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Rating Resource Efficiency of Building Materials
Speakers:
Becker, N.1
1
VDI Zentrum Ressourceneffizienz GmbH, Berlin, Germany
Abstract: Aiming for sustainability resource efficiency plays a major role as the building industry is
one of the world’s largest consumers of resources. This shows the example of Germany: its building
industry is responsible for 85 % of the countries extraction of mineral raw material and produces
more than 50 % of the countries waste accumulation [1]. Therefore the building sector is one of the
focal points of the German Resource Efficiency Programme (ProgRess)[2]. It largely contributes to
the central indicator for national resource efficiency, i. e. the raw material productivity. This is
defined as the quotient of GDP in Euro and abiotic material in tons. The central aim is to double it
until 2020 as compared to 1994[3].
Beside this very general indicator on a country wide scale it is useful to evaluate resource efficiency
also on the material’s level in order to improve the situation from bottom up. Based on a complete life
cycle analysis a set of four indicators has been derived. These indicators have been used to analyse
the resource efficiency of insulation materials and supporting structures.
Resource efficiency, life cycle analysis, insulation material, supporting structures
Introduction
So far the discussion on sustainability has very much focused on the reduction of the
building’s energy consumption during use, i. e. on an increase of energy efficiency. However
it is essential to also widen the view for the construction and demolition period and to gain
thereby material efficiency. In the combination of energy and material efficiency resource
efficiency can be achieved. To evaluate it the following set of indicators has been derived:
•
•
•
•
type of raw material,
embodied energy,
greenhouse gas emission during production,
options for disposal.
Two groups of building materials have so far been analysed with these indicators: insulation
materials and supporting structures. Insulation materials are essential for the reduction of the
energy consumption during the use of a building and the actual retrofitting era. The
supporting structure plays a major role as it accounts for a large proportion of the weight of a
building.
Resource Efficiency of Insulation Materials
The set of indicators has been applied to analyse the resource efficiency of the wide variety of
insulation materials. In order to compare the different materials it has been asumed that a
poorly insulated construction shall be improved to a thermal transmission coefficient of U =
1
0.15 W/m²K. The necessary data on the embodied energy and the greenhouse gas emission
has been extracted from the German database Ökobau.dat 2011 which lists nearly all in
Germany available building materials [4].Additionally, Environmental Product Declarations
(EPDs) have been used [5].The results for the most common materials can be seen in figure 1.
Insulating Material
Production
Embodied Energy,
Greenhouse Gas
End of Life
Type of Raw
non-renewable
Emission
Disposal
Material
[MJ/m²]
[kg CO2-Eqv./m²]
mineral
glas wool
mineral (recycling)
121,9 - 426,7
7,2 - 25,2 dump category 1/2
mineral wool
mineral
61,6 - 144,6
3,6 - 9,1 dump category 1/2
porous concrete
mineral
397,0
35,8 dump category 2
foam glass
mineral
433,5
31,0 dump category 1/2
rock wool
vacuum isolation
panel
mineral
mineral (main
comp.)
208,0 - 659,5
15,1 - 47,9 dump category 1/2
EPS
fossil
345,3 - 497,7
11,8 - 17,3 thermal utilisation
PUR
fossil
437,9 - 517,3
22,0 - 25,1 thermal utilisation
extruded PS
fossil
642,5
28,9 thermal utilisation
flax
renewable
356,1
hemp
renewable
357,0
wood fibre board
renewable
223,0 - 1978,1
-63,3 - -3,9 therm. utilisation/composting
cork
renewable
280,1
-30,8 therm. utilisation/composting
cellulose fibre
renewable (recycl.)
189,6
9,4 mat./therm. utilisation
synthetic
renewable
36,9
cellulose fibre board renewable (recycl.)
528,3
Figure 1: Comparision of Resource Efficiency of Insulation Materials
5,7 therm. utilisation/composting
6,1 thermal utilisation
-7,0 thermal utilisation
12,3 thermal utilisation
To evaluate the results a large resource depletion has been marked in red, a medium in yellow
and a low in green. For a number of materials a range of values is given for the embodied
energy and the greenhouse gas emission. They have their origin in different applications of
the insulation material: for example glas wool is available for the insulation of a roof as well
as for the insulation of walls. The different applications influence the necessary compressive
strength and hence the required density and material consumption. Therefore the values for
the external insulation of a flat roof are clearly worse than the values for a common rafter
insulation. Overall, cellulose fibres show the lowest resource depletion. However they only
apply for a limited number of installation situations. The highest depletion comes from PUR
and etruded PS. Nevertheless figure 2 shows that they might be an option for the external
insulation of basement walls as for this special situation only a very limited number of
insulations materials is available. All of them figure a comparatively hight resource depletion.
2
700,0
642,5
600,0
497,7
500,0
517,3
483,8
437,9
433,5
Embodied Energy, nonrenewable [MJ/m²]
400,0
300,0
Greenhouse Gas Emission
[kg CO2-Eqv./m²]
PUR (w/o lamination)
23,6
22,0
28,9
extruded PS
25,1
PUR (aluminium lamination)
17,3
PUR (mineral fibre lamination)
31,0
EPS (Perimeter)
100,0
foam glass
200,0
0,0
Figure 2: Embodied Energy and Greenhouse Gas Emission for External Insulation of Basement Wall
With respect to the disposal all materials have been marked in red and yellow beside the
vacuum isolation panels. This highlightens the need for improvements with regard to the
circuitry. So far only vacuum isolation panels partily allow for material utilisation. Often
insulation materials are attached to buildings in a manner which does not allow for a sorted
demolition. This means that decisions allready taken during the planning and construction
period hamper a reusage and recycling at the end of life of a building in a number of decades.
In order to improve the resource efficiency of insulation materials it is necessary to develop
concepts for a sorted demolition of buildings and for a material reusage and recycling.
Resource Efficiency of Supporting Structures
The resource efficiency of supporting structures has been analysed using the example of a 3
meter high column that is loaded with 100 kN. It has been designed in wood, reinforced
concrete and steel. Figure 3 shows the results of a comparison for all four indicators.
Wood
type of raw material
Production
End of Life
Reinforced Concrete Steel
renewable
mineral mineral/recycled
embodied energy, nonrenewable [MJ]
185,0
118,4
835,4
greenhouse gas
emission [kg CO₂-Eqv.]
-52,4
17,2
60,6
material/thermal recycling/utilisation/
utilisation
disposal
recycling
disposal
Figure 3: Comparision of Resource Efficiency of Supporting Structures
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Regarding the first indicator, i.e. the type of raw material, wood stands out as a renewable
material whereas concrete and steel are of mineral origin. For steel the use of recycling
material is positive. The options for disposal of wood and steel have to be evaluated positively
as wood applies for material and thermal utilisation and steel can be fully recycled. The
disposal of reinforced concrete is improvable as most of it is reutilised for lower-grade
purposes and some of it is landfilled while only a small proportion is recycled. The
establishment of a recycling for the same purpose i. e. the usage in new buildings offers great
potentials for an increase in resource efficiency especially with regard to the large weight of
concrete and its wide usage. It can be concluded that wood is clearly the most resource
efficient material for supporting structures.
Conclusions
The used set of indicators show that the resource efficieny varies largely between the different
building materials. In order to increase it two major points can be identified: the selection of
special materials and the type of construction. The first determines the resource depletion due
to the production of the building material whereas the second largely influences the
possiblities for a sorted demolition. This is key to a reusage and recycling and central for a
significant reduction of resource depletion by the building industry.
References
[1] Bundesministerium für Umwelt, Naturschutz und Reaktorsicherheit (2012) Deutsches
Ressourceneffizienzprogramm (ProgRess), p. 74
[2] Federal Ministry for Enviroment, Nature Conservation and Nuclear Safety (2012)
German
Resource
Efficiency
Programme,
URL:
http://www.bmub.bund.de/en/topics/economy-products-resources/resourceefficiency/german-resource-efficiency-programme-progress/
[3] Die Bundesregierung (2002) Nationale Nachhaltigkeitsstrategie “Perspektiven für
Deutschland“, URL: http://bfn.de/fileadmin/NBS/documents/Nachhaltigkeitsstrategielangfassung.pdf
[4] Informationsportal
Nachhaltiges
Bauen
Ökobau.dat
2011,
URL:
http://www.nachhaltigesbauen.de/oekobaudat/
[5] Institut Bauen und Umwelt e. V. Umwelt-Produktdeklarationen (EPDs), URL:
http://bau-umwelt.de/hp6253/EPDs.htm
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