SIST-TS CEN/TS 14780:2005

SLOVENSKI STANDARD
SIST-TS CEN/TS 14780:2005
01-november-2005
Trdna biogoriva – Metode za pripravo vzorcev
Solid biofuels - Methods for sample preparation
Feste Biobrennstoffe - Verfahren zur Probenherstellung
Biocombustibles solides - Méthodes de préparation des échantillons
Ta slovenski standard je istoveten z: CEN/TS 14780:2005
ICS:
75.160.10 Trda goriva Solid fuels
SIST-TS CEN/TS 14780:2005 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TS CEN/TS 14780:2005

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SIST-TS CEN/TS 14780:2005
TECHNICAL SPECIFICATION
CEN/TS 14780
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
August 2005
ICS 75.160.10

English Version
Solid biofuels - Methods for sample preparation
Biocombustilbles solides - Méthodes de préparation des Feste Biobrennstoffe - Verfahren zur Probenherstellung
échantillons
This Technical Specification (CEN/TS) was approved by CEN on 19 March 2005 for provisional application.
The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their
comments, particularly on the question whether the CEN/TS can be converted into a European Standard.
CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available
promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS)
until the final decision about the possible conversion of the CEN/TS into an EN is reached.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 14780:2005: E
worldwide for CEN national Members.

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Contents Page
Foreword .3
Introduction.4
1 Scope .5
2 Normative references .5
3 Terms and definitions.5
4 Symbols and abbreviations.7
5 Principles of correct sample reduction .7
6 Apparatus .7
7 Sample reduction – general principles.10
8 Methods for reducing combined samples.12
9 Method for reducing laboratory samples to sub-samples and general analysis samples.15
10 Storage and labelling of sub-samples.18
Bibliography.19

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Foreword
This Technical Specification (CEN/TS 14780:2005) has been prepared by Technical Committee CEN/TC 335
“Solid biofuels”, the secretariat of which is held by SIS.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to announce this Technical Specification: Austria, Belgium, Cyprus, Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland
and United Kingdom.

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Introduction
Biofuels are a major source of renewable energy. Technical Specifications are needed for production, trade
and use of solid biofuels. For sampling and sample preparation of biofuels the following Technical
Specifications can be used:
CEN/TS 14778-1, Solid biofuels Sampling – Part 1: Methods for sampling
CEN/TS 14778-2, Solid Biofuels Sampling – Part 2: Methods for sampling particulate material transported in
lorries
CEN/TS 14779, Solid biofuels – Sampling – Methods for preparing sampling plans and sampling certificates
CEN/TS 14780, Solid biofuels - Methods for sample preparation
Current practice and the best available knowledge have been used to write these Technical Specifications.
The results of recent sampling experiments may be used to improve the sampling plans.
These Technical Specifications can be used by production and trading of solid biofuels. They are also useful
for buyers of solid biofuels, regulators, controllers and laboratories.
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1 Scope
This Technical Specification describes methods for reducing combined samples to laboratory samples and
laboratory samples to sub-samples and general analysis samples, and is applicable to solid biofuels that are
either:
 fine and regularly-shaped particulate materials, particle sizes up to about 10 mm that can be sampled
using a scoop or pipe, for example: sawdust, olive stones and wood pellets;
 coarse or irregularly-shaped particulate materials, particle sizes up to about 200 mm that can be sampled
using a fork or shovel, for example: wood chips and nut shells, forest residue chips, and loose straw;
 large pieces with nominal top size above 200 mm;
The methods described in this Technical Specification may be used for sample preparation, for example,
when the samples are to be tested for bulk density, durability, particle size distribution, moisture content, ash
content, ash melting behaviour, calorific value, chemical composition, and impurities. The methods are not
intended to be applied to the very large samples required for the testing of bridging properties.
2 Normative references
The following referenced documents are indispensable for the application 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.
CEN/TS 14588, Solid biofuels – Terminology, definitions and descriptions.

CEN/TS 14774-1, Solid biofuels – Methods for determination of moisture content – Oven dry method – Part 1:
Total moisture – Reference method.
CEN/TS 14774-2, Solid biofuels – Methods for determination of moisture content – Oven dry method – Part 2:
Total moisture – Simplified procedure.
CEN/TS 15149 (all parts), Solid biofuels – Methods for the determination of particle size distribution.
3 Terms and definitions
For the purposes of this Technical Specification, the terms and definitions given in CEN/TS 14588 and the
following apply.
3.1
combined sample
sample consisting of all the increments taken from a sub-lot
NOTE The increments may be reduced by division before being added to the combined sample.
3.2
common sample
sample collected for more than one intended use
NOTE Adapted from ISO 13909
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3.3
general analysis sample
sub-sample of a laboratory sample having a nominal top size of 1 mm or less and used for a number of
chemical and physical analyses
3.4
increment
portion of fuel extracted in a single operation of the sampling device
NOTE Adapted from ISO 13909
3.5
laboratory sample
combined sample, or a sub-sample of a combined sample, or an increment, or a sub-sample of an increment
sent to a laboratory
3.6
lot
defined quantity of fuel for which the quality is to be determined
NOTE 1 See also sub-lot.
NOTE 2 Adapted from ISO 13909
3.7
mass-reduction
reduction of the mass of a sample or sub-sample
3.8
moisture analysis sample
sample taken specifically for the purpose of determining total moisture according to EN 14774 part 1 and part
2
3.9
nominal top size
aperture size of the sieve used in the CEN/TS 15149 method for determining the particle size distribution of
solid biofuels through which at least 95 % by mass of the material passes
NOTE Adapted from ISO 13909
3.10
sample
quantity of material, representative of a larger quantity for which the quality is to be determined
3.11
size analysis sample
sample taken specifically for the purpose of determining particle size distribution
3.12
size-reduction
reduction of the nominal top size of a sample or sub-sample
3.13
sub-lot
part of a lot for which a test result is required
NOTE Adapted from ISO 13909
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EXAMPLE Consider a power station that receives 20 lorry-loads of wood chips a day. Every single lorry-load is
tested for moisture content. One lorry-load is selected at random for other tests. In this example, the lot could be the
quantity of fuel delivered in a day (20 lorry-loads) and the sub-lot could be a single lorry-load.
3.14
sub-sample
portion of a sample
3.15
test portion
sub-sample of a laboratory sample consisting of the quantity of material required for a single execution of a
test method
4 Symbols and abbreviations
d nominal top size, mm
m mass of a sample, g
M moisture, %
5 Principles of correct sample reduction
The main purpose of sample preparation is that a sample is reduced to one or more test portions that are in
general smaller than the original sample. The main principle for sample reduction is that the composition of
the sample as taken on site shall not be changed during each stage of the sample preparation. Each sub
sample shall be representative for the original sample. To reach this goal every particle in the sample before
mass-reduction shall have an equal probability of being included in the sub-sample retained after mass-
reduction during a mass-reduction stage. Two basic methods are used during the sample preparation. These
methods are:
 Mass-reduction of the sample by division;
 Particle size-reduction of the sample.
Care is needed to avoid loss of fine particles during milling and other operations.
If a sub-sample is required for the determination of moisture content, then the sample reduction shall be
carried out by a procedure that does not conflict with the requirements of CEN/TS 14774 (determination of
moisture content). It is recommended that, if moisture content of the material (as sampled) is to be determined,
a separate moisture analysis sample is taken (as there is a risk of changing the moisture content by sample
reduction operations).
For materials that have to be examined for moisture content, care must be taken for any significant heat build-
up and risk of drying.
6 Apparatus
6.1 Apparatus for mass-reduction
6.1.1 Riffle boxes
A riffle box shall have at least 16 slots, with adjacent slots directing material into different sub-samples, and
the width of the slots shall be at least 2,5 times the nominal top size of the material to be riffled (see Figure 1).
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Key
1 slot, width is at least the nominal top size of the material
Figure 1 — Example of a riffle box

6.1.2 Rotary sample dividers
A rotary sample divider shall have a feeder device adjusted so that the divider rotates at least 20 times while
the sample is being divided. See Figure 2 for an example of a rotating divider.
The manufacturers manual shall always be followed. The inner dimensions of the equipment where the
sample is fed shall be at least 2,5 times as wide as the nominal top size of the material to be processed.

Key
1 feeder
2 funnel
3 rotating receiver
4 divided sample
Figure 2 — Example of a rotary sample divider
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6.1.3 Shovels and scoops
A shovel or scoop used for manual mass-reduction shall have a flat bottom, edges raised high enough to
prevent particles rolling off, and shall be at least 2,5 times as wide as the nominal top size of the material to be
processed. See Figures 3 and 4 for examples of a scoop and a shovel respectively.


Key
d is the nominal top size
Figure 3 — Example of a scoop

Key
l is the length of the shovel
A - A is the width of the shovel
Figure 4 — Example of a shovel
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6.2 Apparatus for size-reduction
6.2.1 Coarse cutting mill or wood crusher
Coarse cutting mills are used for cutting materials into lengths of about 10 mm to 30 mm (depending on the
biofuel and the analyses to be performed). The equipment shall have a minimum of drying effect either by
heating the materials or blowing air through them. The equipment shall be designed so that it does not lose
dust or contaminate the material with pieces of metal, and shall be easy to clean. A cutting mill with no
screens may be suitable for small quantities.

NOTE to prevent losses of moisture during the grinding process a grinder that is possible to drive at low
speed is preferred.
6.2.2 Cutting mill
Cutting mills are used for reducing the nominal top size of materials used as biofuels from about 10 mm to
30 mm down to about 1 mm or less (depending on the biofuel and the analyses to be performed). The mill
shall be provided with screens of various aperture sizes covering this range, including an appropriate sieve to
control the nominal top size of the material produced. Other apparatus may be used provided that they are
designed so that they do not get blocked with the material that is being processed. Avoid the use of cutting
mills whose cutting faces contain significant quantities of an element that is to be determined in the analysis.
NOTE Cross beater mills can be used without any excessive dusting, when fitted with dust filters (like a filter sock)
between the mill and the receiving container. They are suitable for final grinding of hard, wood type materials after the pre-
grinding with cutting type mills.
6.2.3 Axe
An axe is used for cutting wood logs or coarse material down to maximum 30 mm thickness or suitable size to
be processed in a cutting mill provided with a 30 mm sieve.
6.2.4 Hand saw
A hand saw is used to saw off wood logs or coarse material down to maximum 30 mm thickness or suitable
size to be processed in a cutting mill provided with a 30 mm sieve.
NOTE A chain saw may contaminate the sample by chain oil and should therefore not be used. A saw machine
should not be used for size reduction to avoid the risk of losing moisture in the sample by friction heat.
6.3 Sieves
A wire-mesh sieve with an aperture size of 1,00 mm is required to check the nominal top size of general
analysis samples. A wire-mesh sieve with an aperture size of 0,250 mm will be required if sub-samples with
this as the nominal top size are required.
6.4 Balance
A balance is required that is capable of determining the mass of samples to an accuracy of 0,1 % of the
sample mass, and the mass of sub-samples to an accuracy of 0,1 % of the sub-sample mass.
7 Sample reduction – general principles
For every mass-reduction stage to be carried out it is important that a sufficient mass of material is retained,
otherwise the sub-samples produced may not be representative of the original sample. Table 1 gives the
minimum masses that shall be retained after each mass-reduction stage, depending on the nominal top size
and the bulk density
...