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Sustainable housing is still a problem: Sisulu

Human Settlements Minister Lindiwe Sisulu has reiterated that government is building RDP houses for South African citizens and not just for foreign nationals.
Sisulu says housing in South Africa has caused many problems over the years and this been worsened by foreign nationals coming into South Africa and buying RDP

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houses that are meant for South African citizens at a fraction of the price.

She says her department is currently looking at ways to rectify this problem. “We would like to find a mechanism of how we can cater for people who are here in South Africa but are not South African citizens either through their employers or through rental stock,” she says.
Research has shown that many South Africans who own RDP houses are forced to off load their properties because of circumstances beyond their control.
Sisulu says they don’t encourage people to sell government sponsored RDP houses.
“The law is very clear, anybody who owns an RDP house may not sell before they have lived in it for eight years. We have noticed that people are selling their homes before the stipulated time and this creates huge problems for the owners and government. So, what I am saying is, if home-owners have not managed to get themselves out the poverty trap or their circumstances haven’t changed – they should hold onto the property. If they continue to sell property at reduced prices to foreign nationals, they will only fall heavier into debt.”
Source: The New Age


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Case Study: Bio-climatic Building design for tropical climates

By Antoine Perrau

Environmental design in the humid tropics requires special consideration. This chapter is based on two case studies which attempt to develop a practical approach to including key elements of bio- climatic design in tropical regions.

Location: Reunion Island
Population 840,000 inhabitants
Area: 2512km 2
Geology: Volcanic island
Highest point: Mount des Neiges 3070m
Rainfall: Reunion holds all world records for precipitation between 12 hours and 15 days

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Case Study 1: Malacca flores

Promoter: SIDR (Semi-Public Social Housing) Architects: Michel Reynaud / Antoine Perrau Environmental quality department: LEU Meeting City: Le Port
Altitude: 10 m leeward coast
Delivery: 2011
Total floor area: 8950 m2

The Context:

The project is located in a Development Zone and the objectives include: opening the city towards the sea, to reinvigorate the city centre, create a link between the periphery and centre of the community, and to implement the principles of sustainable development through a green master plan.
The projects location and surroundings were thus crucial to its success.

The Site:

The site of a project and its concomitant micro climate is of particular importance in the tropics. Favourable conditions on site will impact the performance of buildings constructed there.

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For instance the presence of trees plays a fundamental role in the areas micro-climate.

Our firm’s offices are in the centre of the island, allowing us to illustrate these differences.

During February, the month with the highest temperatures in the Southern Hemisphere, a temperature differential of 7 ° C was measured between the street and the inside of the office (without air conditioning). This is achieved in part, by planting buffers of vegetation such as grass and shrubs between the street and the building. The effect of the plants is to cool the air through evapotranspiration, and reduces the albedo effect by shading the concrete and other hard surfaces.

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The role of plants in reducing the urban heat island effect has also been demonstrated in the city of Paris by researchers from Météo France. The diagram below illustrates the difference in temperature between the suburbs and the city center during a summer’s day, which was 4 ° C.

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We therefore sought a favourable site for the project, and special effort was taken to re-vegetate surrounding buildings and find space on natural land.

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Shading:

The second step was to determine the most favourable orientation of the shading devices through computer simulations of sunscreen designs.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Parallel to this reflection, we verified the thermal comfort. It should be noted that the concept of comfort temperature is different from the temperature measured with a thermometer and is not absolute but depends on several parameters: humidity, air velocity, air temperature, the radiation

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temperature of the walls, metabolism and clothing. One can evaluate the effect on internal comfort of a building as influenced by the first four factors mentioned above using the comfort graph developed by Givonni:

Red air velocity of 1m / s Yellow air velocity of 0.5 m / s Green air velocity of 0m / s

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The graph demonstrates how essential it is to ensure natural ventilation, which is achieved through the porosity of the facades, and in this latitude, there should be a minimum porosity of 20% between two opposite facades.

Effective implementation of these interventions allows urban and architectural buildings to reduce their energy consumption by between 28 and 41 kWh / m2 / year. In fact spaces designed in this way provide thermal comfort without the need for air conditioning, even in the tropics.

 

 

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Additional Features:

Beyond these provisions, the specification proposes a number of other environmental features:

Implementation of solar hot water panels and photovoltaic roof panels

These panels are also used to shield the roof from high levels of solar radiation. 70% of the heat input comes through the roof, and so this element of the design should be treated with the utmost consideration and care.

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This dual purpose of the solar devices can increase their efficiency and reduce overall cost. Increased use of wood to reduce the carbon footprint of the project Wood was specified for the structure of corridors, sidings, sunscreens and pergolas.

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Grey water recycling

We used a filtration system with a settling tank and a filter zeolite vertical which provided regular contributions of water for irrigation.

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Source: Continue reading to Case Study 2 in the Green Building Handbook Volume 4, pg 146


 

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What are Green Materials and Technologies?

By Llewellyn van Wyk

Introduction

The potential impact of climate change and global warming is without doubt one of the most life-threatening challenges that face humanity. Central to this challenge is our dependence on fossil fuels as the primary source of energy – the major contributors of greenhouse gases (GHGs) including carbon dioxide (CO2) – and the extensive use of non-renewable resources.

It is now widely recognised that the climate systems are warming: there is also medium confidence that other effects of regional climate change on natural and human environments are emerging, although many are difficult to discern due to adaptation and non-climatic drivers. Global GHG emissions due to human activities have grown since pre-industrial times, with an increase of 70 per cent between 1970 and 2004. Anthropogenic warming could lead to some impacts that are abrupt or irreversible, depending upon the rate and magnitude of the climate change, including severe species loss.

Nevertheless, a wide range of adaptation options is available, although a more progressive rate of adaptation than is currently evident is required. Given an increase in adaptation rates, many impacts can be reduced, delayed or avoided. There is thus a causal relationship between climate change mitigation and sustainable development: sustainable development can reduce vulnerability to climate change by enhancing adaptive capacity and increasing resilience.

The construction and maintenance of the built environment has a fundamental role to play in this challenge: green materials and technologies for new and existing buildings could considerably reduce CO2 emissions while simultaneously improving indoor and outdoor air quality, social welfare, energy security, and ecological goods and services.

Background

The built environment is where the majority of the world’s population now reside: one out of every two people live in a city (UN 1996). Global population has expanded more than sixfold since 1800 and the gross world product more than 58-fold since 1820. As a result, the ecological footprint (EF) of humanity exceeds earth’s capacity by about 30 per cent. If we continue on the same development trajectory, by the early 2030s two planets will be required to keep up with humanity’s demand for goods and services.

In 2013, the global building stock was 138.2 billion m2, of which 73 per cent was in residential buildings (Bloom & Goldstein 2014:2). It is forecast that the commercial and residential segments will experience compound annual growth rates (CAGRs) in the next 10 years of 2,1 per cent and 2,2 per cent respectively (Bloom & Goldstein 2014:3).

Overall it is projected that the total building stock will grow to 171.3billion m2 at a GAGR of 2,2 per cent over the next decade (Bloom & Goldstein 2014:3).

Most of the growth is expected to occur in China, where nearly 2.0 billion m2 are added to the commercial and residential building stock every year. However, North America and Europe are each likely to make a significant contribution to the total building stock (Bloom & Goldstein 2014).

Interestingly enough, Bloom & Goldstein claim that commercial, residential, and industrial buildings are responsible for 47 percent of global greenhouse gas (GHG) emissions and 49 percent of the world’s energy consumption (2014:1).

As stated earlier, the construction industry plays a critical role in the growth of the economy through its creation of immovable fixed assets. Because of this role Government has declared the construction industry a national priority (Cidb 2012:10).

According to StatisticsSA Gross Domestic Product, Quarter 1, 2014 (Statistical release P0441), the construction industry expanded R4 billion to R31 billion from the Q4: 2013 to Q1: 2014 (2014:4). Were this to continue at current rates investments in construction works should reach R124 billion by Q4: 2014.

Gross Fixed Capital Formation (GFCF) for the residential sector fell -2,2 percent year-on-year in Q4: 2011 based on constant 2005 prices, from R24,83 bn to R24,29 bn. The non-residential sector fell by 1,3 percent year-on-year in Q4: 2011, to R37,08 bn from R37,56 bn in Q4: 2010. GFCF in construction works rose 2,3 per cent year-on-year in Q4: 2011, the highest growth rate over the past seven quarters with investment in construction works increasing to R110,36bn in Q4: 2011 from R107,89bn in Q4: 2010 (Industry Insight 2012:18).

The total GDP for South Africa in 2013 was approximately R3,3 trillion of which the non-residential sector contributed 1,41 per cent directly, 1,55 percent indirectly, and 2,39 percent induced (SAPOA 2014:51).

During 2013 the real estate sub-sector contributed R1,32 billion to the fixed capital stock of South Africa, while the gross fixed capital formation added R97,856 million to this figure over the same period, representing 20,9 percent and 14,95 percent respectively of the whole economy (SAPOA 2014:15). Of this capital formation, R69,697 million or 71,2 percent, is attributable to non-residential buildings (SAPOA 2014:15).

It is also a significant consumer of resources especially materials, energy and water: globally the construction industry is responsible for about 50per cent of all materials used, 45 per cent of energy generated to heat, cool and light buildings and a further 5per cent to construct them, 40 per cent of water used (in construction and operation), and 70 per cent of all timber products that end up in construction

(Edwards 2002). In South Africa, buildings account for 23 per cent of electricity used, and a further 5 per cent in the manufacturing of construction products (CIDB 2012).

The construction industry has traditionally been a slow adopter of new technologies in general, mainly due to the perceived associated risks ( Woudhuysen and Abley, 2004). The building sector in particular is reluctant to adopt new technologies due to potential buyer resistance ( Woudhuysen and Abley, 2004). Thus, the sector undertakes most of its work with conventional technologies.

Green technologies really came into consideration with the emergence of the formal green building movement lead by the British Research Establishment (BRE), and Professors’ Feist and Adamson in the late 1990s. This saw the release of green building systems such as British Research Establishment’s Environmental Assessment Method (BREEAM), and the Passivhaus concept respectively. Since then a number of new green building systems have emerged, including the Green Star® system as adopted by the Green Building Council of South Africa (GBCSA).

The introduction of these systems has heightened interest in green building, and in the technologies they use. While much of the technology remains conventional to meet some of the performance requirements, green technology is required.

High Performance Green Building

Because buildings are often used for centuries, the rapid pace of development increasingly means that it is impossible to imagine the demands that future uses will place on buildings. Consequently, products and systems should be chosen that make adaptation easier. While aesthetic appeal will always be a component of building design, the real challenge is to create built environments that are durable and flexible, appropriate in their surroundings and provide high performance with less detrimental impacts.

In response to this challenge, a global initiative launched by the World Business Council for Sustainable Development (WBCSD) and supported by over 40 global companies aims to “transform the way buildings are conceived, constructed, operated and dismantled” to achieve zero energy consumption from external sources and zero net carbon dioxide emissions while being economically viable to construct and operate. Included in the initiative is the identification of the full range of present and future opportunities with regard to “ultra- efficient building materials and equipment”. Additionally, this aim is enhanced by using the“cradle-to-cradle”concept of producing, using and later re-using building materials, a design evolution needed to achieve sustainability for buildings.

The current generation of‘green’ buildings already offer significant improvements over conventional buildings inasmuch as they consume less energy, materials, and water; provide demonstrably healthier living and working environments; and greatly enhance the quality of the built environment, including the neighbourhood. However, these improvements are offered through the use of existing materials and products, design approaches, and construction methods. Because of this conventional approach to design and construction, it remains difficult to incorporate truly innovative technologies into current construction practice.

Good design is fundamental to sustainable construction. Decisions made at the initial design stage have the greatest effect on the overall sustainability impact of projects. The issues to be faced by radical

high-performance “green” buildings favours construction products and methods that are flexible, light and durable: it is here that green materials and technologies emerge as a material-driven construction system capable of achieving the prerequisite performance standards.

Prudent use of natural resources results in both greater industry efficiency and a restricted usage of natural materials. Practices such as materials recycling, waste minimisation, local product resourcing, land decontamination, and construction- and demolition-waste disposal make sound business sense and encourage good construction housekeeping. Application of the principles of ‘lean construction’ and life-cycle assessment is equally important.

The characteristics of high-performance green building as suggested by Fujita Research (2000) include:

1. Optimal environmental and economic performance;

2. Integrated processes, innovative design and increased efficiencies to save energy and resources;

3. Satisfying, healthy, productive, quality indoor spaces;

4. Employing lean construction methodologies and tools to improve waste management and reduce the environmental impact of construction waste;

5. Increasing the emphasis, at R&D stage, of whole-building design, construction and operation over the entire life cycle;

6. Fully integrated approach including teams, processes and systems;

7. Renewal engineering methods;

8. Management and business practices;

9. New standards, open buildings, advance jointing and assembly techniques, process engineering;

10. Materials and systems: new function integrated building components, durability, repairability, and retrofit- ability of components.

In High Performance construction, the key issue is how the choice of construction products and methods can create scope for reducing burdens.

Green Materials

The market for building materials is predicted to grow steadily into the foreseeable future. The primary driver for growth by sheer volume is the ongoing government investment in new buildings and other physical infrastructure in developing countries such as South Africa. At the same time, the demand for building materials is shifting towards environmentally preferable or “green” materials due to consumer demand; and an ever growing number of mandatory environmental regulations and standards.

Green materials use is predicated on the replacement of future flows of conventional building materials with “green” materials. From an environmental perspective, “green” materials would need to be those materials with the least “embodied effects”, where the word embodied refers to attribution or allocation in an accounting sense as opposed to true physical embodiment. In the building community, the tendency is to refer only to “embodied energy” (Trusty and Horst, 2006). However, as implied by the comprehensive list of effect categories (Table 1) typically investigated in a Life Cycle Assessment (LCA) study, all the extractions from and releases to nature are embodied effects, and there are also embodied effects associated with the making and moving of energy itself (known as pre-combustion energy).

Table 1: Embodied effects typically investigated in a Life Cycle Assessment.

Until the 1970s, the construction industry sector made little attempt to establish objective and comprehensive methods for environmental assessment and improvement of buildings. The concept of Sustainable Construction which is “The creation and operation of a healthy built environment based on ecological principles” (Kibert, 1994) was first mooted in the wake of the 1987 Brundtland Report and the 1992 Rio Accords. Starting with the launch of the Building Research Establishment Environmental Assessment Method (BREEAM) in 1990, a large number of building rating systems have been developed around the world to provide the basis for putting sustainable construction into practice.

However, rating tools are not underpinned by robust science. The environmental improvements suggested are not benchmarked against empirical data (Reijnders and van Roekel, 1999). There is a lack of credits dealing directly with the environmental problems (embodied effects) of concern to society (Zimmerman and Kibert, 2007). These deficiencies are most notable in the case of materials selection which is generally informed by prescriptive easy-to-follow directions, for example, use materials with recycled content (Blom, 2006; Trusty, 2007).

Green Technologies

Green technologies in the building sector can be defined as those technologies which reduce the environmental impact of building on the environment. These technologies would either reduce environmental impact through the development of more environmentally sustainable materials and products, or through the generation and/ or conservation of resources such as energy and water.

Conclusion

The construction industry sector is the largest documented user of materials by weight. The market for building materials is predicted to grow steadily into the foreseeable future driven by ongoing investments in built infrastructure and the consumer demand for “green” products.

Sustainable materials use is thus predicated on the replacement of future flows of conventional with innovative building materials which have the least embodied effects where the “effects” in question are flows of key natural resources – energy, land, materials and water; and emissions to air, land and water.

Source: Green Building Handbook: Materials ad Technology


 

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A House That’s Sustainable From the Inside Out

The Passive House Che has recently been built in a forest in Romania and is currently still being evaluated to receive the Passive House standard certification. As such, it is of course equipped with all sorts of sustainable features, which also include an indoor lawn. It was designed by the local firm Tecto Architectura.

The main aim of the project was to create a sustainable, two-story home which would blend into its forest surroundings. The house is bigger than one has come to expect from a sustainable building, and measures 2,700 square feet (250 square meters). The living quarters are built around a central courtyard, which is where the interior lawn is located. Over this lawn hangs an aptly named “net-lounge”, which is basically a large net hammock suspended over the courtyard where the inhabitants can relax. The home was also fitted with large floor to ceiling windows and doors which let in plenty of natural daylight and offer great ventilation.

Source: Jetson Green


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Optimising Daylight in South Africa: A case study

Light is of decisive importance in experiencing architecture. The same room can be made to give very different spatial impressions by a simple expedient of changing the size and locations of its openings. Moving a window from the middle of a wall to a corner will utterly transform the entire character of the room. To most people a good light means only much light. If we do not see a thing well enough we simply demand more light. And very often we find that it does not help because the quantity of light is not nearly as important as its quality. (Rasmussen, 1964)

At the moment lighting accounts for around 35% of the energy used within non-residential buildings and between 0% and 28%1 in residential buildings. Electricity usage (%) in the residential sector for high/ middle income residences consume typically 5% for fluorescent and 12% for incandescent types of lighting. (UNEP, 2009). Designers are encouraged to use natural daylight in their designs to reduce the energy used (SANS 204-2, 2008).

The use of daylight to supplement or as a substitute for electric light in the window zones of interiors with side windows or over the entire area of spaces with skylights can save lighting energy. This saving should be balanced against the energy required to compensate for heat gains and losses through the daylight openings. During times of low external temperatures more heating and during times of high external temperatures and sunshine more cooling of the interior will be required in order to maintain a constant internal air temperature. The use of daylight therefore will only be energy effective and cost-effective if the savings on lighting exceed the extra expenditure for climate control (SANS 10114-1, 2005)

Uses of Daylight

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Natural daylight is a very important and interesting source of lighting in buildings. Natural daylight can inter alia be used for functional1, decorative2 and artistic3 purposes. In the SANS 204-2 and 10114-1 norms the emphasis is mostly on functional uses. The light levels, power and energy usage for the building is determined in accordance with a lookup table 14 (SANS 204-2, 2008).This table describes the recommended light levels, power and energy for various classes of buildings. The light levels range from 50 lx for entertainment and public assembly to 700 lx for high risk industrial type of spaces.

The developments in electric lighting have not eliminated a widespread preference for daylight in buildings, wherever practicable. The reliance on daylight is greater in homes, offices, schools and patient areas in hospitals than in factories and shops.

The factors listed below will be different for different types of interior, different methods of daylight admission and for different climates (See Table 6.2). Recommendations regarding daylight should inter alia allow for the following factors (SANS 10114-1, 2005): Levels and uniformity. Daylight provides variability and, when it enters through side windows, creates a specific modeling and luminance distribution in the interior. It therefore contributes to visual satisfaction. The quantity of daylight is usually specified by the daylight factor, both with regard to illuminance and uniformity. In interiors with side windows, the available daylight decreases rapidly with distance from the windows. In many cases such as living rooms and small offices this non uniformity is acceptable and even appreciated. In other cases, supplementary electric lighting is required. Roof lights (skylights) can provide ample and highly uniform daylighting, but should be carefully designed to avoid solar overheating and glare.

• External view. Where natural light is used throughout the day for reasons of convenience and economy, an additional advantage is the view of the outside environment. However this is not always possible in large industrial or commercial buildings. The best position, shape and dimensions of the windows will depend on the nature of the outside environment. It also depends on the building design and will take into account architectural, lighting, visual, thermal and acoustic considerations.

Glare from the sun or sky. Daylight can produce sky glare and can adversely affect the comfort in the interior. Direct sunlight is desirable for various types of buildings, such as homes in moderate climates, but should generally be avoided in work areas. Means to avoid direct sun irradiation are appropriate orientation of windows and skylights, the use of various types of curtains or blinds and the use of louvres or screens. The latter are also effective in reducing sky glare and are particularly important on the upper floors of high-rise buildings where large parts of the sky might be visible. Small windows have an effect on the sky glare only to the extent that they prevent parts of bright skies or bright opposite facades or buildings from being seen. When appreciable areas of a bright sky remain in the field of view some glare such as discomfort5 glare or disability6 glare should be expected. Therefore, even with small glass areas, work areas directly facing windows should be avoided. If this is not possible, some means should be provided to reduce possible sky glare. Other techniques to reduce window glare are:

• The use of external or internal devices, such as louvres.
• Deep splayed reveals on the side of the windows, finished with a high reflectance surface and

with the same finish applied to any frames and glazing bars.
• The use of tinted low transmission glazing.
• Arranging for light in the interior to fall on the wall area adjacent to the windows, either from roof lights or from specially located luminaires.

Heat gains and losses. The heat gain through windows might require cooling of the interior during

the warm season, but might reduce heating costs during the cold season. However, heat losses through the window during the cold season can offset the savings and can increase heating costs. The use of daylight as an illuminant can save energy used for electric lighting, but this should be balanced against the energy required to compensate for the heat gains and heat losses through the glazing. Means to avoid excessive solar heat are:

  • Appropriate orientation of glazing.
  • Reduction of areas of glazing.
  • Use of an appropriate daylight system (Table 6.2)
  • Use of heat-reflecting or heat-absorbing glass or coated glass.

The International Energy Agency (IEA, 2000) recognizes a wide range of innovative daylight strategies and systems. Some are rarely used in South Africa. The IEA recognizes two basic types of daylight system i.e. daylighting systems with Shading and daylighting systems without shading. The latter type consists of four subdivisions:

• Diffuse light-guiding systems
• Direct light-guiding systems
• Light-scattering or diffusing Systems • Light transport systems

Gallery below provides some examples of the various types.

Luminance and iLLuminance

Luminance is a photometric measure of the luminous intensity per unit area of light travelling in a given direction. It describes the amount of light that passes through or is emitted from a particular area and falls within a given solid angle. The SI unit for luminance is candela per square metre (cd/ m2). Luminance is often used to characterize emission or reflection from flat diffuse surfaces. The luminance indicates how much luminous power will be detected by an eye looking at the surface from a particular angle of view. Luminance is thus an indicator of how bright the surface will appear. In this case, the solid angle of interest is the solid angle subtended by the eye’s pupil.

For a perfectly diffusing surface, the luminance can be calculated in accordance with the following formula (SANS 10114-1, 2005):

where

L is the luminance, candelas per square metre; E is the illuminance, in lux;
r is the reflection factor.

For example, if a matt surface that has a reflection factor of 0.5 is exposed to an illuminance of 200 lx, the luminance is

cd/m2

Illuminance is a photometric measure of the total luminous flux incident on a surface per unit area. It is a measure of the intensity of the incident light, wavelength-weighted by the luminosity function to correlate with the human brightness perception. Similarly, luminous emittance is the luminous flux per unit area emitted from a surface. Luminous emittance is also known as luminous exitance.

In the SI system these are measured in lux (lx). lluminance was formerly often called brightness, but this leads to confusion with other uses of the word. “Brightness” should never be used for quantitative description, but only for nonquantitative references to physiological sensations and perceptions of light.

4. Daylight factor
The daylight factor is the ratio of internal light level to external light level and is defined as:

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where:

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For example, if a matt surface that has a reflection factor of 0.5 is exposed to an illuminance of 200 lx, the luminance is

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Illuminance is a photometric measure of the total luminous flux incident on a surface per unit area. It is a measure of the intensity of the incident light, wavelength-weighted by the luminosity function to correlate with the human brightness perception. Similarly, luminous emittance is the luminous flux per unit area emitted from a surface. Luminous emittance is also known as luminous exitance.

In the SI system these are measured in lux (lx). lluminance was formerly often called brightness, but this leads to confusion with other uses of the word. “Brightness” should never be used for quantitative description, but only for nonquantitative references to physiological sensations and perceptions of light.

4. Daylight factor
The daylight factor is the ratio of internal light level to external light level and is defined as:

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where:

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There are basically three paths (daylight factor components) along which light can reach a point inside a room, i.e. through a glazed window, rooflight or aperture as follows:
• The sky component (SC) that is direct light from part of the sky or sun at the point considered.
• The externally reflected component (ERC) that is light reflected from an exterior surface and then

reaching the internal point measured.
• The internally reflected component (IRC) that is light entering through the window but reaching

the point only after reflection from an internal surface.

The sum of the three components gives the illuminance level in lux at the point measured. The daylight factor only gives the proportion of daylight from outside that reaches the interior of the building and does not indicate the absolute level of illumination that will occur.

To calculate daylight factors requires complex repetition of calculations. It is normally undertaken by a software product such as Radiance. This is a suite of tools for performing lighting simulation which includes a renderer as well as other tools for measuring the simulated light levels. It uses ray tracing to perform all lighting calculations. The design day used for daylight factors is based upon the standard Commission Internationale de l’Eclairage (CIE) overcast sky for 21 September at 12h00 and where the ground ambient light level is 11921 lux. Since the CIE standard overcast sky assumes no orientation effects, the estimates of the daylight contribution can be wrong. To correct for this, orientation factors have been derived to be applied to the daylight factors. More recently the CIE has derived a standard based on the spatial distribution of daylight, i.e. the CIE Standard General Sky (CIE, 2002).

Rooms with a DF of 2% are considered daylit. However a room is only considered as well daylit when the DF is above 5%.

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Case study

The following is an example of how a designer might approach a design analysis to optimize daylight in a building. The first step is to determine the solar angles at different times of the year accurately. With the advent of Google Earth it has become much easier to determine these accurately. This is the basis for the calculation of solar angles.

Read the entire article in the Green Building Handbook Volume 4 on pg 114 here. Or sign-up to download the digital version of the handbooks here.


 

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Green Building With Renewable Rice Straw

For every ton of rice that is grown, 500 lbs of rice husks and straw are created. Typically, those husks and straw are burned as waste. But two innovations on opposite sides of the world are changing that.

In India, 16-year-old Bisman Deu saw all those rice husks being burned and wondered whether they couldn’t be put to better use. So she started experimenting in the family kitchen and came up with a material she calls Green Wood.

Her creation is a waterproof participle board that is fungus resistant and mud-proof, making it a good alternative to the earthen bricks used by many poor farming families around the world, especially when monsoon season arrives. Turning the rice waste into a useful building product instead of burning it keeps carbon dioxide out of the air and augments farm income because now farmers can sell the waste rather than destroying it.

Deu has been recognized by a Junior Achievement award and praise from UNICEF for her creation.

Meanwhile, in Goleta, California, a start-up company called Oryzatech, formed by architect  Ben Korman and  his partner Jay Ruskey, is experimenting with building blocks made from compressed rice straw and glue. Looking much like oversized Legos, their Stak Blocks have three times the insulating power of a 2X6″ studded wall and are easier to handle than straw bales, which have become popular for making sustainable buildings.

A 1′ by 1′ by 2′ long Stak Block weighs 30 pounds and can be easily maneuvered by one worker. Like straw bales, they require a concrete foundation and must be kept dry with exterior siding. Sheetrock and paneling can be screwed to the interior surface. Korman thinks the blocks will sell for about $8.00 each once production ramps up.

Both products take waste agricultural products and turn them into carbon neutral, sustainable building materials. Both can be made locally near where rice grows, reducing the energy and expense needed to haul the waste to a factory.

Source: Green Building Elements


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