Sustainability of Steel Buildings
BACKGROUND & USER GUIDE
October 2013
Deliverable of a project carried out with a financial grant
from the Research Fund for Coal and Steel of the European Community
Background & User Guide | III
CONTENTS
1 SIMPLIFIED METHODOLOGIES FOR BUILDING LIFE CYCLE ASSESSMENT 4 1.1 INTRODUCTION............................................................................................................................ 4 1.2 CLASSIFICATION OF BUILDING TYPOLOGY...................................................................................... 5 1.3 SCOPE OF THE ANALYSIS ............................................................................................................. 6 1.4 BUILDING CHARACTERISTICS ........................................................................................................ 7 1.5 MULTI-CRITERIA ANALYSIS ........................................................................................................... 8 1.6 ALGORITHM FOR LIFE CYCLE ASSESSMENT BASED IN MACRO-COMPONENTS ................................... 8 1.6.1 General steps ................................................................................................................................... 8 1.6.2 Allocation of recycling materials ..................................................................................................... 10 1.6.3 Characterization of macro-components ......................................................................................... 10 1.6.4 Illustrative example of a macro-components assemblage.............................................................. 11 1.7 ALGORITHM FOR ENERGY QUANTIFICATION (USE PHASE) ............................................................. 16 1.7.1 Introduction .................................................................................................................................... 16 1.7.2 Building location and climate .......................................................................................................... 16 1.7.3 Energy need calculation method .................................................................................................... 20 2 USER GUIDE & DESIGN EXAMPLE ................................................................ 27 2.1 BUILDING DESIGN IN THE CONCEPTUAL STAGE OF DESIGN ............................................................ 27 2.1.1 Selection of climatic zone and building location ............................................................................. 27 2.1.2 Selection of building type ............................................................................................................... 28 2.1.3 Macro-components selection ......................................................................................................... 29 2.1.4 Selection of type of analysis........................................................................................................... 33 2.1.5 Selection of building area ............................................................................................................... 34 2.1.6 Input for energy calculation ............................................................................................................ 34 2.1.7 Output: Operational energy calculation .......................................................................................... 36 2.1.8 Output: Life cycle environmental analysis ...................................................................................... 43 2.2 BUILDING DESIGN IN THE PRELIMINARY STAGE OF DESIGN ............................................................ 48 2.2.1 General input data ......................................................................................................................... 48 2.2.2 Selection of type of analysis........................................................................................................... 48 2.2.3 Selection of building area ............................................................................................................... 48 2.2.4 Outputs: operational energy and LCA impacts............................................................................... 49 REFERENCES ..................................................................................................... 50 4 | SB_Steel – Sustainability of steel buildings|
1 SIMPLIFIED
METHODOLOGIES
FOR
BUILDING
LIFE
CYCLE ASSESSMENT
1.1 Introduction
The aim of this tool is to provide a quick evaluation, in the early stages of design,
of the sustainability of steel-framed buildings, taking into account the life cycle
environmental performance of the building, including the use stage (use of
operational energy).
In the early stages of design, a building designer often faces different questions in
relation to: (i) the building location (which is usually not really a decision of the
building designer but of the owner of the building); (ii) the building orientation; (iii)
the building shape; (iv) the structural system to be adopted; (v) the building
envelope and (vi) the interior finishes.
Naturally, this is a challenging procedure as each question has a wide range of
different alternatives that globally will lead to an even wider range of different
solutions. In addition, from the point of view of the environmental assessment, the
problem is more complex as one constructional solution may be beneficial in some
environmental categories and simultaneously be very harmful in others.
The developed approach aims to provide the building designer guidance to the
above questions. Therefore, the general flowchart of the methodology is illustrated
in Fig. 1.1 and a detailed description of the main steps is provided in the following
sub-sections.
Selection of
building type
Selection of
building solution(s)
Selection of
climatic zone
Quantification of
operational energy
Selection of
scope of analysis
Quantification of
environmental impacts
Input of building
characteristics
yes
More
alternatives ?
Database of macrocomponents
Multi-criteria
analysis
Reports
no
Fig. 1.1: General flowchart of the software tool
Background & User Guide | 5
1.2 Classification of building typology
Buildings can be clustered into different classifications according to different
criteria. Since, in the developed approach, some typical parameters will be
adopted for cases where quantitative information is not available, a classification
scheme was developed in order to achieve the goal of the approach. Given the
wide variability of building solutions and the need to calibrate and validate each
sub-set, the classification scheme focuses on steel-intensive buildings.
In a simple perspective of functionality, buildings can be broadly classified as
residential buildings and non-residential buildings. Residential buildings can be
further classified according to their size in (IEE-project TABULA, 2012): (i) single
family houses; (ii) row houses; (iii) multi-family houses; and (iii) apartment blocks.
Non-residential buildings can be classified into: (i) office buildings; (ii) commercial
buildings; and (iii) industrial buildings. However, this tool focuses only on
residential and office buildings.
Steel is a common material used in the construction of buildings. The application of
steel in a building varies from simple service ducting to the main frame of the
building. In order to differentiate buildings in terms of steel content, different
applications of steel in the construction can be considered (CORUS, 2011):
•
•
•
•
•
the structure, including the frame and metal floor decking;
the envelope, including roofing and wall cladding;
the sub-structure, including foundations and sheet piling;
internal fit-out, including wall partitions and service ducting;
furnishing, fittings and finishes.
Therefore, in relation to the parameter “steel content”, three main categories are
defined: (i) category 1, representing steel-intensive buildings, in which the main
structure (frame and metal floor decking) and/or sub-structure (foundations and
sheet piling) are made of steel components; (ii) category 2, representing buildings
in which the main structure is not made of steel but the envelope (roofing and wall
cladding), is made of steel; and (iii) category 3, representing buildings in which
only secondary components such as service ducting, furnishings, fittings and
finishes are made of steel.
Taking these aspects into account, the classification matrix of Table 1.1 is
considered, in which the columns represent the building categories in terms of
“steel content” and the rows the building typologies in terms of building
functionality.
In the scope of the tool, the following three main types of buildings are considered:
(i) single and multi-family houses; (ii) apartment blocks and (iii) office buildings.
6 | SB_Steel – Sustainability of steel buildings|
Table 1.1: Matrix for classification of steel buildings
Since, the focus of the project was on steel buildings, the scope of the tool was
limited to buildings in Category 1 and Category 2.
1.3 Scope of the analysis
The sustainability assessment is undertaken in accordance with recent European
standards EN 15804 (2012) and EN 15978 (2011).
The modular concept of the aforementioned standards, which is represented in
Table 1.2, is adopted in the methodology. In the tool, the life cycle environmental
analysis of the building comprehends the product stage (modules A1 to A3), the
construction stage (module A4), the use stage (modules B2 to B6), the end-of-life
stage (modules (C1 to C4) and the benefits and loads due to recycling processes
(module D). However, the designer is able to select between a cradle-to-gate
analysis (modules A1 to A3), a cradle-to-gate analysis plus recycling (modules A1
to A3 and module D) or a cradle-to-grave analysis plus recycling (modules A to D).
Background & User Guide | 7
Table 1.2: Building information modules (according to EN 15978)
Operational water use
Demolition
Transport
Waste processing
Disposal
A5
B1
B2
B3
B4
B5
B6
B7
C1
C2
C3
C4
D
x
-
-
x
x
x
x
x
-
x
x
x
x
x
Reuse/Recycling
t ti l
Operational energy use
x
Refurbishment
x
Replacement
Transport
Manufacturing
A3 A4
Repair
x
A2
Maintenance
A1
Transport
Raw material supply
stage
End-of-life stage
Use
Construc Use stage
. stage
Construction process
Product
1.4 Building characteristics
The geometric characteristics of the building should be defined in order to enable
the quantification of the environmental impacts and of the energy needs of the
building. The introduction of data is distinguished between the concept stage and
the preliminary stage. In the former, the building is assumed to be of a rectangular
shape, in which the user has only to define the length (L) and width (B) of the
building (see Fig. 1.2a). The glazing areas of each façade are computed
automatically according to the building orientation and the climatic zone, based on
predefined parameters for each building typology.
For the preliminary stage, the input of the building geometric characteristics is
more detailed since building plans already exist. In this case, either a few predefined solutions are provided as indicated in Fig. 1.2.
(a)
(b)
Fig. 1.2: Plan shapes of the buildings
(c)
8 | SB_Steel – Sustainability of steel buildings|
1.5 Multi-criteria analysis
Once different solutions are defined for the building, the final step of the approach
is the comparison between different building solutions. The comparison is based
on the indicators that describe the embodied impacts and in the energy
consumption of the building. Different methods are available in the literature for
multi-criteria analysis in the context of sustainability (Gervásio and Simões da
Silva, 2012). In order to avoid trade-offs between criteria, outranking based
methods are preferred to aggregating methods (or single criterion methods)
because they involve weaker trade-offs (Gervásio and Simões da Silva, 2012).
Therefore, the method adopted for the combination of criteria is the Preference
Ranking Organization Methodology of Enrichment Evaluation (PROMETHEE)
(Brans, 1982). According to this method, the information within each criterion is
based on pair wise comparisons. A complete ranking of the alternatives is provided
by PROMETHEE II (Brans and Mareschal, 2005), thus enabling a quicker
identification of the most efficient solution.
1.6 Algorithm for life cycle assessment based in macro-components
The building fabric, external and internal, plays a major role in the behaviour of the
building in terms of the energy consumption and environmental burdens. This led
the way for the creation of pre-assembled solutions for the main components of the
building, i.e., the macro-components. Therefore, macro-components are predefined assemblages of different materials that fully compose the same
component of a building (SB_Steel, 2014).
For each building component different solutions were pre-assembled and the
model used for the life cycle analysis of building, based on macro-components, is
detailed in the following paragraphs.
1.6.1 General steps
1.6.1.1 Goal and scope
The goal of the tool is to quantify the environmental impacts of a simple building or
building components (in m2), using predefined macro-components. Therefore, the
approach enables the assessment to be made at two different levels: (i) the
component level (single macro-components); and (ii) the building level.
1.6.1.1.1 Functional unit
At the building level, the functional unit is a building with a defined typology (e.g.
residential, office, etc) designed for a predefined period of life (e.g. 50 years)
fulfilling all the standard requirements.
Background & User Guide | 9
At the level of a building component, the functional unit (in m2) is a building
component with a defined typology (e.g. external wall, internal slab, etc) used for a
period of life (e.g. 50 years). In this case, the function of the building component
may be included or not (in case of comparative assertions, then the function of the
building component should be included).
1.6.1.1.2 System boundaries
The life cycle environmental analysis comprehends the stages Table 1.2.
1.6.1.2 Life Cycle Inventory
Most environmental datasets are provided from the Ecoinvent database (2007),
except for the steel data. In addition, steel datasets are provided by Worldsteel
Association (2002).
1.6.1.3 Life Cycle Impact Assessment
The environmental categories selected to describe the environmental impacts of
the building are indicated in Table 1.3 and correspond to the environmental
categories recommended in the European standards for the assessment of
environmental performance of buildings (EN 15804 and EN 15978).
Table 1.3: Parameters describing environmental impacts
Impact category
Global Warming
Ozone Depletion
Acidification for
soil and water
Eutrophication
Photochemical ozone
creation
Depletion of abiotic
resource - elements
Depletion of abiotic
resources – fossil fuels
Characterization factor
Global warming potential (GWP)
Depletion potential of the stratospheric ozone layer
(ODP)
Unit
kg CO2 eq.
Acidification potential of soil and water (AP)
Kg SO2 eq.
Eutrophication potential (EP)
kg (PO4)-3 eq.
Formation potential of tropospheric ozone (POPC)
kg C2H4 eq.
Abiotic depletion potential (ADP – E) for non-fossil
resources
Abiotic depletion potential (ADP – F) for fossil
resources
kg R11 Eq.
kg Sb eq.
MJ
As already mentioned, the modular concept of the aforementioned standards was
adopted in the approach. Therefore, the output of the life cycle environmental
analysis of the building is provided per module.
The life cycle environmental analysis of each macro-component was performed by
SimaPro software (2010).
10 | SB_Steel – Sustainability of steel buildings|
1.6.2 Allocation of recycling materials
During the life cycle of steel, scrap arises from the manufacture phase, the final
processing phase and the end-of-life phase (see Fig. 1.3). Thus, an allocation
procedure has to be taken into account for scrap outputs from the whole life
system. Furthermore, as described further down in the text, steel is processed via
different production routes, and the allocation of scrap inputs to steelmaking is
another issue to be considered.
Primary steel manufacture
secondary steel manufacture
Steel product manufacture
Final processing
scrap scrap Use phase End‐of‐life scrap Fig. 1.3: System boundary of LCI including end-of-life data on scrap (LCI, 2001)
The adopted methodology to address the allocation problem of steel is the closed
material loop recycling approach developed by the Worldsteel Association (LCI,
2001). This methodology was developed in order to generate LCI data of steel
products, accounting for end-of-life recycling. The adoption of a closed-loop
approach is justified by the fact that scrap is re-melted to produce new steel with
little or no change in its inherent properties. In this case, following the guidance of
ISO standard 14044 (2006), the need for allocation is avoided since the use of
secondary material replaces the use of raw (primary) materials.
According to the European standards, all benefits due to steel recycling are
allocated to module D.
1.6.3 Characterization of macro-components
Macro-components were defined for different building components according to
the UniFormat classification scheme (2010). The following categories are
considered: (A) Substructure, (B) Shell and (C) Interiors. Each main category is
further sub-divided. The detailed classification scheme is represented in Table 1.4.
Background & User Guide | 11
Table 1.4: Building component classification scheme (UniFormat, 2010)
(A)
Substructure
(A40) Slabs-ongrade
(B10)
Superstructure
(A4010) Standard
slabs-on-grade
(B1010) Floor
construction
(B1020) Roof
construction
(B) Shell
(B2010) Exterior walls
(B20) Exterior
vertical enclosures
(C) Interiors
(B30) Exterior
horizontal
enclosures
(C10) Interior
construction
(C20) Interior
finishes
(B1010.10) Floor structural
frame
(B1010.20) Floor decks,
slabs and toppings
(B1020.10) Roof structural
frame
(B1020.20) Roof decks,
slabs and sheathing
(B2010.10) Ext. wall veneer
(B2010.20) Ext. wall
construction
(B2020) Exterior
windows
(B2050) Exterior doors
(B3010) Roofing
(B3060) Horizontal
openings
(C1010) Interior
partitions
(C2010) Wall finishes
(C2030) Flooring
(C2050) Ceiling
finishes
Within each building component (see Table 1.4) the corresponding macrocomponents have the same function and have similar properties.
The information provided by each macro-component is illustrated by the example
in Table 1.5. Apart from the characteristics of the different layers of materials, the
coefficient of thermal transmittance (U) (taking into account thermal bridges if
applicable) and the thermal inertia (κm) are also provided to enable for the
quantification of the operational energy of the building.
1.6.4 Illustrative example of a macro-components assemblage
The aim of this sub-section is to provide an illustrative example of a macrocomponents assemblage.
In some cases, in order to fulfil the function of a building component, different
macro-components have to be considered simultaneously. The following example
refers to the interior slab of a residential building.
1.6.4.1 Assemblage of macro-components
For an interior slab of a building the following macro-components are selected:
(i)
a macro-component for flooring (C2030),
a macro-component for a floor structural system (B1010.10),
(ii)
a macro-component for ceiling finishes (C2050).
(iii)
12 | SB_Steel – Sustainability of steel buildings|
The selected assemblage of macro-components is illustrated in Table 1.5. In this
case, the value of thermal transmittance (U) is not provided as the macrocomponent corresponds to an interior slab and therefore, it does not influence the
calculation of energy needs.
Table 1.5: Macro-components assemblage for an interior slab
Macro-components
assemblage
Macrocomponents
C2030
Flooring
C2030
B1010.1
B1010.10
Floor structural
C2050
system
C2050 Ceiling
finishes
Material
Thickness
(mm)/
Uvalue
Density
(kg/m2)
(W/m2.
K)
Ceramic
tiles
31 kg/m2
Concrete
screed
13 mm
OSB
18 mm
Air cavity
160 mm
Rock wool
40 mm
Light
weight steel
14 kg/m2
Gypsum
board
15 mm
Painting
0.125
kg/m2
-
κm
(J/m2.
K)
61062
1.6.4.2 Functional unit and estimated service life of materials
The functional unit of the building component is an interior slab (per m2) of a
residential building, with a required service life of 50 years. The selected macrocomponents have to fulfil the same functional unit of the building component.
Therefore, the estimated service life of the different materials has to be taken into
account. Table 1.6 indicates the estimated service life of the materials.
Table 1.6: Estimated service life of the materials
Macro-component
Material
Flooring
Ceramic tiles
Concrete screed
Cold Formed Steel
Rock wool
OSB
Gypsum Board
Paint
Floor structural system
Floor deck
Ceiling finishes
Unit
m2
m2
kg/m2
m2
m2
m2
m2
Estimated service life
[years]
25
50
50
50
50
50
10
Background & User Guide | 13
Therefore, in order to fulfil the functional unit, some of the materials have to be
replaced or rehabilitated according to a pre-defined scenario.
1.6.4.3 Scenarios and assumptions
In order to fulfil the environmental information in all modules, scenarios and
assumptions are needed.
The functional unit is related to a time-span of 50 years. This means that each
material in the macro-component needs to fulfil this requirement. Hence, materials
with an expected service life lower than 50 years need to be maintained or even
replaced during this period. Therefore, different scenarios are assumed for each
material in order to comply with the time span of the analysis. Likewise, in the endof-life stage, each material has a different destination according to its inherent
characteristics. Thus, for each material an end-of-life scenario is considered taking
into account the properties of each material.
All the aforementioned scenarios are set in accordance with the rules provided in
EN 15804 and EN 15978.
1.6.4.3.1 Scenarios for the transportation of materials (Modules A4 and C2)
The transportation distances between the production plants to the construction site
(module A4) and the distances between the demolition site and the respective
recycling/disposal places (module C2) are assumed, by default, to be 20 km and
the transportation is made by truck with a payload of 22 tonnes. However, the
designer is able to specify other distances, enabling sensitivity analysis to be made
in relation to the transportation of different materials.
1.6.4.3.2 Scenarios for the use stage (Modules B1:B7)
Scenarios are pre-defined for the different materials in order to fulfil the required
time span of 50 years. Therefore, in relation to the above macro-components
assembly, the following scenarios are set:
• substitution of ceramic tiles every 25 years;
• painting of ceiling every 10 years.
1.6.4.3.3 Scenarios for the end of life stage (Modules C1:C4) and recycling (Module
D)
Different end-of-life scenarios are specified for the materials according to their
inherent characteristics, as indicated in Table 1.7. Thus, OSB is considered to be
incinerated (80%) in a biomass power plant and credits are given to energy
recovery. Steel is recycled, assuming a recycling rate of 90%, and credits are
obtained due to the net scrap in the end of the life-cycle process. Likewise, rock
wool is considered to be recycled (80%). However, due to the lack of data of the
14 | SB_Steel – Sustainability of steel buildings|
recycling process, no credits are obtained apart from the reduction of waste sent to
landfill.
Table 1.7: EOL options for materials
Material
Ceramic tiles
Concrete screed
Gypsum plasterboard
Rock wool
OSB
Light-weight steel
Disposal/Recycling scenario
Landfill (100%)
Landfill (100%)
Landfill (100%)
Recycling (80%) + Landfill (20%)
Incineration (80%) + Landfill (20%)
Recycling (90%) + Landfill (10%)
Credits
Credit due to energy recovery
Credit due to net scrap
All the remaining materials were considered to be sent to a landfill of inert
materials.
1.6.4.4 Environmental analysis
The results of the macro-component assemblies illustrated in Table 1.5, are
represented in Table 1.8, per m2.
Table 1.8: Life cycle environmental analysis of macro-components (per m2)
Impact
category
ADP elem.
[kg Sb-Eq.]
ADP fossil
[MJ]
AP [kg SO2
Eq.]
EP [kg PO4Eq.]
GWP
[kg
CO2 Eq.]
ODP
[kg
R11 Eq.]
POCP [kg
Ethene Eq.]
A1-A3
A4
B4
C2
C4
D
TOTAL
1.86E-03
6.59E-09
1.83E-03
5.76E-09
5.93E-07
2.47E-01
7.91E-04
9.14E-02
6.85E-04
1.01E-02
2.61E-02
1.82E-04
1.40E-02
1.57E-04
1.54E-03
8.38E+01
1.77E-01
6.48E+01
1.54E-01
-1.01E-03 4.09E-02
6.80E+00 1.45E+01 1.41E+02
2.80E-06
3.09E-12
2.04E-06
2.70E-12
1.27E-09
1.76E-07
5.01E-06
3.41E-02
-2.58E-04
1.43E-02
-2.23E-04
2.62E-03
-1.07E-02
3.98E-02
-1.96E-04 3.49E-03
1.31E+03 2.45E+00 8.12E+02 2.14E+00 2.31E+01 3.35E+02 1.82E+03
-4.45E-02
3.05E-01
The contribution analysis per module is displayed in Fig. 1.4. Modules A1-A3
predominate for all impact categories (above 50% for most environmental
categories), followed by Module B4 with a contribution varying from 10% to 20%.
Module D has a significant contribution (close to 10%) for most impact categories.
Less significant is the contribution of module C4 (close to 5% in some cases),
followed by the remaining modules, with a negligible importance.
Background & User Guide | 15
A1-A3
A4
B4
C2
C4
D
POCP [kg Ethene-Equiv.]
ODP [kg R11-Equiv.]
GWP [kg CO2-Equiv.]
EP [kg Phosphate-Equiv.]
AP [kg SO2-Equiv.]
ADP fossil [MJ]
ADP elements [kg Sb-Equiv.]
-20%
0%
20%
40%
60%
80%
2
Fig. 1.4: Life cycle environmental impacts for a macro-component (per m )
All macro-components were computed in a similar way.
100%
16 | SB_Steel – Sustainability of steel buildings|
1.7 Algorithm for energy quantification (use phase)
1.7.1 Introduction
As previously mentioned, EN 15978 (2011) assigns all potential environmental
impacts of all aspects related with the building throughout its life cycle (materials
production, use, end-of-life and reuse, recovery and recycling potential) in a
modular system. According to this system, Module B6 corresponds to the
operational energy use, i.e., building energy consumption.
Module B6 boundaries have to be compliant with EPBD through the use of EN
15603 (2008) and shall include the energy used for heating, cooling, domestic hot
water supply, ventilation, lighting and auxiliary systems.
The adopted simplified approach is based on the characteristics of the building and
its installed equipment. It addresses the quantification of the energy needs for
space heating and cooling, and domestic hot water supply. The energy need for
mechanical ventilation and lighting are not addressed, since these two
components are not directly related to the construction system adopted for the
building. The calculation of heating and cooling consumptions follows the monthly
quasi-steady-state method provided by ISO 13790 (2008). This standard covers all
aspects of the heat components involved in the thermal calculations and provides
correlation factors to take the dynamic thermal effects into account. The energy
needs for DHW production is calculated according to EN 15316-3-1 (2007).
1.7.2 Building location and climate
In order to compute the operational energy of a building during its use phase, it is
important to take into account the most influencing variables related with thermal
behaviour and energy efficiency of a building.
Fig. 1.5: Major key-factors with influence on buildings energy consumption (Santos et al., 2012)
Background & User Guide | 17
The parameters could be grouped in four sets, namely: climate, building envelope,
building services and human factors as illustrated in Fig. 1.5. Most of these factors
are considered in the algorithm as detailed described in the next paragraphs.
The location of the building, in terms of climate conditions, is of vital importance in
thermal behaviour calculations (Santos et al., 2011, 2012). Regarding this matter,
two major climate parameters must be defined in order to undertake an energy
need calculation:
i)
air temperature;
ii)
solar radiation on a surface with a given orientation.
300
25
250
20
200
15
150
10
100
5
50
0
0
Air Temperature [˚C]
Solar Radiation [W/m2]
Fig. 1.6 graphically illustrates this average monthly data for the city of Timisoara in
Romania.
North
East
South
West
Horiz.
Air Temp.
‐5
Jan
Feb Mar Apr May Jun
Jul
Aug
Sep
Oct
Nov Dec
Fig. 1.6: Monthly average external air temperature and incident solar radiation: Timisoara (RO)
The methodology is currently calibrated for five climatic regions (classified
according with the Köppen-Geiger climate classification): (i) Csa; (ii) Csb; (iii) Cfb;
(iv) Dfb; (v) Dfc. The Köppen-Geiger climate classification is one of the most widely
used climate classification systems (Kottek at al., 2006). Fig. 1.7 presents the
Köppen-Geiger climate classification for Europe. It is clearly visible the importance
of latitude, altitude and coast vicinity on the climate in these regions. In regions
with lower latitudes (below 45ºN) (southern Europe, e.g. Mediterranean countries)
the climate is labelled as Csa and Csb, i.e., “C - warm temperate” with “s Summer dry” and “a - hot Summer” or “b - warm Summer”.
Above these latitudes (between 45-55ºN), in western central European countries,
the climate is mainly categorized as Cfb, i.e., “C - warm temperate” with “f - fully
humid” and “b - warm Summer”. In eastern central European countries (far away
from the Atlantic coast) the climate is labelled as Dfb, i.e., “D - snow” with “f - fully
humid” and “b - warm Summer”.
In regions with even higher latitudes (above 55ºN), in Nordic European countries,
the climate is mostly frequently labelled as Dfc, i.e., “D - snow” with “f - fully humid”
18 | SB_Steel – Sustainability of steel buildings|
and “c - cool Summer”. This climate has some similarities with eastern central
European countries, the main difference being the cooler Summer season.
Dfc
Dfb
Cfb
Csb
Csa
Fig. 1.7: European map of Köppen-Geiger climate classification (Kottek et al., 2006; Google Earth,
2014).
A database with weather data for different European locations was implemented.
Table 1.9 present a list of 48 cities for which this information was already obtained.
Most of this climate data was obtained in the EnergyPlus energy simulation
Background & User Guide | 19
software weather database (EERE-USDoE, 2014) and the remaining was provided
by research project partners.
Table 1.9: List of locations with obtained weather-data
City Amsterdam
Ankara Arhanglesk
Athens Barcelona Berlin Bilbao Bratislava Brussells Bucharest Coimbra Genova Graz Hamburg Helsinki Istambul Kiev Kiruna La Coruña Lisbon Ljubljana London Madrid Marseille Milan Minsk Montpellier
Moscow Munich Nantes Nice Oslo Ostersund Paris Porto Prague Rome Salamanca Sanremo Country
Netherlands
Turkey
Russia
Greece
Spain
Germany
Spain
Slovakia
Belgium
Romania
Portugal
Italy
Austria
Germany
Finland
Turkey
Ukraine
Sweden
Spain
Portugal
Slovenia
England
Spain
France
Italy
Belarus
France
Russia
Germany
France
France
Norway
Sweden
France
Portugal
Czech Republic
Italy
Spain
Italy
Climatic Region
Cfb
Csb
Dfc
Csa
Csa
Cfb
Cfb
Cfb
Cfb
Cfa
Csb
Csb
Dfb
Cfb
Dfb
Csa
Dfb
Dfc
Csb
Csa
Cfb
Cfb
Csa
Csa
Cfb
Dfb
Csa
Dfb
Cfb
Cfb
Csb
Dfb
Dfc
Cfb
Csb
Cfb
Csa
Csb
Csb
20 | SB_Steel – Sustainability of steel buildings|
Sevilla Stockholm Tampere Thessaloniki Timisoara Vienna Vigo Warsaw Zurich Spain
Sweden
Finland
Greece
Romania
Austria
Spain
Poland
Switzerland
Csa
Dfb
Dfc
Cfa
Cfb
Dfb
Csb
Dfb
Cfb
1.7.3 Energy need calculation method
The adopted approach enables to calculate energy needs on a monthly basis for
space heating, space cooling and DHW production. In order to determine the
contribution of each term involved in the thermal calculations it is necessary to rely
on several standards, as shown in Fig. 1.8, for the space cooling and space
heating.
Fig. 1.8: Flowchart of the algorithm and the reference standards for space conditioning
As observed from Fig. 1.8, ISO 13790 (2008) is the main standard used, which
addresses specific calculations to other standards. Taking into account the
importance of the DHW production in the building’s energy consumption, mainly at
residential buildings, it is also essential to estimate its share. As mentioned before,
this is undertaken under the guidance of EN 15316-3-1 (2007).
Backg
ground & User Guide
G
| 21
The procedure
e and arch
hitecture off the algorrithm used
d to calcula
ate energy
y needs
are presented
p
in Fig. 1.9..
Fig. 1.9
9: Flowchart of the calcullation of the energy
e
consumption of th
he building
Sub--modules 1 and 2, corresponding, res
spectively, to the U
U-value an
nd heat
capa
acity of th
he envelop
pe elemen
nts, are ca
alculated for the m
macro-comp
ponents
seleccted by the
e user. Su
ub-module 3 covers the heat trransfer thrrough the ground.
Sub--modules 4,
4 5 and 6 address the
t sub-rou
utines use
ed to calculate the efffects of
the shading
s
de
evices and shading due to the shape
s
of th
he floor pla
an.
1.7.3
3.1 Energyy need for space
s
heatting and cooling
Eq. (1
1.1) and Eq
q. (1.2) are the basic main equa
ations defin
ned in ISO
O 13790 (2
2008) to
quan
ntify the monthly,
m
( ), energyy need as
ssuming continuous,
c
, (
operration (refer to ISO 13
3790 for no
omenclature):
,
Eq. (1
1.1)
,
,
, ,
,
,
,
.
.
,
,
), systems
s
22 | SB_Steel – Sustainability of steel buildings|
,
,
,
,
,
, ,
.
,
, ,
,
Eq. (1.2)
where,
,
,
,
,
, heating energy need (kWh);
, cooling energy need (kWh);
, total heat transfer by transmission (kWh);
, total heat transfer by ventilation (kWh);
, gain utilization factor (-);
, loss utilization factor (-).
The methodology followed to calculate all these parcels of the energy need was
addressed as prescribed in ISO 13790 (2008).
1.7.3.2 Energy need for DHW production
The energy needed for DHW production, in
/
, is calculated following EN
15316-3-1 (2007). It is influenced by the type of building, its floor area and the
temperature difference between the inlet water and the one desired at the tapping
point, according to,
,
,
4,182.
,
.
,
,
Eq. (1.3)
where,
,
,
,
is the monthly DHW volume need as prescribed in EN 15316-3-1
(2007);
is the temperature of DHW at tapping point [˚C];
, temperature of the inlet water [˚C].
For a single dwelling the daily volume of domestic hot water need is based in the
floor area and calculated (in m3/day) as follows,
.
1000
Eq. (1.4)
where,
, unit requirement based on litres of water at 60˚C/day;
, number of units to be taken into account.
Background & User Guide | 23
The monthly volume of DHW needed, , , could be obtained by multiplying the
daily value, , by the number of days of the month.
The parameters,
and
, depend on the type of building and its
occupation/activity and could be calculated depending on the floor area,
, as
follows,
30
If
, then
.
Eq. (1.5)
If 15
30
, then
2
Eq. (1.6)
1.7.3.3 Energy consumption
The energy need calculated does not take into account the efficiency of the
building’s systems installed to condition the interior space neither to produce DHW.
The algorithm considers that the building may have systems with different
efficiencies, since it is not often that, for example, the heating and cooling COPs
are the same. Hence, each energy need (space cooling, space heating, DHW
production) is affected of the efficiency of the respective equipment. The general
formulae to calculate the energy consumption that could be applied for each type
of energy need is:
Eq. (1.7)
where,
, energy need;
, system’s efficiency.
The adopted default values of system’s energy efficiency and the type of energy
consumed are presented in the following tables. Mostly of these values where
obtained from RCCTE (2006).
24 | SB_Steel – Sustainability of steel buildings|
Table 1.10: Space heating system’s efficiency and energy used
,
Type of energy
Heat system
,
Electric resistance
1
Electricity
Gas Fuel Heater
0.87
Gas Fuel
Liquid Fuel Heater
0.8
Liquid Fuel
Solid Fuel Heater
0.6
Solid Fuel
4
Electricity
Split (Heating)
Table 1.11: Space cooling system’s efficiency and energy used
Heat system
,
Type of energy
Split (Cooling)
Refrigeration machine
(compression cycle)
Refrigeration machine
(absorption cycle)
3
Electricity
3
Electricity
0.8
Electricity
Table 1.12: DHW system’s efficiency and energy used
Heat system
Electric boiler
0.9
Type of energy
Electric
Gas boiler
0.6
Gas
Stand-alone heater
condensation
Stand-alone heater
0.72
Gas
0.4
Gas
,
The total energy consumption in the building is determined through the sum of all
energy use:
,
,
,
,
,
,
,
Eq. (1.8)
The primary energy is computed by multiplying the conversion factor,
,
[kgoe/kWh] by the energy consumption,
,
,
.
,
,
.
,
,
.
,
Eq. (1.9)
The conversion factor from energy consumption (or use) to primary energy depend
on the fuel (or type of energy) for each system. The values default values were
obtained from RCCTE (2006) and are presented in Table 1.13.
Background & User Guide | 25
Table 1.13: Conversion factor from energy use to primary energy (RCCTE, 2006)
Energy type
Electricity
Gas, liquid or solid fuel
[kgoe/kWh]
0.29
0.086
1.7.3.4 Thermal inertia
Regarding thermal inertia, the internal heat capacity of the building,
calculations
were performed as suggested by ISO 13790. The internal heat capacity per area
of each macro-component was computed according the prescriptions within annex
A of EN ISO 13786 (2007). This is a simplified procedure base in the penetration
depth of the heat wave, calculated for the materials adjacent to the interior surface,
which is suitable for this type of calculations. In the prescribed method, the heat
capacity of the layers is considered, until a maximum thickness of 100 mm
(counting from the internal surface).
1.7.3.5 Thermal bridges
The effect of repeating thermal bridges (e.g. originated by steel studs as illustrated
in Fig. 1.10) within the construction elements (e.g. walls and slabs) are taken into
account in the thermal transmittance (U-value). Linear and punctual thermal
bridges effect is neglected.
Neglecting thermal bridges
2
U = 0.162 W/(m K)
With steel frame thermal bridge
U = 0.227 W/(m2K)
Fig. 1.10: Effect of thermal bridges in the thermal transmittance values for a LSF external floor
26 | SB_Steel – Sustainability of steel buildings|
The U-value of thermal bridged elements were determined with the method
presented in Section 6 of ISO 6946 (2007) and perfected by Gorgolewski (2007),
since the first is only applicable if the insulation layer is not bridged by steel
frames. The second method relies in the determination of two limits for the thermal
resistance of the construction element and correction factors dependent on the
stud dimensions and spacing. A lower limit is calculated by combining the parallel
resistances of the layers, i.e. assuming that each plane is at the same
temperature. An upper limit of thermal resistance is also calculated by summing
the resistances of each heat path.
Whenever there is no thermal bridge in the element, then it is applied the method
for homogenous layers, which takes into account the circuit of thermal resistances
in series.
Background & User Guide | 27
2 USER GUIDE & DESIGN EXAMPLE
In this section a step-by-step example of a building design is provided. First the
building is assessed in the conceptual stage of design. Then the building is recalculated in the preliminary stage of design, when more detail data is assumed to
be known.
The input screen of the SB_Steel tool is illustrated in Fig. 2.1. Besides the main tab
display area on the centre, the generic input screen presents different information,
including: the SB_Steel project and partners logos, name of the tab, sequence tab
identification, home and administrator login buttons, “Back” and “Next” tab buttons.
Home (1st tab) button
Administrator
login button
Project logo
Tab name
Sequence tab
identification
Sequence of
tab names
Input 1
Main tab display area
Input 2
Partner’s logos
“Back” and “Next”
tab buttons
Fig. 2.1: Example of an input screen of the SB_Steel tool
2.1 Building design in the conceptual stage of design
2.1.1 Selection of climatic zone and building location
The climatic zone is selected according to the Köppen-Geiger climate classification
described in sub-section 2.2. Five climatic zones are available within European
continent (Fig. 2.2). After, a city for the building location should be selected among
a list of available cities for the previously designated climatic zone.
28 | SB_Steel – Sustainability of steel buildings|
Fig. 2.2: Selection of climatic zone and city of the building location
2.1.2 Selection of building type
The building type is selected from a matrix defined by the building usage (e.g.
single & multi-family low-rise buildings, apartments blocks, offices) and by the steel
use category, changing from Category 1 (higher intensive steel use) to Category 3
(more reduced use of steel). In this example a lightweight steel framed (Category
1) low-rise single family building is evaluated (Fig. 2.3).
Background & User Guide | 29
Fig. 2.3: Selection of building type
2.1.3 Macro-components selection
The construction elements of the building envelope (e.g. roof, floors and walls) are
defined by selecting macro-components from the database of the software. Fig. 2.4
displays a print-screen of the tab to define the roof macro-component of the
building. Each constructive element is defined by three different macrocomponents: (1) structural frame; (2) interior sheathing/finishes; and (3) exterior
sheathing/finishes. Moreover, the thickness of each layer could be changed by the
user. The thermal transmittance (U-value) and the areal heat capacity (related with
thermal inertia) of each building element is automatically calculated. However, if
the user wants to use its own values, he only needs to check the box “User
Values” and type them.
Fig. 2.5 to Fig. 2.8 displays the layout of the software to define the remaining
macro-components of the building envelope: interior floor, ground floor, exterior
and interior walls, respectively.
30 | SB_Steel – Sustainability of steel buildings|
Fig. 2.4: Selection of roof macro-components
Fig. 2.5: Selection of interior floor macro-components
Background & User Guide | 31
Fig. 2.6: Selection of ground floor macro-components
32 | SB_Steel – Sustainability of steel buildings|
Fig. 2.7: Selection of exterior wall macro-components
Background & User Guide | 33
Fig. 2.8: Selection of interior wall macro-components
2.1.4 Selection of type of analysis
The user must select the design stage for the analysis (Fig. 2.9): Conceptual or
preliminary stage. Furthermore, the lifespan and the scope of analysis should be
selected, being available three choices for the later as illustrated in Fig. 2.9.
Fig. 2.9: Selection of stage, scope and lifespan of the analysis
34 | SB_Steel – Sustainability of steel buildings|
2.1.5 Selection of building area
At the conceptual design stage the availability of data is scarce and therefore only
rectangular architectural floor plans are available (Fig. 2.10). In this case study the
total area of construction is about 200.0 m2, with 100.0 m2 on the ground floor and
100.0 m2 on the first floor. The total height of the building is 6 m.
The glazing areas of each façade are also provided as a percentage of the area of
the corresponding façade.
Fig. 2.10: Selection of the building orientation, dimensions, n. of floors and glazing areas
2.1.6 Input for energy calculation
In this section the inputs needed for the operational energy calculation are
presented, namely: the indoor conditions (Fig. 2.11), the building systems (Fig.
2.12) and the operational specifications (Fig. 2.13).
Regarding the indoor conditions, the user must define the comfort temperature
range by selecting the heating and cooling set points (Fig. 2.11). Additionally, the
ventilation rates for heating and cooling modes should be inputted (in this example
0.6 and 1.2 air-change per hour, respectively).
Background & User Guide | 35
Fig. 2.11: Selection of heating/cooling set points and ventilation rates
The next tab of the software is used to define the building systems as displayed in
Fig. 2.12. Several space heating and cooling systems are available, as well to
produce domestic hot water (DHW). Additionally, if there is an option to include
renewable energy sources, namely to produce electricity (e.g. photovoltaic panels)
or DHW (solar collectors). Furthermore, the ventilation type (natural or mechanical)
should be selected. There is also a checkbox that should be selected whenever
there is a mechanical ventilation heat recovery system, being its efficiency defined
in this circumstance.
Fig. 2.12: Selection of building system
36 | SB_Steel – Sustainability of steel buildings|
The remaining operational specifications are defined in a tab as illustrated in Fig.
2.13. The software database has included the properties for different available
constructive solutions and building envelope characteristics that can be selected
by the user. This includes the type of glass (e.g. single or double) and the frame
material of windows (e.g. aluminium or wood), the shading devices (e.g. exterior or
interior), the colour of the opaque envelope (e.g. light or dark), the ground floor
type (e.g. slab-on-ground or suspended floor) and the soil type (e.g. clay/silt or
sand/gravel).
Fig. 2.13: Selection of operational specifications
2.1.7 Output: Operational energy calculation
In this section the outputs of the operational energy calculation are described. Fig.
2.14 illustrates an output screen example of the SB_Steel tool software. The main
difference with the input screen (Fig. 2.1) is that now are available two additional
buttons highlighted in red (Fig. 2.14). The “Report” button allows generating a PDF
file format report of all the calculations that will be sent to an e-mail address
provided by the user. The “Add Solution” button allows the user to obtain a
different building construction solution and compare the results.
Background & User Guide | 37
“Report” and
“Add Solution”
buttons
Fig. 2.14: Example of an output screen of the SB_Steel tool
Fig. 2.15 shows a layout of the obtained results for energy need for space heating,
including the several parts of the heat balance: the heat transfer by transmission
(through walls, windows, ground, roof and a total value), the heat transfer by
ventilation, the solar heat gains via opaque and glazed envelope, and internal heat
gains. Furthermore, the heating season length and the monthly values of the
energy need for space heating are also presented including the normalised ones
per square meter. Moreover, the breakdown of the annual energy values for space
heating is presented, including: the energy need, the delivered energy, the
renewable energy and the primary energy.
38 | SB_Steel – Sustainability of steel buildings|
Fig. 2.15: Building space heating energy outputs
The heat transfer breakdown (in percentage) is also presented in a chart format as
illustrated in Fig. 2.16.
Fig. 2.16: Heat transfer breakdown
The layouts of the outputs tabs for space cooling are very similar as illustrated in
Fig. 2.17 and Fig. 2.18.
Background & User Guide | 39
Fig. 2.17: Building space cooling energy outputs
Fig. 2.18: Cooling transfer breakdown
Regarding the energy to produce domestic hot water (DHW), the energy need
monthly and annual values are displayed as presented in Fig. 2.19. Additionally,
the total delivered and primary energy, as well the energy from renewable sources
(e.g. solar collectors) to produce DHW is presented.
40 | SB_Steel – Sustainability of steel buildings|
Fig. 2.19: Energy for domestic hot water production outputs
In the next tab (Fig. 2.20) an overview of the energy (monthly and annual values)
for space heating, space cooling and to produce DHW is displayed. Furthermore,
the breakdowns (in percentage) of these annual total values for the energy need
and energy consumption are displayed in a chart format as presented in Fig. 2.21.
Fig. 2.20: Total energy outputs
Background & User Guide | 41
Fig. 2.21: Total energy need and delivered breakdown chart outputs
Since the solar heat gains have an important role in the thermal energy balance of
the building, these monthly values for the glazed and opaque envelope are
displayed in table and chart formats as illustrated in Fig. 2.22 and Fig. 2.23 for the
heating and cooling modes, respectively.
42 | SB_Steel – Sustainability of steel buildings|
Fig. 2.22: Solar heat gains through the glazed and opaque envelope: heating mode
Background & User Guide | 43
Fig. 2.23: Solar heat gains through the glazed and opaque envelope: cooling mode
2.1.8 Output: Life cycle environmental analysis
In this section the outputs of the life cycle environmental analysis are described.
Firstly the environment impacts are presented for each building macro-component,
namely: roof (Fig. 2.24), interior floor (Fig. 2.25), ground floor (Fig. 2.26), interior
wall (Fig. 2.27), exterior wall (Fig. 2.28) and glazing (Fig. 2.29). Then, as illustrated
in Fig. 2.30, the life cycle environment impacts of all the previous building
components are displayed.
44 | SB_Steel – Sustainability of steel buildings|
Fig. 2.24: Roof environment impacts
Fig. 2.25: Interior floor environment impacts
Background & User Guide | 45
Fig. 2.26: Ground floor environment impacts
Fig. 2.27: Interior wall environment impacts
46 | SB_Steel – Sustainability of steel buildings|
Fig. 2.28: Exterior wall environment impacts
Fig. 2.29: Glazing environment impacts
Background & User Guide | 47
Fig. 2.30: Total environment impacts
Fig. 2.31 illustrates the first two pages of a PDF report generated by the software
whenever the user click in the “Report” button illustrated in Fig. 2.14.
Fig. 2.31: Example of a report in PDF format: first two pages
48 | SB_Steel – Sustainability of steel buildings|
2.2 Building design in the preliminary stage of design
2.2.1 General input data
The initial input tabs of the preliminary stage of design are the same as for the
conceptual stage (see Fig. 2.2 to Fig. 2.8). The only two different input tabs are
presented in the next sections: “Selection of type of analysis” and “Selection of
building area”.
2.2.2 Selection of type of analysis
In this input screen the design stage of analysis selected by the user should be
“Preliminar stage” as highlighted in red in Fig. 2.32.
Fig. 2.32: Selection of design stage, scope and lifespan of the analysis
2.2.3 Selection of building area
The main difference in relation to the conceptual stage (Fig. 2.10) is that now
(preliminary design stage) more detailed information is available and therefore two
additional architectural floor plans are available: L-shape and T-shape as
highlighted in red Fig. 2.33. In this example an L-shaped floor plan was selected.
Background & User Guide | 49
Fig. 2.33: Selection of the building shape, orientation, dimensions, n. of floors and glazing areas
2.2.4 Outputs: operational energy and LCA impacts
The preliminary design stage outputs for the operational energy and life cycle
environmental impacts are the same as presented previously for the conceptual
design stage (see sections 2.1.7 and 2.1.8, and Fig. 2.14 to Fig. 2.30). Similarly, a
PDF report of the calculations could be generated for this stage of design as
exemplified before for the conceptual stage of design in Fig. 2.31.
50 | SB_Steel – Sustainability of steel buildings|
REFERENCES
Brans, J. (1982). L’ingénièrie de la décision; Elaboration d’instruments d’aide à la décision. La
méthode PROMETHEE. In R. Nadeau and M. Landry, editors, L’aide à la décision: Nature,
Instruments et Perspectives d’Avenir, pages 183–213, Québec, Canada. Presses de l’Université
Laval.
Brans, J. and Mareschal, B. (2005). PROMETHEE methods, pp. 163–195, Chapter of book. In:
Figueira, J., Greco, S., Ehrgott, M., (Eds.), Multiple Criteria Analysis – State of the Art Surveys, vol.
78, International Series in Operations Research and Management Sciences. Springer, New York,
USA.
CORUS. 2011. Sustainable Steel Construction – Building a better future. A sustainable strategy for
the UK steel construction sector developed by the Steel Construction Sector Sustainability
Committee, Corus (available from www.steel-sci.org)
DesignBuilder software v3.0.0.105, www.designbuilder.co.uk/, 2012
Ecoinvent Centre. 2007. Ecoinvent data v2.0. Ecoinvent reports No.1-25. Swiss Centre for Life
Cycle Inventories, Dübendorf. (retrieved from: www.ecoinvent.org)
EERE-USDoE, Energy Efficiency and Renewable Energy Website from the United States
Department of Energy: http://apps1.eere.energy.gov/buildings/energyplus/cfm/weather_data2.cfm/
region=6_europe_wmo_region_6 (last accessed March 2014)
EN 13363-1. (2007). Solar protection devices combined with glazing - Part 1: Simplified method.
CEN - European Committee for Standardization.
EN 15193, (2007) Thermal performance of buildings - Energy requirements for lighting, CEN –
European Committee for Standardization.
EN 15265, (2007) Energy performance of buildings - Calculation of energy needs for space heating
and cooling using dynamic methods - General criteria and validation procedures. CEN - European
Committee for Standardization.
EN 15316-3-1, (2007) Heating systems in buildings – Method for calculation of system energy
requirements and system efficiencies – Part 3.1 Domestic hot water systems, characterisation of
needs (tapping requirements), CEN – European committee for Standardization.
EN 15804. 2012. Sustainability of Construction Works — Environmental product declarations –
Core rules for the product category of construction products. European Committee for
Standardization, Brussels, Belgium.
EN 15978. 2011. Sustainability of Construction Works — Assessment of environmental
performance of buildings — Calculation method. European Committee for Standardization,
Brussels, Belgium.
EN ISO 13786, (2007) Thermal performance of building components - Dynamic thermal
characteristics - Calculation methods, CEN – European Committee for Standardization.
EN ISO 6946, (2007) Building components and building elements - Thermal resistance and thermal
transmittance - Calculation method, CEN – European Committee for Standardization.
Gervásio, H. and Simões da Silva, L. (2012). A probabilistic decision-making approach for the
sustainable assessment of infrastructures, Expert Systems With Applications 39 (8) (2012), pp.
7121-7131, DOI information: 10.1016/j.eswa.2012.01.032.
Background & User Guide | 51
Google Earth Software Website: www.google.co.uk/intl/en_uk/earth/ (last accessed January 2014).
Gorgolewski, M. (2007) Developing a simplified method of calculating U-values in light steel
framing. Building and Environment, 42(1), 230–236.
IEE-Project TABULA. 2012. www.building-typology.eu
ISO 10077, (2006) Thermal performance of windows, doors and shutters - Calculation of thermal
transmittance - Part 1: General, ISO - International Organization for Standardization.
ISO 13370, (2007) Thermal performance of buildings - Heat transfer via the ground - Calculation
methods, ISO - International Organization for Standardization.
ISO 13789, (2007) Thermal performance of buildings - Transmission and ventilation heat transfer
coefficients - Calculation method, ISO - International Organization for Standardization.
ISO 13790, (2008) Energy performance of buildings - Calculation of energy use for space heating
and cooling, CEN – European committee for Standardization.
ISO 14040. 2006. Environmental management – life cycle assessment – Principles and framework.
International Organization for Standardization. Geneva, Switzerland.
ISO 14044. 2006. Environmental management – life cycle assessment – Requirements and
guidelines. International Organization for Standardization, Geneva, Switzerland.
Kottek M, Grieser J, Beck C, Rudolf B and Rubel F (2006) World map of Köppen-Geiger climate
classification updated. Meteorologische Zeitschrift, 15(3): 259–263.
LCI, 2001. World Steel Life Cycle Inventory. Methodology report 1999/2000. International Iron and
Steel Institute. Committee on Environmental Affairs, Brussels.
Pré Consultants. 2010. SimaPro LCA software.
RCCTE (2006) Portuguese code of practice for thermal behaviour and energy efficiency of
residential buildings. Decreto-Lei n.80/2006. Regulamento das Características Térmicas dos
Edifícios (in Portuguese:). Lisboa, Portugal: Diário da Républica.
Santos P., Gervásio H., Simões da Silva L., & Gameiro A. (2011). Influence of climate change on
the energy efficiency of light-weight steel residential buildings. Civil Engineering and Environmental
Systems, 28, 325–352.
Santos P., Simões da Silva L., & Ungureanu V. 2012. Energy Efficiency of Light-weight Steelframed Buildings. European Convention for Constructional Steelwork (ECCS), Technical
Committee 14 - Sustainability & Eco-Efficiency of Steel Construction, ISBN 978-92-9147-105-8, N.
129, 1st edition.
SB_Steel, 2014. Sustainable Building Project in Steel. Draft final report. RFSR-CT-2010-00027.
Research Programme of the Research Fund for Coal and Steel
UniFormat™: A Uniform Classification of Construction Systems and Assemblies (2010). The
Constructions Specification Institute (CSI), Alexandria, VA, and Construction Specifications Canada
(CSC), Toronto, Ontario. ISBN 978-0-9845357-1-2.
Worldsteel organization. http://www.worldsteel.org/index.php (last accessed in 31/08/2009)