Current concerns about the effect of carbon dioxide emissions in relation to climate change has focussed attention on the zero rating of wood fuel.
It is widely accepted that during their growth, trees absorb carbon dioxide from the atmosphere equal to the quantity released during combustion. Important also are the moisture figures and the recommended periods for seasoning.
The CEN/TC 335 European Standard specification states logs should have a maximum moisture content of:
Most appliance manufacturers recommend moisture levels of less than 20% for best performance.
This can be achieved by splitting, stacking and air drying for a period suitable for the wood type.
Burning unseasoned wood is an inefficient practice, Much of the energy released from the fuel is used to dry the fuel and boil off the water within the core of the log. Poorly seasoned wood results in serious problems associated with condensation in the flue.
Water vapour, driven off during the combustion process, will travel up the chimney together with flue gasses. Should the flue gas temperature cool to ‘dew point’ the water will condense on the internal surface of the flue to form water droplets. Whilst in contact with the flue gas the water entrains some of the combustion by- products to form something resembling creosote. This can seep into brickwork and cause staining and can shorton the life of a lined flue.
For a local log supplier in Southampton visit www.daves-logs.co.uk