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MIPS analysis of natural resource consumption in two university buildings
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Building and Environment 41 (2006) 657–668 www.elsevier.com/locate/buildenv
MIPS analysis of natural resource consumption in two university buildings Paula Sinivuoria, Arto Saarib, a
Finnish Association for Nature Conservation, Kotkankatu 9, FIN-00510 Helsinki, Finland Department of Civil and Environmental Engineering, Laboratory of Construction Economics and Management, Helsinki University of Technology, P.O. Box 2100, FIN-02015 HUT, Finland
b
Received 23 September 2004; received in revised form 9 February 2005; accepted 23 February 2005
Abstract This article presents the findings of a study to investigate the scale and content of natural resource consumption in two Finnish university buildings, as well as the sensitivity of these calculations to the particular assumptions used. The calculations were made using the MIPS method. In the Physicum building, the main factors contributing to abiotic natural resource consumption were, in order of importance, use-phase electrical energy, mechanical and electrical services, rock excavation, the building’s frame and usephase heating. In the Viikki Info Centre building, the role of heating was less significant. Consumption of biotic natural resources was marginal. In both buildings the majority of water resource consumption was the result of use-phase electrical energy use. Air consumption was mainly the result of the building’s heating and electricity use. For abiotic natural resource consumption, the calculations were most sensitive to a halving of the service life of the building. The consumption of water and air was strongly influenced by the type of power plant from which the building’s energy sources originated. Reducing the natural resource consumption of a building is something that should be targeted right from the start, at the design stage. Since most of a building’s natural resource use is attributable to just a few factors, the calculation and control activities should focus on these very factors, such as use-phase energy, earthworks, the building’s frame and copper-containing mechanical and electrical services. r 2005 Elsevier Ltd. All rights reserved. Keywords: MIPS; Eco-efficiency; Natural resource consumption; Management; Life cycle; Buildings
1. Introduction The traditional environmental policy aims at preventing the effects of individual harmful substances, such as pollutants and toxins. It has been suggested by SchmidtBleek [1] that even though this is important, it is not sufficient by itself. Instead of focusing only on harmful substances, we should pay attention to our usage of all kinds of natural resources, also the non-toxic ones. In today’s world, we transfer an enormous amount of different kinds of natural materials from one place to another in the course of creating material prosperity for Corresponding author. Fax: +358 9 4513758.
E-mail address: arto.saari@hut.fi (A. Saari). 0360-1323/$ - see front matter r 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.buildenv.2005.02.022
ourselves: sand, gravel, water, air, mining waste, ore, etc. By doing this, we cause changes in the environment. The bigger the material flows, the bigger the environmental changes. Dematerialization, meaning a significant reduction in natural resource consumption in human activity, has therefore been set as an important goal. The MIPS method developed at the German Wuppertal Institute for Climate, Environment, Energy is a useful tool for measuring and managing the humaninduced material flows. MIPS stands for Material Input Per Service unit. It is a value that can be calculated for all final products that provide a service. The MIPS value relates the natural resources consumed by a product during its entire life cycle to the overall benefit derived
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from it. It provides a rough—but nevertheless indicative—approximation of the product’s potential environmental load. The smaller a product’s MIPS value, the lower its environmental load is considered to be, because it will be consuming fewer natural resources in relation to the amount of service it produces [1]. The construction and property sector is a significant user of natural materials. Materials are used not only in building and maintenance but also in producing the energy used in buildings. The composition of natural resource consumption in buildings has not previously been studied in any comprehensive manner in Finland. MIPS calculations have been made for buildings in other countries, however, but the results have not been widely published. This article presents the findings of a study to investigate the scale and content of natural resource consumption in two Finnish buildings (the Physicum and Viikki Info Centre buildings of the University of Helsinki), as well as the sensitivity of these calculations in relation to the particular assumptions made. Paula Sinivuori (Author 1) [2] has completed a Master’s thesis in connection with the study presented here, under the supervision of Arto Saari (Author 2).
2. Methods and materials 2.1. Calculating the MIPS value Expressed as an equation, MIPS appears as follows: MIPS ¼ MI=S;
(1)
where MI is the material input, S the service unit. The material input (MI) forming the MIPS numerator refers to the total amount of natural resources needed
for the creation and use of the product in question and for its waste management. It includes not only the materials bound up within it and those required for its production, but also all the materials involved in its transportation, equipment and packaging throughout its life cycle. The material input also includes the resources extracted from nature and used for producing the energy needed by the product. It thus encompasses the natural resources consumed throughout the product’s entire life cycle and expresses this as a unit of mass, for example kilograms. The waste flows associated with the product are not included as waste flows in the material input, because they are outputs from the product’s life cycle, not inputs. However, waste flows will have appeared as inputs in the life cycle of the product at an earlier stage, and so to this extent their mass is taken into account in the MIPS calculation. The MI must include the consumption of natural resources throughout the product’s entire life cycle, because the production process will generally involve transfer of a greater amount of material than those contained in the product itself. These natural resource transfers generated by, but not included in, the product are known as the product’s ecological rucksack. The ecological rucksack is often considerably heavier than the product [1]. All natural resources are not, however, calculated in the same MI but are divided into five different categories in the MIPS calculation: abiotic natural resources, biotic natural resources, water, air, and what is termed ‘earth movement in agriculture and forestry’ (Table 1). Five different MIPS values can thus be calculated for any product. The calculation of MIs makes use of the MI factors already calculated for many widely used materials, such as steel, cement and glass, and for different means of
Table 1 Natural resource categories in MIPS analysis [3] Abiotic materials
Biotic materials
Water
Air
Mineral raw materials
Biomass of plants from
All water actively
All air or its constituents Erosion that are actively used by Mechanical tillage of the
from mines, quarries and smelting plants Fossil fuels Rock and earth that are moved during the quarrying or excavation of abiotic raw materials Unused extracted earth from, for example, the construction and maintenance of buildings and transport infrastructure
human cultivation Biomass derived from uncultivated land but for human use, e.g. wild animals, fish and wild plants
extracted from nature, i.e. by technical means Water flowing through a water wheel located in a natural channel and water displaced by a ship’s propeller are not included
humans, e.g. the air needed for combustion and the air used in chemical and physical reactions. The calculations include only the weight of the components of air that are actually used, for instance the amount of oxygen consumed in the combustion process
Earth movements in agriculture and forestry
soil, such as ploughing and harrowing
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electricity production and transportation [4]. The MI factor expresses in kilograms the amount of natural resources needed to create 1 kg of material or 1 kW h or 1 tonne km [5]. The MI factor thus describes the material intensity of the particular material, energy production method or form of transport in question. In practice, MI is calculated by multiplying the material and energy consumptions and transportations of the product being studied for the whole of its life cycle by the corresponding MI factors. If the necessary MI factor does not exist, the natural resource consumption will have to be calculated separately right from the beginning [4]. The service unit (S) forming the MIPS denominator refers to the benefit derived from the product [1]. It cannot be measured like a MI but is instead determined separately for each product. The total amount of usage times or years of use during the life cycle are examples of what may be selected as the service unit of a product [5]. The concept of service unit highlights the fact that people do not actually need the product itself but simply the service provided by it [1]. 2.2. Application of MIPS calculations to this study 2.2.1. Cases studied The cases chosen for this study were two buildings of the University of Helsinki. The reason for this choice was the fact that the study was partially made for the Technical Department of the University of Helsinki, which was interested in testing the MIPS calculation method on its buildings. The Physicum building (Figs. 1 and 2) was completed in 2001. It has a gross floor area of 17,871 m2 and a net useable floor area of 14,578 m2. The building is located in the Kumpula campus of the University of Helsinki, Finland. Its occupants include the Departments of Physical Sciences, Geology and Geography, all in the Faculty of Science, plus their laboratories and the Kumpula Science Library. The main part of the building is five stories high, the lowest of which is built into the rock. The library wing is two stories high. The second building in this study, the Viikki Info Centre (Figs. 3 and 4), was completed in 1999 and has a gross floor area of 11,150 m2 and a net useable floor area of 9104 m2. It is located in the Viikki campus of the University of Helsinki, Finland. Its occupants include the Viikki Science Library and a branch of the Helsinki City Library. It has five stories, the lowest of which is below ground level. Specification of structures of the Physicum and Viikki Info Centre buildings is presented in Table 2. Even though the buildings studied are both university buildings, they are not completely similar in terms of functionality. The most significant difference is the fact that the Physicum building has many laboratories,
Fig. 1. Physicum (2nd floor plan). Drawing: Architects Lahdelma & Mahlama¨ki Ltd.
whereas the Viikki Info Centre has none. Therefore the action that takes place in the Physicum building differs to some extent from the one in the Viikki Info Centre. 2.2.2. Selecting building components for the calculations The MIPS calculations for the buildings are not all encompassing, in that they do not cover all the components. The calculations do, however, cover those components which together account for the majority of the material flows, i.e. components with a large total mass and/or high MI factor. Calculations concerning the mechanical and electrical services were made only for the Physicum building, as the necessary data for the Viikki Info Centre was not fully available. The services components were the copper wiring of the computer network cabling, the copper and aluminium in the electrical wiring for the electrical, automatic and fire alarm systems, the ladder racks and
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Fig. 2. Physicum, Helsinki (photo: Jussi Tiainen). Fig. 4. Viikki Info Centre, Helsinki (photo: Jussi Tiainen).
related parts, the ventilation system, the pipes in the fire extinguishing system, the pipes in the heating system, the water and chilled water pipes, the laboratory pipes, the drains and the rainwater disposal system. To ensure that the results of the MIPS calculations could be used for overall comparisons, the rough assumption was made that the MIPS values for the mechanical and electrical services of each building per gross floor area unit per year were the same. The MIPS values for the Viikki Info Centre’s mechanical and electrical services were thus made on the basis of the MIPS values for the Physicum building.
Fig. 3. Viikki Info Centre, Helsinki (Street level floor plan). Drawing: ARK-house architects.
2.2.3. Selection of service unit The service produced by a building is the particular net useable floor area that it offers the user over a particular time period. The service unit used in the MIPS calculations for the buildings was selected as ‘the net useable floor area (m2)/the service life of the building in years’. The service life of the building (i.e. the period during which the building is assumed to be in use) was selected for the service unit calculation because it usefully indicates the amount of service produced by the
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Table 2 Specification of structures of the Physicum and Viikki Info Centre buildings
Excavation Fillings Foundations
Frame
Slabs Partions
Exterior walls
Roof construction
Physicum Building
Viikki Info Centre Building
Excavation in rock (cellar) Gravel filling Footings Foundation walls and beams Concrete slab Steel columns Reinforced concrete loadbearing partition walls Reinforced concrete and steel beams Reinforced concrete hollow-core slabs Also some thin-shell slabs and slabs cast in situ Mainly of laminated veneer lumber chipboard; also a number of partitions of calcium-silicate brick Steel and aluminium framed glazed walls (1) Concrete+min.wool+block masonry+aluminium grilles, (2) steel+min.vool+steel, and (3) glazed walls
Excavation (cellar) Gravel filling Piles+pile footings Foundation walls and beams Concrete slab Reinforced concrete and steel columns Reinforced concrete loadbearing partition walls Reinforced concrete and steel beams Reinforced concrete slabs cast in situ Also some thin-shell slabs and composite slabs Mainly of steel-framed plasterboard and calciumsilicate brick masonry Steel framed glazed walls The dominant type of exterior wall is a double elevation consisting of an inner wall of light aggregate concrete block masonry and an outer steel-framed glass wall (the space between the inner and outer exterior walls is used for the fresh-air intake of the ventilation system) Expanded clay aggregate+conrete covering+asphalt roofing
Expanded clay aggregate+conrete covering+asphalt roofing
building: the longer a building lasts, the more service it produces. The assumption made in the basic calculations was that the buildings will be in use for 100 years. The service unit measure also required an indication of the size of the building, because this, too, affects the amount of service produced. The service unit selected for the MIPS calculations was the surface area that the user would consider as the service-providing area. The net useable floor area [6] is calculated as the sum of the floor areas that constitute the premises in question, plus the cross-sectional area of the nonloadbearing partitions inside the premises. The net useable floor area does not include the cross-sectional area of loadbearing and fire partitions, ducts or batteries of ducts, or the technical facilities serving the building. Neither did this study include the plan area of the stairwells in the total net useable floor area of the buildings. 2.2.4. Calculating the MIPS values On account of the scale and complexity of the buildings in this study, a simplified MIPS calculation method was used. Calculation of the MIs of the building components took into account only the materials present within the components, and their amounts were multiplied by the MI factor for each material. This allows a relatively quick and reliable calculation of the MI for the buildings [4]. The calculation did not therefore look at, for example, the full life cycle process chains of the plasterboard in the partition walls of the buildings, which would include the material and energy
inputs and transportation required at the plasterboard’s different production stages. Instead, the calculations took into account only the material composition of the finished product. Nevertheless, certain general assumptions for all materials were made in regard to transportation and surplus building materials (see Section 2.2.6). The calculations took into account the renewal of building components and the direct consumption of electricity, heat and water during the use phase of the building. The fate of the building towards the end of its life cycle was not considered in the calculations. Four different MIPS values were calculated for the two buildings: consumption per service unit of abiotic natural resources, of biotic natural resources, of water and of air. The fifth MIPS category, namely ‘earth movement in agriculture and forestry’, was not included because it is mainly of significance only when there are products derived from agriculture and forestry. 2.2.5. Sources used in the calculations Information about the total amount of each building component was obtained from the cost estimates drafted for the two buildings, which were itemised by component. The main source for examining the structure of the building components consisted of the structural detail drawings, which show each building component in profile. These drawings also provided information on the amount of different products and materials in the component. Where any of the material and quantity data could not be ascertained from the drawings, further
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Table 3 MI factors used in the calculations Material
Abiotic natural resources (kg/kg)
Biotic natural resources (kg/kg)
Water (kg/kg)
Air (kg/kg)
Source of MI factors and electricity consumption data
0.00 0.00 0.00 0.00 0.75 0.00 0.00 0.00 4.72 0.00 0.00 0.00 0.00 0.00 5.51 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
8.71 0.00 0.00 7.79 93.60 18.68 33.79 6.61 33.50 30.70 111.33 0.00 0.00 136.82 34.92 4990.19 260.00 142.23 64.90 373.10 54.89 1.00 6.70 8.71 0.00 164.00 1003.08 0.00 175.63 195.80 370.60 208.33 63.26 1.3
0.04 0.00 0.00 0.004 0.33 0.03 0.02 0.00 0.11 0.71 0.34 0.00 0.00 1.52 0.08 3.57 2.00 1.13 2.10 0.25 0.27 0.00 0.27 0.04 0.00 2.80 4.68 0.00 0.75 0.13 0.26 0.30 0.96 0.001
a
0.67 0.07 0.20
0.00 0.00 0.00
304.60 0.17 0.84
0.22 0.00 0.33
e
0.03
0.00
0.17
0.08
h
Concrete 1.24 Filler * 1.00 Sand * 1.18 Calcium silicate bricks (calcareous sandstone) 1.20 Board * 1.86 Light aggregate (perforated brick) 1.73 Gypsum 1.40 Rubberised bitumen (bitumen) * 2.60 Spruce 0.24 Glass 2.39 Chipboard (medium-density fibreboard) 0.54 Fly ash * 1.00 Broken rock * 1.00 Mineral wool 2.23 Pine 0.41 Primary aluminium 19.36 Primary copper * 500.00 Primary steel (basic-oxygen steel) 5.19 Polyethylene PE * 5.40 Polyvinyl chloride PVC 3.37 Portland cement 2.53 Rain water 0.00 Cellulose * 1.71 Cement mortar (cement) 1.24 Pebbles (gravel) * 1.18 Expanded polystyrene (polystyrene) * 2.51 Expanded polyurethane SPU 7.67 Gravel * 1.18 Wind baffle panel (hardboard) 0.60 Recycled aluminium 1.00 Recycled copper 4.84 Recycled steel (electrical steel) 0.62 Cast iron (crude iron) 4.78 Water * 0.01
b a a c a a d a a a b b a a a a a a a a
c a a c a a b a a a a c
Electricity and heating production Finnish electricity production (average) Wind power District heating from Helsinki Energy
f g
Transportation Road haulage (only diesel fuel taken into account)
The MI factors for the materials were adjusted to match the electricity consumption circumstances in Finland with the aid of the MI factors for Finnish electricity production used in this study (see the table on electricity and heating production below). For the materials marked with an asterisk (*) this amendment was not possible because no electricity consumption data was available for them. If no individual MI factors were found for a material, the MI factors of some other material judged to be as similar as possible to it were used. These instances are indicated in the table above by showing the name of the other material in parentheses. In some cases, an estimate was made of the MI factors. a Wuppertal Institut—Abteilung Stoffstro¨me und Strukturwandel, 17.7.1998. MI-Werte. /http://www.wupperinst.org/Projekte/mipsonline/ download/MIWerte.pdfS. b Estimate (Arto Saari Dr Tech), Laboratory of Construction Economics and Management, Helsinki.University of Technology. c Wuppertal Institute for Climate, Environment and Energy, 28.10.2003. Material intensity of materials, fuels, transport services. Version 2. /http://www.wupperinst.org/Projekte/mipsonline/download/MIT_v2.pdfS. d Christopher Manstein, Factor 10 Institute, Austria, personal communication by e-mail 3.11.2003. e Estimated by eco-efficiency consultant Michael Lettenmeier (Finnish Association for Nature Conservation). f Hacker, J. 2003. Bestimmung des lebenszyklusweiten Naturverbrauches fu¨r die Elektrizita¨tsproduktion in den La¨ndern der Europa¨ischen Union (Determination of the life-cycle-wide nature consumption for power production in the EU countries). Diplomarbeit. Wien: Technische Universita¨t Wien. Fakulta¨t fu¨r Elektrotechnik und Informationstechnik. 87 p. (in German). g Calculated by eco-efficiency consultant Michael Lettenmeier (Finnish Association for Nature Conservation). h Calculated by Arto Saari Dr Tech (Laboratory of Construction Economics and Management, Helsinki University of Technology).
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inquiries were made from the product manufacturer or a search was made of the manufacturer’s website. Material and quantity data were also sought from the building specifications for the two buildings. 2.2.6. General assumptions made in the calculations A building materials wastage figure of 10% was assumed. This meant that the mass quantities of the building component materials in the MIPS calculation were multiplied by a factor of 1.1. The wastage consists of the amount of materials that remain unused after construction is completed. In transporting the materials, it was assumed that land resources are transported an average of 50 km, and other materials an average of 200 km. All transportation was assumed to be by road. The renewal cycles used for the building components are mainly those given in the publication Kiinteisto¨jen ylla¨pidon kustannustieto [7]. Renewal cycle means the amount of time the building component is expected to last before it needs replacing. Components are also sometimes renewed for operating reasons, for example the removal of partition walls and their replacement with new ones when a reorganization of the interior space is needed. The figures used for the annual direct consumption of electricity, heat and water in the two buildings were determined by calculating the averages for the period since completion of the buildings. The assumption was therefore made that electricity, heat and water consumption throughout the service life of the buildings will remain at the average recorded for their first years of service. In the case of building materials it was assumed that they were all made in Finland. The MI factors for these materials were therefore amended so that for production chain electricity consumption they would reflect the material intensity for Finnish power production. At the time of the study, the available MI factors for different materials were mainly based on the material intensity figures for German power production, which are very different in scale from the corresponding data for Finnish power production. For example, the MI factor for abiotic materials for mains electricity in Germany is about seven times greater than the same coefficient for Finnish power production used in this study, and the MI factor for air almost three times greater. By contrast, the MI factor for water in Finnish power production in this study is 3.7 times greater than the equivalent German figure. It was not possible to adjust the MI factor for all materials, however, because data on production chain electricity consumption was not available for all the materials. The MI factors used and their sources are given in Table 3. 2.2.7. Sensitivity analysis With the aid of sensitivity analysis the study examined the effect of various factors on the MIPS values for the
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buildings. The aim of the sensitivity analysis was firstly to establish how sensitive the MIPS method was to certain assumptions made in the calculations, and secondly to investigate the effect of different actions aimed at reducing natural resource consumption on the MIPS values for the buildings.
3. Results 3.1. The structure of natural resource consumption in the two buildings studied The aim of this study has been to calculate the lifecycle-wide consumption of natural resources in two university buildings with the aid of the MIPS method. The results of the calculations are given in Table 4. The service unit used in the calculations was the net useable floor area of the building divided by the service life of the building. Table 5 presents the results in terms of gross floor area. The MIPS values for the Physicum building are larger than those for the Viikki Info Centre building in every natural resource category (Table 4). The clearest differences are in the MIPS values for air and water: the Physicum MIPS for air was 91% greater than that of the Viikki Info Centre, and its MIPS for water was 39% greater. For both the Physicum and Viikki Info Centre buildings, construction and maintenance together consumed the most abiotic natural resources (Table 4). Usephase electricity consumption accounted for about one third of abiotic natural resource use, and heating energy for about one tenth. The biotic material figures were almost insignificant compared with the figures for abiotic materials. In both buildings, water consumption was attributable almost entirely to use-phase electrical energy use. Air consumption was mainly attributable to use-phase heating and electricity. Fig. 5 shows the breakdown of abiotic natural resource consumption in construction and maintenance for the Physicum building, by building component. The most significant share, 37%, was accounted for by the mechanical and electrical services, especially copper pipes and wires. The next largest share, 31%, was from rock excavation; this was because the building has a basement floor built into the rock. The building frame accounted for a total of 16% and fillings for 7%. The remaining proportion was only 9%. The considerable share accounted for by the mechanical and electrical services was due to the copper wiring, as the primary copper used in the wiring has an MI factor for abiotic materials of as much as 500 kg/kg. This means that 1 kg of copper used in the building will have necessitated the use of 499 kg of abiotic natural resources in addition to its own weight. The reasons for
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Table 4 MIPS values for the two buildings (unit: kg natural resources/m2(net)/yr) Abiotic (kg/m2(net)/yr) Physicum Building Construction and building component renewal Use phase heat energy consumption Use phase electrical energy consumption Tap water consumption Total Viikki Info Centre Building Construction and building component renewal Use phase heat energy consumption Use phase electrical energy consumption Tap water consumption Total
%
Biotic (kg/m2(net)/yr)
%
Water (kg/m2(net)/yr)
%
Air % kg/m2(net)/yr
154
55
0.31
100
1090
3
7
7
35
13
0.00
0
145
0
58
62
88
31
0.00
0
39985
96
29
31
2 279
1 100
0.00 0.31
0 100
261 41481
1 100
0 94
0 100
163
68
0.28
100
1000
3
7
13
13
6
0.00
0
54
0
22
44
63
26
0.00
0
28619
96
21
42
2 241
1 100
0.00 0.28
0 100
274 29947
1 100
0 49
0 100
Table 5 MIPS values for the two buildings (unit: kg natural resources/m2(gross)/yr) Abiotic (kg/m2(gross)/yr) Physicum Building Construction and building component renewal Use phase heat energy consumption Use phase electrical energy consumption Tap water consumption Total Viikki Info Centre Building Construction and building component renewal Use phase heat energy consumption Use phase electrical energy consumption Tap water consumption Total
%
Biotic (kg/m2(gross)/yr)
%
Water (kg/m2(gross)/yr)
%
Air (kg/m2(gross)/yr)
%
126
55
0.25
100
889
3
5
7
29
13
0.00
0
118
0
47
62
72
31
0.00
0
32617
96
23
31
2 228
1 100
0.00 0.25
0 100
213 33837
1 100
0 76
0 100
139
68
0.24
100
852
3
6
13
11
6
0.00
0
46
0
19
44
54
26
0.00
0
24391
96
18
42
2 206
1 100
0.00 0.24
0 100
234 25524
1 100
0 42
0 100
such a sizeable ecological rucksack include the large amount of waste rock in mining copper. The MI factor for abiotic materials in recycled copper is only a fraction of that for primary copper, at 4.84 kg/ kg. The reinforced concrete frame, heavy in terms of its mass, has a much lower figure for the consumption of abiotic natural resources than the mechanical and electrical services, a much lighter item, because the MI factor for concrete is only 1.24 kg/kg, and for steel just 5.19 kg/kg.
3.2. Results of the sensitivity analysis The sensitivity of the calculations presented in Section 3.1 was analysed in relation to the following factors: service life of the building, length of the renewal cycle for the building components, proportion of recycled metals used in construction and maintenance,
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reduction in room temperature, saving in use-phase electrical energy and use of wind energy.
The sensitivity analysis focused on abiotic natural resources and water and air. The consumption of biotic natural resources was not considered at all in the sensitivity analysis because the MIPS values for biotic materials in the two buildings studied were extremely low. The results of the sensitivity analysis are given in Tables 6 and 7.
Mechanical and electrical services 37%
Excavation 31%
Fillings 7% Special partitions 1% Foundations 1% Partitions Load bearing walls 3% 4% Floor surface casting Columns 3% 0% Roofing 1% Roof Beams Slabs 5% construction Exterior 1% 2% walls 4% Fig. 5. The breakdown of the Physicum building’s abiotic natural resource consumption of construction and building component renewal.
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3.2.1. Changing the service life of the building A halving of the service life, from 100 to 50 years, increased the MIPS value for abiotic materials by more than 50% for the Physicum building, and by almost 70% for the Viikki Info Centre. By contrast, a doubling of the service life, from 100 to 200 years, reduced the MIPS value for abiotic materials by about one third in both cases. Changing the service life had only a very small effect on the MIPS values for water, and a fairly small effect on the MIPS values for air, in the case of both buildings. 3.2.2. Changing the length of the renewal cycle The effect of changing the length of the building components renewal cycle on the MIPS values was studied by comparing the MIPS values from the basic calculations with those calculated for renewal cycles that were 50% shorter and 50% longer. The shorter interval increased the MIPS value for abiotic materials in the Physicum building by about one quarter, and in the Viikki Info Centre by about one third. The longer renewal cycle reduced the MIPS value for abiotic materials in both cases by about 10%. Changing the renewal cycle had a very small effect on the two buildings’ MIPS values for water. In both buildings the shorter renewal cycle increased the MIPS values for air by 4–9%, and the longer interval reduced the numbers by a few percentage points. 3.2.3. Using only recycled steel, copper and aluminium In the basic calculations it was assumed that all the steel in both buildings was primary steel. In the case of copper and aluminium, the study investigated or sought
Table 6 Sensitivity of the Physicum building’s MIPS calculations to certain selected factors Abiotic (kg/m2(net)/yr) Basic calculation of the Physicum Building
Change (%)
Water (kg/m2(net)/yr)
Change (%)
Air (kg/m2(net)/yr)
Change (%)
279
0
41500
0
94
0
+154 77
+55 28
+1100 600
+3 1
+7 3
+7 4
+67 27
+24 10
+700 300
+2 1
+4 2
+4 2
52
19
0
0
1
1
3
1
0
0
6
6
Energy saving: 14 % lower power consumption than in basic calculation
12
4
5600
13
4
4
Using wind power: 100% of power consumption is produced by wind power
79
28
40000
96
29
31
Service life of building: 50 years 200 years Renewal cycles of building components: 50% lower than in basic calculation 50% higher than in basic calculation Use of recycled metals: 100% of used metals are recycled Reducing room temperature: 2 1C lower than in basic calculation
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Table 7 Sensitivity of MIPS calculations for the Viikki Info Centre building to certain selected factors Abiotic (kg/ m2(net)/yr) Basic calculation of the Viikki Info Centre Building
Change (%)
Water (kg/ m2(net)/yr)
Change (%)
Air (kg/ m2(net)/yr)
Change (%)
241
0
29900
0
49
0
+163 81
+68 34
+200 500
+1 2
+7 3
+13 7
Renewal cycles of building components: 50% lower than in basic calculation 50% higher than in basic calculation
+85 23
+35 10
+700 200
+2 1
+4 2
+9 3
Use of recycled metals: 100% of used metals are recycled
50
21
0
0
1
2
1
0
0
0
2
4
Energy saving: 14 % lower power consumption than in basic calculation
9
4
4000
13
3
6
Using wind power: 100% of power consumption is produced by wind power
56
23
28600
96
20
42
Service life of building: 50 years 200 years
Reducing room temperature: 2 1C lower than in basic calculation
to estimate the relative proportions of primary and recycled materials used. In the sensitivity calculations, the results from the basic calculations were compared with a situation in which all the steel, copper and aluminium in the buildings was recycled material. This resulted in a drop of about one fifth in the MIPS values for abiotic materials in each building. The MIPS values for air were only cut by a few percent, and the effect on the MIPS values for water was insignificant. 3.2.4. Reduction in room temperature In the sensitivity analysis it was assumed that a reduction of 2 1C in the room temperature during the winter season would reduce heating consumption in the buildings by about 10%. The reduction in the room temperature of 2 1C reduced the MIPS value for abiotic materials only a little, and the MIPS value for air by about 5%. The effect on the MIPS values for water was negligible for both buildings.
values for abiotic materials by a little under 5%, the MIPS values for water by over 10% and the MIPS values for air by about 5%. 3.2.6. All the electricity used in the buildings is produced by wind power If all the electricity used in the buildings were to be produced by wind power, their MIPS values for abiotic materials would drop by 23–28%, their MIPS values for water by 96% and their MIPS values for air by 31–42%, when compared with a situation in which the MIPS values for electricity consumption are calculated using the average material intensity data for Finnish power production. Using wind power to produce the electricity would thus produce a significant reduction in natural resource consumption for both buildings, especially in their water consumption.
4. Discussion 3.2.5. Reduction in electricity consumption In the sensitivity analysis it was assumed that 30% of the electricity consumption was accounted for by the mechanical and electrical services and 70% by the electricity consumption of the building’s users, for instance through the use of computers and lighting. The sensitivity analysis examined the likely effect on the MIPS values if the above-mentioned 70% figure were reduced by a factor of 20%, i.e. decreasing total electricity consumption by 14%. This reduced the MIPS
4.1. Main findings The life cycle consumption of natural resources in two university buildings has been calculated with the aid of the MIPS method. In the Physicum building, the principal factors contributing to the consumption of abiotic natural resources were, in order of importance, use-phase electrical energy, mechanical and electrical services, rock excavation, the building frame and
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use-phase heating. In the Viikki Info Centre building, the role of heating was less significant. In both buildings the majority of water consumption was the result of use-phase electrical energy use. This is because in Finland, regulated hydro power is being used to produce electricity: 12.7% of the total electricity supply in the country, and 6.7% of the electricity produced within Finland itself, was from hydro power in 2002 [8]. Most of the air consumption during the buildings’ life cycles was the result of the use-phase heating and the electricity consumed in the building, i.e. the result of burning fossil fuels. The life cycle air consumption calculated in the MIPS method consists mostly of oxygen consumed in the combustion process, which is linked to carbon dioxide emissions. Indeed, an interesting subject for further study would be to look at how the air consumed during the life cycle of a building correlates with the building’s climatic impact (CO2 equivalent). The sensitivity of the MIPS calculations for the two buildings was studied by halving and doubling the service life, by reducing and increasing the renewal cycle for building components by 50%, by raising the proportion of recycled metals used in construction and maintenance to 100%, by reducing the room temperature by 2 1C, by a saving of 14% in use-phase electrical energy and by using wind energy in power production. The calculations of abiotic natural resource consumption were most sensitive to a halving of the service life of the building. If the building’s service life were cut from 100 to 50 years, the consumption of abiotic natural resources would rise by over 50%. The calculations of water and air consumption were most sensitive to the use of wind energy. If the building were to use electrical energy produced completely by wind power, water consumption would fall to a fraction of its level otherwise. In summary, the following can be stated: (1) Full and complete MIPS calculations for a building would be very demanding to carry out. (2) Most of the abiotic and biotic natural resource consumption in a building is attributable to just a few factors. (3) Even if only a relatively small proportion of the electrical energy used in a building is produced through regulated hydro power, the building’s consumption of water resources will be attributable to the amount of electrical energy it uses. For both buildings in this study, 96% of their water consumption was attributable to the electrical energy used in the buildings. It should, however, be noted that the MI factor for power production used in the study was an extremely rough estimate and so introduces some uncertainty in the result.
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(4) The air consumption of the building was attributable mainly to the heating and electrical energy used. 4.2. Relevance to previous studies In a doctoral thesis, Spies-Wallbaum [9] calculated the natural resource consumption of a semi-detached house in Flintenbreite, an ecological residential district in Germany. The figure for the service life of the building used in the calculations was an estimated 80 years. Spies-Wallbaum’s results show that the house’s annual consumption of abiotic natural resources, biotic natural resources, water and air per net surface area (Geba¨udenutzfla¨che) per year was 118, 4, 358 and 19 kg, respectively. The calculation took into account the building frame, use-phase gas consumption, electrical systems, windows and renewal of building components. The last-mentioned of these accounted for 53% of the combined consumption of abiotic and biotic natural resources; the building frame accounted for 37%, electrical systems for 6%, gas consumption for 3% and windows for 1%. The results for the Physicum and Viikki Info Centre buildings cannot be compared directly with the Spies-Wallbaum results because of the different surface area units used and different building components included in the calculations. Koskela et al. [10] studied a standard Finnish threestorey concrete apartment block and found that the abiotic and biotic natural resource consumption during construction of the principal parts of the building frame was 1685 kg/m2(gross) and annual use-phase energy consumption 32 kg/m2(gross). These calculations did not include the renewal of building components, but the effect of renewing the components of a mainly reinforced concrete frame would be minor, because most of the frame would last at least 100 years. Thus, if the service life of the building were 100 years, the abiotic and biotic natural resource consumption during the construction phase would be a total of 17 kg/m2(gross)/yr. The calculations made by Koskela et al. took no account of the natural resource consumption associated with earth excavation or mechanical and electrical services. However, in a study by Saari and Tuomela [11], which used the LCA method to calculate the environmental burden caused by the electrical, computer and elevator systems in a typical Finnish apartment block, the mass of the electric wires and power cables installed at the construction phase was calculated to be 0.51 kg/m2(gross). Multiplying this by the MI factor for the abiotic materials in primary copper gives a figure of 255 kg/m2(gross). If the electric wires and cables are replaced twice during a 100-year period, the natural resource consumption involved in construction is 2.5 kg/m2(gross)/yr and in renewal 5.1 kg/m2(gross)/yr, or a total of about 8 kg/m2(gross)/yr. The building may
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also contain copper water pipes, but their effect can be assumed to be less than that of electrical wires and cables. The natural resource consumption attributable to other materials in the components of the mechanical and electrical services is smaller still. The sum of the abiotic and biotic values for construction and renewal of building components in the Physicum and Viikki Info Centre buildings in this study is approximately five times greater than the combined results of both Koskela et al. [10] and Saari and Tuomela [11]. Among the factors explaining this difference is that the Physicum and Viikki Info Centre buildings both involved earth or rock excavation for the basement floor (+33 kg/m2 (gross) in the Physicum building, +39 kg/m2(gross) in the Viikki Info Centre), and that the buildings incorporate a lot of mechanical and electrical services (+30 kg/m2(gross) in the Physicum building). If these figures are subtracted from the Physicum calculation, the remaining sum is 57 kg/ m2(gross), and from the Viikki Info Centre calculation, 76 kg/m2(gross). These two figures are still high in relation to the combined total of Koskela et al. [10] and Saari and Tuomela [11] (25 kg/m2(gross)). This is partly because the calculations performed in the present study were more wide-ranging than those by Koskela et al. [10] and because the latter did not include renewal of building components. 4.3. Practical significance The study produced information on the magnitude of natural resource consumption per service unit in the two buildings studied, and information on which factors are most significant in the natural resource consumption of these types of building. The study also provided useful information on which measures are worth pursuing to reduce the natural resource consumption of such buildings. This type of information can be utilised in planning, construction and usage of these kinds of buildings.
Acknowledgements The MIPS study presented in the article was funded by the Technical Department of the University of Helsinki and the Finnish Association for Nature Conservation. The authors would like to thank the study’s steering group members for their constructive cooperation: Mr. Teppo Salmikivi, Mrs. Virpi Pyy, Mr. Jarmo Ilmoniemi and Mr. Matti Hoikkala of the Technical Department of the University of Helsinki,
and Mr. Michael Lettenmeier of the Finnish Association for Nature Conservation.
References [1] Schmidt-Bleek F. Wieviel Umwelt braucht der Mensch? MIPS— das Mass fu¨r o¨kologisches Wirtschaften (How much environment man requires? MIPS—the measure for an ecological economy). Berlin: Birkha¨user Verlag; 1994. 302pp. [in German]. [2] Sinivuori P. Kahden Helsingin yliopiston rakennuksen luonnonvarojen kulutuksen selvitta¨minen MIPS-laskennan avulla (Analysis of natural resource consumption in two University of Helsinki buildings with the aid of MIPS calculations). Master’s Thesis in Environmental Sciences. Helsinki: Department of Biological and Environmental Sciences, University of Helsinki; 2004. 51pp.+appendices 40pp. Available at: http://ethesis.helsinki.fi/julkaisut/bio/bioja/pg/sinivuori/ [in Finnish]. [3] Schmidt-Bleek F. Das MIPS-Konzept: weniger Naturverbrauch—mehr Lebensqualita¨t durch Faktor 10 (The MIPSconcept: Factor 10 for less nature consumption and more quality of life). Mu¨nchen: Droemersche Verlaganstalt; 1998. 320pp. [in German]. [4] Ritthoff M, Rohn H, Liedtke C. Calculating MIPS. Material productivity of products and services. Wuppertal Spezial 27e. Wuppertal: Wuppertal Institute for Climate, Environment and Energy at the Science Centre North Rhine-Westphalia; 2002. 52pp. [5] Autio S, Lettenmeier M. Ekotehokkuus—business as future. Yrityksen ekoteho-opas (Ecoefficiency—business as future. A corporate guide to eco-efficiency) Dipoli reports C, environmental training. Espoo: Helsinki University of Technology Lifelong Learning Institute Dipoli; 2002. 80pp. [In Finnish]. [6] Haahtela Y, Kiiras J. Talonrakennuksen kustannustieto 2004 (Construction cost data 2004) Helsinki: Haahtela-kehitys Oy; 2004. 388pp. [in Finnish]. [7] Kiinteisto¨jen ylla¨pidon kustannustieto. Hoito- ja kunnossapitokustannukset seka¨ elinkaaren kustannuslaskelmat (Property operating and maintenance cost data 1992, Operating and maintenance costs and life cycle cost calculations) Helsinki University of Technology, Department of Civil and Environmental Engineering, Construction Economics and Management, Report 119 (Otaniemi, 1993), 1992. 235pp. [in Finnish]. [8] Statistical Yearbook of Finland. Helsinki: Statistics Finland; 2003. 704pp. [9] Spies-Wallbaum, H. Denk- und Kommunikationsansa¨tze zur Bewertung des nachhaltigen Bauens und Wohnens (Thinking and communication approaches for an assessment of sustainable construction and housing). Dissertation. Hannover: Universita¨t Hannover, Fachbereich Architektur; 2002. 237pp. [in German]. [10] Koskela S, Seppa¨la¨ J, Leivonen J. Ympa¨risto¨vaikutukset rakennusten ekotehokkuuden arvioinnissa (Taking environmental effects into account in the assessment of eco-efficiency in buildings). Suomen ympa¨risto¨ (The Finnish environment) No. 585. Helsinki: Finnish Environment Institute; 2002. 56pp. [in Finnish]. [11] Saari A, Tuomela S. Asuintalon sa¨hko¨-, tieto- ja hissija¨rjestelmien ympa¨risto¨kuormitus (Environmental loading from electrical, computer and elevator systems in a residential building). Helsinki University of Technology’s Construction Economics and Management Unit reports 195, Espoo, 2001. 37pp. [in Finnish].
Building and Environment 41 (2006) 657–668 www.elsevier.com/locate/buildenv
MIPS analysis of natural resource consumption in two university buildings Paula Sinivuoria, Arto Saarib, a
Finnish Association for Nature Conservation, Kotkankatu 9, FIN-00510 Helsinki, Finland Department of Civil and Environmental Engineering, Laboratory of Construction Economics and Management, Helsinki University of Technology, P.O. Box 2100, FIN-02015 HUT, Finland
b
Received 23 September 2004; received in revised form 9 February 2005; accepted 23 February 2005
Abstract This article presents the findings of a study to investigate the scale and content of natural resource consumption in two Finnish university buildings, as well as the sensitivity of these calculations to the particular assumptions used. The calculations were made using the MIPS method. In the Physicum building, the main factors contributing to abiotic natural resource consumption were, in order of importance, use-phase electrical energy, mechanical and electrical services, rock excavation, the building’s frame and usephase heating. In the Viikki Info Centre building, the role of heating was less significant. Consumption of biotic natural resources was marginal. In both buildings the majority of water resource consumption was the result of use-phase electrical energy use. Air consumption was mainly the result of the building’s heating and electricity use. For abiotic natural resource consumption, the calculations were most sensitive to a halving of the service life of the building. The consumption of water and air was strongly influenced by the type of power plant from which the building’s energy sources originated. Reducing the natural resource consumption of a building is something that should be targeted right from the start, at the design stage. Since most of a building’s natural resource use is attributable to just a few factors, the calculation and control activities should focus on these very factors, such as use-phase energy, earthworks, the building’s frame and copper-containing mechanical and electrical services. r 2005 Elsevier Ltd. All rights reserved. Keywords: MIPS; Eco-efficiency; Natural resource consumption; Management; Life cycle; Buildings
1. Introduction The traditional environmental policy aims at preventing the effects of individual harmful substances, such as pollutants and toxins. It has been suggested by SchmidtBleek [1] that even though this is important, it is not sufficient by itself. Instead of focusing only on harmful substances, we should pay attention to our usage of all kinds of natural resources, also the non-toxic ones. In today’s world, we transfer an enormous amount of different kinds of natural materials from one place to another in the course of creating material prosperity for Corresponding author. Fax: +358 9 4513758.
E-mail address: arto.saari@hut.fi (A. Saari). 0360-1323/$ - see front matter r 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.buildenv.2005.02.022
ourselves: sand, gravel, water, air, mining waste, ore, etc. By doing this, we cause changes in the environment. The bigger the material flows, the bigger the environmental changes. Dematerialization, meaning a significant reduction in natural resource consumption in human activity, has therefore been set as an important goal. The MIPS method developed at the German Wuppertal Institute for Climate, Environment, Energy is a useful tool for measuring and managing the humaninduced material flows. MIPS stands for Material Input Per Service unit. It is a value that can be calculated for all final products that provide a service. The MIPS value relates the natural resources consumed by a product during its entire life cycle to the overall benefit derived
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from it. It provides a rough—but nevertheless indicative—approximation of the product’s potential environmental load. The smaller a product’s MIPS value, the lower its environmental load is considered to be, because it will be consuming fewer natural resources in relation to the amount of service it produces [1]. The construction and property sector is a significant user of natural materials. Materials are used not only in building and maintenance but also in producing the energy used in buildings. The composition of natural resource consumption in buildings has not previously been studied in any comprehensive manner in Finland. MIPS calculations have been made for buildings in other countries, however, but the results have not been widely published. This article presents the findings of a study to investigate the scale and content of natural resource consumption in two Finnish buildings (the Physicum and Viikki Info Centre buildings of the University of Helsinki), as well as the sensitivity of these calculations in relation to the particular assumptions made. Paula Sinivuori (Author 1) [2] has completed a Master’s thesis in connection with the study presented here, under the supervision of Arto Saari (Author 2).
2. Methods and materials 2.1. Calculating the MIPS value Expressed as an equation, MIPS appears as follows: MIPS ¼ MI=S;
(1)
where MI is the material input, S the service unit. The material input (MI) forming the MIPS numerator refers to the total amount of natural resources needed
for the creation and use of the product in question and for its waste management. It includes not only the materials bound up within it and those required for its production, but also all the materials involved in its transportation, equipment and packaging throughout its life cycle. The material input also includes the resources extracted from nature and used for producing the energy needed by the product. It thus encompasses the natural resources consumed throughout the product’s entire life cycle and expresses this as a unit of mass, for example kilograms. The waste flows associated with the product are not included as waste flows in the material input, because they are outputs from the product’s life cycle, not inputs. However, waste flows will have appeared as inputs in the life cycle of the product at an earlier stage, and so to this extent their mass is taken into account in the MIPS calculation. The MI must include the consumption of natural resources throughout the product’s entire life cycle, because the production process will generally involve transfer of a greater amount of material than those contained in the product itself. These natural resource transfers generated by, but not included in, the product are known as the product’s ecological rucksack. The ecological rucksack is often considerably heavier than the product [1]. All natural resources are not, however, calculated in the same MI but are divided into five different categories in the MIPS calculation: abiotic natural resources, biotic natural resources, water, air, and what is termed ‘earth movement in agriculture and forestry’ (Table 1). Five different MIPS values can thus be calculated for any product. The calculation of MIs makes use of the MI factors already calculated for many widely used materials, such as steel, cement and glass, and for different means of
Table 1 Natural resource categories in MIPS analysis [3] Abiotic materials
Biotic materials
Water
Air
Mineral raw materials
Biomass of plants from
All water actively
All air or its constituents Erosion that are actively used by Mechanical tillage of the
from mines, quarries and smelting plants Fossil fuels Rock and earth that are moved during the quarrying or excavation of abiotic raw materials Unused extracted earth from, for example, the construction and maintenance of buildings and transport infrastructure
human cultivation Biomass derived from uncultivated land but for human use, e.g. wild animals, fish and wild plants
extracted from nature, i.e. by technical means Water flowing through a water wheel located in a natural channel and water displaced by a ship’s propeller are not included
humans, e.g. the air needed for combustion and the air used in chemical and physical reactions. The calculations include only the weight of the components of air that are actually used, for instance the amount of oxygen consumed in the combustion process
Earth movements in agriculture and forestry
soil, such as ploughing and harrowing
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electricity production and transportation [4]. The MI factor expresses in kilograms the amount of natural resources needed to create 1 kg of material or 1 kW h or 1 tonne km [5]. The MI factor thus describes the material intensity of the particular material, energy production method or form of transport in question. In practice, MI is calculated by multiplying the material and energy consumptions and transportations of the product being studied for the whole of its life cycle by the corresponding MI factors. If the necessary MI factor does not exist, the natural resource consumption will have to be calculated separately right from the beginning [4]. The service unit (S) forming the MIPS denominator refers to the benefit derived from the product [1]. It cannot be measured like a MI but is instead determined separately for each product. The total amount of usage times or years of use during the life cycle are examples of what may be selected as the service unit of a product [5]. The concept of service unit highlights the fact that people do not actually need the product itself but simply the service provided by it [1]. 2.2. Application of MIPS calculations to this study 2.2.1. Cases studied The cases chosen for this study were two buildings of the University of Helsinki. The reason for this choice was the fact that the study was partially made for the Technical Department of the University of Helsinki, which was interested in testing the MIPS calculation method on its buildings. The Physicum building (Figs. 1 and 2) was completed in 2001. It has a gross floor area of 17,871 m2 and a net useable floor area of 14,578 m2. The building is located in the Kumpula campus of the University of Helsinki, Finland. Its occupants include the Departments of Physical Sciences, Geology and Geography, all in the Faculty of Science, plus their laboratories and the Kumpula Science Library. The main part of the building is five stories high, the lowest of which is built into the rock. The library wing is two stories high. The second building in this study, the Viikki Info Centre (Figs. 3 and 4), was completed in 1999 and has a gross floor area of 11,150 m2 and a net useable floor area of 9104 m2. It is located in the Viikki campus of the University of Helsinki, Finland. Its occupants include the Viikki Science Library and a branch of the Helsinki City Library. It has five stories, the lowest of which is below ground level. Specification of structures of the Physicum and Viikki Info Centre buildings is presented in Table 2. Even though the buildings studied are both university buildings, they are not completely similar in terms of functionality. The most significant difference is the fact that the Physicum building has many laboratories,
Fig. 1. Physicum (2nd floor plan). Drawing: Architects Lahdelma & Mahlama¨ki Ltd.
whereas the Viikki Info Centre has none. Therefore the action that takes place in the Physicum building differs to some extent from the one in the Viikki Info Centre. 2.2.2. Selecting building components for the calculations The MIPS calculations for the buildings are not all encompassing, in that they do not cover all the components. The calculations do, however, cover those components which together account for the majority of the material flows, i.e. components with a large total mass and/or high MI factor. Calculations concerning the mechanical and electrical services were made only for the Physicum building, as the necessary data for the Viikki Info Centre was not fully available. The services components were the copper wiring of the computer network cabling, the copper and aluminium in the electrical wiring for the electrical, automatic and fire alarm systems, the ladder racks and
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Fig. 2. Physicum, Helsinki (photo: Jussi Tiainen). Fig. 4. Viikki Info Centre, Helsinki (photo: Jussi Tiainen).
related parts, the ventilation system, the pipes in the fire extinguishing system, the pipes in the heating system, the water and chilled water pipes, the laboratory pipes, the drains and the rainwater disposal system. To ensure that the results of the MIPS calculations could be used for overall comparisons, the rough assumption was made that the MIPS values for the mechanical and electrical services of each building per gross floor area unit per year were the same. The MIPS values for the Viikki Info Centre’s mechanical and electrical services were thus made on the basis of the MIPS values for the Physicum building.
Fig. 3. Viikki Info Centre, Helsinki (Street level floor plan). Drawing: ARK-house architects.
2.2.3. Selection of service unit The service produced by a building is the particular net useable floor area that it offers the user over a particular time period. The service unit used in the MIPS calculations for the buildings was selected as ‘the net useable floor area (m2)/the service life of the building in years’. The service life of the building (i.e. the period during which the building is assumed to be in use) was selected for the service unit calculation because it usefully indicates the amount of service produced by the
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Table 2 Specification of structures of the Physicum and Viikki Info Centre buildings
Excavation Fillings Foundations
Frame
Slabs Partions
Exterior walls
Roof construction
Physicum Building
Viikki Info Centre Building
Excavation in rock (cellar) Gravel filling Footings Foundation walls and beams Concrete slab Steel columns Reinforced concrete loadbearing partition walls Reinforced concrete and steel beams Reinforced concrete hollow-core slabs Also some thin-shell slabs and slabs cast in situ Mainly of laminated veneer lumber chipboard; also a number of partitions of calcium-silicate brick Steel and aluminium framed glazed walls (1) Concrete+min.wool+block masonry+aluminium grilles, (2) steel+min.vool+steel, and (3) glazed walls
Excavation (cellar) Gravel filling Piles+pile footings Foundation walls and beams Concrete slab Reinforced concrete and steel columns Reinforced concrete loadbearing partition walls Reinforced concrete and steel beams Reinforced concrete slabs cast in situ Also some thin-shell slabs and composite slabs Mainly of steel-framed plasterboard and calciumsilicate brick masonry Steel framed glazed walls The dominant type of exterior wall is a double elevation consisting of an inner wall of light aggregate concrete block masonry and an outer steel-framed glass wall (the space between the inner and outer exterior walls is used for the fresh-air intake of the ventilation system) Expanded clay aggregate+conrete covering+asphalt roofing
Expanded clay aggregate+conrete covering+asphalt roofing
building: the longer a building lasts, the more service it produces. The assumption made in the basic calculations was that the buildings will be in use for 100 years. The service unit measure also required an indication of the size of the building, because this, too, affects the amount of service produced. The service unit selected for the MIPS calculations was the surface area that the user would consider as the service-providing area. The net useable floor area [6] is calculated as the sum of the floor areas that constitute the premises in question, plus the cross-sectional area of the nonloadbearing partitions inside the premises. The net useable floor area does not include the cross-sectional area of loadbearing and fire partitions, ducts or batteries of ducts, or the technical facilities serving the building. Neither did this study include the plan area of the stairwells in the total net useable floor area of the buildings. 2.2.4. Calculating the MIPS values On account of the scale and complexity of the buildings in this study, a simplified MIPS calculation method was used. Calculation of the MIs of the building components took into account only the materials present within the components, and their amounts were multiplied by the MI factor for each material. This allows a relatively quick and reliable calculation of the MI for the buildings [4]. The calculation did not therefore look at, for example, the full life cycle process chains of the plasterboard in the partition walls of the buildings, which would include the material and energy
inputs and transportation required at the plasterboard’s different production stages. Instead, the calculations took into account only the material composition of the finished product. Nevertheless, certain general assumptions for all materials were made in regard to transportation and surplus building materials (see Section 2.2.6). The calculations took into account the renewal of building components and the direct consumption of electricity, heat and water during the use phase of the building. The fate of the building towards the end of its life cycle was not considered in the calculations. Four different MIPS values were calculated for the two buildings: consumption per service unit of abiotic natural resources, of biotic natural resources, of water and of air. The fifth MIPS category, namely ‘earth movement in agriculture and forestry’, was not included because it is mainly of significance only when there are products derived from agriculture and forestry. 2.2.5. Sources used in the calculations Information about the total amount of each building component was obtained from the cost estimates drafted for the two buildings, which were itemised by component. The main source for examining the structure of the building components consisted of the structural detail drawings, which show each building component in profile. These drawings also provided information on the amount of different products and materials in the component. Where any of the material and quantity data could not be ascertained from the drawings, further
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Table 3 MI factors used in the calculations Material
Abiotic natural resources (kg/kg)
Biotic natural resources (kg/kg)
Water (kg/kg)
Air (kg/kg)
Source of MI factors and electricity consumption data
0.00 0.00 0.00 0.00 0.75 0.00 0.00 0.00 4.72 0.00 0.00 0.00 0.00 0.00 5.51 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
8.71 0.00 0.00 7.79 93.60 18.68 33.79 6.61 33.50 30.70 111.33 0.00 0.00 136.82 34.92 4990.19 260.00 142.23 64.90 373.10 54.89 1.00 6.70 8.71 0.00 164.00 1003.08 0.00 175.63 195.80 370.60 208.33 63.26 1.3
0.04 0.00 0.00 0.004 0.33 0.03 0.02 0.00 0.11 0.71 0.34 0.00 0.00 1.52 0.08 3.57 2.00 1.13 2.10 0.25 0.27 0.00 0.27 0.04 0.00 2.80 4.68 0.00 0.75 0.13 0.26 0.30 0.96 0.001
a
0.67 0.07 0.20
0.00 0.00 0.00
304.60 0.17 0.84
0.22 0.00 0.33
e
0.03
0.00
0.17
0.08
h
Concrete 1.24 Filler * 1.00 Sand * 1.18 Calcium silicate bricks (calcareous sandstone) 1.20 Board * 1.86 Light aggregate (perforated brick) 1.73 Gypsum 1.40 Rubberised bitumen (bitumen) * 2.60 Spruce 0.24 Glass 2.39 Chipboard (medium-density fibreboard) 0.54 Fly ash * 1.00 Broken rock * 1.00 Mineral wool 2.23 Pine 0.41 Primary aluminium 19.36 Primary copper * 500.00 Primary steel (basic-oxygen steel) 5.19 Polyethylene PE * 5.40 Polyvinyl chloride PVC 3.37 Portland cement 2.53 Rain water 0.00 Cellulose * 1.71 Cement mortar (cement) 1.24 Pebbles (gravel) * 1.18 Expanded polystyrene (polystyrene) * 2.51 Expanded polyurethane SPU 7.67 Gravel * 1.18 Wind baffle panel (hardboard) 0.60 Recycled aluminium 1.00 Recycled copper 4.84 Recycled steel (electrical steel) 0.62 Cast iron (crude iron) 4.78 Water * 0.01
b a a c a a d a a a b b a a a a a a a a
c a a c a a b a a a a c
Electricity and heating production Finnish electricity production (average) Wind power District heating from Helsinki Energy
f g
Transportation Road haulage (only diesel fuel taken into account)
The MI factors for the materials were adjusted to match the electricity consumption circumstances in Finland with the aid of the MI factors for Finnish electricity production used in this study (see the table on electricity and heating production below). For the materials marked with an asterisk (*) this amendment was not possible because no electricity consumption data was available for them. If no individual MI factors were found for a material, the MI factors of some other material judged to be as similar as possible to it were used. These instances are indicated in the table above by showing the name of the other material in parentheses. In some cases, an estimate was made of the MI factors. a Wuppertal Institut—Abteilung Stoffstro¨me und Strukturwandel, 17.7.1998. MI-Werte. /http://www.wupperinst.org/Projekte/mipsonline/ download/MIWerte.pdfS. b Estimate (Arto Saari Dr Tech), Laboratory of Construction Economics and Management, Helsinki.University of Technology. c Wuppertal Institute for Climate, Environment and Energy, 28.10.2003. Material intensity of materials, fuels, transport services. Version 2. /http://www.wupperinst.org/Projekte/mipsonline/download/MIT_v2.pdfS. d Christopher Manstein, Factor 10 Institute, Austria, personal communication by e-mail 3.11.2003. e Estimated by eco-efficiency consultant Michael Lettenmeier (Finnish Association for Nature Conservation). f Hacker, J. 2003. Bestimmung des lebenszyklusweiten Naturverbrauches fu¨r die Elektrizita¨tsproduktion in den La¨ndern der Europa¨ischen Union (Determination of the life-cycle-wide nature consumption for power production in the EU countries). Diplomarbeit. Wien: Technische Universita¨t Wien. Fakulta¨t fu¨r Elektrotechnik und Informationstechnik. 87 p. (in German). g Calculated by eco-efficiency consultant Michael Lettenmeier (Finnish Association for Nature Conservation). h Calculated by Arto Saari Dr Tech (Laboratory of Construction Economics and Management, Helsinki University of Technology).
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inquiries were made from the product manufacturer or a search was made of the manufacturer’s website. Material and quantity data were also sought from the building specifications for the two buildings. 2.2.6. General assumptions made in the calculations A building materials wastage figure of 10% was assumed. This meant that the mass quantities of the building component materials in the MIPS calculation were multiplied by a factor of 1.1. The wastage consists of the amount of materials that remain unused after construction is completed. In transporting the materials, it was assumed that land resources are transported an average of 50 km, and other materials an average of 200 km. All transportation was assumed to be by road. The renewal cycles used for the building components are mainly those given in the publication Kiinteisto¨jen ylla¨pidon kustannustieto [7]. Renewal cycle means the amount of time the building component is expected to last before it needs replacing. Components are also sometimes renewed for operating reasons, for example the removal of partition walls and their replacement with new ones when a reorganization of the interior space is needed. The figures used for the annual direct consumption of electricity, heat and water in the two buildings were determined by calculating the averages for the period since completion of the buildings. The assumption was therefore made that electricity, heat and water consumption throughout the service life of the buildings will remain at the average recorded for their first years of service. In the case of building materials it was assumed that they were all made in Finland. The MI factors for these materials were therefore amended so that for production chain electricity consumption they would reflect the material intensity for Finnish power production. At the time of the study, the available MI factors for different materials were mainly based on the material intensity figures for German power production, which are very different in scale from the corresponding data for Finnish power production. For example, the MI factor for abiotic materials for mains electricity in Germany is about seven times greater than the same coefficient for Finnish power production used in this study, and the MI factor for air almost three times greater. By contrast, the MI factor for water in Finnish power production in this study is 3.7 times greater than the equivalent German figure. It was not possible to adjust the MI factor for all materials, however, because data on production chain electricity consumption was not available for all the materials. The MI factors used and their sources are given in Table 3. 2.2.7. Sensitivity analysis With the aid of sensitivity analysis the study examined the effect of various factors on the MIPS values for the
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buildings. The aim of the sensitivity analysis was firstly to establish how sensitive the MIPS method was to certain assumptions made in the calculations, and secondly to investigate the effect of different actions aimed at reducing natural resource consumption on the MIPS values for the buildings.
3. Results 3.1. The structure of natural resource consumption in the two buildings studied The aim of this study has been to calculate the lifecycle-wide consumption of natural resources in two university buildings with the aid of the MIPS method. The results of the calculations are given in Table 4. The service unit used in the calculations was the net useable floor area of the building divided by the service life of the building. Table 5 presents the results in terms of gross floor area. The MIPS values for the Physicum building are larger than those for the Viikki Info Centre building in every natural resource category (Table 4). The clearest differences are in the MIPS values for air and water: the Physicum MIPS for air was 91% greater than that of the Viikki Info Centre, and its MIPS for water was 39% greater. For both the Physicum and Viikki Info Centre buildings, construction and maintenance together consumed the most abiotic natural resources (Table 4). Usephase electricity consumption accounted for about one third of abiotic natural resource use, and heating energy for about one tenth. The biotic material figures were almost insignificant compared with the figures for abiotic materials. In both buildings, water consumption was attributable almost entirely to use-phase electrical energy use. Air consumption was mainly attributable to use-phase heating and electricity. Fig. 5 shows the breakdown of abiotic natural resource consumption in construction and maintenance for the Physicum building, by building component. The most significant share, 37%, was accounted for by the mechanical and electrical services, especially copper pipes and wires. The next largest share, 31%, was from rock excavation; this was because the building has a basement floor built into the rock. The building frame accounted for a total of 16% and fillings for 7%. The remaining proportion was only 9%. The considerable share accounted for by the mechanical and electrical services was due to the copper wiring, as the primary copper used in the wiring has an MI factor for abiotic materials of as much as 500 kg/kg. This means that 1 kg of copper used in the building will have necessitated the use of 499 kg of abiotic natural resources in addition to its own weight. The reasons for
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Table 4 MIPS values for the two buildings (unit: kg natural resources/m2(net)/yr) Abiotic (kg/m2(net)/yr) Physicum Building Construction and building component renewal Use phase heat energy consumption Use phase electrical energy consumption Tap water consumption Total Viikki Info Centre Building Construction and building component renewal Use phase heat energy consumption Use phase electrical energy consumption Tap water consumption Total
%
Biotic (kg/m2(net)/yr)
%
Water (kg/m2(net)/yr)
%
Air % kg/m2(net)/yr
154
55
0.31
100
1090
3
7
7
35
13
0.00
0
145
0
58
62
88
31
0.00
0
39985
96
29
31
2 279
1 100
0.00 0.31
0 100
261 41481
1 100
0 94
0 100
163
68
0.28
100
1000
3
7
13
13
6
0.00
0
54
0
22
44
63
26
0.00
0
28619
96
21
42
2 241
1 100
0.00 0.28
0 100
274 29947
1 100
0 49
0 100
Table 5 MIPS values for the two buildings (unit: kg natural resources/m2(gross)/yr) Abiotic (kg/m2(gross)/yr) Physicum Building Construction and building component renewal Use phase heat energy consumption Use phase electrical energy consumption Tap water consumption Total Viikki Info Centre Building Construction and building component renewal Use phase heat energy consumption Use phase electrical energy consumption Tap water consumption Total
%
Biotic (kg/m2(gross)/yr)
%
Water (kg/m2(gross)/yr)
%
Air (kg/m2(gross)/yr)
%
126
55
0.25
100
889
3
5
7
29
13
0.00
0
118
0
47
62
72
31
0.00
0
32617
96
23
31
2 228
1 100
0.00 0.25
0 100
213 33837
1 100
0 76
0 100
139
68
0.24
100
852
3
6
13
11
6
0.00
0
46
0
19
44
54
26
0.00
0
24391
96
18
42
2 206
1 100
0.00 0.24
0 100
234 25524
1 100
0 42
0 100
such a sizeable ecological rucksack include the large amount of waste rock in mining copper. The MI factor for abiotic materials in recycled copper is only a fraction of that for primary copper, at 4.84 kg/ kg. The reinforced concrete frame, heavy in terms of its mass, has a much lower figure for the consumption of abiotic natural resources than the mechanical and electrical services, a much lighter item, because the MI factor for concrete is only 1.24 kg/kg, and for steel just 5.19 kg/kg.
3.2. Results of the sensitivity analysis The sensitivity of the calculations presented in Section 3.1 was analysed in relation to the following factors: service life of the building, length of the renewal cycle for the building components, proportion of recycled metals used in construction and maintenance,
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reduction in room temperature, saving in use-phase electrical energy and use of wind energy.
The sensitivity analysis focused on abiotic natural resources and water and air. The consumption of biotic natural resources was not considered at all in the sensitivity analysis because the MIPS values for biotic materials in the two buildings studied were extremely low. The results of the sensitivity analysis are given in Tables 6 and 7.
Mechanical and electrical services 37%
Excavation 31%
Fillings 7% Special partitions 1% Foundations 1% Partitions Load bearing walls 3% 4% Floor surface casting Columns 3% 0% Roofing 1% Roof Beams Slabs 5% construction Exterior 1% 2% walls 4% Fig. 5. The breakdown of the Physicum building’s abiotic natural resource consumption of construction and building component renewal.
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3.2.1. Changing the service life of the building A halving of the service life, from 100 to 50 years, increased the MIPS value for abiotic materials by more than 50% for the Physicum building, and by almost 70% for the Viikki Info Centre. By contrast, a doubling of the service life, from 100 to 200 years, reduced the MIPS value for abiotic materials by about one third in both cases. Changing the service life had only a very small effect on the MIPS values for water, and a fairly small effect on the MIPS values for air, in the case of both buildings. 3.2.2. Changing the length of the renewal cycle The effect of changing the length of the building components renewal cycle on the MIPS values was studied by comparing the MIPS values from the basic calculations with those calculated for renewal cycles that were 50% shorter and 50% longer. The shorter interval increased the MIPS value for abiotic materials in the Physicum building by about one quarter, and in the Viikki Info Centre by about one third. The longer renewal cycle reduced the MIPS value for abiotic materials in both cases by about 10%. Changing the renewal cycle had a very small effect on the two buildings’ MIPS values for water. In both buildings the shorter renewal cycle increased the MIPS values for air by 4–9%, and the longer interval reduced the numbers by a few percentage points. 3.2.3. Using only recycled steel, copper and aluminium In the basic calculations it was assumed that all the steel in both buildings was primary steel. In the case of copper and aluminium, the study investigated or sought
Table 6 Sensitivity of the Physicum building’s MIPS calculations to certain selected factors Abiotic (kg/m2(net)/yr) Basic calculation of the Physicum Building
Change (%)
Water (kg/m2(net)/yr)
Change (%)
Air (kg/m2(net)/yr)
Change (%)
279
0
41500
0
94
0
+154 77
+55 28
+1100 600
+3 1
+7 3
+7 4
+67 27
+24 10
+700 300
+2 1
+4 2
+4 2
52
19
0
0
1
1
3
1
0
0
6
6
Energy saving: 14 % lower power consumption than in basic calculation
12
4
5600
13
4
4
Using wind power: 100% of power consumption is produced by wind power
79
28
40000
96
29
31
Service life of building: 50 years 200 years Renewal cycles of building components: 50% lower than in basic calculation 50% higher than in basic calculation Use of recycled metals: 100% of used metals are recycled Reducing room temperature: 2 1C lower than in basic calculation
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Table 7 Sensitivity of MIPS calculations for the Viikki Info Centre building to certain selected factors Abiotic (kg/ m2(net)/yr) Basic calculation of the Viikki Info Centre Building
Change (%)
Water (kg/ m2(net)/yr)
Change (%)
Air (kg/ m2(net)/yr)
Change (%)
241
0
29900
0
49
0
+163 81
+68 34
+200 500
+1 2
+7 3
+13 7
Renewal cycles of building components: 50% lower than in basic calculation 50% higher than in basic calculation
+85 23
+35 10
+700 200
+2 1
+4 2
+9 3
Use of recycled metals: 100% of used metals are recycled
50
21
0
0
1
2
1
0
0
0
2
4
Energy saving: 14 % lower power consumption than in basic calculation
9
4
4000
13
3
6
Using wind power: 100% of power consumption is produced by wind power
56
23
28600
96
20
42
Service life of building: 50 years 200 years
Reducing room temperature: 2 1C lower than in basic calculation
to estimate the relative proportions of primary and recycled materials used. In the sensitivity calculations, the results from the basic calculations were compared with a situation in which all the steel, copper and aluminium in the buildings was recycled material. This resulted in a drop of about one fifth in the MIPS values for abiotic materials in each building. The MIPS values for air were only cut by a few percent, and the effect on the MIPS values for water was insignificant. 3.2.4. Reduction in room temperature In the sensitivity analysis it was assumed that a reduction of 2 1C in the room temperature during the winter season would reduce heating consumption in the buildings by about 10%. The reduction in the room temperature of 2 1C reduced the MIPS value for abiotic materials only a little, and the MIPS value for air by about 5%. The effect on the MIPS values for water was negligible for both buildings.
values for abiotic materials by a little under 5%, the MIPS values for water by over 10% and the MIPS values for air by about 5%. 3.2.6. All the electricity used in the buildings is produced by wind power If all the electricity used in the buildings were to be produced by wind power, their MIPS values for abiotic materials would drop by 23–28%, their MIPS values for water by 96% and their MIPS values for air by 31–42%, when compared with a situation in which the MIPS values for electricity consumption are calculated using the average material intensity data for Finnish power production. Using wind power to produce the electricity would thus produce a significant reduction in natural resource consumption for both buildings, especially in their water consumption.
4. Discussion 3.2.5. Reduction in electricity consumption In the sensitivity analysis it was assumed that 30% of the electricity consumption was accounted for by the mechanical and electrical services and 70% by the electricity consumption of the building’s users, for instance through the use of computers and lighting. The sensitivity analysis examined the likely effect on the MIPS values if the above-mentioned 70% figure were reduced by a factor of 20%, i.e. decreasing total electricity consumption by 14%. This reduced the MIPS
4.1. Main findings The life cycle consumption of natural resources in two university buildings has been calculated with the aid of the MIPS method. In the Physicum building, the principal factors contributing to the consumption of abiotic natural resources were, in order of importance, use-phase electrical energy, mechanical and electrical services, rock excavation, the building frame and
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use-phase heating. In the Viikki Info Centre building, the role of heating was less significant. In both buildings the majority of water consumption was the result of use-phase electrical energy use. This is because in Finland, regulated hydro power is being used to produce electricity: 12.7% of the total electricity supply in the country, and 6.7% of the electricity produced within Finland itself, was from hydro power in 2002 [8]. Most of the air consumption during the buildings’ life cycles was the result of the use-phase heating and the electricity consumed in the building, i.e. the result of burning fossil fuels. The life cycle air consumption calculated in the MIPS method consists mostly of oxygen consumed in the combustion process, which is linked to carbon dioxide emissions. Indeed, an interesting subject for further study would be to look at how the air consumed during the life cycle of a building correlates with the building’s climatic impact (CO2 equivalent). The sensitivity of the MIPS calculations for the two buildings was studied by halving and doubling the service life, by reducing and increasing the renewal cycle for building components by 50%, by raising the proportion of recycled metals used in construction and maintenance to 100%, by reducing the room temperature by 2 1C, by a saving of 14% in use-phase electrical energy and by using wind energy in power production. The calculations of abiotic natural resource consumption were most sensitive to a halving of the service life of the building. If the building’s service life were cut from 100 to 50 years, the consumption of abiotic natural resources would rise by over 50%. The calculations of water and air consumption were most sensitive to the use of wind energy. If the building were to use electrical energy produced completely by wind power, water consumption would fall to a fraction of its level otherwise. In summary, the following can be stated: (1) Full and complete MIPS calculations for a building would be very demanding to carry out. (2) Most of the abiotic and biotic natural resource consumption in a building is attributable to just a few factors. (3) Even if only a relatively small proportion of the electrical energy used in a building is produced through regulated hydro power, the building’s consumption of water resources will be attributable to the amount of electrical energy it uses. For both buildings in this study, 96% of their water consumption was attributable to the electrical energy used in the buildings. It should, however, be noted that the MI factor for power production used in the study was an extremely rough estimate and so introduces some uncertainty in the result.
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(4) The air consumption of the building was attributable mainly to the heating and electrical energy used. 4.2. Relevance to previous studies In a doctoral thesis, Spies-Wallbaum [9] calculated the natural resource consumption of a semi-detached house in Flintenbreite, an ecological residential district in Germany. The figure for the service life of the building used in the calculations was an estimated 80 years. Spies-Wallbaum’s results show that the house’s annual consumption of abiotic natural resources, biotic natural resources, water and air per net surface area (Geba¨udenutzfla¨che) per year was 118, 4, 358 and 19 kg, respectively. The calculation took into account the building frame, use-phase gas consumption, electrical systems, windows and renewal of building components. The last-mentioned of these accounted for 53% of the combined consumption of abiotic and biotic natural resources; the building frame accounted for 37%, electrical systems for 6%, gas consumption for 3% and windows for 1%. The results for the Physicum and Viikki Info Centre buildings cannot be compared directly with the Spies-Wallbaum results because of the different surface area units used and different building components included in the calculations. Koskela et al. [10] studied a standard Finnish threestorey concrete apartment block and found that the abiotic and biotic natural resource consumption during construction of the principal parts of the building frame was 1685 kg/m2(gross) and annual use-phase energy consumption 32 kg/m2(gross). These calculations did not include the renewal of building components, but the effect of renewing the components of a mainly reinforced concrete frame would be minor, because most of the frame would last at least 100 years. Thus, if the service life of the building were 100 years, the abiotic and biotic natural resource consumption during the construction phase would be a total of 17 kg/m2(gross)/yr. The calculations made by Koskela et al. took no account of the natural resource consumption associated with earth excavation or mechanical and electrical services. However, in a study by Saari and Tuomela [11], which used the LCA method to calculate the environmental burden caused by the electrical, computer and elevator systems in a typical Finnish apartment block, the mass of the electric wires and power cables installed at the construction phase was calculated to be 0.51 kg/m2(gross). Multiplying this by the MI factor for the abiotic materials in primary copper gives a figure of 255 kg/m2(gross). If the electric wires and cables are replaced twice during a 100-year period, the natural resource consumption involved in construction is 2.5 kg/m2(gross)/yr and in renewal 5.1 kg/m2(gross)/yr, or a total of about 8 kg/m2(gross)/yr. The building may
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also contain copper water pipes, but their effect can be assumed to be less than that of electrical wires and cables. The natural resource consumption attributable to other materials in the components of the mechanical and electrical services is smaller still. The sum of the abiotic and biotic values for construction and renewal of building components in the Physicum and Viikki Info Centre buildings in this study is approximately five times greater than the combined results of both Koskela et al. [10] and Saari and Tuomela [11]. Among the factors explaining this difference is that the Physicum and Viikki Info Centre buildings both involved earth or rock excavation for the basement floor (+33 kg/m2 (gross) in the Physicum building, +39 kg/m2(gross) in the Viikki Info Centre), and that the buildings incorporate a lot of mechanical and electrical services (+30 kg/m2(gross) in the Physicum building). If these figures are subtracted from the Physicum calculation, the remaining sum is 57 kg/ m2(gross), and from the Viikki Info Centre calculation, 76 kg/m2(gross). These two figures are still high in relation to the combined total of Koskela et al. [10] and Saari and Tuomela [11] (25 kg/m2(gross)). This is partly because the calculations performed in the present study were more wide-ranging than those by Koskela et al. [10] and because the latter did not include renewal of building components. 4.3. Practical significance The study produced information on the magnitude of natural resource consumption per service unit in the two buildings studied, and information on which factors are most significant in the natural resource consumption of these types of building. The study also provided useful information on which measures are worth pursuing to reduce the natural resource consumption of such buildings. This type of information can be utilised in planning, construction and usage of these kinds of buildings.
Acknowledgements The MIPS study presented in the article was funded by the Technical Department of the University of Helsinki and the Finnish Association for Nature Conservation. The authors would like to thank the study’s steering group members for their constructive cooperation: Mr. Teppo Salmikivi, Mrs. Virpi Pyy, Mr. Jarmo Ilmoniemi and Mr. Matti Hoikkala of the Technical Department of the University of Helsinki,
and Mr. Michael Lettenmeier of the Finnish Association for Nature Conservation.
References [1] Schmidt-Bleek F. Wieviel Umwelt braucht der Mensch? MIPS— das Mass fu¨r o¨kologisches Wirtschaften (How much environment man requires? MIPS—the measure for an ecological economy). Berlin: Birkha¨user Verlag; 1994. 302pp. [in German]. [2] Sinivuori P. Kahden Helsingin yliopiston rakennuksen luonnonvarojen kulutuksen selvitta¨minen MIPS-laskennan avulla (Analysis of natural resource consumption in two University of Helsinki buildings with the aid of MIPS calculations). Master’s Thesis in Environmental Sciences. Helsinki: Department of Biological and Environmental Sciences, University of Helsinki; 2004. 51pp.+appendices 40pp. Available at: http://ethesis.helsinki.fi/julkaisut/bio/bioja/pg/sinivuori/ [in Finnish]. [3] Schmidt-Bleek F. Das MIPS-Konzept: weniger Naturverbrauch—mehr Lebensqualita¨t durch Faktor 10 (The MIPSconcept: Factor 10 for less nature consumption and more quality of life). Mu¨nchen: Droemersche Verlaganstalt; 1998. 320pp. [in German]. [4] Ritthoff M, Rohn H, Liedtke C. Calculating MIPS. Material productivity of products and services. Wuppertal Spezial 27e. Wuppertal: Wuppertal Institute for Climate, Environment and Energy at the Science Centre North Rhine-Westphalia; 2002. 52pp. [5] Autio S, Lettenmeier M. Ekotehokkuus—business as future. Yrityksen ekoteho-opas (Ecoefficiency—business as future. A corporate guide to eco-efficiency) Dipoli reports C, environmental training. Espoo: Helsinki University of Technology Lifelong Learning Institute Dipoli; 2002. 80pp. [In Finnish]. [6] Haahtela Y, Kiiras J. Talonrakennuksen kustannustieto 2004 (Construction cost data 2004) Helsinki: Haahtela-kehitys Oy; 2004. 388pp. [in Finnish]. [7] Kiinteisto¨jen ylla¨pidon kustannustieto. Hoito- ja kunnossapitokustannukset seka¨ elinkaaren kustannuslaskelmat (Property operating and maintenance cost data 1992, Operating and maintenance costs and life cycle cost calculations) Helsinki University of Technology, Department of Civil and Environmental Engineering, Construction Economics and Management, Report 119 (Otaniemi, 1993), 1992. 235pp. [in Finnish]. [8] Statistical Yearbook of Finland. Helsinki: Statistics Finland; 2003. 704pp. [9] Spies-Wallbaum, H. Denk- und Kommunikationsansa¨tze zur Bewertung des nachhaltigen Bauens und Wohnens (Thinking and communication approaches for an assessment of sustainable construction and housing). Dissertation. Hannover: Universita¨t Hannover, Fachbereich Architektur; 2002. 237pp. [in German]. [10] Koskela S, Seppa¨la¨ J, Leivonen J. Ympa¨risto¨vaikutukset rakennusten ekotehokkuuden arvioinnissa (Taking environmental effects into account in the assessment of eco-efficiency in buildings). Suomen ympa¨risto¨ (The Finnish environment) No. 585. Helsinki: Finnish Environment Institute; 2002. 56pp. [in Finnish]. [11] Saari A, Tuomela S. Asuintalon sa¨hko¨-, tieto- ja hissija¨rjestelmien ympa¨risto¨kuormitus (Environmental loading from electrical, computer and elevator systems in a residential building). Helsinki University of Technology’s Construction Economics and Management Unit reports 195, Espoo, 2001. 37pp. [in Finnish].