To what specifications are your pellets guaranteed?

Forever Fuels supplies two sizes of premium-quality pellets - 6mm and 8mm, by diameter. 6mm is available in bulk and bags throughout England and Wales. 8mm is available in bulk in certain parts of the country (if you would prefer 8mm, give us a ring and find out if it is available locally or at additional charge for longer haulage). In some locations, we may also offer pellets from local producers, whose specifications will vary according to the producer.

Our pellets are specified (and sampled and analysed to test conformance) according to the CEN/TS 14961 draft European standard classification. That terminology is compact but opaque, so we provide a guide below.

Our 8mm Swedish pellets from from Skellefteå Kraft, one of the largest and longest-established producers in Sweden, have proved highly popular due to their exceptional quality. But some boilers cannot accept 8mm pellets. Skellefteå are now introducing a range of 6mm pellets, produced at the same factories with the same inputs and to the same high standards as their 8mm pellets, to meet this gap in the market. We will shortly be taking delivery of the first boatload of 6mm Swedish pellets, and are therefore harmonizing the specifications of our top-grade 6mm and 8mm pellets.

6mm top-grade

Our 6mm top-grade pellets are specified (to CEN/TS 14961 specification) to D06 M10 A0.7 E4.9 DU97.5 F2.0 N0.3 S0.05 Cl0.03, i.e. 6 mm Diameter, no more than 10% Moisture and 0.7% Ash, greater than 97.5% mechanical DUrability and 4.9 kWh/kg Energy density, etc.

8mm top-grade

Our 8mm top-grade pellets are specified (to CEN/TS 14961 specification) to D08 M10 A0.7 E4.9 DU97.5 F2.0 N0.3 S0.05 Cl0.03.

Many of the above parameters are the highest spec. envisaged in the standard. In practice, the Skellefteå pellets are significantly better than this specification in some aspects, For example, the moisture content should be under 7%, the ash content is expected to be nearer to 0.5%, and the sulphur, nitrogen and chlorine contents are so low as to be negligible (0.01%, 0.1% and 0.01% respectively). Some customers have reported to us that our Swedish pellets seem to burn slower than the pellets they had been used to (in other words, a store-load lasts a little longer), which we assume is due to their high energy-density.

The pellets are produced from sawdust and shavings from pine and spruce. Only the highest-quality, clean, fresh wood is used in our top-grade pellets (no recovered materials, minimal bark), sourced from the forestry and timber industries.

Local and industrial-grade pellets

Pellets from local producers will vary in quality. Some are now addressing the demand for high-grade pellets, to the above specifications. Many are limited (by the feedstock available within the area and the lower technical sophistication of smaller-scale equipment) to producing a lower-specification, industrial-grade pellet, e.g. D08 M12 A1.0 E4.6 DU95 F3.0 N1.0 S0.1 Cl0.1.

We recommend only top-grade pellets for small-to-medium-sized boilers, but if you have robust equipment capable of taking a more robust pellet, we will be happy to discuss supplying you with industrial-grade pellets. You will have the assurance of our substantial stocks of high-grade pellets to fall back on if the local producer's output varies, or if your equipment proves less happy with industrial-grade pellets than you had hoped.

CEN/TS 14961

CEN/TS 14961 is a draft European standard that provides a way to describe the specification of biomass fuels. For pellets, the following components may be specified (click the links for more detail on each aspect):

D = Diameter, e.g. D06 = 6mm diameter (max. 30mm length, with allowance for upto 45mm length in 20% of the stock)

M = Moisture, e.g. M10 = ≤10% moisture

A = Ash, e.g. A0.7 = ≤0.7% ash

E = Energy density, e.g. E4.7 = ≥4.7 kWh/kg Net Calorific Value, dry basis

DU = Durability, e.g. DU97.5 = ≥97.5% durability (i.e. less than 2.5% by weight of the pellets break off to form fines under stress-testing)

F = Fines, e.g. F2.0 = ≤2.0% fines (at the factory gate. Premium 8mm and 6mm pellets will be cleaned before loading on the delivery vehicle to minimize the delivered fines-content)*

N = Nitrogen, e.g. N0.5 = ≤0.5% nitrogen

S = Sulphur, e.g. S0.05 = ≤0.05% sulphur

Cl = Chlorine, e.g. Cl0.07 = ≤0.07% chlorine

Additionally (also referenced in 14961), we prefer pellets with no additives, and specify a maximum additive-level of 2% by weight, dry basis. As per recommendation in 14961, only products from agricultural and forestry biomass that have not been chemically modified are approved to be added as pressing aids.

* The delivered fines-content will depend on many factors, including the design of your installation.