Summary of the publication: Applications of environmental data and declarations for building materials

Building research institutes in Norway, Sweden, Finland and Denmark have carried out a project concerning environmental data on building materials supported by the Nordic Council of Ministers. The project period was from 1993 to 1997.

In 1994 guidelines were prepared for collecting and processing environmental data on building materials. Furthermore, environmental data were collected on building materials, concrete and timber, and standard data on fuel, electricity and transportation. The data were published in the publication: Environmental Data for Building Materials in the Nordic Countries (TemaNord 1995:577).

In 1995 data on steel products were collected and these data will be published in an article in an international journal. The article compares the collected data and includes discussions of applications of standard data, allocation rules and data uncertainty.

The project was completed with a workshop in 1997. At the workshop examples from applications of environmental data were discussed. Participants in the workshop were researchers, producers, and building authorities. The project was lead by the Danish Building Research Institute: Summary of the discussion at the nordic workshop

Extract of the publication

The building sector uses large amounts of materials for construction of buildings and large amounts of fossil fuels for heating buildings both causing great environmental impacts. This leads to development of methods for environmental design and assessment of buildings. These methods are based on life-cycle assessment (LCA) and can be used to point out processes and phases with important environmental impacts.

Environmental data for materials are very important in LCA of buildings, but the requirements to data depend on the application of LCA. LCA can be used internally to develop new products or externally to document environmental effects from products.

The purpose of this project is to demonstrate the environmental performance of building elements in a concrete panel building and in a multi-storey wooden building using available data and existing methods for the inventory analysis and the impact assessment.

Life-Cycle Assessment

Principles of LCA are discussed both in Europe and all over the world. ISO standards for LCA are being developed, and standards for LCA will be available within 2-3 years. Today it is generally agreed that a LCA consists of:

  • Goal and scope including a definition of the functional unit
  • Inventory analysis
  • Impact assessment
  • Interpretation of results.

These steps are followed in this project, which is part of a Nordic Wood Programme with the aim of increasing application of wood in buildings (reference 1).

Goal and scope
The purpose of this project is to assess environmentally selected pilot projects and to compare wood with other building materials. The project should also demonstrate use of available data and existing methods.

It has not been the goal to collect new data and develop new methods, and therefore the project does not show a realistic comparison between the different buildings because of missing data and incomplete methods.

It was decided to limit the assessments to some important building elements in two selected buildings: Outer walls, inner walls and floorings in a building of concrete panels and in a new developed wooden building constructed of prefabricated units. The wooden building will be built in 3-5 storeys.

The method should include all important environmental effects which can be assessed quantatively within the three main categories: Ressources, human health and ecological health. This project includes environmental parameters for energy sources, scarce materials, global warming, ozone depletion, acidification and formation of photochemical oxidants, nutrient enrichment, human toxicity, ecotoxicity and different types of waste.

The functional unit describes the service of a product quantitatively as well as qualitatively. The unit also includes the service life. As the building and the building elements have many services it is difficult to select one property for defining the functional unit. In this project the functional unit is defined as 1 m2 of the building element, and the service life is fixed at 50 years for all the materials involved.

Inventory analysis

At this stage, a system should be carefully defined and the necessary data for the materials involved should be collected.

System
The system includes all technical aspects, but does not include social and economic aspects. The technical system includes processes of supply, processes of life-cycle of a building, and processes of disposal. This project deals only with some phases of a life-cycle of a building, from "cradle to construction of the building".

Illustration-fra-Rap306.jpg

Figure 1. The figure shows the system boundaries for the technical system and life-cycle of a building.

The project includes an inventory analysis and an impact assessment for parameters which can be assessed quantatively. The inventory analysis includes data for supply of fuels, electricity, heat, water and by-products and calculates the amounts of different types of waste, but does not include data for the disposal of the waste.

The project includes a qualitative assessment of the working environment at the construction and the demolition place together with a qualitative assessment of the indoor climate related to building elements. These assessments are not included in this paper.

Selected building elements
This project includes an inventory analysis for floorings, inner walls and outer walls. The materials used in the two selected buildings are given in table 1.

Table 1. Materials in floorings, inner walls and outer walls.

Building of concrete

Wooden building

Floorings

floorings of reinforced concrete

gypsum/plast/gypsum on steel framework
mineral fibres
chip board mineral fibres
fibre board1

Inner walls

reinforced concrete

gypsum/mineral fibres/gypsum on wooden
framework

Outer walls

concrete
mineral fibres
clay bricks

gypsum/mineral fibres/plast
gypsum/mineral fibres/gypsum on wooden
framework
facing of cedar with impregnated laths2

1. Environmental data for glue are not included.
2. Environmental data for impregnating agents are not included.

The inventory analysis should include all important materials, but it has not been possible to obtain available data for glue in chip and fibre boards.

Environmental parameters
LCA should include all the important environmental impacts and in this project data were collected on energy consumption, emissions to air, amount of waste and harmful chemicals (reference 2).

Inventory analysis
The inventory analysis uses mass balances to calculate the amount of used materials and the emissions related to these materials. The inventory analysis uses a tool developed at the Danish Building Research Institute. The tool needs composition of building elements and data for the building materials involved (reference 3). Results from the analysis are given in table 2.

The table lists:

  • Consumption of scarce non-renewable energy sources and materials
  • Use of by-products
  • Consumption of energy
  • Emissions to air, calculated from the consumption of energy
  • Production of waste.

Table 2. Input and output data for building elements from "cradle to construction of the building".

Floorings concrete building

Floorings wooden building

Inner walls concrete building

Inner walls wooden building

Outer walls concrete building

Outer walls wooden building

Energy sources

Oil

Natural gas

kg

Nm3

6,5

0,85

2,9

0,54

9,3

1,7

3,9

0,66

7,6

9,7

2,6

0,59

Materials

Zinc

kg

0,2

By-products

Fly ash

Waste gypsum

Scrap iron

Iron oxide

kg

kg

kg

kg

9,9

1,0

16

14

0,8

7

0,3

32

10

0,5

4,9

0,2

17

Energy1

MJ

540

520

7 90

340

1070

330

Feedstock Energy1

MJ

610

94

280

Emissions

CO2

SO2

NOx

Pb

Cd

Hg

CO

VOC

kg

kg

kg

mg

mg

mg

g

g

61

0,099

0,21

30

0,9

0,6

91

4,8

23

0,12

0,10

350

9

2

140

16

86

0,17

0,31

45

2

1

58

7

19

0,12

0,095

2

0,1

0,1

19

8,0

96

0,20

0,30

32

1

1

59

8,3

17

0,11

0,077

1

0,09

0,1

28

9,8

Waste

Bulk waste

Slag and ashes

Hazardous waste

Com­bustible waste

kg

g

g

kg

19

350

10

0

8

350

0,04

7,5

37

530

5

0

7,3

230

0,6

2,9

31

540

4

0

2,7

220

2003

7,0

  • Feedstock energy is not included in the energy.
  • Feedstock energy is calculated from the higher heating value of materials which can also be used as fuels.
  • Hazardous waste are impregnated laths.

Table 3. Waste from demolition of buildings.

Floorings concrete building

Floorings wooden building

Inner walls concrete building

Inner walls wooden building

Outer walls concrete building

Outer walls wooden building

Reuse

Concrete

Clay bricks

Steel

277

-

3

-

-

3

406

-

8

-

-

-

270

153

5

-

-

-

To combustion

Chip and fibre boards

Laths

-

-

21

9

-

-

-

5

-

-

-

13

To disposal

Gypsum

Mineral fibres

Mortar

Impreg­nated wood

-

-

-

-

22

5

-

-

-

-

-

-

43

4

-

-

-

4

81

-

25

7

-

2

By-products are waste produced in one process and used as materials in another process eg flyash and waste gypsum. The use of by-products saves raw materials, and burning of combustible waste saves energy sources.

Disposal of materials
In table 3 on the previous page the waste from demolition of building elements is listed. In Denmark steel is recovered, concrete and clay bricks are crushed and reused. Mineral fibres and gypsum boards are dumped as they cannot be recycled today. All combustible waste is burned in refuse disposal plants producing heat and electricity. From the results it can be seen that building elements in the wooden building give most waste to disposal.

Impact assessment

Impact assessment includes classification, characterization, normalization and evaluation. The environmental parameters are classified according to environmental impacts, eg CO2 on global warming, SO2 and NOx on acidification. To calculate the contribution to an environmental impact, the emission is multiplied by an equivalency factor. The impacts are calculated per year of service life using an estimate of service life. In this project all materials have a service life of 50 years.

The impacts are normalized by division with a normalization reference. The normalization reference is the environmental impact divided by the affected population, eg total global warming divided by the population of the world. The unit for the normalized environmental impacts is person equivalent, PE. For resources the impacts are multiplied by a weighting factor and give the unit person reserve, PR.

Table 4. Normalized environmental impacts of building elements from "cradle to construction". The service life for all building materials are fixed at 50 years.

Environ­mental impacts

Floorings concrete building

Floorings wooden building

Inner walls concrete building

Inner walls wooden building

Outer walls concrete building

Outer walls wooden building

Resources

Oil

Natural gas

µPR

µPR

5

0,7

2

0,4

7

1,4

3

0,5

8

8

0,05

0,1

Environ­mental impacts

Global warming

Acidification

Nutirent enrichment

Photo.­oxidant.

Persistent toxicity

Human toxicity

µPE

µPE

µPE

µPE

µPE

µPE

140

40

20

6

7

15

55

31

9

12

43

17

199

62

28

6

17

21

43

30

9

3

1

8

220

67

28

7

12

22

38

26

7

5

1

7

Waste

Bulk waste

Slag and fly ashes

Hazardous waste

µPE

µPE

µPE

280

19

10

110

20

0,04

550

30

5

120

13

0

454

32

4

41

13

1941

1. Impregnated wood is assumed to be hazardous waste.

The results in table 4 show that the most important impacts are global warming, acidification and nutrient enrichment. All these impacts are larger for the concrete panel building than for the wooden building. Persistent toxicity is large for floorings in the wooden building because of galvanized steel studs.

Harmful substances
Today there is a general desire to reduce use of chemicals as they may cause human health and ecological health impacts. However, it is difficult to assess the impacts from the chemicals as exposure data are missing. Therefore it was decided to emphasize the use of harmful chemicals. These chemicals are mentioned in lists of hazardous and environmentally harmful substances.

The Danish Environmental Protection Agency has also published a list of unwanted substances (reference 4). Formaldehyde and phenol are on that list.

Table 5. Harmful substances used in the production of the building elements.

Hazardous substances

Aquatic environment (List I)

Hazardous waste
(Annex II)

Ammonium chloride Glycol

Formaldehyde

Phenol

Phosphoric acid

Resorcinol

Yes

Yes

Yes

Yes

Yes

Yes

No

No

No

No

No

No

No

No

No

Yes

Yes

No

Commission Directive 93/101/EEC adaptable to technical progress for 20th Council Directive 67/548/EEC.
Council Directive of 4 May 1976 on pollution caused by certain dangerous substances
discharged into aquatic environment of the Community (76/464/EEC). Substances on list 1.
Council Directive on hazardous waste (91/689/EEC), substances in Annex II.

Glycol is used as a grinding agent in cement production. Ammonium chloride and formaldehyde are constituents in glue for chip boards, and resorcinol is an reactant in the glue. Laths are impregnated with chemicals like phosphoric acid, formaldehyde and dicyandiamide.

Discussion

The results show that the most important environmental impacts are related to the consumption of energy. The energy consumption is larger for building elements in the concrete panel building than in the wooden building (see table 6).

The most important impact is global warming caused by emission of CO2. The emission of CO2 depends on the consumption of fossil fuels. It is normally assumed that biofuels are CO2neutral. Biofuels are used for drying of wooden products. Therefore the emission of CO2 is smaller for the elements in the wooden building than in the concrete building (see table 7).

Acidification is caused by emissions of SO2 and NOx. The results show that the SO2 emission is of the same order for all the building elements, while the emission of NOx is much larger for elements in the concrete panel building than for the elements in the wooden building.

Table 6. Energy consumption for building elements "from cradle to construction".

Building of concrete MJ/m2

Wooden building
MJ/m2

Floorings

540

520

Inner walls

790

340

Outer walls

1070

330

Table 7. Emission of CO2 for buildings elements "from cradle to construction".

Building of concrete
kg/m2

Wooden building
kg/m2

Floorings

61

23

Inner walls

86

19

Outer walls

96

17

Environmental improvements of building elements

It is important to suggest environmental improvement. Therefore, it is necessary to know the contribution from each material separately (see table 8). For floorings in the concrete panel building the production of cement and the production of concrete panels are responsible for the emission of CO2, SO2 and NOx, while emission of Pb comes from the production of galvanized steel studs.

Table 8. Inventory data as consumption of energy, emissions of CO2, SO2, NOx and Pb divided into materials.

Floorings

Mass

Energy

CO2

SO2

NOx

Pb

Total for concrete floorings

310 kg

540 MJ

61 kg

99 g

210 g

30 mg

Cement

Steel

Sand and stone

Production

41 kg

4 kg

246 kg

42 %

15 %

5 %

38 %

62 %

10 %

3 %

24 %

33 %

16 %

4 %

46 %

67 %

4 %

11 %

17 %

22 %

76 %

0 %

2 %

Total for wooden
floorings

67 kg

520 MJ

23 kg

120 g

100 g

350 mg

Wood products

Gypsum

Galvanized steel

Mineral fibres

34 kg

24 kg

3 kg

6 kg

44 %

23 %

18 %

16 %

18 %

28 %

31 %

22 %

20 %

35 %

17 %

28 %

38 %

38 %

13 %

12 %

0 %

1 %

99 %

0 %

Harmful substances:
Glycol in the cement production.
Formaldehyde and ammonoum chloride in glue in chip boards. Phenol and resorcinol in glue in fibre boards.
Formaldehyde and phenol in the glue in mineral fibres.

Environmental declaration and labelling
The environmental parameters in environmental declaration and labelling of materials should include the most important parameters within the categories: Ressources, human health, and ecological health. These include energy consumption, use of materials, requirements to recycling of materials, and to production of waste together with restrictions of chemicals. In table 9 these parameters are compared with the environmental parameters in this project.

Table 9. Environmental parameters in environmental declaration and labelling.

Categories

Effects

Environ­mental
declaration,
proposal (ref. 7)

Environ­mental
labelling,
boards (ref. 5)

Environ­mental
labelling,
floor (ref. 6)

Environ­mental
parameters,
this project

Resources

Scarce energy
sources

Total energy

Total energy
Fossil energy

Total energy1

Consumption of oil and natural gas

Scarce materials

Consumption of
materials

Use of
non-renewable
raw materials
30 % recycled

Renewable raw
materials
Non tropical wood2

Scarce materials

Ground water

Landscape

Human
health

Working
environment

Qualitative

Indoor climate

Formalde­hyde
Radio activity
Emission of fibres

Wood:
Formalde­hyde

Qualitative

In the environment

Harmful substances

Ecological
health

Global warming

CO2-eq

CO2-eq

Depletion of ozone

CFC11-eq

Acidification

SO2-eq

SO2-emission

SO2-eq

Nutrient
enrichment

N-eq

N-eq

Photo­chemical
oxidant

C2H4-eq

Not for wood:
Emission of VOC

C2H4-eq

Ecotoxicity

Board produced by
wet processes: COD Carton and paper:
Restrictions of chlorocom­pounds,
COD, surfactants

Persistent toxicity

Harmful substances

Others

Waste

Bulk waste
Hazardous waste

Use of waste

Waste

Bulk waste
Hazardous waste
Slag and ashes

Harmful substances

Harmful and
unwanted substances

Restrictions of:
CRAN-substances, formalde­hyde,
harmful substances

Ban on:
Certain substances

Restrictions of:
CRAN-substances, formalde­hyde,
harmful substances

Ban on:
Certain substances

Harmful substances Unwanted substances

Others

Environmental policy Annex with emissions

Instruction for use

Wearability
Product information

1. Not including embodied energy for plastic.
2. Wood from sustainable forest management.

Conclusion

The results show that it is possible with available data and existing methods to assess building elements environmentally. The most important environmental impacts are related to consumption of energy. The methods do not calculate the impact from disposal of waste, but calculate only the amount of different types of waste. For chemicals only the harmful ones are listed as exposure data, and easy methods to assess them are non-existent.
Environmental labelling of building materials very often uses environmental parameters related to energy consumption and gives some restrictions for the use of chemicals.

References

  1. Krogh, H., Baadsgaard-Jensen, J., Abildgaard, A., Riberholt, H. 'Miljøvurdering af fleretages træhuse'. Nordisk Industrifond under Nordic Wood programmet "Træhus i flere etager". Delprojekt IV: Miljø- og kulturprofil af fleretages træhuse. DTI Træteknik. 1998.
  2. Hansen, K., Krogh, H., Hoffmann, L., Glavind, M., Jensen, J. B., Hansen, H., Nielsen, P. A., Poulsen, T. S. 'Miljørigtig projektering. Miljødata for byggematerialer'. Miljø- og Energiministeriet. Miljøstyrelsen (forventes udgivet i 1998). Rapporten indgår også i Håndbog i miljørigtig projektering. Publikation 121, bind 2. BPS-Centret, DTI Byggeri, Taastrup. 1998.
  3. Petersen, E. 'Database og opgørelsesværktøj for bygningsdeles og bygningers miljøparametre'. SBI-rapport 275. 2. udgave. Statens Byggeforskningsinstitut. Hørsholm. 1998.
  4. 'Chemicals – Status and perspectives'. Excerpts from a discussion paper from Danish EPA. Ministry of the Environment and Energy. Danish Environmental Protection Agency. Copenhagen. 1996.
  5. 'Platematerialer til bygnings-, innrednings- og møbelindustri'. Versjon 2.1. Kriteriedokument 16. juni 1995 – 15. juni 1998. Nordisk Miljømærkning.
  6. 'Miljømærkning av gulv'. Versjon 2.0. Kriteriedokument 6. februar 1997 – 4. oktober 2000. Nordisk Miljømærkning.
  7. Toldsted, J. D., Stranddorf, H. K., Hansen, L. E. 'Miljøvaredeklarationer'. Arbejdsrapport nr. 47 fra Miljø- og Energiministeriet. Miljøstyrelsen. København. 1997.

Summary of the discussion at the nordic workshop

Mere om: Miljødata for bygningsdele og materialer

Forskere

Hanne Krogh et al.

Sidst opdateret 17. februar 2006