SIST EN 14778:2011

Solid biofuels - Sampling

This European Standard describes methods for preparing sampling plans and certificates and taking samples of solid biofuels, for example, from the place where the raw materials grow, from production plant, from deliveries e.g. lorry loads, or from stock. It includes both manual and mechanical methods, and is applicable to solid biofuels that are either:
-   fine (particle size up to about 10 mm) and regularly-shaped particulate materials 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 straw;
-   baled materials for example: baled straw or grass;
-   large pieces (particles sizes above 200 mm) which are either picked manually or automatically;
-   vegetable waste, fibrous waste from virgin pulp production and from production of paper from pulp that has been dewatered;
-    round wood.
It may be possible to use this standard on other solid biofuels. The methods described in this European Standard may be used, for example, when the samples are to be tested for moisture content, ash content, calorific value, bulk density, durability, particle size distribution, ash melting behaviour and chemical composition. The methods are not intended for obtaining the very large samples required for the testing of bridging properties.

Feste Biobrennstoffe - Probenahme

Diese Europäische Norm legt Verfahren zur Erstellung von Probenahmeplänen und  zertifikaten sowie zur Probenahme von festen Biobrennstoffen, z. B. vom Ort des Vorkommens der Rohstoffe, aus einer Produktionsanlage, aus Lieferungen, z. B. aus LKW Ladungen, oder aus einem Lager fest. Sie umfasst sowohl manuelle als auch mechanische Verfahren und gilt für feste Biobrennstoffe, die eines der folgenden Merkmale aufweisen:
-   feine (mit einer Partikelgröße bis etwa 10 mm) und regelmäßig geformte aus Partikeln bestehende Materialien, von denen mit einer Probenahmeschaufel oder einem Rohr Proben entnommen werden können, z. B.: Sägespäne, Olivensteine und Holzpellets;
-   grobe oder unregelmäßig geformte aus Partikeln bestehende Materialien mit einer Partikelgröße bis etwa 200 mm, von denen mit einer Gabel oder einer Schaufel Proben entnommen werden können, z. B.: Holzhackschnitzel und Nussschalen, Waldrestholz Hackschnitzel und Stroh;
-   Materialien in Ballenform, z. B.: Stroh  oder Grasballen;
-   große Stücke (Partikelgröße über 200 mm), die entweder mit der Hand oder automatisch entnommen werden;
-   pflanzliche Abfälle, faserige Abfälle aus der Herstellung von natürlichem Zellstoff und aus der Herstellung von Papier aus Zellstoff, die entwässert wurden;
-   Rundholz.
Möglicherweise kann diese Norm auch auf andere feste Biobrennstoffe angewendet werden. Die in dieser Europäischen Norm festgelegten Verfahren dürfen z. B. angewendet werden, wenn Proben im Hinblick auf Wasser  und Aschegehalt, Energiegehalt, Schüttdichte, Festigkeit, Partikelgrößenverteilung, Ascheschmelz-verhalten und chemische Zusammensetzung zu prüfen sind. Die Verfahren sind nicht für das Herstellen der für die Prüfung der Neigung von Brückenbildung erforderlichen sehr großen Proben vorgesehen.

Biocombustibles solides - Echantillonnage

La présente Norme européenne décrit les méthodes de préparation des plans et certificats d'échantillonnage,
ainsi que les méthodes de prélèvement d'échantillons des biocombustibles solides, par exemple, depuis
l'endroit où sont cultivées les matières premières, depuis l’usine de production, depuis les livraisons (par
exemple les camions) ou depuis l'amoncellement. Elle inclut des méthodes à la fois manuelles et mécaniques
et elle s'applique aux biocombustibles solides pouvant être :
- des matériaux fins (dont la taille maximale des particules est d’environ 10 mm) et dont la forme des
particules est régulière et qui peuvent être prélevés à l'aide d'une pelle d’échantillonnage ou d'un tube,
par exemple : la sciure, les noyaux d'olives et les pastilles de bois ;
- des matériaux grossiers (dont la taille maximale des particules est d’environ 200 mm) ou dont la forme
des particules est irrégulière et qui peuvent être prélevés à l'aide d'une fourche ou d'une pelle, par
exemple : les copeaux de bois et les coquilles de noix, les rémanents forestiers et la paille ;
- des matériaux en balle, par exemple : les balles de paille ou d'herbe ;
- de grands morceaux (dont la taille des particules dépasse les 200 mm) ramassés manuellement ou
automatiquement ;
- des déchets végétaux, des déchets fibreux venant de la production de la pâte vierge et de la production
de papier à partir de pâte ayant été déshydratée ;
- du bois rond.
Il est possible d'utiliser la présente norme pour d'autres biocombustibles solides. Les méthodes décrites dans
la présente Norme européenne peuvent être utilisées, par exemple, lorsque les échantillons doivent être
soumis à essai afin de déterminer leur taux d’humidité, leur teneur en cendres, leur pouvoir calorifique, leur
masse volumique, leur durabilité, leur distribution granulométrique, leur fusibilité de cendres et leur
composition chimique. Ces méthodes ne visent pas à s’appliquer aux très grands échantillons utilisés pour
évaluer les propriétés de pontage.

Trdna biogoriva - Vzorčenje

Ta evropski standard določa metode za jemanje vzorcev trdnih biogoriv, na primer iz kraja, kjer rastejo surovine, iz proizvodnega obrata, iz pošiljk in iz zalog. Vključuje ročne in mehanske metode ter velja za trdna biogoriva, ki so lahko:
- drobni delci pravilnih oblik z velikostjo do približno 10 mm, ki se lahko vzorčijo z zajemalko ali cevjo, na primer: žagovina, olivne koščice in lesni peleti;
- grobi delci ali delci nepravilnih oblik z velikostjo do približno 200 mm, ki se lahko vzorčijo z vilami ali lopato, na primer: lesni sekanci in lupine oreškov, sekanci gozdnih ostankov in nevezana slama;
- balirani materiali, ki zahtevajo uporabo posebnega orodja za vzorčenje, če se bale pri tem ne razdirajo, na primer: balirana slama ali trava;
- večji kosi (z velikostjo nad 200 mm), ki se pobirajo ročno:
- vlaknasti in rastlinski odpadki, posušeni v tračni stiskalnici.
Metode, opisane v tem standardu, se lahko na primer uporabljajo pri preskusu vzorcev za volumensko gostoto, trajnost, porazdelitev velikosti delcev, vsebnost vlage, vsebnost pepela, karakterizacijo tališča pepela, kalorično vrednost, kemično sestavo in nečistoče. Metode niso primerne za uporabo pri zelo velikih vzorcih, potrebnih za preskušanje premostitvenih lastnosti.

General Information

• Status: Withdrawn
• Public Enquiry End Date: 09-Feb-2011
• Publication Date: 08-Aug-2011
• Withdrawal Date: 30-May-2017
• ICS: 75.160.40 - Biofuels
• Technical Committee: AGO - Refuse derived fuel
• Current Stage: 9900 - Withdrawal (Adopted Project)
• Start Date: 25-May-2017
• Due Date: 17-Jun-2017
• Completion Date: 31-May-2017
• Mandate: M/298 - Mandate to CEN for standardisation in the field of solid biofuels
• Ref Project: EN 14778:2011 - Solid biofuels - Sampling

Relations

• Replaces: SIST-TS CEN/TS 14778-1:2006 - Solid biofuels - Sampling - Part 1: Methods for sampling
• Effective Date: 01-Sep-2011
• Replaces: SIST-TS CEN/TS 14779:2005 - Solid biofuels - Sampling - Methods for preparing sampling plans and sampling certificates
• Effective Date: 01-Sep-2011
• Replaces: SIST-TS CEN/TS 14778-2:2005 - Solid biofuels - Sampling - Part 2: Methods for sampling particulate material transported in lorries
• Effective Date: 01-Sep-2011
• Replaced By: SIST EN ISO 18135:2017 - Solid Biofuels - Sampling (ISO 18135:2017)
• Effective Date: 01-Jul-2017

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Feste Biobrennstoffe - ProbenahmeBiocombustibles solides - EchantillonnageSolid biofuels - Sampling75.160.10Trda gorivaSolid fuelsICS:Ta slovenski standard je istoveten z:EN 14778:2011SIST EN 14778:2011en,fr,de01-september-2011SIST EN 14778:2011SLOVENSKI
STANDARDSIST-TS CEN/TS 14779:2005SIST-TS CEN/TS 14778-2:2005SIST-TS CEN/TS 14778-1:20061DGRPHãþD

EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 14778
June 2011 ICS 75.160.10 Supersedes CEN/TS 14778-1:2005, CEN/TS 14778-2:2005, CEN/TS 14779:2005English Version
Solid biofuels - Sampling
Biocombustibles - Echantillonnage
Feste Biobrennstoffe - Probenahme This European Standard was approved by CEN on 5 May 2011.
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, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre:
Avenue Marnix 17,
B-1000 Brussels © 2011 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 14778:2011: ESIST EN 14778:2011

Model Sampling Plan and Sampling Certificate . 32Annex B (informative)
Sampling from large stockpiles . 35B.1Initial assessment of the stockpile . 35B.2Taking samples . 35B.3Marking, packaging and dispatch of samples . 35SIST EN 14778:2011

Bulk densities of biofuels . 36Annex D (informative)
Empirical values for PL, VI and VPT . 37D.1Introduction . 37D.2Large shipment of wood pellets from different sources . 37Annex E (informative)
Guidelines for the number of increments to be taken . 41E.1General . 41E.2Estimation of the number of increments from empirical values . 41E.3Examples for determining VPT, VI, NSL and nmin . 46Annex F (informative)
Quality parameters for various solid biofuels in BioNorm projects and large shipments of wood pellets . 50F.1General . 50F.2Products investigated as part of the BioNorm projects . 50F.3Summary of results from BioNorm projects . 51F.4Large shipments . 57Bibliography . 63 SIST EN 14778:2011

This European Standard can be used with regard to production, trading, controlling and analysis of solid biofuels in general. It is also useful for buyers of solid biofuels, regulators, controllers and laboratories. This standard creates new working methods and practices for a broad fuel source, while for coal there are many years of experience for a single fuel source. This standard is based on the coal sampling methods, however due to the limited experience of biomass sampling, it is recognized that this standard will change in future versions when more experience is gained. What today is utilized as solid biofuels may change in the future. SIST EN 14778:2011

round wood. It may be possible to use this standard on other solid biofuels. The methods described in this European Standard may be used, for example, when the samples are to be tested for moisture content, ash content, calorific value, bulk density, durability, particle size distribution, ash melting behaviour and chemical composition. The methods are not intended for obtaining 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. EN 14588:2010, Solid biofuels — Terminology, definitions and descriptions EN 14780, Solid biofuels — Sample preparation 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 14588:2010 and the following apply. 3.1
bias systematic error that leads to the average value of a series of results being persistently higher or persistently lower than those that are obtained using a reference sampling method 3.2 combined sample sample consisting of all the increments taken from a lot or sub-lot NOTE The increments may be reduced by division before being added to the combined sample. SIST EN 14778:2011

part of a lot for which a test result is required 3.15 sub-sample portion of a sample SIST EN 14778:2011

is the difference between individual pair members mlot is mass of the lot or sub-lot, tonnes n is number of increments per (sub)-lot nmin is minimum number of increments per (sub)-lot nP is the number of pairs (for estimating VPT) nmp
is the maximum practicable number of increments per sub-lot
N L, N SL
is the number of lots/sub-lots PL is the overall precision for the sampling, sample preparation and testing for the whole biofuel lot at 95 % confidence level PSL
is similar to PL but then for the sub-lot s
is the sample estimate of the population standard deviation VSPT is the total variance of the results for replicate samples Volincrement
is volume of an increment, litre Volmin is minimum volume of increment, litre
VI is the primary increment variance VPT
is the preparation and testing variance
W
is width of a sampling tool, mm xi
is the value of the analysed parameter 5 Principle The main principle of correct sampling is to obtain a representative sample (samples) from the whole lot concerned. Every particle in the lot or sub-lot to be represented by the sample should have an equal probability of being included in the sample. In order to do so a sampling plan is needed. Figure 1 shows the actions needed for the development of a sampling plan. When sampling is to be carried out according to the same plan repeatedly or continuously (e.g. daily), a full sampling plan shall be prepared according to 6.2 (it is necessary to do this only once). A brief sampling plan shall be prepared for routine use according to 6.3 SIST EN 14778:2011

NOTE The numbers in Figure 1 refer to the clauses in this document. Figure 1 — Procedure for sampling 6 Establishing a sampling scheme (sampling plan)
6.1 Principle The sampler shall prepare a full sampling plan either by copying the forms presented in Annex A or by preparing his own forms or documents containing the appropriate items selected from those shown in Annex A. Each sampling plan shall be given a unique reference number or a code/name. 6.2 Full sampling plan A Model Sampling Plan is presented in Annex A as forms that are to be completed by the sampler. Once completed these forms become sampling certificates. SIST EN 14778:2011

Also consider including the following items:  the name of the sampler;  the mass or volume of the sub-lot or the lot;  the identity of the carrier (transport company);  storage information of the lot (like weather conditions, storage inside or outside)  sampling technique, e.g. shovelling, cross stream cutter, hammer sampler, probe, stopped belt, etc.  any other details that change from sample to sample. 6.4 Division of lots
The lot may be sampled as a whole, resulting in one sample, or divided into a number of sub-lots resulting in a possible sample from each. In case of manual sampling a lot may be sampled as a whole only when it has a maximum of 2 500 tonnes or as a series of sub-lots each to a maximum of 2 500 tonnes e.g. fuel dispatched or delivered over a period of time, a ship load, a train load, a wagon load, or fuel produced during a certain period, e.g. a shift. Such division into a number of sub-lots can be necessary to:
a) achieve the required precision (calculated by the procedure in 8.2), b) maintain the integrity of the sample, e.g. avoiding bias that can result from the loss of moisture due to standing or changing of calorific value caused by biological activity, c) create convenience when sampling lots over a long period, e.g. on a shift basis, d) keep sample masses manageable, taking into account the maximum lifting capacity, e) distinguish different components of a mixture of fuels, e.g. different biofuel types within one lot. EXAMPLE Consider a power station that receives 140 lorry-loads of wood chips a month totalling 3 500 tonnes. In this example 4 sub-lots can be created where a sub-lot could be the quantity of fuel delivered in a week (about 35 lorry-loads).
NOTE In case of mechanical sampling e.g. from large shipments, the recommended maximum (sub) lot size should be decided by the parties involved. SIST EN 14778:2011

8 Number of increments
8.1 General
In all methods of sampling, sampling preparation and analysis, errors are incurred and the experimental results obtained from such methods for any given parameter deviate from the true value of that parameter. As the true value cannot be known exactly, it is not possible to assess the accuracy of the experimental results, i.e. the closeness with which they agree with the true value. However, it is possible to make an estimate of the precision of the experimental results, i.e. the closeness with which the results of a series of experiments made on the same fuel agree among themselves. It is possible to design a sampling scheme that, in principle, can achieve a desired level of precision with a material determined lower limit. Precision is the closeness of agreement between the results obtained by applying the experimental procedure several times under prescribed conditions, and is a characteristic of the sampling scheme used and the variability of the biofuel being sampled. The smaller the random errors of the scheme, the more precise the scheme is. A commonly accepted index of precision is two times the sample estimate of the population standard deviation, and this index of precision is used throughout this European Standard. If a large number of replicate samples are taken from a sub-lot of biofuel, prepared and analysed separately, the precision of a single observation, P, is given by Equation (1): SPTVsP22==
(1) where s
is the sample estimate of the population standard deviation; VSPT is the total variance of the results for replicate samples. Here VSPT is given by Equation (2): SLPTSLISPTNVnNVV+⋅= (2) Therefore the final overall precision, PL, for the total quantity of biofuel: SLPTSLILNVnNVP+=2 (3) where PL
is the overall precision for the sampling, sample preparation and testing for the whole biofuel lot at 95 % confidence level SIST EN 14778:2011

is the primary increment variance; n
is the number of increments per (sub)-lot; NSL
is the number of sub-lots in the lot; VPT
is the sample preparation and testing variance. NOTE In the case that a total quantity of biofuel is divided into sub-lots, all sub-lots must be sampled. The number of sub-lots can be 1. 8.2 Primary increment variance (VI) The primary increment variance, VI, depends upon the type and nominal top size of the fuel, the degree of pre-treatment and mixing, the absolute value of the parameter to be determined and the mass of increment taken. In general the increment variance (VI) is different for the different parameters (in the same material) in practice. The calculation of the minimum number of increments should be based on different numbers on VI, VPT and PL for each of the required parameters and the highest minimum number of increments should be selected (see also 8.5 for calculation of minimum number of increments). The value of the primary increment variance, VI, required for the minimum number of increments using Equation (6) or precision using Equation (3) can be obtained by either: a) Determining it directly on the biofuel to be sampled by taking at least 30 increments spread over an entire lot of the same type of fuel and analysing each increment separately on the required parameters, preferably ash (dry basis) and total moisture.
(4) where xi
is the value of the analysed parameter; See E.3 for an example for the determination of VI. b) Assuming values of VI from similar materials or from previous characterization experience with similar fuel handling and sample preparation. The assumptions could preferably be verified afterwards if possible. c) Assuming values of VI listed in Annex D for the same type of materials. The assumptions could preferably be verified afterwards if possible. 8.3 Preparation and testing variance (VPT) The value of the sample preparation and testing variance, VPT, required for the calculation of the minimum number of increments using Equation (6) or precision using Equation (3) can be obtained by either: a) Determining it directly on the fuel to be sampled by constituting at least 20 sub-samples spread over the entire lot of the same type of fuel. Each sub-sample is divided into two parts (constituting a pair) and prepared so that split portions of each sub-sample are taken at the first division stage. Each portion shall be prepared and tested for the parameters of interest, preferably ash (dry basis) and total moisture. The same analytical methods are applied as are used in routine operations. The difference between the two results shall be calculated for each pair and the preparation and testing variance, VPT, can be calculated as follows: SIST EN 14778:2011

(5) where di
is the difference between individual pair members np
is the number of pairs See E.3 for an example for the determination of VPT. b) Assuming values of VPT from similar materials or from previous characterization experience with similar fuel handling and sample preparation. The assumptions could preferably be verified afterwards if possible. c) Assuming values of VPT listed in Annex D for the same type of materials. The assumptions could preferably be verified afterwards if possible. 8.4 Overall precision (PL) The required overall precision for each relevant parameter on a lot should be agreed upon between parties concerned. In the absence of such an agreement, the values given in Tables D.1 to D.10 may be assumed. By keeping track of the results of the analyses, changes in the composition over time can be identified, which could be an indication to re-evaluate VI and VPT. This can be done using 8.2 and 8.3. 8.5 Calculation of number of increments per (sub)-lot Determine the number of sub-lots required for practical reasons and then estimate the number of increments for a desired overall precision by transposing Equation (6) (rounded up): PTLSLIVPNVn442min−=
(6) where NSL
is the number of sub-lots in the lot, when the lot is not divided NSL=1 nmin
is the (minimum) number of increments per sub-lot, or per lot if the lot is not divided into sub-lots (N=1); if calculated if nmin is less than 10, it shall be set to nmin=10 unless agreed upon otherwise VI
is the primary increment variance PL
is the overall precision for the sampling, sample preparation and testing for the whole biofuel lot at 95 % confidence level VPT
is the preparation and testing variance NOTE 1 Equation (3) is rewritten to yield Equation (6) NOTE 2 Parties can agree on a different minimum number of increments, this can also be below 10. Parties should be aware of the possibility that extracting increments of extreme content will influence the final measured value.
Examples utilizing this equation are given in E.3. A calculated value of nmin of infinity or a negative number indicates that the errors of preparation and testing are such that the required precision cannot be achieved with this number of sub-lots. In such cases, or if nmin SIST EN 14778:2011

a)
Choose a new number of sub-lots corresponding to a convenient sub-lot mass, recalculate nmin from Equation (6) and repeat this process until nmin is a practicable number. b)
Decide on the maximum practicable number of increments per sub-lot, nmp,
and calculate NSL according to Equation (7): 2)(4LmpPTmpISLPnVnVN+=
(7) Adjust NSL upwards if necessary to a convenient number and recalculate nmin. A calculation example is found in E.3.
As described in 8.1 to 8.3, the tables in Annex D show reference or default values for VI and VPT when no other information is available. Tables D.1 to D.10 show empirical values for VI and VPT when no other information is available. It is recommended to measure the VI and Vpt per type, group and/or supplier of biofuel.
The required overall precision on a lot should be agreed between the parties concerned. In the absence of such agreement, the values given in Tables D.1 to D.10 may be assumed. By keeping track of the results of the analyses, changes in the composition over time can be identified, which could be an indication to re-evaluate the measured VI and VPT. 9 Calculation of the size of increment The minimum volume of the increment shall be: Volincr
= 0,5
for
d95 < 10 (8) Volincr
= 0,05 · d95 for d95 ≥ 10
(9) where Volincr
is the minimum volume of the increment, litre; d95
is the nominal top size, mm. The sampler shall estimate and record the appropriate sampling tool. Take care, that samples are large enough for analyses. 10 Combined sample – Calculation of the volume of the combined sample The sampler shall refer to 8.5 for the minimum number of increments nmin and the minimum volume of the individual increments VolIncr according to Clause 9 for the circumstances covered by the sampling plan.
The sampler shall consider what tests are to be done and calculate the required volume (mass) needed for the required determinations (Volreq). In particular, the calculation shall take into account the need in some test methods for duplicate test portions, and for extra material to be available in case dubious results are obtained. The calculated volume of the combined sample shall be of such a size that sufficient material is provided for all the tests to be performed, that is VolCombined Sample > Volreq. Therefore the minimum sample volume should be estimated from the sampling plan. If the calculated volume is too small, the size or the number of increments SIST EN 14778:2011

The sampler shall calculate the volume VolCombined Sample required for the combined sample: incrVolnVol×=minmpleCombinedSa (10) where VolCombined Sample is the volume required for the combined sample, litre; nmin
is the minimum number of increments; Volincr
is the minimum volume of the individual increments, litre. Table A.1 in Annex A can be used to record the results of the calculation. Annex C gives typical bulk densities of biofuels. 11 Sampling equipment 11.1 General The equipment shall enable the sampler to take unbiased increments to provide a representative sample.
The opening of the sampling device shall be at least 2,5 times the nominal top size. The volume of the sampling device shall comply with the minimum required increment volume, Volincr, as described in Clause 9. Sampling tools shall be robust, and be able to withstand physical force, wear and prolonged use without compromising functionality. All moving parts should be accessible to inspection and maintenance. It is recommended that mechanical sampling equipment and manual sampling procedures shall be tested for bias after implementation, and this shall be repeated with a frequency that reflects the consequences of a possible bias. Bias testing of mechanical sampling equipment can be done according to ISO 13909-8, and manual sampling procedures according to the same principles.
The choice of sampling tool shall enable the sampler to extract the biofuel safely. 11.2 Equipment for manual sampling
11.2.1 Sampling box for falling-stream The sampling box shall have a square or rectangular opening at the top. The opening W of the top of the sampling box shall be at least 2,5 times the nominal top size. The dimensions of the top opening of the sampling box shall be large enough so that the box cuts the whole of the stream to be sampled. The height of the sampling box shall be large enough to ensure that the box does not become full during sampling of the increment. The sampling box shall be provided with a handle or some other means of support (for instance mounted on rails) that enables the sampler to pass the box safely through the whole cross section of the falling stream of the biofuel to be sampled. Figure 2 shows an example of a sampling box. SIST EN 14778:2011

Key
1 W is the width of the sampling box
NOTE For biofuel with large particle size, or high material flows, sampling boxes might become too big and heavy for manual sampling and mechanical sampling is recommended.
Figure 2 — Example of a sampling box
11.2.2 Scoops A scoop can be designed as illustrated in Figure 3, complying with the general requirements for equipment design.
Key
1 W width and height of the scoop should be > 2,5 times nominal top size Figure 3 — Example of a scoop SIST EN 14778:2011

Figure 4 — Example of a shovel 11.2.4 Forks When using a fork, see Figure 5, the smaller particles of the material being sampled will fall between the tines of the fork. The sampler shall check that the fork to be used for sampling a material has tines sufficiently close together to minimize the amount of particles falling between them. Any material losses will affect the quality of the sample and may lead to a biased result. SIST EN 14778:2011

Figure 5
— Example of a fork
11.2.5 Grabs Both an open type grab and a closed type grab may be used. Figure 6 contains drawings of examples of a grab.
Figure 6 — Examples of grabs (open and closed type) SIST EN 14778:2011

Key
1 W aperture of the probe shall be > 2,5 times nominal top size Figure 7 — Example of a probe SIST EN 14778:2011

Figure 8 — Example of a pipe (spear) 11.2.8 Frames A sampling frame shall be used if increments are taken manually from a temporarily stopped conveyor. The sampling frame shall consist of two parallel metal plates with a distance between the two side plates of at least 2,5 times the nominal top size of the material to be sampled. The shape of the plates shall fit into the profile of the conveyor belt from which the sample is to be removed. The supports between the plates shall ensure a stable construction. A suitable tool shall be used to extract the material between the plates. Figure 9 is a schematic drawing of a sampling frame placed on a stopped conveyor belt. SIST EN 14778:2011

Figure 9 — Frame 11.2.9 Hooks For sampling baled straw like material without taking apart the entire bale, a hook can be used, see Figure 10. The hook shall be constructed with a barb, so that it can be pushed into the bale and extract some straw when pulled back.
Figure 10 – Hook 11.2.10 Drills (augers) A drill, see Figure 11, can be manually or mechanically driven. The centre should be encapsulated to prevent gaining or losing material that does not belong to the increment.
Figure 11 – A drill
NOTE The radius of the drill is the opening W of this sampling device. SIST EN 14778:2011

11.3.1 Falling-stream sampler A falling stream sampler (cross stream cutter), see Figure 12, can be used for sampling materials that are free falling, for instance at the end of a conveyor belt. The device generally consists of a mechanically driven box, that moves at constant speed across (through) the falling material, with the opening (aperture) of the box at an angle as close to normal to the direction of the falling material as possible. The following design parameters shall be respected: a) The cutter shall extract a complete cross section of the stream. b) The cutter shall have parallel edges, ensuring even width of the cut across the stream. c) The cutter shall move through the stream with constant velocity, avoiding slowing down as the cutter fills up. d) The opening (aperture) of the cutter shall be minimum 2,5 times the nominal top particle size, to minimize the risk of blocking the flow into the cutter. e) The cutter shall not be filled more than two thirds at maximum conveyor load. f) The cutter edges shall be robust and able to withstand the force of the falling material during prolonged use.
Figure 12 — Falling stream sampler 11.3.2 Cross-belt sampler A cross-belt sampler (cutter) can be used for sampling materials from a moving conveyor belt. The equipment shall be designed so that it extracts a full cross cut of the material in the conveyor, it shall not only traverse over the full width of the belt, but it is important that the equipment extracts material all the way to the bottom of the belt. The sides (edges) of the cutter shall be parallel to ensure an even representation of all fractions of the flow. The equipment shall be strong and durable, as it will have to retain the remaining flow of material while passing through the stream. For the same reason, normally no limitations are put on the speed of the cutter. However, it shall not be too high either, as too much material will be pushed off the belt from the leading edges of the cutter. The following design parameters shall be respected: a) Cutter edges (sides) shall be parallel. b) The cutter shall take a complete cross-section of the stream. The cut shall have an equal width across the belt (a “slice” with equal thickness across the belt width).
An example of a cross-belt cutter is shown in Figure 13. The right hand part of the figure illustrates the ideal extracted cut across the belt, with parallel sides.
Key 1 cutter 2 belt supported to maintain curvature Figure 13 — Example of cross-belt sampler NOTE Often cross-belt samplers have difficulties extracting ideal increments, as especially fines are left at the bottom of the belt and material at the leading edges of the cutter, that should ideally be in the increment, is not extracted. In general it is recommended to use falling stream cutters instead. 11.3.3 Mechanical probes The principle of a mechanical probe is similar to a manual probe, see 11.2.6 (manual probes), but driven by pneumatics or a motor. Often mechanical probes are preferred, as it is difficult to manually drive a probe into a compact material. SIST EN 14778:2011

12 Sampling in practice 12.1 General It is difficult to take samples in a way that satisfies the principle of correct sampling, stating that all individual parts of the lot shall have an equal probability of becoming part of the final sample. The chance that this can be achieved when the material is stationary (for example, in a silo or stockpile, or in a lorry or ship) is low. It is easier when the material is moving (for example, on a conveyor belt, or being loaded into or unloaded from transport equipment). Hence sampling from moving materials is to be preferred wherever possible. It is important to regularly ensure that the equipment in use is properly cleaned and maintained. If the equipment show signs of not functioning in accordance with the intended use, action shall be taken to test and repair or replace it.
The integrity of the sampled material shall be ensured, e.g. avoiding loss or gain of moisture, fines etc. All sampling equipment shall be handled according to the described use, and it is important to ensure uniform extractions in repeated use.
The sampler shall always ensure that all extracted material is transferred from the sampling device to a sample container, without loss or gain.
If an increment or combined sample mass (volume) is too large to be handled or transported, the mass shall be reduced according to the methods described in EN 14780. All personnel performing sampling shall be properly instructed or trained in the specific use of the device or method, and preferably understand the consequences of improper use of it and to avoid human influence on sample quality. All rules and legislation with regard to health and safety shall be respected at all times.
12.2 Methods for sampling stationary material 12.2.1 Sampling from small packages (< 50 kg) When sampling a lot consisting of individual packages, a primary increment consists of an entire or partial package. Packages shall be chosen at random from the entire lot, making sure all packages have an equal probability of being selected. The number of selected packages (incr
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