BS EN 14780:2011 pdf free download Solid biofuels — Sample preparation
1 Scope
This European Standard describes methods for reducing combined samples (or increments) to laboratorysamples and laboratory samples to sub-samples and general analysis samples and is applicable to solidbiofuels.
The methods described in this European Standard may be used for sample preparation, for example, whenthe samples are to be tested for calorific value, moisture content, ash content, bulk density, durability, particlesize distribution, ash melting behaviour, chemical composition, and impurities.The methods are not intendedto be applied to the very large samples required for the testing of bridging properties.
Normative references
The following referenced documents are indispensable for the application of this document.For datedreferences,only the edition cited applies. For undated references, the latest edition of the referenceddocument (including any amendments) applies.
EN 14588:2010,Solid biofuels – Terminology, definitions and descriptions
EN 14774-1, Solid biofuels — Determination of moisture content—Oven dry method— Part 1:Total moisture— Reference method
EN 14774-2,Solid biofuels —Determination of moisture content—Oven dry method— Part 2:Total moisture-Simplified procedure
3Terms and definitions
For the purposes of this document, the terms and definitions given in EN 14588:2010 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
general analysis sample
sub-sample of a laboratory sample having a nominal top size of 1 mm or less and used for a number ofchemical and physical analyses
3.3
increment
portion of fuel extracted in a single operation of the sampling device3.4
laboratory sample
combined sample or a sub-sample of a combined sample for use in a laboratory
3.5
lot
defined quantity of fuel for which the quality is to be determined
3.6
moisture analysis sample
sample taken specifically for the purpose of determining total moisture according to EN 1 4774-1 and EN 1 4774-2
3.7
nominal top size
aperture size of the sieve used in CEN, method for determining the particle size distribution of solid fuels,through which at least 95 % by mass of the material passes
3.8
particle size-reduction
reduction of the nominal top size of a sample or sub-sample3.9
sample
quantity of material, representative of a larger quantity for which the quality is to be determined3.10
sample division
division of a sample or sub-sample to a appropriate size. This usually always leads to a mass reduction of asample or sub-sample
3.11
size analysis sample
sample taken specifically for the purpose of determining particle size distribution
3.12
sub-lot
part of a lot for which a test result is required3.13
sub-sample
portion of a sample3.14
test portion
sub-sample either of a laboratory sample or a test sample
3.15
test-sample
laboratory sample after an appropriate preparation made by the laboratory
4 Symbols and abbreviations
Mpis the moisture loss, in percentagemsample,1 is the initial mass of the sample, g
mample,2 is the mass of the sample after pre-drying, g
wis the width and is at least 2,5 times the nominal top size of the material
5Principles of correct sample reduction
The main purpose of sample preparation is that a sample is reduced to one or more test portions that are ingeneral smaller than the original sample. The main principle for sample reduction is that the composition ofthe sample as taken on site shall not be changed during each stage of the sample preparation. Each subsample shall be representative of the original sample. To reach this goal every particle in the sample before sample division shall have an equal probability of being included in the sub-sample following sample division.Two basic methods are used during the sample preparation. These methods are:
Because of the risk of changes in the moisture content (loss of moisture), a sub-sample (moisture analysis sample) shall be separated at the earliest possible stage of the sample preparation procedure. As an alternative, a separate moisture analysis sample may be taken. The sample reduction shall be carried out by a procedure that does not conflict with requirements of EN 1 4774-1 or EN 1 4774-2. For materials that have to be examined for moisture content, care shall be taken to avoid any significant heat build-up and risk of drying.