ISO 23499:2026

International
Standard
ISO 23499
Third edition
Coal — Determination of bulk
2026-02
density of coal as it is handled in
industrial practices
Charbon — Détermination de la masse volumique en vrac du
charbon tel qu'il est traité dans les pratiques industrielles
Reference number
© ISO 2026
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Method 1 . 1
4.1 Principle .1
4.2 Apparatus .2
4.2.1 Measuring boxes .2
4.2.2 Cones and tripod frame .2
4.3 Sampling and preparation .3
4.3.1 Sampling for bulk density of coal up to a 45 mm nominal top size .3
4.3.2 Preparation of sample .3
4.4 Procedure for bulk density of coal up to a 45 mm nominal top size .3
5 Method 2 . 5
5.1 Principle .5
5.2 Sampling and preparation .6
5.3 Apparatus .6
5.4 Procedure .8
6 Expression of results . 9
6.1 Method 1 .9
6.2 Method 2 .9
7 Reporting of results .10
7.1 Precision . . .10
7.2 Repeatability for Method 1 and Method 2 .10
7.3 Reproducibility .10
8 Test report .10
Bibliography .12

iii
Foreword
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in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
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This document was prepared by Technical Committee ISO/TC 27, Coal and Coke, Subcommittee SC 1, Coal
preparation: Terminology and performance.
This third edition cancels and replaces the second edition (ISO 23499:2013), which has been technically
revised.
The main changes are as follows:
— addition of an alternate method using a smaller sized box of 0,028 37 m for bulk density of coal up to
45 mm nominal top size;
— addition of method for determining bulk density of a dry coal powder at minus 63 micrometres nominal
top size.
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
Introduction
This document describes two methods for determining:
a) the bulk density for crushed coal of up to 45 mm nominal top size as that charged into coke ovens;
b) the bulk density for fine dry coal powders typically less than 63 micrometres nominal top size used in
pulverized fuel fired boilers and cement kilns.

v
International Standard ISO 23499:2026(en)
Coal — Determination of bulk density of coal as it is handled
in industrial practices
1 Scope
This document specifies a cone procedure for determining an uncompacted bulk density of crushed coal
up to −45 mm nominal top size, as it is handled in industrial practices. It focuses on the uncompacted
bulk density of coal resulting from flowing the material into a measuring container (box) in the absence
of compacting forces. The determination of the bulk density of coal charged into coke ovens is a typical
example.
This document also provides a method for determining the bulk density of dry powdered coal at
−63 micrometres for boiler or utility application. It does not cover the determination of bulk density of coal
in storage piles.
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 589, Hard coal — Determination of total moisture
ISO 1213-1, Coal and coke — Vocabulary — Part 1: Terms relating to coal preparation
ISO 1213-2, Coal and coke — Vocabulary — Part 2: Terms relating to sampling, testing and analysis
ISO 1953, Coal — Size analysis by sieving
ISO 13909-2, Coal and coke — Mechanical sampling — Part 2: Sampling of coal from moving streams
ISO 13909-4, Coal and coke — Mechanical sampling — Part 4: Preparation of test samples of coal
ISO 18283, Coal and coke — Manual sampling
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 1213-1 and ISO 1213-2 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 Method 1
4.1 Principle
Bulk density for coal up to a nominal 45 mm top size is determined by filling a container (measuring box) of
known mass and volume with coal and determining the increase in mass.

4.2 Apparatus
4.2.1 Measuring boxes
A cubical container of 0,1 m capacity and internal dimensions of 465 mm. see Figure 1 a). The volume of the
box is 0,465 × 0,465 × 0,465 = 0,1 m
For coals greater than 45 mm nominal top size, the internal edge dimension of the measuring box should be
approximately ten times nominal top size
An alternate cubic container of 0,028 73 m capacity and internal dimensions of 305 mm may also be used.
see Figure 1 b). The volume of the box is 0,305 × 0,305 × 0,305 = 0,028 73 m (see Reference [1]).
The boxes shall be constructed of metal of sufficient thickness to ensure the rigidity of the walls and the
base of the container under the conditions of the test (minimum wall thickness of 3 mm is recommended). It
is also recommended that the boxes have a smooth inner surface, using stainless steel in their construction
and be fitted with handles.
The exact volume of the boxes, in cubic metres, shall be determined with a precision of 0,000 1 m (100 ml),
using water of known density.
4.2.2 Cones and tripod frame
4.2.2.1 General
3 3
Cones and tripod frame, for filling the 0,1 m and 0,028 37 m boxes, should conform to Figure 1 a) and b).
See Figure 2 for a reference for the iron shutters (two) to fit the base of the cones.
See Figure 3 for a reference for the three adjustable legs on each tripod.
The dimensions of the cones and tripod frames shall be as follows:
4.2.2.2 0,1 m box
Cone and tripod frame: 610 mm high with an inside diameter at the top of 510 mm and a circular opening
of 203 mm in diameter at the bottom. A slide valve consisting of a slide-plate shutter and its supports shall
be welded to the bottom of the cone in such a manner that the valve can be opened and closed with ease by
removing or inserting the shutter in its supporting slides. The cone shall be supported in a tripod frame
having a circular opening at the top of 460 mm in diameter. This frame shall support the cone so that the
top side of the shutter shall be 718 mm from the inside bottom surface of the box. Dimension from the cone
bottom to the top edge of the box shall be a minimum of 250 mm.
4.2.2.3 0,028 37 m box
Cone and tripod frame: 610 mm high with an inside diameter at the top of 510 mm and a circular opening
of 203 mm in diameter at the bottom. A slide valve consisting of a slide-plate shutter and its supports shall
be welded to the bottom of the cone in such a manner that the valve can be opened and closed with ease by
removing or inserting the shutter in its supporting slides. The cone shall be supported in a tripod frame
having a circular opening at the top of 460 mm in diameter. This frame shall support the cone so that the
top side of the shutter shall be 560 mm from the inside bottom surface of the box. Dimension from the cone
bottom to the top edge of the box shall be a minimum of 250 mm.
4.2.2.4 Levelling bar
A steel strip approximately 760 mm long by 40 mm wide and 5 mm thick.
...