How many tonnes of timber must my Attefallshouse be constructed from in order to reach a zero impact standard?
First, we need to set up a mathmatical model. Here’s mine:
In order to use X1kg of float glass in the house, I must sequester Xkg of carbo (C), which equals Xtonnes of timber.
From my previous blog post, we saw that ”one metric ton of dry building timber stores roughly 510 kilograms of carbon, corresponding to 1.8 metric tons of CO2 ” (Link).
And the prouction of this tonne of wood from raw timber to usable product: ”Making one cubic meter of lumber releases a mere 50 kilograms of carbon as greenhouse gas CO2″.
That leaves us with a negative value of 460kg of sequestered C, taken from the atmosphere per metric tonne of timber.
Second lets read up about the Embodied energy of common glass types:
Article: Glass manufacturing is an energy-intensive process and results in significant CO2emissions. However, the overall CO2 balance is favorable when large operational energy savings are considered
”In total, the manufacture of 1 tonne of packed float glass results in the emission of approx 1.2 tonnes of CO2.”
Thus, 1 tonne of produced float glass requires this much ready made timber to have a net neutral balance in terms of Embodied CO2:
1,2t CO2 per cubic metre glass/0,46 t of C per m3 of readily produced timber product=Ratio value= 2,608
1 tone of float glasse thus requires a minimum 2,608 tonnes of ready made timber product in order to remain at a net neutral embodied CO2 balance in the house.
That means if you want to use an average of 8m2 of triple glazed windows in the house, with a standard weight corresponding to 32kg-per-total-m2-of-triple-glazed-window, that means that the total glass in the house would be
WHats the cost of this glass on the environment then?
Weight of glass * ratio value = Minimum amount of timber product weight needed in order to remain at a Neutral CO2 balance
The total CO2 impact for the glazing alone would then be
248kg glass*2,608=646,956=647kg of timber product in the house.
My goal is now to use a minimum of 647kg in the structure, facade and roof of the house.
Related Search ”Embodied CO2 Glass”: