prEN 15761

SLOVENSKI STANDARD
01-januar-2022
Rastni substrati - Določanje dolžine, širine, višine, volumna in prostorninske
gostote
Pre-shaped growing media - Determination of length, width, height, volume and bulk
density
Vorgeformte Kultursubstrate - Bestimmung von Länge, Breite, Dicke, Volumen und
Schüttdichte
Supports de culture préformés - Détermination de la longueur, de la largeur, de la
hauteur, du volume et de la masse volumique apparente
Ta slovenski standard je istoveten z: prEN 15761
ICS:
65.080 Gnojila Fertilizers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2021
ICS 65.080 Will supersede EN 15761:2009
English Version
Pre-shaped growing media - Determination of the
dimensions measured and bulk density
Supports de culture préformés - Détermination de la Vorgeformte Kultursubstrate - Bestimmung von Länge,
longueur, de la largeur, de la hauteur, du volume et de Breite, Dicke, Volumen und Schüttdichte
la masse volumique apparente
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 223.
If this draft becomes a European Standard, 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.

This draft European Standard was established by CEN 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, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 15761:2021 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Principle . 6
5 Apparatus . 6
6 Sampling and sample preparation . 7
7 Procedure . 7
7.1 Accuracy . 7
7.2 Number of measurements . 7
7.2.1 Measurement of 150 mm or less . 7
7.2.2 Measurement of more than 150 mm but less than 600 mm . 7
7.2.3 Measurement of more than 600 mm. 7
7.3 Test procedure . 7
7.3.1 General . 7
7.3.2 Test specimens with holes or grooves . 8
7.4 Determining the weight . 8
8 Calculations and expression of results. 8
8.1 Length, width, diameter and height . 8
8.2 Volume . 8
8.2.1 Accuracy . 8
8.2.2 Test specimens with no recesses . 8
8.2.3 Test specimens with recesses. 9
8.3 Bulk density . 10
9 Precision . 10
10 Test report . 10
Annex A (informative) Results of an inter-laboratory trial . 11
A.1 Trials. 11
A.2 Results . 12
Bibliography. 13

European foreword
This document (prEN 15761:2021) has been prepared by Technical Committee CEN/TC 223 “Soil
improvers and growing media”, the secretariat of which is held by NEN.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 15761:2009.
In comparison with the previous edition, the following technical modifications have been made:
— the text has been editorially revised, no technical changes to the described method itself have been
made;
— plugs have been excluded from the scope;
— updated references in Clause 2;
— the terms and definitions are aligned with CEN/TS 17732:—;
— a dimensional measuring instrument has been added to Clause 5 and 7.3.1;
— a clause on sampling has been added;
— descriptions for other shapes, such as (truncated) conical material and cylindrical material, have
been added to the text.
This document has been prepared under a Standardization Request given to CEN by the European
Commission and the European Free Trade Association.
Introduction
This document has been developed so that there is a standard method to measure and weigh pre-shaped
growing media and to calculate the volume and bulk density.
The volume of growing media is a useful attribute for growers and is critical for ensuring plants have
sufficient growing media for their root system.
The bulk density is crucial as the reporting of all chemical analyses is expressed in units of weight per
volume, and the volume is determined from the weight of the sample used for the chemical analyses.
NOTE 1 In this document, mass and weight are used interchangeably with the same meaning.
Pre-shaped growing media are generally made from mineral wool, some are manufactured using
polyurethane and others from stabilized organic material. They are known by various names, typically:
— “plugs” are small blocks used for seedlings, which are generally cylindrical in shape; once the seed
has germinated the seedling in the plug might then be placed into “blocks”;
NOTE 2 Plugs are excluded in the scope of this document.
— “blocks” might have holes to take plugs and can vary in size; they are generally used for propagation
purposes;
— “slabs” are used for growing vegetables and range in size.
1 Scope
This document describes a method for the determination of and the dimensions measured of the bulk
density of pre-shaped growing media.
In this document, “pre-shaped growing media”:
— includes solid, regular shaped, stable growing media sold, which are ready for use as a growing
media, where the dimensions and any corners are stable;
— does not include plugs;
— does not include solid growing media that has to be hydrated for it to form, varies in dimension with
varying water content – for example, coir or peat slabs or growing bags.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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.
CEN/TS 17732 , Soil improvers and growing media — Terminology
3 Terms and definitions
For the purposes of this document, the terms and definitions given in CEN/TS 17732 and the following
apply.
3.1
length
l
longer linear dimension of the major surface of the test specimen
3.2
width
w
shorter linear dimension of the major surface of the test specimen measured at right angles to the length
3.3
height
h
linear dimension measured top to bottom
3.4
depth
d
linear dimension measuring how deep recess intrude into the media
3.5
diameter
D
chord that runs through the centre point of the circle

Under preparation. Current stage is: FprCEN/TS 17732:2021.
3.6
bulk density
indication of how much 1 l of the product weighs, being determined in a standardized way
Note 1 to entry: The bulk density is expressed in grams per litre (g/l) or in kilograms per cubic metre (kg/m ).
3.7
plug
pre-shaped growing medium that consists of small blocks used for seedlings, which are generally
cylindrical in shape
Note 1 to entry: Once the seed has germinated the seedling in the plug might then be placed into a “block”.
3.8
block
pre-shaped growing medium that might have holes to take plugs
Note 1 to entry: Blocks are generally used for propagation purposes.
Note 2 to entry: Blocks can vary in size.
3.9
slab
pre-shaped growing medium used for growing vegetables
Note 1 to entry: Slabs can vary in size.
4 Principle
The test specimen is placed on a flat surface.
For regular rectangular material, measurements for the length, width and height are taken.
For (truncated) conical material and cylindrical material, measurements for height and diameter are
taken.
The volume is calculated from these dimensions and, after the determination of the weight, the bulk
density is calculated.
5 Apparatus
5.1 Flat surface, horizontal, flat stable surface, e.g. table top, which is large enough for the test
specimen and the measuring devices.
5.2 Metal rule or metal tape, graduated in millimetres and permitting reading to 0,5 mm or less.
NOTE Measures conforming to the requirements of OIML R35-1:2007, Material measures of length for general
use. Part 1: Metrological and technical requirements [2], Class II are appropriate. This can be obtained from
http://www.oiml.org/publications/.
5.3 Height gauge, having a maximum scale interval of 0,5 mm.
5.4 Pressure plate, square with a flat base and having sides of dimensions 100 mm × 100 mm, which
weighs (50 ± 1) g.
NOTE Any other linear measuring device might be used if the results can be determined to within 0,5 mm.
5.5 Balance, having a maximum scale interval of 0,1 g.
NOTE Any balance conforming to the requirements of OIML R76-1:2006, Non-automatic weighing instruments.
Part 1: Metrological and technical requirements – Tests [3], Class II is appropriate. This can be obtained from
http://www.oiml.org/publications/.
5.6 Dimensional measuring instrument, with a maximum scale of 0,5 mm.
...