oSIST prEN ISO 16994:2025

SLOVENSKI STANDARD
01-september-2025
Trdna biogoriva in pirogenski ogljik iz biomase - Določanje vsebnosti žvepla in
klora (ISO/DIS 16994:2025)
Solid biofuels and pyrogenic biocarbon - Determination of sulfur and chlorine content
(ISO/DIS 16994:2025)
Biogene Festbrennstoffe - Bestimmung des Gesamtgehaltes an Schwefel und Chlor
(ISO/DIS 16994:2025)
Biocombustibles solides et biocarbone pyrogène - Détermination de la teneur en soufre
et en chlore (ISO/DIS 16994:2025)
Ta slovenski standard je istoveten z: prEN ISO 16994
ICS:
75.160.40 Biogoriva Biofuels
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
International
Standard
ISO/DIS 16994
ISO/TC 238
Solid biofuels and pyrogenic
Secretariat: SIS
biocarbon — Determination of
Voting begins on:
sulfur and chlorine content
2025-06-19
ICS: 75.160.40; 27.190
Voting terminates on:
2025-09-11
THIS DOCUMENT IS A DRAFT CIRCULATED
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Reference number
ISO/DIS 16994:2025(en)
DRAFT
ISO/DIS 16994:2025(en)
International
Standard
ISO/DIS 16994
ISO/TC 238
Solid biofuels and pyrogenic
Secretariat: SIS
biocarbon — Determination of
Voting begins on:
sulfur and chlorine content
ICS: 75.160.40; 27.190
Voting terminates on:
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2025
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
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Published in Switzerland Reference number
ISO/DIS 16994:2025(en)
ii
ISO/DIS 16994:2025(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 .6
9.3 Sulfur .7
10 Performance characteristics . 7
11 Test report . 7
Annex A (informative) Performance data . 8
Bibliography .10

iii
ISO/DIS 16994:2025(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 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 on the meaning of ISO specific terms and expressions related to conformity assessment,
as well as information about ISO's adherence to the WTO principles in the Technical Barriers to Trade (TBT)
see the following URL: Foreword - Supplementary information.
The committee responsible for this document is ISO/TC 238, Solid biofuels and pyrogenic biocarbon.
This third edition cancels and replaces the second edition (ISO 16994:2016), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— Fluorine and bromine are added to the scope and calculation in 9.2
— Normative references are updated
— Update of the detection methods and more details about the techniques
— The decomposition method with acid digestion and ICP for chlorine is removed

iv
ISO/DIS 16994:2025(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 is to 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 standard.
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 carri
...