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Volumetric Control

European Method for performing volumetric control

While the cultivation substrates are sold on a volumetric basis, due to the nature of their composite materials, including a solid state (incoherent solids), a liquid state (water in varying amounts) and a gaseous state (macro and microporosity), they are subject to volume changes as a result of the steps that take place from the time of their production to the time of their use, mainly during the storage and transport stages.

For this reason, methods have been developed in order to allow for the repeated assessment of material’s apparent volume.

The official method, on a European wide scale, is the EN 12580 method, which was also implemented in 2002 by the Italian organization for Standardization (UNI).

This method allows us to determine the amount (volume) of the substrate being sold, whether in bulk or packaged.
The material is weighed in a container of known volume, after which the apparent density is determined and the volume is calculated based on these values.

Equipment

Measuring cylinder

The measuring cylinder must be rigid and must have a volume equal to 20 ± 0.4 litres, with a height/diameter ratio ranging from 0.9:1 and 1:1. The cylinder’s volume, V1, must be known with an accuracy of 10 ml at 20°C. (note: the specific gravity of water at 20°C is 997.15 g). It is therefore not necessary to make any corrections in relation to the pressure.

Collar

The collar must be rigid and must be the same diameter as the measuring cylinder, with a height of 75±2 mm.

Disaggregation screen

A sieve with a 20 mm, 40 mm or 60 mm mesh, based on the material, positioned no more than 50 mm above the collar.

Calculation and expression of the results

The material’s volumetric mass or apparent density (Da) is calculated, in grams per litre, using the following expression:

controllo volumetrico

where:

  • m3 is the weight (mass) of the measuring cylinder in grams;
  • m4 is the weight (mass) of the measuring cylinder and its contents in grams;
  • V1 is the volume of the measuring cylinder in litres.
In order to evaluate the cubic meters, proceed as follows: fill a 20 litre container with the product to be sold, passing the product through a sieve with a mesh size of 20, 40 or 60 mm, based on the type of product, and without exerting any mechanical pressure.
The net weight of the product inside the 20 litre container multiplied by 50, is equal to the weight of one cubic metre (m3).

Example

  • Net weight of 20 litres = 6 kg;
  • 6 x 50 = 300 kg, or rather the net weight of one cubic metre (m3) of product.
he total weight of the bulk product or the packaging, whether in big bags or in XPro Packs, must be divided by the weight of one cubic meter of product, measured according to the EN system, in order to determine the number of declared cubic metres (m3).
  • XPro Pack = 1200 Kg
  • Volume of the XPro Pack = 1200/300 = 4 m3
THE PRODUCT WILL ONLY BE SOLD ACCORDING TO THESE CONDITIONS. THE CUSTOMER MUST USE THE SAME METHOD WHEN VERIFYING THE VOLUME OF THE PRODUCT RECEIVED.