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Sustainable Architecture Analysis of constructive processes, techniques and materials

Mariana Mota Medeiros Pinto

ABSTRACT

The current consumption rate of fossil fuels and natural resources in the construction activities is

unsustainable. Actually this activity consumes resources well above natural systems restoration capacity, being

responsible for 30% of world’s carbon emissions. The efforts to increase sustainability using energy from renewable

resources should include innovation in the construction methods and the valorisation of waste through its reuse or

transformation which has obvious economic and environmental advantages, allowing savings of natural and material

resources.

The present work aims to evidence the contribution that existent materials and constructive techniques can

provide for sustainable development in the construction sector, supporting innovative ad eco-friendly techniques and

processes that reduce Environmental Impact, identifying the reasoning for preservation of the natural resources and

endorsing the use of renewable energies. The outcome of this research presents the results related with sustainable

architectural techniques and processes, using “environmentally friendly” materials, and analyses its applicability in a

physical architectural model developed in this work. With the aim of attaining a sustainable architecture, an evaluation

is proposed at the different life cycle stages, as the CO2 emissions calculation and the analysis of the network

supplied energy savings provided by the renewable energies used, as well as the feasibility of material’s recycling at

the end of its useful life.

Key words: Sustainable architecture, renewable energies, natural resources, construction waste, environmental

performance

1. INTRODUCTION

Currently the construction sector is an activity that consumes natural resources quite beyond their restoration

capacity, thus causing severe damages to the environment. The pressure for speedy building’s construction, including

at project level, the initial costs down-sizing, the risk of legal responsibility or even some cultural perceptions, are not

favourable to changing practices or mentalities (Santos, 2010). As we know, humanity has been consuming resources

above their restocking capacities and the restoration capacity of the natural systems.

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Human society will always depend on the critical balance keeping, between three key variables: population,

natural resources and environment. With the increase of population and the high level of urbanization along the

centuries, construction sector trends have become unbearable, and the buildings have consumed the main share of

the material resources, approximately 3.000 million of tones each year (Torgal et al., 2010). Approaching these main

themes (resources, materials, construction and wastes) the present work intends to spread awareness and

responsiveness among agents, stakeholders, sellers, buyers, constructors or dealers. A sustainability construction

process should consider an adequate balance between the capacity rate that environment has to provide resources

and absorb waste, without depletion and minimizing environmental impacts, and the requests placed by Humanity.

Subsequently, a building could be considered as sustainable when (Gil, 2000):

Consumes the less possible quantity of energy during its life cycle;

Uses renewable, reused or recycled materials;

Generates the slightest quantity of wastes and pollution;

Satisfies the needs of its users, in the present and the future.

2. SUSTAINABLE ARCHITECTURE

Sustainable architecture has emerged through a variety of concepts since the beginning of 20th century: Low-

energy, Solar design, Bioclimatic and Passive, Ecological, Green, Self-sufficient and Zero-energy. The variations

among these concepts are based mostly on the context and the time they occurred. Among the whole package of

concepts that sustainable architecture can be expressed for, the bioclimatic is the most extensive one. The concept of

bioclimatic architecture has been attributed to a type of architecture which is adapted to the environment and takes

into account the visual impact and disruption it causes to nature. Inside this concept is the Zero-energy one, which

also concerns about the use of individual supply systems (water, sewage and electricity) or the use of renewable

energies in order to keep them “low-emissions”. In short, the main concepts to achieve a sustainable architecture, and

which I try to incorporate as much as possible in the design of the Eco-house are, as follow:

Site Planning: Site Planning starts with the site analysis, where issues of particular concern are climate, landscaping,

sunlight and solar gain, daylight and views, wind, noise and air quality. Bioclimatic design capitalizes on the

characteristics of the site in order to minimize the energy needs of the building and to create a more comfortable

environment (thermal, acoustic, natural light) adapted to the ways and lifestyles of the inhabitants. In addition, special

attention is dedicated to respect the existing landscape and the building’s integration in it.

Natural Ventilation: Natural ventilation is driven by wind or by air flows resulting from heat transference between the

interior and the exterior, depending on the air pressure and temperature differences. The wind could always influence,

in an active and meaningful way, the energetic performance of the building.

Passive Strategies: In a building conception design, when the right climate strategies are used, the thermal comfort

conditions are closer to be achieved with minimum energy consumption. The adoption of these strategies improves

the building performance in terms of interior thermal comfort as they are distribution agents of the heat-energy by

natural transference processes. In cooling passive systems the purpose is to get advantage of cold sources. These

strategies should be developed concerning the solar orientation, natural ventilation, the right size of the portholes and

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the activity of each space. Furthermore we can use the solar energy to complement active heating systems without

compromising the emission of gases and pollutants. We have to keep in mind that passive architecture and its thermal

and comfort conditions are often successfully provided by the user himself. He should keep the system active,

changing all the needed features to maintain the air quality and interior environmental conditions.

Reusing of Water: The increasing demand for water can be met either by intensifying the capacity of supply (e.g. by

building new reservoirs), by reducing the consumption of water or by reusing water wherever possible. Reusing water

has the main objective of creation of new supply sources to overcome population growth, helping to decrease the

Environmental impact.

Renewable Energies: The management and transformation of natural resources formulate a massive and central

theme in seeking for sustainability. An intensive exploitation of natural resources beyond their capacity of renovation

causes environmental problems. This study proposes the extensive use of renewable energy either in the construction

phase or in the useful life for the household needs, in order to avoid as much as possible the use of fossil and other

scarce natural resources. “Renewable energy is derived from natural processes that are replenished constantly. In its

various forms, it derives directly from the sun, or from heat generated deep within the Earth. Included in the definition

is electricity and heat generated from solar, wind, ocean, hydropower, biomass, geothermal resources, and biofuels

and hydrogen derived from renewable resources” (EIA).

Waste Management: Waste appreciation represents a double advantage, once it avoids the waste landfill and also

values the waste as “new” resources. The management of theses wastes is promoted as a major vector in the

sustainable use of resources. The objectives of the Priority Waste Streams Programme (Symonds Group) respond to

the waste management hierarchy, which prefers waste prevention or reduction to reusing, reusing to recycling or

recovery (including the use of waste as a source of energy), and all of these to final disposal via landfill or incineration

without energy recovery. Although not expressed in these terms in any of the key documents, the hierarchy is

generally summarized as:

Prevention or reduction (sometimes termed avoidance or minimization);

Reusing;

Recycling or materials recovery;

Energy recovery;

Disposal in a safe manner.

Disposal of buildings in most industrial and emerging industrial countries is wasteful and problematic. Waste

from building demolition (partial demolition for renovation, or total demolition for building removal) represents 30-50%

of total waste in most of these countries. A number of economic and social benefits can be fulfilled by shifting towards

better materials recovery practices in the construction sector.

Deconstruction is an alternative to demolition. It calls for buildings to be dismantled or disassembled, in the

reverse of its construction, and for the components to be reused or recycled. Deconstruction saves landfill space,

reduces pollution and energy consumption associated with manufacturing and production of new materials, and it can

reduce site impacts in terms of dust, soil compaction, and loss of vegetation.

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3. IMPACT OF CONSTRUCTION MATERIALS

A comprehensive knowledge of the importance of construction materials in the sustainable context should

involve a full understanding of which have been the environmental impacts caused by raw material extraction and their

production. In this context one of the most pressing environmental questions relies on the possibility of non-renewable

raw materials exhaustion.

Besides the remarkable question concerning the possibility of non-renewable raw materials depletion and the

associated environmental impact due to their extraction, there are others that should be considered in the context of

sustainable construction materials (Santos, 2010). Their choice should privilege the materials, (1) nontoxic; (2) with

low embodied-energy; (3) recyclable; (4) durable; (5) which could allow the reuse and recover of wastes; (6) that

provide from renewable sources; (7) associated to low emissions of gases and toxicities; (8) and the ones where an

analyse of their Life Cycle is done.

The range of impacts of buildings on the environment is diverse. Problems which result from construction –

related processes, such as global warming, ozone depletion, loss of natural habitat and biodiversity, soil erosion and

release of toxic pollutants are now well known.

3.1 Life Cycle Analysis

To establish the true environmental impact of a building the analysis may be carried out in a way that reflects

the relative importance of different building elements and processes, and the priorities for reducing environmental

impacts. This is called Life Cycle Analysis (LCA, also known as Life Cycle Assessment and cradle-to-grave analysis).

A LCA is based on ISO 14040 and it consists in a technique to assess environmental impacts associated with all the

stages of a product's life. LCA can help avoid a slight outlook on environmental concerns by compiling and evaluating

the potential impacts of products and materials associated with identified inputs and environmental releases;

interpreting the results to help making a more knowledgeable decision.

In life cycle assessment, an environmental product declaration (EPD) is a standardized way of quantifying the

environmental impact of a product or system. Declarations include information on the environmental impact of raw

material acquisition, energy use and efficiency, content of materials and chemical substances, emissions to air, soil

and water and waste generation. Product and company information is also included. The EPD project contributes to

the implementation of an LCA approach and eco-design of the products.

3.2 Embodied Energy

Embodied energy in building materials has been studied for the past several decades by researchers

interested in the relationship between building materials, construction processes, and their environmental impacts.

There are two methods of embodied energy in buildings: (1) Initial embodied energy; and (2) Recurring embodied

energy. The recurring embodied energy in buildings represents the non-renewable energy consumed to maintain,

repair, restore, refurbish or replace materials, components or systems during the life of the building.

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As buildings become more energy-efficient, the ratio of embodied energy to lifetime consumption increases.

Clearly, for buildings claiming to be "zero-energy" or "autonomous", the energy used in construction and final disposal

takes on a new significance. Typically, embodied energy is measured as a quantity of non-renewable energy per unit

of building material, component or system.

Implicit in the measure of embodied energy are the associated environmental implications of resource

depletion, greenhouse gases, environmental degradation and reduction of biodiversity. As a rule of thumb, embodied

energy is a reasonable indicator of the overall environmental impact of building materials, assemblies or systems.

4. PROPOSAL: ECO-HOUSE

This project is about designing a passive and zero-energy house in Portugal containing climate-optimized

structure. The solution should be within the requirements of a Net Zero-Energy Building (NZEB), but also look to

obtain a holistic sustainable elucidation. The house would be adapted to common sense and world reality, which

means that it was chosen to articulate functionality, aesthetical parameters and passive strategies. It would have an

ecological performance with a balance of the user’s needs, achieving the comfort and respecting its function.

In order to analyse the conditions of the site it is important that a precise place is established. The Eco-house

will be developed for a Mediterranean climate, specifically in the suburbs of Lisbon, Portugal, once there is more

pollution and density which make the temperatures increase (about 2ºC) and surrounding buildings change wind and

solar conditions. In Portugal the availability of the solar resource is high; standing well above the European average

(the average annual number of hours of sunshine in Portugal is approximately 2500 hours).

4.1 Design Strategies

4.1.1 Modular System

Modular housing construction allows a variety of alternatives and design possibilities, offering a wide range of

options to customize the house. It is possible to modify or upgrade the construction specifications, designing different

floor plans and choosing, for instance, the strategy of the façades. Reducing costs is implicit in this type of

construction due to the time saving and process easiness, although it is not the aim of this work to reflect on this

question. Thus, modular home construction is more environmentally friendly than its site-built counterpart relating to

the wastes management: all the excess construction materials are able to be recycled in site. Thus, the main idea for

the Eco-house is to be built by a timber modular system (2.10m * 4.00 m), which will be the structure of the house.

The arrangement of the plan is made according to the needs specified for this project by coupling the modules.

4.1.2 Passive Cooling system

The natural ventilation strategy relies on two different approaches: natural ventilation achieved by the windows

and allowing the natural movement of the wind; and a Passive Cooling system using buried pipes. This system will be

provided by the air entering the house through buried pipes using the important cooling potential in the soil (cold

source): the outside air is insufflate inside the house by natural or forced convection using small fans. With this

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purpose 20 tubes were placed in cement pipes – with a diameter of 20 cm – constituting the heat exchanger. It should

be noticed that pipes were chosen based on the material’s high thermal conductivity1 to enhance heat exchanges. The

air entrance is made from a feeding well about 15 meters away from the house. When inside the house the pipes don’t

need to promote heat exchanges anymore so the tubes are metallic. Once again, the user’s behaviour is crucial to the

well function and performance of this passive system.

4.1.3 Renewable energies

It is crucial to have a saving system for the house in order to store the rainwater allowing its reuse. With this

aim it is placed a tank with a capacity for 25 120 litres outside the house where the rainwater gets in by the roof pipes

- gutters. The water is kept in the tank until it is necessary. In summer, or even in some winter days, in case there is

no stored water the house will be supplied by the public network. Before entering the house the water will pass

through a Bio-Disk purification system. The system is installed near the tank and it will recycle the rain water, purifying

it and allowing its use inside the house. Despite purification the water may not be ready to drink as potable so it is

advisable an extra caution to the occupants. When inside the house the water will be kept in a cylinder with capacity

for 300 litres capacity where it will be heated by solar thermal energy. Based on the information of electrical energy

needs, the Photovoltaic cells installed on the Eco-house have an overall area of 30 m2 which means a monthly

produce of 375 kWh of electricity.

Another strategy which relies on the renewable energy resources is the Solar Thermal collectors placed on

roof of the Eco-hand and transferring the heat energy collected into the tank by forced circulation of the working fluid

between collector and the tank. This system allows saving electrical consumption from the national grid, making the

house self-sufficient in terms of hot water and electrical needs.

4.2 Design Outcome

Following the analysis of the design strategies for the eco-house it is presented the final result: a geometrical

and unpretentious volume with the main glazing façade towards south/south-east which confers transparency and

connection with the surrounding environment. The white façades confer lightness to the structure and the tile roof

gives the house a traditional and typical appearance.

Figure 1: 3D model of the Eco-house

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4.2.1 Materials

The choice of materials and components has an important role in the calculation of the energy performance.

The constructive solution for the different elements (walls, roof and floor) is explained below, as the material’s

composition.

Figure 2: Constructive detail for external walls

Figure 3: Constructive detail for the roof

Figure 4: Constructive detail for the floor

To culminate this matter I would like to clarify that the materials chosen are not assumed to be recycled:

instead they are recyclable. This choice relies on the possibility of allowing the calculations cradle-to-gate (LCA) and

studied the embodied energy of the materials in the production and construction phase, recognizing their

sustainability.

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4.3 Performance Analysis

The surfaces and volumes of component materials, illustrated below, will permit the determination of the

Thermal transmission, the CO2 emissions that are released during the manufacture and construction phase, and the

recyclable magnitude of the model.

Material

Surface

[m2]

thickness

[m]

Volume

[m3] ρ [kg/m3] Weight [kg]

Structure Timber [module] 137,0 0,200 27,41 550,00 15.074,4

Timber [truss] 30,2 0,200 6,05 550,00 3.326,4

External Wall

Beech wood 117,0 0,030 3,51 700,00 2.457,0

Cork 106,2 0,030 3,19 120,00 382,3

Rock wool 117,0 0,045 5,27 45,00 236,9

OSB 106,2 0,050 5,31 400,00 2.124,0

Internal Wall

Beech wood 128,7 0,030 3,86 700,00 2.702,7

Cork 122,7 0,020 2,45 120,00 294,5

OSB 122,7 0,050 6,14 400,00 2.454,0

Roof

Rock wool 172,8 0,050 8,64 45,00 388,8

PET (polypropylene) 172,8 0,030 5,18 900,00 4.665,6

Tile (ceramic) 172,8 0,010 1,73 1.800,00 3.110,4

OSB 172,8 0,050 8,64 400,00 3.456,0

Floor

Concrete 151,2 0,200 30,24 800,00 24.192,0

Mortar 151,2 0,010 1,51 1.800,00 2.721,6

Rock wool 151,2 0,050 7,56 45,00 340,2

Quick step 151,2 0,020 3,02 1.700,00 5.140,8

Betuminous 151,2 0,010 1,51 1.000,00 1.512,0

Windows Glass 59,4 0,025 1,49 2.700,00 4.009,5

Aluminium (frame) 5,3 0,300 1,58 2.700,00 4.276,8

Outside Door

Dark Timber 5,4 0,100 0,54 800,00 432,0

Table 1: Assets of the construction materials used in the Eco-house

4.3.1 Thermal Transmission

The coefficient of thermal transmission is a characteristic of the materials which can be defined by the thermal

processes, such as convection, radiation and conduction, and represents the capacities of each material against heat

exchanges between two surfaces (e.g. interior and exterior).

In Lisbon, according to RCCTE1, the maximum reference value for the coefficient of thermal transmission is

1.8 (W/m2

ºC) for vertical elements (walls) and 1.25 (W/m2

ºC) for horizontal ones (roof and floor). The results of the

calculation of the U value are shown below in table 2. As it is demonstrated, they are lower than the maximum

reference values; this means the house will not have excessive heat exchanges either from the external walls or roof.

So, the energy can be used in an efficient way since the one that is used for warming or cooling the house will stay

inside, unless the windows are open or it is allowed ventilation with the exterior environment.

1RCCTE: Regulamento das Características do Comportamento Térmico dos Edifícios

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U value

External Wall 0,41 < U ref. (1.8)

Roof 0,56 < U ref. (1.25)

Floor 0,68 < U ref. (1.25)

Table 2: Results of the U-value calculation

4.3.2 Life Cycle Stages

The aim of the first analysis is to evaluate the amount of CO2 released to the atmosphere in the manufacture

and construction phase in order to confirm their environmental efficiency. Currently, the purpose is to analyse how

much CO2 is released, correlating the emissions values for manufacture and construction process excluding

transportation, with the material mass needed for built the Eco-house.

Another important consideration is the comparison term in order to evidence the positive results and success

of all the strategies adopted. A study concerning the Sustainability and Life Cycle Analysis in Residence Buildings

(CWC – Canada Wood Council) analysed three different construction types of a typical house (wood, steel and

concrete) with the same assumptions for the thermal insulations and the constructive details. The Global Warming

Potential for the wood construction is 60 kg CO2 and for concrete (the most extreme among the three case-studies) is

nearby 96 kgCO2. Concerning the Eco-house calculations, the results are shown in table 3 where it is perceptible the

reducing of CO2 emissions confronting with the sustainable residential house proposed by CWC.

Material Weight [kg] CO2 emissions [kg/kg]

Source: D.J Gielen, 1997

TOTAL

[kgCO2]

Structure Timber [module] 15.074,4 0,30 4.522,3

Timber [truss] 3.326,4 0,30 997,9

External Wall

Beech wood 2.457,0 0,40 982,8

Cork 382,3 0,00 0,0

Rock wool [1] 236,9 1,10 260,6

OSB 2.124,0 0,30 637,2

Internal Wall

Beech wood 2.702,7 0,40 1.081,1

Cork 294,5 0,00 0,0

OSB 2.454,0 0,30 736,2

Roof

Rock wool [1] 388,8 1,10 427,7

PET, recycled 4.665,6 1,00 4.665,6

Tile (ceramic) 3.110,4 0,15 466,6

OSB 3.456,0 0,30 1.036,8

Floor

Concrete 24.192,0 0,85 20.563,2

Mortar [2] 2.721,6 0,30 816,5

Rock wool [1] 340,2 1,10 374,2

Quick step 5.140,8 0,40 2.056,3

Betuminous 1.512,0 0,30 453,6

Windows Glass 4.009,5 0,70 2.806,7

Aluminium, Recycled [frame] 4.276,8 1,00 4.276,8

Outside Door Dark Timber 432,0 0,40 172,8

[1] Flury, 2012

47.334,8

[2] Source: Limeco Ltd HyperLime

Table 3: Manufacture and Construction stages, and related CO2 emissions, excl. transportation

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In order to confirm the efficiency of the renewable energies systems used in the Eco-house, I propose a

second analysis of Eco-house performance, concerning the energy savings during 20 years. In Portugal the average

electrical consumption is nearby 4.000 kWh/year (ADENE, 2010), including electrical heating (approx. 800 kWh/year).

In 2011, electrical energy produced in Portugal has been generated from renewable energies (46%), natural gas

(28%), coal (18%) and other thermal sources (8%) (REN, 2011). Following this chain of thought, table 3 shows the

proportions between the amount of CO2 release into the atmosphere (WEC, 2004), provided from each one of the

electrical production source, and the percentage (%) of their use.

Resource kgCO2/100kWh Electricity origin

by source (%) Weighted

emissions

Coal 90 18 16,2

Natural Gas 40 28 11,2

Renewable 5 46 2,3

Other 60 8 4,8

34,5 kgCO2/100kWh

Table 4: Share of Electrical Production Sources in Portugal, year 2011

For the forward comparison it will be assumed that electrical energy needs are supplied by electrical

production from the grid, instead of using the PVs. Taking into consideration that the Eco-house consumes 4200

kWh/year, it is possible to observe that the electrical needs using renewable energies (PV system) will release 210

kgCO2/year (4200 kWh/year x 5 KgCO2/100kWh); but, if the electricity was provided by the national grid it will emit approx.

1 449 kgCO2/year (4200 kWh/year x 34.5 KgCO2/100kWh). Concerning hot water consumption, the Eco-house has its own

production by the Thermal Solar Collectors system, with a typically output between 1000 and 2500 kWh/year (sub-

chapter 4.4.6.2). This means that the energy production will be sufficient to supply the user’s needs (900 kWh/year by

the information illustrated in figure 4.21), even if it do not perform at 100% efficiency. So, the collector system will

avoid that the national electrical network had to provide that amount of energy, 900 kWh/year. This corresponds to a

saving of 310.5 kgCO2/year. The cooling consumption has an average value in the typical house of 200 kWh/year,

and once it is not used in the Eco-house due to the Passive Cooling System projected, it means a saving of 69.0

kgCO2/year (200 kWh/year x 34.5 KgCO2/100kWh).

The calculations show that the Eco-house, for avoiding electrical consumption from the electrical national grid,

will save in a period of 20 years approx. 24 780 kgCO2 due to PVs system; 6 210 kgCO2 due to the use of Thermal

Solar Collectors, and plus 1 380 kgCO2 resulting from the Passive Cooling system.

Finally, to ensure that the materials chosen for the Eco-house are reusable and recyclable (which means they

have to be easily deconstructed), at the end of their useful life, the following figure illustrates the quantity of recyclable

materials existents in the Eco-house, being 82% able to recycle.

Figure 5: Feasibility of recycling during the Eco-house end of life stage

recyclable

75% recyclable

non-recyclable

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4.3.3 Green Certification

BREEAM is “the world's leading environmental assessment method to assess new, existing buildings and

community scale development (BRE Global). By BREEAM’s website (www.bre.com) is it possible to access the

information needed to the evaluation of constructive solutions chosen for the Eco-house, which are not exactly the

same as BREEAM suggested solutions, so I had to choose the most similar ones to evaluate the ranking. The results

for the possible Green Certification of the Eco-house are shown on table 4.

Category Element type Rating

Ground Floor Construction

Suspended timber, H02 OSB/3 decking on timber joists with insulation,

over 100mm oversite concrete A

Roof Construction

Pitched roof timber Timber trussed rafters and joists with insulation,

OSB/3 deck, breather membrane, standing seam organic coated steel sheet.

A+

External Wall Construction

Rendered or Fairfaced Blockwork

Fair face solid blockwork outer leaf, insulation, timber frame, vapour control layer, plasterboard

on battens, paint A+

Internal Wall Framed partitions Timber stud, OSB/3 facing, paint A

Insulation CorkBoard Corkboard insulation - density 120kg/m³ A

Rockwool Stone wool insulation - density 45 kg/m³ A+

Table 5: Possible Ranking for the Green Certification. Adapted from BREEAM

5. CONCLUSIONS

This work analyses and deepens the topic of sustainability and environmental concepts applied in the

construction sector. It aims to demonstrate how it is possible to achieve a sustainable use of natural resources,

contributing to their preservation and reducing the environmental impacts. Also it highlights the overwhelming

importance of this world’s issue, as well as gives a detailed explanation of how the constructive sector can play an

important role to fulfil this goal.

Although technological progress is in a continuous and steep growth and we should follow and make the most

profit from this development, it is of crucial importance to keep in mind the simple, natural and inherent ideas and

concepts of sustainable practice. Actually we must avoid being trapped by the trends of technological evolution, which

are basically oriented towards speedy gains in competitiveness, namely by cost reductions in non-sustainable

materials incorporated in the construction process, no matter their scarcity in nature or their embodied energy and,

consequently the related GHG emissions.

Reaching the end of the study I consider that the main goals proposed were achieved, including the

architectural model developed which proves and summarizes the ideas presented and discussed throughout the text

as: evidence how a rigorous selection of construction materials can give a positive and valuable contribution to a

sustainable practice by analysing their main environmental characteristics, such as embodied energy and CO2

emissions; identify the deconstruction concept as a way for preserving the materials life and signal the importance of

reusing and recycling processes and; last but not the least, validate the use of renewable energies in an architectural

design, matters which should be integrated through the initial decisions.

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