) and the method used;

h) in case of C-method, the results of the test including the basis on which they are expressed and

application of the isotope correction;

i) the biomass content expressed as a percentage by mass, calorific value and/or carbon content,

rounded to the nearest 0,1 %;
j) any operation not included in this document, or regarded as optional;
k) any unusual features noted during the test procedure.
6 © ISO 2021 – All rights reserved
---------------------- Page: 18 ----------------------
SIST EN ISO 21644:2021
ISO 21644:2021(E)
Annex A
(normative)
Determination of the biomass content based on the C method
A.1 General

The two proposed methods for C measurement, Proportional Scintillation Method (PSM) or

Accelerated Mass Spectrometry (AMS), require specialised personnel and instrumentation. However,

the preparation step for instrumental analysis can be completed as normal routine laboratory activity.

For the collection from the sample of the C fraction, generally accepted methods for the conversion of

the carbon present in the sample to CO are described.
A.2 Principle

The methods for the determination of the biomass content specified in this annex are based on the

determination of the C content. The amount of biomass carbon in solid recovered fuel is proportional

to this C content.

The carbon present in the sample is converted to CO by combustion. The combustion is carried out

in a way to comply with the requirements of the subsequent measurement of the C content. This

measurement is carried out according to one of the two following methods, Proportional Scintillation

Method (PSM) or Accelerated Mass Spectrometry (AMS). These methods are considered equivalent,

giving the same results within the scope of this document. The results are expressed as the percentage

biomass carbon of the total carbon content. The fraction of biomass content by mass and the fraction of

biomass by energy content are calculated from the carbon content of biomass, using the carbon content

of biomass and the energy content of the biomass fraction that is present in the sample.

A.3 Limitations
For the limitation of this method see Annex D.
A.4 Symbols
For the purposes of this annex, the following symbols apply.
C symbol for element carbon
C carbon isotope with an atomic mass of 14
AMS Accelerator Mass Spectrometry
β beta particle, electron emitted during radioactive decay
Bq Bequerel, disintegrations per second
d on dry base
DPM disintegrations per minute
CPM counts per minute
© ISO 2021 – All rights reserved 7
---------------------- Page: 19 ----------------------
SIST EN ISO 21644:2021
ISO 21644:2021(E)
CV coefficient of variation
GM Geiger Müller
LCV Low calorific value
LLD Lower Limit of Detection
m mass expressed as a percentage by mass
M moisture expressed as a percentage by mass
MOP 3-Methoxy 1-propyl amine
NCV Net Calorific Value
LSC Liquid Scintillation Counter or Liquid Scintillation Counting
REF reference value of 100 % biogenic carbon
pmC percentage
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.