EN ISO 16994:2026
(Main)Solid biofuels and pyrogenic biocarbon - Determination of sulfur and chlorine content (ISO 16994:2026)
General Information
- Abstract
This document describes methods for the determination of sulfur and chlorine content in solid biofuels and pyrogenic biocarbon and specifies two methods for decomposition of the fuel and different analytical techniques for the quantification of the elements in the decomposition solutions. The determination of other elements such as fluorine and bromine are also possible with the methods in this document, however performance data for these elements are not provided. The use of automatic equipment is also included in this document, provided that a validation is carried out as specified and that the performance characteristics are similar to those of the method described in this document.
- Status
- Published
- Publication Date
- 16-Jun-2026
- Technical Committee
- CEN/TC 335 - Solid biofuels
- Current Stage
- 6060 - Definitive text made available (DAV) - Publishing
- Start Date
- 17-Jun-2026
- Completion Date
- 17-Jun-2026
Overview
EN ISO 16994:2026 is an international standard developed by CEN and ISO for the determination of sulfur and chlorine content in solid biofuels and pyrogenic biocarbon. Sulfur and chlorine are significant components in biomass fuels, as their presence can lead to corrosion, harmful emissions, and operational challenges in energy production systems. This standard provides harmonized, reliable procedures for laboratories to accurately quantify these elements, supporting compliance, quality assurance, and environmental responsibility in the bioenergy sector.
Key Topics
Test Methods: The standard specifies two main decomposition methods for sample preparation:
- Method A: Combustion in an oxygen-filled closed vessel, suitable for the simultaneous determination of sulfur, chlorine, fluorine, and bromine.
- Method B: Acid digestion in a closed vessel, primarily for sulfur analysis.
Analytical Techniques: Quantification is carried out using validated techniques including:
- Ion chromatography - preferred for detecting sulfate, chloride, fluoride, and bromide.
- Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) - for sulfur determination.
- Other acceptable techniques include titration and photometric methods, provided they meet the standard’s validation requirements.
Automatic Equipment: The use of automatic instruments, such as elemental analyzers or combustion ion chromatography, is permitted if validated with reference materials.
Quality Requirements: The standard emphasizes calibration, blank testing, and the use of certified reference materials to ensure accuracy and repeatability.
Scope Extensions: While the document focuses on sulfur and chlorine, it also notes that with the described methods, fluorine and bromine can be analyzed when applicable.
Applications
EN ISO 16994:2026 is critical for a spectrum of applications within the solid biofuels and biocarbon industries:
- Fuel Quality Assessment: Provides a standardized approach to measure sulfur and chlorine, crucial for ensuring fuels meet technical specifications and legal requirements.
- Environmental Monitoring: Enables accurate reporting and limitation of hazardous emissions from bioenergy operations.
- Compliance and Certification: Assists manufacturers, traders, and energy producers in demonstrating compliance with regional and global standards for solid biofuels.
- Research and Development: Laboratories and institutions can use the methodologies to study fuel characteristics, optimize production, and develop cleaner combustion processes.
- Operational Safety: Helps prevent equipment corrosion and plant failures caused by high sulfur and chlorine contents.
Related Standards
For a comprehensive approach to solid biofuel analysis and quality control, consider these related standards:
- ISO 10304-1: Water quality - determination of dissolved anions by ion chromatography.
- ISO 11885: Water quality - determination of selected elements by ICP-OES.
- ISO 14780: Solid biofuels - sample preparation.
- ISO 16967: Solid biofuels - determination of major elements.
- ISO 18125: Solid biofuels - determination of calorific value.
- ISO 18134-3: Solid biofuels - determination of moisture content.
- CEN Guide 13: Validation of environmental test methods.
Practical Value
Implementing EN ISO 16994:2026 provides several key benefits:
- Standardization: Enhances consistency and comparability of analytical results across laboratories and industries.
- Risk Mitigation: Reduces the risk of corrosion and environmental impact, ensuring safer, more efficient fuel utilization.
- Market Access: Facilitates international trade in solid biofuels by using recognized testing protocols.
- Regulatory Alignment: Supports alignment with legal and environmental regulations for sustainable biofuel production.
By adopting EN ISO 16994:2026, organizations reinforce the quality and environmental compatibility of their solid biofuels and pyrogenic biocarbon products.
Relations
- Effective Date
- 06-Mar-2024
- Effective Date
- 01-Jul-2026
- Effective Date
- 01-Jul-2026
- Effective Date
- 01-Jul-2026
- Effective Date
- 01-Jul-2026
- Effective Date
- 01-Jul-2026
- Effective Date
- 01-Jul-2026
- Referred By
EN 15821:2010 - Multi-firing sauna stoves fired by natural wood logs - Requirements and test methods - Effective Date
- 24-Jun-2026
- Effective Date
- 24-Jun-2026
- Effective Date
- 24-Jun-2026
- Effective Date
- 24-Jun-2026
- Effective Date
- 24-Jun-2026
- Referred By
EN 14961-1:2010 - Solid biofuels - Fuel specifications and classes - Part 1: General requirements - Effective Date
- 24-Jun-2026
- Referred By
EN 15296:2011 - Solid biofuels - Conversion of analytical results from one basis to another - Effective Date
- 24-Jun-2026
- Effective Date
- 24-Jun-2026
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Frequently Asked Questions
EN ISO 16994:2026 is a standard published by the European Committee for Standardization (CEN). Its full title is "Solid biofuels and pyrogenic biocarbon - Determination of sulfur and chlorine content (ISO 16994:2026)". This standard covers: This document describes methods for the determination of sulfur and chlorine content in solid biofuels and pyrogenic biocarbon and specifies two methods for decomposition of the fuel and different analytical techniques for the quantification of the elements in the decomposition solutions. The determination of other elements such as fluorine and bromine are also possible with the methods in this document, however performance data for these elements are not provided. The use of automatic equipment is also included in this document, provided that a validation is carried out as specified and that the performance characteristics are similar to those of the method described in this document.
This document describes methods for the determination of sulfur and chlorine content in solid biofuels and pyrogenic biocarbon and specifies two methods for decomposition of the fuel and different analytical techniques for the quantification of the elements in the decomposition solutions. The determination of other elements such as fluorine and bromine are also possible with the methods in this document, however performance data for these elements are not provided. The use of automatic equipment is also included in this document, provided that a validation is carried out as specified and that the performance characteristics are similar to those of the method described in this document.
EN ISO 16994:2026 is classified under the following ICS (International Classification for Standards) categories: 27.190 - Biological sources and alternative sources of energy; 75.160.40 - Biofuels. The ICS classification helps identify the subject area and facilitates finding related standards.
EN ISO 16994:2026 has the following relationships with other standards: It is inter standard links to EN ISO 16994:2016, CEN Guide 13:2008, ISO 18125:2017, ISO 14780:2017, ISO 18134-3:2023, ISO 10304-1:2007, ISO 16559:2022, EN 15821:2010, EN 14961-2:2011, EN 1860-3:2023, EN 14961-6:2012, EN 14961-3:2011, EN 14961-1:2010, EN 15296:2011, EN 14961-4:2011. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
EN ISO 16994:2026 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
SLOVENSKI STANDARD
01-september-2026
Nadomešča:
SIST EN ISO 16994:2016
Trdna biogoriva in pirogenski bioogljik - Določanje vsebnosti žvepla in klora (ISO
16994:2026)
Solid biofuels and pyrogenic biocarbon - Determination of sulfur and chlorine content
(ISO 16994:2026)
Biogene Festbrennstoffe - Bestimmung des Gesamtgehaltes an Schwefel und Chlor
(ISO 16994:2026)
Biocombustibles solides et biocarbone pyrogène - Détermination de la teneur en soufre
et en chlore (ISO 16994:2026)
Ta slovenski standard je istoveten z: EN ISO 16994:2026
ICS:
75.160.40 Biogoriva Biofuels
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN ISO 16994
EUROPEAN STANDARD
NORME EUROPÉENNE
June 2026
EUROPÄISCHE NORM
ICS 27.190; 75.160.40 Supersedes EN ISO 16994:2016
English Version
Solid biofuels and pyrogenic biocarbon - Determination of
sulfur and chlorine content (ISO 16994:2026)
Biocombustibles solides et biocarbone pyrogène - Biogene Festbrennstoffe - Bestimmung des
Détermination de la teneur en soufre et en chlore (ISO Gesamtgehaltes an Schwefel und Chlor (ISO
16994:2026) 16994:2026)
This European Standard was approved by CEN on 22 May 2026.
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, Türkiye 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
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 16994:2026 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
European foreword
This document (EN ISO 16994:2026) has been prepared by Technical Committee ISO/TC 238 "Solid
Biofuels and Pyrogenic Biocarbon" in collaboration with Technical Committee CEN/TC 335 “Solid
Biofuels and Pyrogenic Biocarbon” the secretariat of which is held by SIS.
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 December 2026, and conflicting national standards
shall be withdrawn at the latest by December 2026.
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 ISO 16994:2016.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
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, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 16994:2026 has been approved by CEN as EN ISO 16994:2026 without any modification.
International
Standard
ISO 16994
Third edition
Solid biofuels and pyrogenic
2026-06
biocarbon — Determination of
sulfur and chlorine content
Biocombustibles solides et biocarbone pyrogène —
Détermination de la teneur en soufre et en chlore
Reference number
ISO 16994:2026(en) © ISO 2026
ISO 16994:2026(en)
© ISO 2026
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 16994:2026(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
4.1 General .1
4.2 Decomposition of the biofuel .2
4.3 Determination of the analytes in the decomposition solution .2
4.4 Automatic equipment .2
5 Reagents . 2
6 Apparatus . 3
6.1 General .3
6.2 Method A .3
6.3 Method B .3
7 Preparation of the test sample. 3
8 Procedure . 4
8.1 Decomposition .4
8.1.1 Method A: Combustion in a closed combustion vessel .4
8.1.2 Method B: Digestion in a closed vessel .5
8.1.3 Blank test .5
8.2 Detection methods .6
8.2.1 Ion chromatography .6
8.2.2 Other detection methods .6
8.3 Calibration of the apparatus .6
8.4 Analyses of the decomposition solutions .6
9 Expression of results . 6
9.1 General .6
9.2 Chlorine, fluorine and bromine .7
9.3 Sulfur .7
10 Performance characteristics . 7
11 Test report . 7
Annex A (informative) Performance data . 8
Bibliography .10
iii
ISO 16994:2026(en)
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
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 238, Solid biofuels and pyrogenic biocarbon, in
collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/TC 335,
Solid Biofuels and Pyrogenic Biocarbon, in accordance with the Agreement on technical cooperation between
ISO and CEN (Vienna Agreement).
This third edition cancels and replaces the second edition (ISO 16994:2016), which has been technically
revised.
The main changes are as follows:
— fluorine and bromine added to the scope and calculation in 9.2;
— normative references updated;
— detection methods updated and additional details about the techniques added;
— decomposition method with acid digestion and ICP analyses for chlorine removed.
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 16994:2026(en)
Introduction
Sulfur and chlorine are present in solid biofuels and pyrogenic biocarbon in varying concentrations. During
the combustion process, they are usually converted to sulfur-oxides and chlorides. The presence of these
elements and their reaction products can contribute significantly to corrosion and to environmentally
harmful emissions.
Chlorine can be present in different organic and inorganic compounds and can exceed or equal the water-
soluble amount that can be determined by ISO 16995.
Fluorine and bromine can also be present in solid biofuels and pyrogenic biocarbon, but in detectable
concentration only in specific types of biomass, like in aquatic biofuels (Br) or as contamination because
of chemical treatment (F). Both elements can be analysed using the same techniques and equipment as for
chlorine and sulfur described in this document.
Combustion in an oxygen atmosphere in a closed combustion vessel is the preferred method to digest biomass
samples for a determination of sulfur, chlorine, fluorine and bromine content. An advantage of the method
is that the digestion can be carried out in connection with the determination of the calorific value according
to ISO 18125. Other analytical techniques may also be used for selected analytes. The determination of the
resultant chlorine, sulfur, bromine and fluorine compounds can be done by different techniques.
Automatic equipment and alternative methods may also be used for selected analytes.
A list with typical sulfur, chlorine and fluorine contents of solid biofuels can be found in ISO 17225-1:2021,
Annex B.
v
International Standard ISO 16994:2026(en)
Solid biofuels and pyrogenic biocarbon — Determination of
sulfur and chlorine content
1 Scope
This document describes methods for the determination of sulfur and chlorine content in solid biofuels
and pyrogenic biocarbon and specifies two methods for decomposition of the fuel and different analytical
techniques for the quantification of the elements in the decomposition solutions. The determination of
other elements such as fluorine and bromine are also possible with the methods in this document, however
performance data for these elements are not provided. The use of automatic equipment is also included in
this document, provided that a validation is carried out as specified and that the performance characteristics
are similar to those of the method described in this document.
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 10304-1, Water quality — Determination of dissolved anions by liquid chromatography of ions — Part 1:
Determination of bromide, chloride, fluoride, nitrate, nitrite, phosphate and sulfate
ISO 14780, Solid biofuels — Sample preparation
ISO 16559, Solid biofuels — Vocabulary
ISO 18125, Solid biofuels — Determination of calorific value
ISO 18134-3, Solid biofuels — Determination of moisture content — Part 3: Moisture in general analysis sample
CEN Guide 13:2008, Validation of environmental test methods
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 16559 apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Principle
4.1 General
The determination of the analytes (sulfur, chlorine, fluorine and bromine) is performed in two steps (4.2 and
4.3) or by using automatic equipment (see 4.4).
ISO 16994:2026(en)
4.2 Decomposition of the biofuel
— Combustion in an oxygen atmosphere in a combustion vessel and absorption of the acidic gas components
in an absorption solution (method A).
— Acid digestion in a closed vessel as described in ISO 16967:2015, Part A (method B).
4.3 Determination of the analytes in the decomposition solution
— Ion chromatography, for the determination of sulfate, chloride, fluoride and bromide, in accordance with
the principles of ISO 10304-1.
— ICP, for the determination of sulfur, in accordance with the principles of ISO 11885
4.4 Automatic equipment
Automatic equipment may be used when the method is validated with biomass reference samples of an
adequate biomass type. If automatic equipment is used, sulfur, chlorine and fluorine compounds may be
detected as gaseous components (e.g. by infrared methods). Examples for automatic analysers include
elemental analysers, AOX-analysers, combustion ion chromatography (see EN 17813) and sulfur-analysers.
If automatic equipment or X-ray fluorescence (see ISO/TS 16996) is used, the method shall be validated for
the respective main origin-based biomass group (see ISO 17225-1:2021, Table 1: woody biomass, herbaceous
biomass, fruit biomas
...