Few years ago the Technical Committee CEN/TC 175 published the standard “EN 16449 Wood and wood-based products - Calculation of the biogenic carbon content of wood and conversion to carbon dioxide”
The essentially aim of this document is to assess the amount of CO2 sequestered/absorbed by an element of wood.
By the process of photosynthesis, growing trees absorb (sequester) atmospheric carbon dioxide which is then incorporated. The absorbed carbon dioxide is effectively fixed in the wood as biogenic carbon.
When using wood, that biogenic carbon is transferred to the product.
Wood products therefore constitute a pool (reservoir) of biogenic carbon
for the duration of their service lifetime as those products. At end-of-life, that carbon leaves the product system; in the case of use for energy generation the biogenic carbon is oxidised to carbon dioxide and released back into the atmosphere.
The standard provides a calculation method
to quantify the amount of carbon dioxide sequestered on the basis of the biogenic carbon contained in the wood.
The calculation is based on the atomic weights of carbon (12) and carbon dioxide (44), the product biogenic carbon content, the volume of wood, density and its moisture content.
The following equation shall be used:
Where:For wood-based products
, the volume of wood content is Vω = Vp x Wood Percentage, where Vp = Gross volume of the wood-based product (m3). Let's have an example.
Consider European whitewood incorporated into a building as glulam or cross-laminated timber with the following parameters:
using equation (1):
For any project, estimation of the total amount of carbon dioxide is determined by quantifying the volume of wood of each species used in each wood and wood-based product applying the above calculation and then adding together. (i.e. P1CO2 + P2CO2 etc).
It worth noting that this data can also be considered the basis for environmental product declarations.For info: