Life cycle assessment of a Danish office building designed for disassembly

Figures & data

Table 1. Life cycle stages.

Life cycle stages	Process	Module	DGNB
Production	Extraction of raw materials	A1^a	×
	Transport	A2^a	×
	Production	A3^a	×
Construction	Transport	A4
	Construction/assembly	A5
Use	Commissioning	B1
	Maintenance	B2
	Renovation/repair	B3
	Replacement	B4^a	×
	Refurbishment	B5
	Energy consumption for operation	B6	×
	Water consumption for operation	B7
End of life	Deconstruction/demolition	C1
	Transport	C2
	Waste recovery	C3^a	×
	Disposal	C4^a	×
Next product system	Potential for reuse, recovery and recycling	D^a	×

Notes: Life cycle stages are according to EN, 15978 (2012) and modules included in the Deutsche Gesellschaft für Nachhaltiges Bauen (DGNB) certification scheme.

^aModules included in the study.

Table 2. Construction materials by building element (including technical building services).

Building component	Elements	Element share (%)	Component share (%)	Mass (kg)
Columns	Reinforced concrete	1	1	1.E+05
Beams	Construction steel and reinforced concrete	3	3	4.E+05
Roof	Reinforced concrete	7	8	8.E+05
	Asphalt and plastic	1		8.E+04
	Rockwool insulation	0.3		3.E+04
Foundation	Reinforced concrete	6	6	7.E+05
Ground slab	Reinforced concrete	9	10	1.E+06
	Polystyrene insulation	0.03		4.E+03
	Screed, epoxy and leca stones	2		2.E+05
Concrete sandwich facade	Reinforced concrete	14	15	2.E+06
	Rockwool insulation	1		6.E+04
	Polystyrene insulation	0.03		4.E+03
	Brick shells, mortar and bitumen membrane	1		6.E+04
Floor	Varnish and oak tree flooring	0.1	38	1.E+04
	Glass wool insulation	0.2		2.E+04
	Gypsum	0.2		3.E+04
	Galvanized steel	0.4		5.E+04
	Reinforced concrete	37		4.E+06
	Tiles, mortar and adhesive	0.01		7.E+02
Internal walls	Gypsum	0.4	15	5.E+04
	Rockwool insulation	0.3		3.E+04
	Steel, stainless steel, aluminium	0.1		8.E+03
	Glass	0.4		4.E+04
	Acrylic paint	0.04		4.E+03
	Reinforced concrete	14		2.E+06
	Bitumen membrane	0.002		2.E+02
Staircase	Reinforced concrete	2	2	2.E+05
Technical building services	Stainless steel, galvanized steel and cast iron	1	1	7.E+04
	PVC	0.001		7.E+01
	Sanitary ceramics	0.03		4.E+03
Others	Aluminium windows, doors and solar shading	1	1	8.E+04
	Wooden doors	0.04		5.E+03
Total		100	100	1.E+07

Notes: All building related constructions and technical building services have been considered in the study.

Table 3. Percentage of material shares by weight (kg).

	Scenarios
Material shares (%)	T	DfD	O1	O2	O3	O4
Concrete	81.8	81.4	80.6	76.6	78.0	73.8
Mortar	0.2	0.2	0.01	0.01	0.01	0.01
Glass	1.3	1.3	3.0^a	3.1^a	3.1^a	3.6^a
Gypsum	1.2	1.2	1.3	1.3	1.4	1.6
Insulation	1.7	1.7	1.2	1.2	1.3	1.5
Metals	6.6	7.6^a	7.2	10.4^a	7.2	10.5^a
Paints and varnishes	0.5	0.5	0.5	0.6	0.6	0.7^a
Plastic	0.2	0.2	0.2	0.2	0.2	0.6
Ceramics and clay	1.5	1.5	0.8	0.8	0.8	1.0
Stone and gravel	0.8	0.8	0.8	0.9	0.9	1.0
Wood	0.4	0.4	0.6	0.6	2.2^a	0.7
Asphalt	3.8	3.8	4.1	4.2	4.3	4.9

Notes: Material shares (kg) over a building lifespan of 80 years taking material replacements into account.

^aObvious material share shifting between the scenarios as a result of substituting concrete for other materials.

DfD = design for disassembly; O1 = optimization scenario 1 (concrete columns); O2 = optimization scenario 2 (steel columns); O3 = optimization scenario 3 (wooden columns); O4 = optimization scenario 4 (bubble decks); T = traditional building design.

Figure 1. Contribution of life cycle stages' of environmental impacts over an 80-year building lifespan.

Figure 2. Contribution of building components’ environmental impacts, T, over an 80-year building lifespan.

Figure 3. Contribution of building materials’ environmental impacts, T, over an 80-year building lifespan.

Figure 4. Accumulated embodied CO₂ emissions over an 80-year building lifespan.

Table 4. Potential embodied impact savings of the reusable component compared with no reuse.

Note: Weighted impact savings are calculated as the average impact savings of each reusable component compared with no reuse using equal weighting factors for each environmental impact category assessed. This includes GWP, ODP, POCP, AP, EP, ADPe, ADPf, FAETP, MAETP, HTP and TETP. For abbreviations, see the text.

Table 5. Potential embodied impact savings of the building scenarios compared with T.

Notes: Energy consumption during operation is not included. Weighted impact savings are calculated as the average impact savings of each building scenario compared with no reuse of the reusable components using equal weighting factors for each environmental impact category assessed. This includes: GWP, ODP, POCP, AP, EP, ADPe, ADPf, FAETP, MAETP, HTP and TETP. For abbreviations, see the text.

DfD = design for disassembly; O1 = optimization scenario (concrete columns); O2 = optimization scenario 2 (steel columns); O3 = optimization scenario 3 (wooden columns); O4 = optimization scenario 4 (bubble decks).

EN 15978. (2012). Sustainability of construction works – Assessment of environmental performance of buildings – Calculation method.

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