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Title:
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Open-Bio - Opening bio-based markets via standards, labelling and procurement: Deliverable 3.3: Performance characteristics for horizontal bio-based content standard - round robin assessment results
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Author(s):
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Published by:
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Publication date:
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ECN
Environment & Energy Engineering
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5-10-2016
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ECN report number:
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Document type:
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ECN-E--16-052
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ECN publication
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Number of pages:
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Full text:
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45
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Download PDF
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Abstract:
This report presents the results of the round robin assessment that was held in order to test the procedure proposed for determination and validation of total bio-based content. The round robin assessment was initiated in the frameworks of the European Open-Bio project (www.biobasedeconomy.eu)
Determination of total bio-based content is closely related to the determination of total bio-based carbon content. The latter is typically represented as a fraction of 14C to the total carbon content of a product. For the determination of the total bio-based carbon content, CEN/TS 16640 shall be followed. The procedure described in CEN/TS 16640 for the bio-based carbon content de-termination has been proven by the results of a separate round robin assessment that were pre-sented in Deliverable 3.1 of Open-Bio. It was concluded there that the 14C analysis can be done using well known LSC (Liquid Scintillation Counting) or AMS (Accelerated Mass Spectrometry) techniques. No inconsistencies were observed for the results of the measurements when using AMS or LSC techniques.
Total bio-based content is not restricted only to the bio-based carbon content and can involve contribution from bio-based oxygen and/or hydrogen and/or nitrogen. For the determination of total bio-based content of a product, the knowledge of all its constituents that derived from bio-mass, are needed. Total bio-based content is normally expressed as a percentage of the total mass of the product. Typically the bio-based content of a product is claimed by the producer of the product. However, in practice the claimed values can be over- or underestimated. Therefore a separate procedure for the validation of the bio-based content was proposed by pr EN 16785.
For the determination of the total bio-based content, besides the fraction of bio-based carbon content, the knowledge on other possible bio-based elements (oxygen or/and hydrogen or/and nitrogen) is required. For that purpose, rules for allocation of elements (pr EN 16785) have to be applied. Generally, if oxygen or/and hydrogen or/and nitrogen are bound to a carbon that is de-rived from biomass, then the fractions of these elements that are linked to bio-based carbon, are also considered to be parts of the bio-based content. In practice, it is not always possible to dis-tinguish between elements originating from biomass and from non-biomass by measurements. Therefore in most cases the knowledge from product suppliers are needed in order to calculate the total bio-based content.
This was reflected in the round robin assessment devoted to the validation of the bio-based con-tent of various samples that was stated by the producers of these samples. Validation of stated total bio-based content of several various products was the ultimate goal of initiated round robin assessment. The assessment involved 11 independent laboratories to whom in total 66 samples were delivered (11 equivalent sets of samples, 6 samples each set). Together with the samples, the so-called statements were provided by samples suppliers. Every statement included infor-mation about composition of a given sample, its bio-based carbon content and its total bio-based content. The information mentioned in the statements was checked by the measurements by each of participating laboratories. Then the stated values were validated or not, depending how big was the difference between stated and measured value for each of involved parameters. The validation procedure was described in pr EN 16785 and was sent to each participating laboratory together with the set of samples.
While the results of the first round robin assessment on the bio-based carbon content determi-nation (Deliverable 3.1 of Open-Bio on CEN/TS 16640) indicated a good consistency, determi-nation and validation of the total bio-based content was more challenging among participating laboratories. Therefore a number of suggestions and recommendations were included into pr EN 16785 and resulted in a new version pr EN 16785-1 and finally in EN 16785-1 that currently is official full standard. As a remark, the finalization of the EN 16785-1 has been awaited before this report was finalized. As one of adaptations to EN 16785-1, a clear distinction was made between the products where only 14C analysis and where both 14C and CHN-O analyses are needed in order to validate the bio-based content. For these two cases, two decision trees and two templates for the representation of the results were suggested in order to make the validation procedure more transparent and easy to apply. Furthermore, separate remarks are made for the situations when bio-based content stated by supplier is lower than the calculated one. In this case, even despite the absolute difference between these two can be larger than the permitted limit, nevertheless the number that is stated by the supplier shall be validated as stated. Finally, special care shall be taken when analysing water-containing samples: the analysis and reporting of the results is advised to do on the dry basis.
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