DESIGNING WITH THE SUN
The first step in creating comfort and thermal delight in buildings is to understand
the relationship between the climate and our need for shelter. There is
an enormous variation in climates that buildings experience. These can be at
the scale of global climates, from the Arctic to the Sahara. They can be
regional climates in the centre of a continent or on the seashore. They can be
local climates on the sunny or the shady side of a hill or street. All will influence
the way in which a building should be designed in relation to the sun.
The sun can be a friend or an enemy in buildings. Poor climatic design of
buildings, all too often seen in ‘modern’ architecture, causes many buildings to
overheat, even in temperate or cold climates where such problems traditionally
never existed. The power of the sun should be understood and respected
by good designers of well-designed, passive solar buildings in which the free
energy of the sun is used to power the building but not allowed to interfere
with the comfort and economy of the building’s occupants.
The five things a designer needs to know for a good passive solar design are:
1 how strong the sun at the site is at different times of the year
2 where the sun will be at different times of the year in relation to the site
3 how much of the sun’s heat a building will need, or not need, at different
times of the year to enable the building occupants to be comfortable
4 how much storage capacity the building should have in relation to the
available solar gain at the site to meet those needs
5 what the additional requirements are for controlling the heat gain from
direct solar radiation, convection or conduction in a design and how they
can be met by envelope performance, building form and ventilation.
There are a number of factors that influence the incidence, or strength, of
solar radiation at the site including:
• the latitude of the site
• the altitude and azimuth of the site
• how much shade will be given by any obstacles that exist between the
building and the site
• the weather above the site.
AZIMUTH AND ALTITUDE OF THE SUN AT A SITE
The angle with which the sun strikes at a location is represented by the
terms altitude and azimuth. Altitude is the vertical angle in the sky (sometimes
referred to as height); azimuth is the horizontal direction from which it
comes (also referred to as bearing). Altitude angles range from 0° (horizontal)
to 90° (vertical: directly overhead). Azimuth is generally measured clockwise
from north so that due east is 90°, south 180° and west 270° (or 90°).
Because the Earth revolves around the sun once a year, we have four seasons.
The Earth’s axis remains in a constant alignment in its rotation so
twice a year the incoming solar radiation is perpendicular to the latitude of
the equator and only once a year is it perpendicular to the tropics of Cancer
and Capricorn,
The changing values of azimuth and altitude angles are predominantly a
reflection of the changes in the relative positions of Earth and sun. These are
governed by:
• the rotation of the Earth around the sun
• the rotation of the Earth about its axis.
One of the simplest tools we can use for the derivation of altitude and
azimuth angles is a graph using Cartesian coordinates
incorporates two types of line. Firstly, those representing the variation in altitude
and azimuth over the period of a day (given for the 21st or 22nd day of
each month). Secondly, those joining the points on the altitude–azimuth lines
for a specific hour. Thus the solar angles for 11 a.m. on 21 March may be read
off on the horizontal and vertical axes where these two lines meet (altitude
36°, azimuth 19°). Values for other days may be read by interpolating between
these lines.
It may appear that these are the only determinants of angular position,
however we are actually concerned with the direction of the sun’s radiation
rather than the Earth–sun position. Also, radiation does not travel in an
entirely straight line but is bent slightly by the Earth’s atmosphere.
The distance between the Earth and the sun is approximately 150 million
km, varying slightly through the year with the variation of the azimuth and
altitude angles with time.
All passive solar features involve the transmission of solar radiation through
a protective glazing layer(s) on the sun side of a building, into a building space
where it is absorbed and stored by thermal mass (for example thick masonry
walls and floors or water-filled containers). The typical processes involved are:
• collection – to collect solar energy, double-glazed windows are used on
the south-facing side of the house
• storage – after the sun’s energy has been collected, some heat is immediately
used in the living spaces and some is stored for later use. The storage,
called thermal mass, is usually built into the floors and/or interior walls.
Mass is characterised by its ability to absorb heat, store it and release it
slowly as the temperature inside the house falls. Concrete, stone, brick and
water can be used as mass
• distribution – heat stored in floors and walls is slowly released by radiation,
convection and conduction. In a hybrid system, fans, vents and
blowers may be used to distribute the heat.
There are several types of passive solar system that can be used in homes. The
most common are direct gain, indirect gain and isolated gain.
SYSTEM COMPONENTS
There are three key components to all passive solar systems for heating:
• collector
• mass
• heated space.
DIRECT GAIN SYSTEMS
Direct gain systems are most commonly used in passive solar architecture.
The roof, walls and floor are insulated to a high level. Solar radiation enters
through the windows and is absorbed by the heavy material of the building.
The whole building structure gradually collects and stores solar energy during
the day. Heavy building materials provide thermal storage. The collected
solar energy is gradually released at night when there is no solar gain.
Direct gain systems commonly utilise windows or skylights to allow solar
radiation to directly enter zones to be heated. If the building is constructed
of lightweight materials, mass may need to be added to the building interior
to increase its heat storage capacity. The proportion of a building’s heating
needs that can be met by solar energy increases as the area of sun-facing
glazing increases. Additional mass must therefore be used to reduce interior
temperature swings and delay the release of solar energy into occupied
spaces. While the mass that is directly illuminated by the incident energy,
sunshine, is the most effective for energy storage, long-wave radiation
exchanges and convective air currents in the solar heated rooms allow nonilluminated
mass to also provide effective energy storage.
Learning from green buildings that teach
Kathryn Janda and Alexandra von Meier
Janda and von Meier investigate two ‘green’ academic buildings: the Environmental
Technology Center at Sonoma State University and the Adam Joseph Lewis Center at
Oberlin College. Both are designed for use as teaching tools and both demonstrate
sustainable architecture. Both employ a variety of passive and active systems to achieve
their goals. Both have ‘epic’ stories to tell about the evaluation of their performance. As
self-proclaimed exemplars of sustainable architecture these buildings were set apart
from standard construction practice by a heightened degree of ‘inspection, assessment
and expectation’. But did the measures adopted by engineers and critics reflect the
intentions of the builders or did they quantify something different? What was it that the
buildings were designed to teach? The authors argue that the quantitative data
collected ‘may raise more questions about building performance than they resolve’.
Noting that ‘numbers rarely change our notions of what we already believe to be true’,
Janda and von Meier thus bring into question the use of quantitative data taken at a
particular moment in time as the sole criterion for the ‘goodness’ of buildings.
Introduction
Buildings present a significant challenge for the natural environment. Roodman and
Lenssen (1995: 5) claim, for instance, that buildings account for 16 per cent of the
world’s water use, 20 per cent of its wood harvest and 40 per cent of its material and
energy flows. Although new buildings can be constructed in a more sustainable fashion,
quite often they are not. What can we learn from those constructed to be sustainable?
Technical lessons are often sought from such exemplars. Did the argon-filled, doublepaned
windows in this building save energy? Did using paint low in volatile organic
compounds in that building reduce off-gassing? While such questions are important
stepping stones to ‘better’ designs, each green building example contains a set of
social lessons as well. David Orr (1993) has coined the phrase ‘architecture as pedagogy’
to describe the concept that we learn from buildings, not just in them. Similarly,
W. J. Rohwedder (2003) extends this idea to describe ‘pedagogy of place’.
To explore the lessons learned from specific architectures in particular places, we
investigate two ‘green’ academic buildings: the Environmental Technology Center
(ETC) at Sonoma State University, California
, and the Adam Joseph Lewis Center
(AJLC) at Oberlin College, Ohio. Both are designed to be used as teaching tools and
both demonstrate sustainable architecture. Both employ passive and active systems to
achieve these goals. Both also have ‘epic’ stories to tell about the social structures and
institutional values that resulted in the adoption of some architectural strategies and the
rejection of others. Finally, each author has first-hand knowledge of and daily experience with one of these buildings. Our own participation with these structures and our observation
of other uses and users helps to frame our understanding of the differences and
similarities between them. Through our comparative analysis, we hope to raise new
questions concerning the social and institutional context in which sustainable buildings
are constructed, used and evaluated.
These buildings were designed to be far better than average, but by what measure
are they better? Are there ways in which they are worse? Despite much public critical
acclaim, people involved with both buildings are frequently called on to prove that the
pedagogical, architectural and environmental theories behind them are working in practice.
Among many dimensions, we focus on the presence, absence and use of ‘data’,
looking at several factors with respect to data gathering, use and evaluation. First, we
examine how the presence or absence of quantitative data enhances or obscures
stories of building performance. Second, we describe how institutional requirements
shape the desire for and impact of ‘hard numbers’. Finally, we discuss who learns what
from ‘buildings that teach’: students, faculty and the academic institutions themselves.
Background
Although both the ETC and the AJLC have ample amounts of glass on the south side
and use thermal mass for passive heating and cooling, these buildings do not shout
‘sustainability’ to passers-by. Neither structure relies visually on elements that the
general public would likely identify as ‘green’: a biomorphic shape, obvious photovoltaic
arrays or windmills, or a garden on the roof.1 Instead, both building designs share a modern aesthetic and a geometric vocabulary typical of today’s commercial and institutional
structures (Figs 3.1 and 3.2).
The Environmental Technology Center at Sonoma State University (SSU) is a 2,200
square foot (204 square metre) building with one large seminar room that functions as
an auditorium, classroom and laboratory. It is situated on a site internal to the SSU
campus, which is located about an hour north of San Francisco. Funded in part by
grants from the National Science Foundation and the California Energy Commission
and completed in 2001, the ETC was conceived as a ‘building that teaches’
(Rohwedder 1998), offering an immediate hands-on experience of high-efficiency technology
and green building to general audiences as well as an abundance of real-time
data for building science buffs.
Use of the ETC comprises university classes – including technical courses on
energy, environmental studies courses and selected courses from other departments –
and classes and events involving outside agencies and the general public. These
include, for example, meetings by the local chapter of the Green Building Council,
training workshops for energy auditors, work meetings for Sonoma County’s Climate
Protection Campaign and public events such as the Green Building Expo, with lectures
and vendor exhibits. The ETC has also become a favourite classroom for two other
departments: the Psychology of Yoga class appreciates the warm floor in addition to
the light and spacious feel, and the a cappella Chamber Singers enjoy the acoustics.
The ETC was the subject of Congressional testimony before the House Energy
Subcommittee by its director (von Meier 2001), at the invitation of Congresswoman
Lynn Woolsey (Democrat), who had supported the ETC since its inception. Representative
Woolsey subsequently arranged for an Energy Subcommittee field hearing to
take place at the ETC, chaired by Congresswoman Judy Biggert (Republican, Illinois).
Nationally recognised energy experts testified at the field hearing (US House of Representatives
2002), with the space of the ETC serving as a concrete example of the
concepts of energy efficiency and renewable resource use they advocated.
Like the ETC, the Adam Joseph Lewis Center for Environmental Studies serves many
purposes. The AJLC is a two-storey, 13,600 square foot (1,260 square metre) building
with three classrooms, a library, an auditorium, six offices, a conference room and a
kitchen. It also houses a ‘Living Machine’ that treats and internally recycles wastewater
from within the building, which is sited on the edge of the Oberlin College campus, near
Richardsonian Romanesque academic buildings and down the street from Victorian-era
homes. Like the ETC, it was designed as a building that teaches. In the words of David
Orr, the chair of Oberlin’s Environmental Studies Program, the project team wanted a
building that would ‘help redefine the relationship between humankind and the environment
– one that would expand our sense of ecological possibilities’ (Reis 2000).
The AJLC has enjoyed considerable critical acclaim. It has received architectural
awards from the American Institute of Architects, construction awards from national and
state contractors’ organisations and an Ohio governor’s award for energy efficiency and
has been named one of the thirty ‘Milestone Buildings for the Twentieth Century’ by the
US Department of Energy. An early model of the building is included in an architectural
textbook on the interactive effects of buildings and the environment (Fitch and
Bobenhausen 1999: 336), a diagram appears in a popular environmental science
textbook (Miller 2001b: 537), and it has been the subject of numerous articles in the
press. Part of its notoriety has to do with its star architectural team, William McDonough
and Partners, which is famous for several sustainable buildings as well as a book on the
topic of sustainability (McDonough and Braungart 2002). Part also has to do with the
dedication and eloquence of its on-campus champion, David Orr, who is a prolific writer
and a dynamic speaker and has published several articles about the AJLC’s design
process (Orr 2002, 2003a, 2003b). Orr also plans to use the AJLC as the basis of a
book on the subject of design and organisational learning.
Equally the AJLC has been the subject of much controversy. At the centre of this
debate is a contested statement that one of the goals of the AJLC was to be a ‘net
energy exporter’. An Oberlin faculty member outside the Environmental Studies
Program has argued that the building consumes far more energy than the photovoltaic
(PV) array delivers (Scofield 2002a, 2002b, 2002c). Proponents of the building do not
deny that it currently uses more energy than it generates; early documentation indicates
that the goal of net energy exportation was a long-term one, intended to be reached only
as PV efficiencies improved beyond the 15 per cent that is common today.
We believe that the stories surrounding these two buildings – including the range of
perspectives on how ‘efficient’ or ‘consumptive’ they are, as well as how their performance
is accounted for and by whom – have much to say about how expectations for
sustainable architecture are shaped. Although framed in technical terms (such as air
changes per hour or Btu per square foot) these goals have social implications as well as
technical bases.
Building characteristics
Whatever the climate, a building, such as a house, can be thought of as a mixture
of mass materials (e.g. brick wall, mud brick vault, concrete slab) and insulation
materials (e.g. fibreglass batts in the wall, thatched roof, expanded polystyrene
sandwich cladding panel). How a building performs depends upon the mixture of these materials, but it can be simply thought of in the following way. For the cave
dweller, who lived in a mass building with no insulation, the internal temperature
would settle at the annual average temperature. ForNew Zealand that was 13.1C
in 2005, the fourth highest such annual average on record1 and in the UK it is
8.5–11C2. This explains the old adage that a house with thick stone walls always
felt warm in winter and cool in summer, since that was what it was relative to the
outside temperature, even if the actual indoor air temperature around 10C or
even 13C did not represent comfort. Thus, having a lot of mass in a building
means the internal temperature will tend to be stable. The presence of insulation in
combination with mass will tend to raise the stable internal temperature above the
average annual temperature. The experience with Hockerton houses in the UK,
which have no space heating system apart from the gains from solar energy, the
occupants and the equipment inside, suggests that a 7–8C temperature rise above
the annual average can be achieved with a very high mass construction with
300mm of insulation to walls, roof and floor, and with the best available offthe-
shelf windows. The latter consisted of plantation-grown softwood frames with
triple-glazed units, along with krypton gas filling and low-emissivity coatings on
two of the glass layers (Vale and Vale 2000: pp. 187–194).
Conversely, the temperature inside a house that has minimal mass and insulation
will follow the outside temperature unless energy is put into the house in the form
of sunlight, or from the people and equipment housed in it. Temperatures over a
day are lowest in the night and highest around midday. In a lightweight house,
insulation will lift the internal temperature above the outside temperature.
However, the temperature in the house will still go up and down, following the
track of the outside temperature but a number of degrees above it. The level of
insulation will determine how much the temperature inside is lifted above that
outside. For an unheated house in New Zealand with 150mm of insulation in
walls and floor, and 200mm in the roof, the temperature was lifted about 7C
above that outside when the outside temperature was at its lowest. This meant the
minimum indoor temperature recorded in a bedroom was 14C (Vale and Vale
2001). The windows in this instance were double-glazed with one low-emissivity
coating in aluminium frames with no thermal break.
Although it is true to say that in New Zealand the majority of houses are of the
lightweight model, in many countries houses are a mixture of mass and lightweight
materials, often having masonry walls (mass), concrete slab ground floor
(mass), timber joisted upper floor (lightweight) and a timber frame roof (lightweight),
and hence their characteristic performance, if they are unheated, will
also be somewhere between the two extremes. It is important to have a basic
understanding of how buildings might behave. This is because it may fall to the
user to attempt to correct any shortcomings in the original design at points of major refurbishment in the building lifetime. During any refurbishment it is
unlikely that mass will be added to the building but it is often possible to add
insulation. However, before discussing this subject further, it is also necessary to
consider the behaviour of small buildings in hot climates and the behaviour of
large buildings.
In a hot climate, whether hot wet or hot dry, the aim is usually to keep the
building cooler than outside, although in some desert climates where the nights
are cold it is also desirable at times to try to raise the inside temperature above
that outside. From this it can be seen that in the hot dry desert climate with a
large swing in temperature between night and day, the very high mass building
is a good solution as it will maintain the annual average temperature. For
example, the mean annual temperature in Egypt is 20–25C3, which would
provide a good comfort temperature in a building. The classic high mass
building for this climate was made of mud brick, had few openings to keep
out the sun and formed part of a cluster of buildings to keep as much exterior
surface as possible shaded from exposure to direct sunlight. In a hot, humid
climate the temperature swing day and night and summer to winter is often less,
so there is less need of the tempering effect of mass, and the traditional building
was often lightweight, and open as much as possible to any cooling breezes to
help keep the occupants comfortable. In all hot climates the roof is an important
element in keeping out the sun. Often, ventilation paths would be open
under the roof in order to keep air flowing over its underside, with the aim of
channelling away any heat coming through. Roofs would also be insulated
against heat gain. In all warm climates a light-coloured roof is also an advantage
to reduce the solar gain into the building.
A small building is dominated by the performance of the surface, walls, roof and
floor, as the volume of space enclosed is relatively small. However, a large
building has less surface area for the volume enclosed, so its thermal performance
tends to be dominated by what happens in it – the gains from people and activities
– rather than by the skin, although large areas of glass cladding exposed to the
sun will have an effect on internal performance. Large buildings, with one
exception, also differ because they tend to be used during the working day and
so there is no necessity to maintain comfortable conditions during the night, the
time of lowest external temperatures in climates that need heating. The exception
is the apartment block, which, especially in Asia, is becoming the norm. The
improved performance of such buildings lies more with the designers and constructors
as the improvements to the life cycle impact that can be made by the
users are limited. Because this chapter is about the effect of the building user, the
remainder of the discussion will be centred on the home and the small-scale
building.
WHY SHOULD WE USE WATER WISELY?
Four things are conspiring to make fresh water one of the most
valuable commodities in the twenty-first century:
1 increasing world populations;
2 climate change;
3 man’s ever increasing interference with the natural flow of
water;
4 pollution.
In 1990 the World Health Organization estimated that 1230 million
people did not have access to adequate drinking water. By 2000
this figure was estimated to have risen by 900 million people. Add
to this already chronic problem the devastating impacts of climate
change and the results can be catastrophic, even in the most
developed countries in the world. On top of these issues comes
another: the increasing household demand for water around the
world. In England and Wales alone household water use is
predicted to increase by 10–20 per cent between 1990 and 2021
under a medium-growth scenario without climate change. Per
capita demand for domestic water is predicted to rise owing to
the projected increase in use of dishwashers and other domestic
appliances, with a further increase of 4 per cent with climate
change owing to higher use of personal showers and garden
watering. Demand for spray irrigation of crops in Britain is
predicted to rise by 115 per cent with climate change between
1990 and 2021, with most irrigation water taken from rivers and
groundwater.
This increasing demand for water can be met either by increasing
the capacity of supply (e.g. by building new reservoirs), by
reducing the consumption of water or by re-using water where we
can.
WATER CONSERVATION
Water conservation becomes increasingly important as demand for
water increases and shortfalls in supply occur. A number of water
conservation measures can be used in the home with little impact
on the every day lives of householders. These can involve the
following.
Flow restrictors
Flow restrictors are readily available and can be fitted to many
appliances, but their use has to be appropriate. Where taps can be
left open by careless users and where items are washed under
running water they are a cheap way of reducing water wastage.
However, a more effective but more expensive solution would be
to install taps operated by proximity sensors.
Showers
The average amount of water used by a conventional shower is
approximately 30 l, whilst a bath requires about 80 l. Initially, it
appears that showering is more energy and water efficient, but the
fact is that households with showers use them more frequently
than households without showers use their baths. Also, pumped
and multihead showers are not so water efficient as conventional
showers. Real savings can be made if you choose your products
wisely.
Conventional showerheads can discharge water at between 0.3
and 0.5 l s–1. Low-flow showerheads can reduce this to below
0.2 l s–1 depending on the supply pressure. Research conducted in
the USA has shown that the use of low-flow showerheads can
save approximately 27 l per day per person (for a person who
mainly showers rather than takes baths). This equates to an energy
saving in hot water of 444 kWh per person per year for water
heated by gas (or 388 kWh for water heated by electricity). The
cheaper alternative to low-flow showerheads is to fit a flow restrictor
to the supply to an existing showerhead, although this may
increase the showering time.
WCs
WC cistern water displacement devices are available in all
countries, albeit only a stone or brick in some cases. More imaginative
in the UK, with a typical flush of 6–9 l, is the use of the
plastic bags, ‘Hippo’ and yellow sponges, ‘Soggy Doggy’, thathave been distributed free by water companies to encourage
their customers to conserve water. These devices either
displace or retain water within the WC cistern to reduce the
volume of water that is flushed. Water displacement devices
such as dams and bags are very popular in the USA where
cisterns are generally much larger and less cluttered than UK
cisterns. This is because American cisterns have traditionally
flushed over 15 l of water using compact cistern outlet valves:
‘flappers’. Unfortunately it has been found that some displacement
devices may actually increase the flushing volume if they
are fitted such that they obstruct the flush volume limiting
aperture in a siphon. If the entire volume of water in the cistern
is necessary to clear the WC pan, a reduced flush volume may
not be effective, resulting in the repeated flushing of the cistern
and hence an increase in the amount of water used, rather than
a decrease.
WCs can be flushed with water using compressed air assistance.
Some such cisterns use the pressure of the mains water
supply to compress a volume of air above the stored water. When
the water is released into the bowl it has a much greater velocity
than from a conventional gravity-operated cistern. These products
are used in parts of France and the USA. To be used efficiently
these cisterns need to be matched to WC pans that can use the
higher velocity water effectively. Another type of water and
compressed air toilet uses water to rinse the bowl and
compressed air to evacuate the contents. This type is used in
many types of building in the USA.
Composting toilets
Composting toilets use no water for flushing. In its domestic
form this toilet is usually electrically powered, heating the waste
material to enable composting action to occur. The major
problem with this type of toilet is its size; the smallest domestic
model is about twice the size of a conventional WC suite.
Large (greater than 15 m3) composting toilets do not usually
require the external input of energy for the process, as the
aerobic decomposition is sufficiently exothermic to be selfsustaining.
Large composting toilets may be environmentally
acceptable as they consume only a small volume of water,
require no drainage pipe work and produce compost that can be
used in the garden. However, the questions of adequate hand
washing facilities if there is no available water supply and the
safety of children using toilets with open chutes needs to be
considered.
Waterless toilets
Waterless toilets that do not compost the waste usually require
electricity to operate. Packaging toilets seal the waste into continuous
plastic sacks that require subsequent disposal. Incinerating
toilets burn the waste to produce a sterile ash that can be disposed
of in a garden.
Urinal flushing cistern controllers
Urinal flushing cistern controllers have been widely used in the UK
for some time. Water Byelaws for such appliances have to be
checked for each area. In the UK such Byelaws state the maximum
rate at which cisterns may be filled. Since 1989 new cisterns are
required to be refilled only when the urinal is in use. There are
various methods of sensing use and operation. Some use changes
in water pressure to identify operation of taps and therefore, by
association, the use of urinals; others use passive infrared (PIR)
detectors to detect movement of persons in the room; some
sense the temperature of urine in the urinal traps; and many use
various forms of proximity detector. The essence of these devices
is they all obviate the flushing of urinals when the premises are
not being used and are usually an improvement over the use of
the traditional ‘pet-cock’ that has to be set to drip water at the
required rate into the cistern.
Waterless urinals
Waterless urinals are being increasingly used in the UK. Most
modern designs feature some form of odour suppressant that
requires regular renewal. Claims for large water and maintenance
savings are made about these devices but the pipe work must be
installed and maintained correctly if prolonged service life is to be
achieved. An incinerating urinal is available from the USA, which
produces small volumes of ash. However, at a cost of over £1000
considerable water has to be saved to make it economically viable.
Controls
The use of an occupancy detector to isolate the water supply to a
washroom when unoccupied is another application of PIR technology.
This can minimize the waste in urinal flushing and that caused
by taps being left open. Automatic leak detectors are becoming
increasingly available in the UK. These devices are fitted into the
incoming mains and close when a leak is detected, preventing boththe waste of water and damage to property. Some operate by
sensing a high flow rate and others use conductivity detectors to
activate valves. Automatic closure taps can produce water savings
in commercial and public buildings where there is a risk of taps
being left open accidentally.
Domestic appliances
Presently, 85 per cent of households in the UK possess a washing
machine and 10 per cent a dishwasher. Together, these consume
about 12 per cent of domestic drinking water. The ownership of
these previously luxury goods is increasing. Water Byelaws govern
the maximum permissible volume of water used for a wash:
between 150 and 180 l for a washing machine (depending on drum
size) and about 196 l for an average dishwasher. Modern highefficiency
washing machines use far less water than this and an
AEG washing machine uses as little as 68 l of water for a 5 kg fill
and only 1.4 kWh for a hot and cold fill. This is around one-third of
the water used in a conventional machine. The Oxford Ecohouse
dishwasher is another AEG machine that uses only 15 l of water
and 1.2 kWh electricity for a 50°C biowash cycle. That is less than
one-tenth of a conventional machine.
WASTEWATER SYSTEMS
Wastewater is used water. Wastewater may contain substances
such as human waste, food scraps, oils, soaps and chemicals. In
houses, wastewater can include the water from sinks, showers,
bathtubs, toilets, washing machines and dishwashers.
Businesses and industries also use water for a wide variety of
other purposes.
Wastewater can include stormwater (rainfall) runoff. Although
many people assume that stormwater runoff is clean, it isn’t.
Contaminants such as hydrocarbons wash off urban surfaces such
as roadways, parking lots and rooftops and can harm our rivers,
lakes and marine waters.
We also waste water when we don’t use it wisely. For instance,
when we fill a glass of water to drink, we may run the water to
make sure it’s cold. It is perfectly clean but once it disappears
down the drain it mixes with sewage and polluted water from other
households, businesses and industries.
When we pull the plug in the bathtub or flush the toilet, few of
us give much thought to where the wastewater is going but wastewater
doesn’t just disappear when it leaves our homes and
businesses. There are three types of sewer systems:
1 sanitary sewers carry wastewater from sinks, toilets, tubs and
industry;
2 storm sewers carry runoff from rainfall, called stormwater;
3 combined sewers carry wastewater and stormwater through the
same pipe.
Together, these form our wastewater collection system.
• In the USA each day, the average person produces about
220–450 l of wastewater. That’s enough to completely fill a
bathtub two times.
• We all produce sludge. An adult is responsible for about 32 kg
per year.
• If everyone installed water-saving toilets and showerheads, we
could substantially reduce domestic water consumption.
• Each day, in the USA the average person uses 260 l of water
for domestic purposes. That’s about 7 million l of water in a
lifetime.
• A leaky tap will waste in excess of 90 l of water each day.
KEY DIFFERENCES BETWEEN GREY WATER AND BLACK WATER
1 Grey water contains only one-tenth of the nitrogen of black
water. Nitrogen (as nitrite and nitrate) is the most serious and
difficult-to-remove pollutant affecting our potential drinking water.
As grey water contains far less nitrogen, it is unnecessary for it
to undergo the same treatment process as black water.
2 The medical and health professionals view black water as the
most significant source of human pathogens. Organisms that
threaten human health do not grow outside of the body (unless
incubated) but are capable of surviving especially if hosted in
human faeces. Separating grey water from black water
dramatically reduces the danger posed by such pathogens
because, in grey water the faeces that carry (and may
encapsulate) them are largely absent. However, other bacteria
are present in grey water and can cause rapid growth of any
faecal contamination present in pipes and septic systems. Care
must be taken to ensure that both grey and black water travel
rapidly through the pipes in buildings and that there are no
points in the system where they can stagnate.
3 The organic content typical of grey water decomposes much
faster than the content typical of black water. The amount of
oxygen required for the decomposition of the organic content in
grey water during the first 5 days (Biological Oxygen Demand
over 5 days or BOD5) constitutes 90 per cent of the total or
Ultimate Oxygen Demand (UOD) required for complete
decomposition. BOD5 for black water is only 40 per cent of the
oxygen required. BOD1 for grey water is around 40 per cent ofthe UOD; BOD1 for black water is only 8 per cent of the UOD.
This means that the decomposing matter in black water will
continue to consume oxygen far longer and further away from
the point of discharge than it will in grey water. This faster rate
of stabilization for grey water is advantageous for the prevention
of water pollution as the impact of grey-water discharge generally
does not travel as far from the point of discharge when
combined with wastewaters. This is especially true for sand and
soil infiltration systems. As grey and black waters are so different
it is better to separate them and, more specifically, to keep urine
and faeces out of the water altogether and to treat them
separately for the best protection of health and the environment.
Doing so also has significant savings for homeowners.
In the late 1980s, the American Institute of Architects (AIA) created the
Committee on the Environment (COTE), which has outlets today in just
about every AIA chapter across the country.All across the US and Canada,
architects have led the charge toward sustainable design, working through
local COTE chapters, as well as the US Green Building Council chapters.
Created in 1993, the US Green Building Council (USGBC) aims to
transform the building industry into a more environmentally responsible
activity. Beginning in the mid-1990s, the USGBC undertook, with Šnancial
assistance from the US Department of Energy, the development of a
rating and evaluation system to deŠne what a green building represented.
The Šrst system, dubbed Leadership in Energy and Environmental Design
or LEED, for new construction and major renovations, was piloted or
beta-tested in 1998 and 1999 on about 50 projects in the US. In March
2000, version 2.0 of LEED was introduced as an updated, revised and expanded
version of the original LEEDversion 1.0. Since then version 2.0 has
had two major changes; LEED for New Construction (LEED-NC) version
2.2, eªective since late 2005, is the current standard.
The USGBC enjoyed rapid growth from 1998, when it had only about
100 members, to the beginning of 2007, when membership stood at more
than 7,700 corporate, institutional, governmental and nonproŠt organizations
(it does not have individualmembers).1 Representing all segments of
the building industry and environmental community, the USGBC has
been able to craft a consensus standard for evaluating the environmental
attributes of buildings and developments, by drawing on the resources of
this large ($1 trillion annual construction value) and diverse industry.
Established in 2004, the Canada Green Building Council (CaGBC)
now has more than 1,300 member organizations, with chapters in many provinces.2 The CaGBC uses the LEED evaluation system but has adapted
it for Canadian conditions. By 2007 the CaGBC had more than 225 projects
registered for certiŠcation under the Canadian LEED standard.Green
building in Canada is a fast-growing movement, with a special focus on
energy e‹ciency and indoor air quality suitable for a more northerly and
colder climate.
Current Situation
Owners and developers of residential, commercial and institutional properties
acrossNorthAmerica are discovering that it is often possible to build
green buildings on conventional budgets.Many developers, building owners
and facility managers are advancing the state of the art in commercial
and large residential buildings through new modeling tools, design techniques
and creative use of Šnancial and regulatory incentives. For the past
ten years, in ever-increasing numbers, we have begun to see development
of commercial structures using green building techniques and technologies.
With more than 1,200 corporations issuing sustainability reports of
some formin 2006, it is clear that thismarket will not be a short-lived fad.
Companies want to locate in a space that rešects their values, and a highperformance
building goes a longway toward satisfying that requirement.3
Most long-time participants in the real estate, architectural design
and building construction industries realize that sustainable design is the
biggest sea change in their business careers. The urgency of global warming
and the increasing US dependence on imported fuels have led architects
to urge more concerted action to reduce energy use in buildings. In
late 2005 the American Institute of Architects (AIA), representing more
than 70,000 architects, released amajor policy statement that sets a goal of
reducing the fossil fuel consumption of new buildings by 50% by the year
2010, with additional 10% reductions every Šve years thereafter, to reach
90% reduction from 2005 levels by 2030. While this declaration has no
legal force, it does add pressure to incorporate superior energy performance
into the goals for each project.4 As architect EdwardMazria observes,
one can achieve a 50% reduction with existing building technology at no
extra cost by simply using the right design strategies, such as proper orientation
and form, daylighting, solar control and passive heating and cooling
techniques.
Understanding Green Buildings
What do wemean when we speak of green Architecture or high-performance
buildings? According to the USGBC, these buildings incorporate design
and construction practices that signiŠcantly reduce or eliminate the negative impact of buildings on the environment and occupants in Šve broad
areas:
• Sustainable site planning.
• Safeguarding water and water e‹ciency.
• Energy e‹ciency and renewable energy.
• Conservation of materials and resources.
• Indoor environmental quality.5
Typically, green buildings are measured against code buildings — structures
that qualify for a building permit but do not exceed the minimum
requirements of the building code for health and safety. In addition, green
buildings are often measured according to a system such as the LEED rating
system (usgbc.org), the Collaborative for High-Performance Schools
(CHPS) ratings (chps.net), the Advanced Building™ guidelines (power
yourdesign.com),Green Guide for Healthcare (GGHC)6 or, in some cases,
local utility or city guidelines (a number of utilities have rating systems for
residential buildings). Such buildings must score a minimum number of
points above “standard building” performance thresholds to qualify for a
certiŠcation, or a rating as “green” or high-performance.
Since the introduction of LEED in 2000, it has become essentially the
US national standard for commercial and institutional buildings. LEED is
primarily a performance standard; in other words, it generally allows a developer,
architect or building owner to choose how tomeet certain benchmark
numbers — saving 20% on energy use versus current building
codes, for example — without prescribing speciŠc measures. In this way,
LEED is a šexible tool for new construction or major renovations in almost
all commercial and institutional buildings throughout the US.
Canada has an almost identical version of LEED,7 which has achieved signiŠcant
popularity. Since its inception, LEED has proven to be a valuable
design tool for architectural teams tasked with creating green buildings, as
well as a way to evaluate the Šnal result.
LEED provides for four levels of certiŠcation, in ascending order of
achievement: CertiŠed, Silver, Gold and Platinum. In 2003 and 2004 three
projects in southern California achieved the Platinum rating: one project
for a local utility, another for a county park (in cooperation with the local
Audubon Society) and another for the Natural Resources Defense Council.
By early 2007 the largest LEED Platinum project was the Center for
Health and Healing at Oregon Health & Science University, in Portland, at
412,000 square feet. At the same time, more than 500 projects had completed
the certiŠcation process under LEED for New Construction
(LEED-NC). Platinum-seeking projects that are under construction in
2007 promise to extend the size of the top-rated buildings to more than
onemillion square feet.
Who Is Using LEED?
By the end of 2006, LEED-NC had captured about 4% to 5% of the total
new building market, with nearly 4,000 registered projects encompassing
more than 477 million square feet of new and renovated space. At the beginning
of 2007, more than 100 new projects each month were registered
for evaluation under LEED-NC. Since a project can only be LEED-certiŠed
after it is ready for occupancy, many projects are just nearing completion
of their documentation to qualify for a LEED rating. Given that it
often takes two years ormore for projects tomove fromdesign to completion
(and certiŠcation can only take place after substantial completion of a
project), growth in the number of certiŠed projects will be rapid. Many
Fortune 500 Šrms, universities, government agencies and non-proŠt organizations
are beginning to participate signiŠcantly in the development
of LEED projects.
Just about every conceivable project type has been LEED-registered,
including amostly undergroundOregon winemaking (barrel-aging) facility! For example, the Šrst 150 LEED Gold project certiŠcations (through
the end of 2006) included 10 non-US projects (7 in Canada) and such varied
building types as:
• Renovation of a 100-year-old warehouse into a modern o‹ce building
in Portland,Oregon.
• A developer-driven technology park conversion of an old hospital in
Victoria, British Columbia.
• An o‹ce-warehouse building for a major auto company in Gresham,
Oregon.
• An elementary school in Statesville,North Carolina.
• Two high-rise apartment buildings in NewYork City.
• A new o‹ce building and an o‹ce building renovation for Herman
Miller, Inc., in Zeeland, Michigan. (Commenting on this project, architect
William McDonough observed that moving from a windowless
building to a daylit building increased annual revenues 40% and
that the increase in proŠts paid for the building in about four
months.)8
• Apublic o‹ce building leased to theCommonwealth of Pennsylvania.
• An environmental learning center near Seattle,Washington.
• A city hall in Austin, Texas.
• An aªordable housing complex in SantaMonica, California.
• A new convention center in Pittsburgh, Pennsylvania.
In the late 1980s, the American Institute of Architects (AIA) created the
Committee on the Environment (COTE), which has outlets today in just
about every AIA chapter across the country.All across the US and Canada,
architects have led the charge toward sustainable design, working through
local COTE chapters, as well as the US Green Building Council chapters.
Created in 1993, the US Green Building Council (USGBC) aims to
transform the building industry into a more environmentally responsible
activity. Beginning in the mid-1990s, the USGBC undertook, with Šnancial
assistance from the US Department of Energy, the development of a
rating and evaluation system to deŠne what a green building represented.
The Šrst system, dubbed Leadership in Energy and Environmental Design
or LEED, for new construction and major renovations, was piloted or
beta-tested in 1998 and 1999 on about 50 projects in the US. In March
2000, version 2.0 of LEED was introduced as an updated, revised and expanded
version of the original LEEDversion 1.0. Since then version 2.0 has
had two major changes; LEED for New Construction (LEED-NC) version
2.2, eªective since late 2005, is the current standard.
The USGBC enjoyed rapid growth from 1998, when it had only about
100 members, to the beginning of 2007, when membership stood at more
than 7,700 corporate, institutional, governmental and nonproŠt organizations
(it does not have individualmembers).1 Representing all segments of
the building industry and environmental community, the USGBC has
been able to craft a consensus standard for evaluating the environmental
attributes of buildings and developments, by drawing on the resources of
this large ($1 trillion annual construction value) and diverse industry.
Established in 2004, the Canada Green Building Council (CaGBC)
now has more than 1,300 member organizations, with chapters in many provinces.2 The CaGBC uses the LEED evaluation system but has adapted
it for Canadian conditions. By 2007 the CaGBC had more than 225 projects
registered for certiŠcation under the Canadian LEED standard.Green
building in Canada is a fast-growing movement, with a special focus on
energy e‹ciency and indoor air quality suitable for a more northerly and
colder climate.
Current Situation
Owners and developers of residential, commercial and institutional properties
acrossNorthAmerica are discovering that it is often possible to build
green buildings on conventional budgets.Many developers, building owners
and facility managers are advancing the state of the art in commercial
and large residential buildings through new modeling tools, design techniques
and creative use of Šnancial and regulatory incentives. For the past
ten years, in ever-increasing numbers, we have begun to see development
of commercial structures using green building techniques and technologies.
With more than 1,200 corporations issuing sustainability reports of
some formin 2006, it is clear that thismarket will not be a short-lived fad.
Companies want to locate in a space that rešects their values, and a highperformance
building goes a longway toward satisfying that requirement.3
Most long-time participants in the real estate, architectural design
and building construction industries realize that sustainable design is the
biggest sea change in their business careers. The urgency of global warming
and the increasing US dependence on imported fuels have led architects
to urge more concerted action to reduce energy use in buildings. In
late 2005 the American Institute of Architects (AIA), representing more
than 70,000 architects, released amajor policy statement that sets a goal of
reducing the fossil fuel consumption of new buildings by 50% by the year
2010, with additional 10% reductions every Šve years thereafter, to reach
90% reduction from 2005 levels by 2030. While this declaration has no
legal force, it does add pressure to incorporate superior energy performance
into the goals for each project.4 As architect EdwardMazria observes,
one can achieve a 50% reduction with existing building technology at no
extra cost by simply using the right design strategies, such as proper orientation
and form, daylighting, solar control and passive heating and cooling
techniques.
Understanding Green Buildings
What do wemean when we speak of green buildings or high-performance
buildings? According to the USGBC, these buildings incorporate design
and construction practices that signiŠcantly reduce or eliminate the negative impact of buildings on the environment and occupants in Šve broad
areas:
• Sustainable site planning.
• Safeguarding water and water e‹ciency.
• Energy e‹ciency and renewable energy.
• Conservation of materials and resources.
• Indoor environmental quality.5
Typically, green buildings are measured against code buildings — structures
that qualify for a building permit but do not exceed the minimum
requirements of the building code for health and safety. In addition, green
buildings are often measured according to a system such as the LEED rating
system (usgbc.org), the Collaborative for High-Performance Schools
(CHPS) ratings (chps.net), the Advanced Building™ guidelines (power
yourdesign.com),Green Guide for Healthcare (GGHC)6 or, in some cases,
local utility or city guidelines (a number of utilities have rating systems for
residential buildings). Such buildings must score a minimum number of
points above “standard building” performance thresholds to qualify for a
certiŠcation, or a rating as “green” or high-performance.