There are two types of standard:
ENplus standard pellets for domestic use.
EN-B for industrial and municipal.
This separation of norms allows economical use of fuel pellets and to control the high quality.
In the post-Soviet countries don’t have their own standards, so based on Western evaluation system. In addition to the quality norms and the use of the pellets, there are standards of transportation, storage and production of pellets.
In Europe there are no uniform standards, so there are separate national standards. For example, Austria has regulated the norm ONORM M 7135 Austrian Association pellets. This standard allows you to install the flaws in the quality of raw materials and production phases on certain external features. The essence of the test is to test the pellets on the abrasion with the apparatus of lignostone. Abrasion capable of giving information about the degree of strength and hardness of pellets. Measures the amount of dust released during the experiments with the pellets, and recorded in percentage. The lower the percent attrition, the great quality has fuel.
Germany offers the standard DIN 51731 for wood raw material. But resistance in this case is not considered.
DINplus certification is the most demanding, because it combines two of the previous. The process of defining quality in the context of production and is only possible with the participation of the Institute DIN Certco. Products, successfully passed all the checks, marked with the emblem quality PVD Pelletverband.
There are other standards, conformity with DINplus. For example, in the US it is Standard Regulations & Standards for Pellets in the US: The PFI, and in England-The British BioGen Code of Practice for biofuel.
The main parameter that take into account each of the above standards, it is the ash content. Its high value indicates you have exceeded the content in the feedstock impurities like bark, branches.
High quality pellets can be set visually by the appearance of granules. High quality fuel will have a smooth surface, without any cracks, rough edges. As for diameter, it can be 4, 6, 8 or 10 mm. The diameter must be taken into account when calculating the productivity of the furnace. A decrease or increase in the size of the pellets indicates the deviation from the norms.