Life-cycle Analysis

Exercise 15.5.1: Materials Life Cycle Analysis
Not Currently Assigned

Take about 5 minutes to complete this assignment.

  1. In the life-cycle analysis we showed in the slides, we mention the general outputs of the life-cycle. We list "other impacts". These outputs can have effect on the environment, economy, or society.

    Come up with three other, more specific, outputs during a materials life-cycle and provide some examples (one environmental, one societal, one economic) for a specific material. Classify these outputs as positive or negative.

Exercise 15.5.2: Life Cycle Analysis: Hempcrete
Not Currently Assigned

Take 2-3 minutes on this problem.

  1. Hempcrete is a bio-composite material that is a mixture of hemp hurds (a woody portion of the hemp plant), lime, and a hydraulic additive. It is used for thermal insulation in building construction. Note, cannabis subspecies sativa (not indica), is now federally legal in the US, thanks to the 2018 Farm Bill.

    Bio-composites can have negative $\ce{CO2}$ footprints, as the biological components sequester and store $\ce{CO2}$ from the atmosphere during growth. Hempcrete sequesters 325 kg of carbon per metric ton!

    Which of the situations below (select all that apply) do you expect would be the best choice if you want hempcrete to have the best impact on the environment in terms of $\ce{CO2}$ production? (As you know, $\ce{CO2}$ is a greenhouse gas.) Assume that $\ce{CO2}$ production due to local transportation is negligible.

    1. Hempcrete produced in a nearby factory from local feedstock.
    2. Hempcrete produced in a nearby factory from imported feedstock delivered by air.
    3. Hempcrete that has been reused from a construction project down the road.
    4. The effective $\ce{CO2}$ footprints of all hempcrete products must be the same.