The BS EN 14961 standard has big implications for natural wood biomass fuel suppliers and end users as well as to biomass installers, says Michael Barber-Starkey.
The efficiency of a wood burning boiler or stove relies almost entirely on the quality of the fuel. Get this wrong and heat and cost-saving benefits diminish significantly.

However, standardising wood, particularly when it's in log form, is no mean feat; it is a variable material with size and most importantly, moisture content differing significantly depending on the way it has been treated. When it comes to pellets, this is easier, but regardless of the perceived difficulties it is still a very necessary process.

At the moment, consumers may not understand what they are buying. However, they need to understand in order to get the best out of their biomass equipment. By purchasing sub-standard fuel with high moisture content, they will basically be paying for water.

The table - above left - clearly demonstrates what happens to the kilowatt hour (kWh) as the moisture content goes up. This is a serious effect that will slash any efficiency claims made by a particular product.

BS EN 14961 - Solid biofuels. Fuel specifications and classes. General requirements - has been floating around since 2010, but is only now filtering down into best practice. Reputable pellet suppliers should already be following its guidance, but it is harder to monitor the one-man-bands that deliver logs from the back of a van.

Logs can currently be bought under HETAS' wood assurance scheme. (HETAS is the official body recognised by Government to approve solid fuel domestic heating appliances, fuels and services including the registration of competent installers and servicing businesses).


While a lengthy and pretty boring document, what's important for consumers about BS EN 14961 is understanding its significant parts which should appear on all fuel packaging. For logs and pellets there's length (L) and diameter (D); pellets also show ash content (A). Woodchip uses a P and then a number, which signifies sawdust content and average sizing.

The most important symbol to look out for, however, is M, which relates to the moisture content. This should be between 15 and 20 per cent for optimum efficiency.
The only way the standard has any chance of being enforced, however, is if it is consumer driven. Fuel suppliers should be volunteering proof of compliance information.

As the UK's reliance on renewables becomes increasingly necessary, ensuring these technologies work to the best of their abilities is imperative.

Many end-users still need to be convinced of the benefits of green heating, so moves such as the BS EN fuel standard are vital in making this equipment a viable solution to keep Britain's homes warm.