Last edited 23 Aug 2022

Biobased materials

[edit] Introduction

Biobased is a loose term that describes an organic material or product that contains in whole or in part biogenic (from biological sources) carbon. It refers to materials that derive from living matter and may be used interchangeably with 'biogenic' to describe the same, though the former may only describe the base material rather than the whole. Biomaterials on the other hand have come to have a specific meaning which relates to synthetic, bio-based or natural biomaterials in contact with biological systems such as cells or tissues, these must be biocompatible.

Bio (carbon) content is based on the amount of biogenic carbon present, and defined as the amount of bio carbon in the material or product as a fraction of weight (mass) or percent weight (mass) of the total organic carbon (BS EN 16785-2:2018 or ASTM D6866).

% bio or biobased (carbon) content = Bio (organic) carbon/total (organic carbon) * 100

[edit] Biogenic carbon cycle

Although fossil fuels, such as coal, derive from organic matter from millions of years ago locked in the ground, they are no longer part of the biogenic carbon cycle and therefore non-biogenic. Biogenic materials operate within the bioenergy system, so for example the burning of biomass returns to the atmosphere the carbon that was absorbed as the plants grew and can be replenished by new plants, whereas the burning of coal cannot because of the rate of sequestration.

The IPCC distinguishes between the slow domain of the carbon cycle, which has a turnover beyond 10,000 years, and the fast domain (the atmosphere, ocean, vegetation and soil), which has turnover times of 1– 100 and 10– 500 years, respectively. Fossil fuel use transfers carbon from the slow domain to the fast domain, while bioenergy systems operate within the fast domain. (source: National Council for Air and Stream Improvement)

It is important to note that the use of any material in a building that contains sequestered carbon (coal included) might be seen as a way to stop it being burned and therefore keeping the carbon locked in.

There are a growing number of articles relating to bio-based materials on Designing Buildings, some of which are listed below.

Designing Buildings Anywhere

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