EN 15428:2007

Soil improvers and growing media - Determination of particle size distribution

This document specifies a method of determination of particle size distribution in soil improvers and growing media.

Bodenverbesserungsmittel und Kultursubstrate - Bestimmung der Partikelgrößenverteilung

Amendements du sol et supports de culture - Détermination de la répartition granulométrique

Izboljševalci tal in rastni substrati - Določanje porazdelitve velikosti delcev

General Information

• Status: Published
• Publication Date: 11-Sep-2007
• ICS: 65.080 - Fertilizers
• Technical Committee: CEN/TC 223 - Soil improvers and growing media
• Drafting Committee: CEN/TC 223/WG 4 - Analytical methods
• Current Stage: 9093 - Decision to confirm - Review Enquiry
• Start Date: 03-Sep-2024
• Completion Date: 14-Apr-2025
• Ref Project: SIST EN 15428:2008 - Soil improvers and growing media - Determination of particle size distribution

Overview

EN 15428:2007 (CEN) specifies a standardized laboratory method for the determination of particle size distribution in soil improvers and growing media. The method is based on mechanical sieving of an air‑dried, prepared sample with defined test sieves and a calibrated sieving‑shaking machine. The standard provides procedural steps, apparatus requirements, calculation methods and reporting requirements to ensure consistent, comparable results across laboratories and suppliers.

Key topics and technical requirements

• Principle: Sieving an air‑dried sample and determining weight fractions retained on each sieve to express particle size distribution on a dry‑matter basis.
• Apparatus: Vertical vibrating sieving machine with amplitude adjustment and interval timer; test sieves (200 mm or 300 mm diameter) with stainless steel woven wire and square openings; drying oven (40 °C ± 5 °C); balance (≥4 kg, 0.1 g accuracy); sample divider.
• Specified sieve apertures: Typical apertures listed include 31.5 mm, 16.0 mm, 8.0 mm, 4.0 mm, 2.0 mm, 1.0 mm plus a reception tray.
• Sieving conditions: Standardized sieving cycle (total 7 minutes; intervals of activity/rest) and amplitude optimization (0.5–1.5 mm range). Optimization of the sieving machine is required before first use and annually (Annex A).
• Sample preparation and drying: Sampling per EN 12579 and sample preparation per EN 13040; air‑dry at ~40 °C for ≥16 h; sub‑sample volumes specified (e.g., 375 ml for 200 mm sieve, 750 ml for 300 mm sieve) with adjustment for fine/coarse materials.
• Calculations and precision: Procedures for computing fraction percentages, averaging three sub‑samples, assessing coefficient of variation and repeatability/reproducibility (interlaboratory trials summarized in Annex B).
• Test report: Must include reference to EN 15428, sample identification, methods used, results as mass/mass dry matter, and any deviations or influencing factors.

Applications and users

• Who uses it: Analytical laboratories, manufacturers of growing media and soil improvers, quality control teams, horticultural substrate suppliers, certification bodies, plant nurseries and research organizations.
• Practical uses:
  • Quality control and product specification of composts, peat mixes, bark, perlite and other substrate components.
  • Ensuring batch consistency, meeting label claims, and conforming to regulatory or procurement requirements.
  • Supporting product development (blend optimization) and performance assessment (drainage, aeration, water retention linked to particle size).

Related standards

• EN 12579 - Sampling of soil improvers and growing media
• EN 13040:2007 - Sample preparation and moisture/dry matter determination
• CR 13456:1999 - Labelling and product schedules for soil improvers/growing media
• ISO 565 - Test sieves - nominal opening sizes

Keywords: EN 15428, particle size distribution, soil improvers, growing media, sieving method, test sieves, sample preparation, sieving machine, CEN.

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Soil improvers and growing media - Determination of particle size distributionAmendements du sol et supports de culture - Détermination de la répartition granulométriqueBodenverbesserungsmittel und Kultursubstrate - Bestimmung der KorngrößenverteilungTa slovenski standard je istoveten z:EN 15428:2007SIST EN 15428:2008en,fr,de65.080ICS:SLOVENSKI
STANDARDSIST EN 15428:200801-marec-2008

EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 15428September 2007ICS 65.080 English VersionSoil improvers and growing media - Determination of particlesize distributionAmendements du sol et supports de culture -Détermination de la répartition granulométriqueBodenverbesserungsmittel und Kultursubstrate -Bestimmung der PartikelgrößenverteilungThis European Standard was approved by CEN on 28 July 2007.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN 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 translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, 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 STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2007 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 15428:2007: E

Optimization of the sieving machine.9 Annex B (informative)
Results of an interlaboratory trial to determine particle size.10 Bibliography.18

5 Apparatus 5.1
Sieving-shaking machine, vertical vibrating movement, with amplitude adjustment, and interval timer. Sieving time: 7 min in periods of 10 s shaking and 1 s rest with an amplitude in the range between 0,5 mm and 1,5 mm. 5.2
Test sieves, diameter 200 mm or 300 mm, rim height 55 mm, aperture sizes as listed in ISO 565, of stainless steel woven wire with square openings 31,5 mm, 16,0 mm, 8,0 mm, 4,0 mm, 2,0 mm, 1,0 mm, and reception tray, sieve lid. 5.3
Drying oven, forced air suction, adjustable to 40 °C ± 5 °C. NOTE Care should be taken to prevent loss of fine lightweight particles. 5.4
Three drying trays, rim height ca 50 mm ± 10 mm, minimum bottom area of 400 cm2, heat proof to 50 °C. 5.5
Balance with a weighing range at least 4 kg and an accuracy 0,1 g. 5.6
Apparatus for sample division, comprising any suitable equipment for combining and reducing the samples which preserves the characteristics of the product. Depending on the particle size, material and

6 Optimization of sieving machine Prior to its first use the shaking machine shall be optimized as described in Annex A. Optimization shall be repeated annually. 7 Test sample 7.1 General For the determination of the particle size distribution materials shall be sampled in accordance with EN 12579. This European Standard is applicable to samples supplied in a form in which they are used and is not necessarily applicable to or suitable for all types of growing medium or soil improver, for example material that is not able to flow when used or is sticky. Samples shall be analysed in a state ready to be used. Prepare the test sample in accordance with EN 13040:2007 up to Clause 7. 7.2 Determination of the sub-sample volume First determine the analytical sample size. For fine materials, use a smaller volume than for coarser materials to reduce the risk of blocking the sieves (see Table 1). Place the 8,0 mm mesh sieve (5.2) on the sieving machine with the reception tray under it. Reduce the sample to the size of the sub-sample using an apparatus for sample division (5.6). Transfer the appropriate sub-sample (750 ml for 300 mm sieve and 375 ml for 200 mm sieve) to the sieve and place the lid on the sieve. Secure to the sieving tower and switch on the sieving machine (5.1) for 1 min at the standard setting. For samples in which the moisture content is too high, first air dry the sample in a drying oven for 16 h (5.3). NOTE If the moisture content is too high, the sample will not pass through the sieve. After sieving, weigh the sieve (c), the reception tray with the sample (a), then dry-clean the sieve and reception tray and weigh them empty (d and b respectively).
Calculate the fraction according to 10.1. Table 1 — Sample volumes Sieve diameter Sub-sample portion
If 0 mm to 8 mm fraction ≤ 50 % w/w total Sub-sample portion
If 0 mm to 8 mm fraction > 50 % w/w total
200 mm 375 ml 125 ml 300 mm 750 ml 250 ml

8 Air drying Take three representative appropriate volumes (see Table 1) of the sample as received using an apparatus for sample division (5.6) and place them into 3 separate drying trays. Spread the sample over the surface of the tray as uniformly as possible and weigh. Place the trays in the drying oven (5.3) at 40 °C for at least 16 h and re-weigh. Calculate the moisture loss. After drying, the remaining moisture content in the sub-samples shall not exceed 15 % of the total weight. The moisture content shall be determined as described in EN 13040:2007. 9 Procedure Determine the particle size distribution within 24 h after drying. Store the sample in a dry atmosphere until sieving can be performed.
NOTE As samples absorb moisture, volume changes can occur. Assemble the sieves in order of aperture size, with the largest aperture at the top, on top of the reception tray on the sieving machine. Distribute all the dried sub-sample (Clause 8) equally on the upper sieve. Place the lid on the upper sieve and secure the sieves. Switch on the sieving machine for 7 min at the prescribed setting (Clause 6). Determine the weight fractions of each sieve and of the reception tray. Dry-clean the sieves and the reception tray. When the three sub-samples have been sieved and weighed, determine the empty weights of the sieves and the reception tray. Calculate the fraction distribution as described in 10.2. 10 Calculations and expression of results 10.1 Calculation of fraction distribution during sample pre-treatment Calculate the fraction distribution during sample pre-treatment as follows: The sieving fraction greater than 8 mm is given by
100% )()(-
mass)by
(% mm 8 fraction
Sieving×−+−>badcdc=
(1) The sieving fraction smaller than 8 mm is given by
100% )()( mass)by
(% mm 8-0fraction
Sieving×−+−−badcba=
(2) where a
is the weight of reception tray plus sample, expressed in g; b
is the weight of the empty reception tray, expressed in g; c
is the weight of the 8,0 mm sieve plus sample, expressed in g;

is the weight of the empty 8,0 mm sieve, expressed in g. 10.2 Calculation of fraction distribution of a sample The portion masses are expressed on the total mass of the sample.
weight%100
massraction ×∑xxxAAZZZF
(3) where x = 1.7
1 - sieve 31,5 mm
2 - sieve 16 mm
3 - sieve 8 mm
4 - sieve 4 mm
5 - sieve 2 mm
6 - sieve 1 mm
7 - reception tray
A1.7
= (weight sieve plus sample - weight empty sieve). For each fraction determine the average and round it to the nearest whole percent. Then determine the coefficient of variance of the three sub-samples according to the calculation below (example calculation of portion x). Do this for portions 2 to 6 and only for the three largest fractions. Disregard the portion of > 31,5 mm. If the coefficient of variance of a portion is greater than 20 % the sample should be considered as insufficiently homogenous. The analysis should be repeated in its entirety. nZZZG∑xx verageA
(4) where: n = number of replicates (3 or 4) 100
Variance of oefficient×−−∑x2xxxG1"/!n"G!ZZZVcC
(5) 11 Precision Typical performance characteristics for precision and accuracy are shown in Table B.1 to Table B.7. 12 Test report The test report shall include the following information: a) reference to the European Standard (EN 15428:2007);

Optimization of the sieving machine A.1 Test sample Homogeneous, peat type 1, < 16 mm, fraction 0 to 1 mm 10 to 40 %. A.2 Sample pre-treatment Take a sub-sample of the test sample (for 300 mm sieve take 500 ml, for 200 mm sieve take 250 ml) from which the particles greater than 16 mm have been sieved out manually; dry this sample for 24 h at 40 °C. Place sieves and reception tray on the sieving machine in such
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