SIST EN 15956:2011

• Abstract:

  This document specifies a method for the determination of phosphorus soluble in mineral acids.; The method is applicable exclusively to phosphate fertilizers listed in Regulation (EC) 2003/2003, Annex I (see [2]).

• Status: Published
• Public Enquiry End Date: 30-Jun-2011
• Publication Date: 17-Oct-2011
• ICS: 65.080 - Fertilizers
• Technical Committee: KAT - Soil quality
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 17-Oct-2011
• Due Date: 22-Dec-2011
• Completion Date: 18-Oct-2011
• Directive: 2003/2003 - Regulation (EC) N° 2003/2003 of the European Parlament and of the council of 13 October 2003 relating to fertilisers
• Mandate: M/335 - Standardization Mandate assigned to the CEN concerning the modernisation of the methods of anylysis of Fertilizers
• Ref Project: EN 15956:2011 - Fertilizers - Extraction of phosphorus soluble in mineral acids

• Replaces: SIST-TS CEN/TS 15956:2010 - Fertilizers - Extraction of phosphorus soluble in mineral acids (Method 3.1.1)
• Effective Date: 01-Nov-2011
• Refers: SIST EN 12944-2:2002 - Fertilizers and liming materials and soil improvers - Vocabulary - Part 2: Terms relating to fertilizers
• Effective Date: 28-Jan-2026
• Refers: SIST EN 12944-1:2002 - Fertilizers and liming materials and soil improvers - Vocabulary - Part 1: General terms
• Effective Date: 28-Jan-2026
• Refers: SIST EN 1482-2:2025 - Fertilizers, liming materials and inhibitors - Sampling and sample preparation - Part 2: General sample preparation provisions
• Effective Date: 28-Jan-2026
• Referred By: SIST-TS CEN/TS 17757:2023 - Inorganic fertilizers - Determination of specific nutrients
• Effective Date: 28-Jan-2026
• Revised: kSIST FprEN 15956:2026 - Inorganic fertilizers - Extraction of phosphorus soluble in mineral acids
• Effective Date: 01-Feb-2026

SIST EN 15956:2011 is the Slovenian adoption of EN 15956:2011, published by SIST and prepared by CEN. It specifies a laboratory method for extracting and determining phosphorus soluble in mineral acids in phosphate fertilizers covered by Regulation (EC) No 2003/2003, Annex I. In practice, it is a test method for laboratories, manufacturers, and control bodies working with that fertilizer group.

What does SIST EN 15956:2011 specify?

SIST EN 15956:2011 specifies a method for measuring phosphorus soluble in mineral acids in phosphate fertilizers. The method applies only to the phosphate fertilizers listed in Regulation (EC) No 2003/2003, Annex I, so it is aimed at a defined regulatory product set.

The document is organized into short technical clauses: scope, normative references, terms and definitions, principle, sampling, reagents, apparatus, procedure, and test report. That structure helps a user go straight from the legal scope to the laboratory steps and the reporting requirements.

What are the key requirements of SIST EN 15956:2011?

SIST EN 15956:2011 is built around a simple wet-chemistry extraction method. The important points are the controlled acid extraction, the sample preparation requirements, and the way the result is documented.

• Principle, Clause 4 - Phosphorus is extracted from the fertilizer with a mixture of nitric acid and sulfuric acid under specified conditions. This means laboratories must keep the chemistry and handling consistent so results from different samples can be compared.

• Sampling, Clause 5 - Sampling is outside the method itself, but sample preparation is required to follow EN 1482-2, and grinding of the laboratory sample is recommended for homogeneity. In practice, the analyst must work with a well-mixed sample so the test portion represents the bulk material.

• Reagents, Clause 6 - The method calls for water, sulfuric acid, and nitric acid of specified quality. This matters because reagent quality affects the extraction and the reliability of the final phosphorus result.

• Apparatus, Clause 7 - The method uses standard laboratory equipment, a Kjeldahl flask or an equivalent reflux setup, a graduated flask, and a dry pleated phosphate-free filter. That means the laboratory needs ordinary chemical glassware plus filtration materials that will not add phosphorus.

• Test portion and extraction, Clause 8 - A weighed portion of the laboratory sample is treated with water and acids, heated, cooled, diluted to volume, mixed, and filtered. In practice, this is a controlled digestion step followed by solution preparation for the measurement phase.

• Filtering step, Clause 8 - The first portion of filtrate is discarded. This helps avoid contamination or carryover from the filter and supports a cleaner analytical solution.

• Test report, Clause 9 - The report must identify the sample, state the method used, give the result, record sampling information if known, note when analysis finished, confirm whether the repeatability limit was met, and list any relevant deviations or incidents. This is what makes the result traceable for quality control, auditing, or regulatory use.

What terms does SIST EN 15956:2011 define?

SIST EN 15956:2011 uses the vocabulary from EN 12944-1:1999 and EN 12944-2:1999, so the terms in those standards apply here. The most important working terms in the method are the following:

• Phosphate fertilizers - The product group covered by the method and limited by the cited regulation.
• Mineral acids - The acid mixture used to extract the phosphorus from the fertilizer.
• Laboratory sample - The prepared sample from which the test portion is taken.
• Test portion - The weighed amount of sample used for the extraction step.
• Repeatability limit - The criterion mentioned in the test report for checking whether results agree within the method’s allowed spread.
• Test report - The documented record of the sample, method, result, and any relevant deviations.

Who uses SIST EN 15956:2011?

SIST EN 15956:2011 is used by fertilizer testing laboratories, quality control teams, manufacturers, and regulatory or conformity assessment bodies. It supports routine analysis of phosphate fertilizers when phosphorus soluble in mineral acids needs to be measured for product control, specification checking, or compliance reporting.

What changed in SIST EN 15956:2011 from the previous edition?

SIST EN 15956:2011 supersedes CEN/TS 15956:2009. The stated changes are that the technical specification was adopted as a European Standard and the document was editorially revised.

Which standards are used with SIST EN 15956:2011?

SIST EN 15956:2011 refers to EN 1482-2 for sample preparation, so that part supports the condition of the sample before testing. It also uses EN 12944-1:1999 and EN 12944-2:1999 for the vocabulary applied in the document.

EN 1482-1 is cited as the recommended sampling method in Clause 5 and is listed in the bibliography. The scope also ties the method to Regulation (EC) No 2003/2003, Annex I, which limits the fertilizers to which the method applies.

What does the SIST EN 15956:2011 document contain?

The document contains a short laboratory method rather than a broad test family. It gives the principle of acid extraction, the sampling and sample-preparation link, the reagent list, the apparatus needed, and the step-by-step procedure for preparing the test solution.

It also includes the reporting requirements, which are important when the result will be used in quality records or official checks. The bibliography points readers to the sampling standard and the EU fertilizer regulation that defines the covered product group.

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Gnojila - Ekstrakcija fosforja, topnega v mineralnih kislinahDüngemittel - Extraktion des in Mineralsäuren löslichen PhosphorsEngrais - Extraction du phosphore soluble dans les acides minérauxFertilizers - Extraction of phosphorus soluble in mineral acids65.080GnojilaFertilizersICS:Ta slovenski standard je istoveten z:EN 15956:2011SIST EN 15956:2011en,fr,de01-november-2011SIST EN 15956:2011SLOVENSKI
STANDARDSIST-TS CEN/TS 15956:20101DGRPHãþD

EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 15956
September 2011 ICS 65.080 Supersedes CEN/TS 15956:2009English Version
Fertilizers - Extraction of phosphorus soluble in mineral acids
Engrais - Extraction du phosphore soluble dans les acides minéraux
Düngemittel - Extraktion des in Mineralsäuren löslichen Phosphors This European Standard was approved by CEN on 18 August 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.
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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 15956:2011: ESIST EN 15956:2011
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