Regionalised Life Cycle Assessment of Bio-Based Materials in Construction; the Case of Hemp Shiv Treated with Sol-Gel Coatings

Abstract

Interest in intrinsically low-energy construction materials is becoming mainstream, and bio-based materials form a key part of that group of materials. The goal of this study was to analyse the environmental impact of applying a sol-gel coating on hemp shiv, in order to improve the durability of this innovative bio-based material, using a regionalised LCA model, taking into account regional specific peculiarities. This study analysed the environmental performance of using bio-based materials in the building envelope compared with traditional synthetic construction materials, and compared the impact of a regionalised approach with a global approach. The carbon footprint of treated hemp shiv in a wall with a U-value of 0.15 W/m2.K was compared to untreated hempcrete and a reference cavity wall with the same U-value. Considering the environmental damage caused by the production of hemp shiv, nitrogen fertiliser was the hotspot. The LCA results showed that, using innovative bio-based materials in construction, treated hemp shiv with sol-gel can decrease the carbon footprint of a building envelope through carbon sequestration. Using the more accurate site-specific information in life cycle inventory and impact assessment methods will result in more consistent and site-appropriate environmental results for decision-making.

The Heat Conductivity Properties of Hemp–Lime Composite Material Used in Single-Family Buildings

“…It has a negative carbon footprint because during its growth, hemp absorbs more carbon dioxide than is used later to make building materials [3,4]. Hemp lime has high thermal insulation, heat accumulation, vapour permeability, is non-flammable, can be used as a fertiliser after demolition and is 100% decomposable [5,6].…”

“…We can find many papers related to this issue mostly dealing with the materials acoustic absorption by Kinnane et al [36], or by Gle et al [37]. In the last three years, we can also see that a lot of scientists like Bourebrab et al [38] or Heidari et al [6] are dealing with the surface coating of hemp-lime composites to increase their resistance to humidity or life cycle.…”

Life cycle environmental benchmarks for Flemish dwellings

“…bio-based) building materials. Innovative materials and construction practices could provide lower environmental impacts [66,[77][78][79][80] and would enable definition of more ambitious benchmarks. Secondly, the bottom-up benchmarks should be complemented by top-down benchmarks to reveal their level of ambition with respect to global or national goals.…”

Bio-concretes and GHG emissions reduction: what the scientific literature says?

“…This scenario is completely different when considering the southern hemisphere. In Brazil, the National Industrial Hemp Association (Associação Nacional do Cânhamo Industrial) [14] states that hemp production is not legalised, which means hempcrete production is not a viable option. However, the diversity of agriculture in Brazil increases the possibility of incorporating other biomaterials for the development and production of new bioconcretes that are more appropriate to the reality of tropical and subtropical countries.…”