Passive Solar Housing

Passive Solar Housing
Passive solar systems are self-sufficient buildings which rely on natural
principles insted of mechanical systems to provide a non-polluting
source of heating and cooling.

Introduction

Passive energy is more sustainable than active energy systems because passive
systems use far fewer natural resources to build and maintain. They do not rely so
heavily upon gas for heating or coolants for air conditioning. Passive systems are
designed so that they can take natural energy from the sun to heat a building and
use specific design principles to cool a building. Passive energy systems are also
cheaper than
active systems because they are less susceptible to malfunction since they rely
completely
upon nature, rather than using mechanical equipment to produce energy. In order
to create a home that will maximize the effects of passive solar heating, a designer
must take many different variables into account. Two major ideas crucial to creating
effective passive solar housing are orientation and materials. Passive solar buildings
should be oriented to receive as much southern sun as possible. In the summer,
the hot sun can be blocked by using overhangs or through landscaping like large
foliated trees. In the winter, sun should help heat the house because the sun angle
is lower in the sky allowing more sun to hit the glazing more directly. Thought
should also be given to the specifications of the windows for maximum solar gains
and heat loss. By using the right building materials such as masonry or concrete and
combining them with effective insulation, solar energy can be contained in the
house allowing it to be comfortable year round (Desbarats 1980, 232).

Building Orientation
Building orientation is crucial to maximizing energy production in a passive solar
home. Because passive solar homes rely on natural sunlight to power the building's
utilities, the building should be oriented on the site in a way that will allow it to
maximize the amount of sunlight. The best way to achieve this is to orient the house
on the east-west axis and concentrate most of the house's glazing on the south
wall. This allows the home to receive the most direct sunlight for the longest period
of time (Hibshman 1983, 261). Heat travels through windows very easily, however
heat
does not exit as easily. Once the heat passes through the window, it breaks up and it
takes much longer for that heat to exit (Button 1993, 129). This allows heat that
enters a
building to stay in the building for a long time. This is a helpful principal for heating
a building in the winter and is the reason why windows should receive as much light
as possible in the winter. However, in the summer, the hot sun can become an
uncomfortable problem. To alleviate some of this heat, passive solar homes should
be designed with attic fans or some sort of operable clerestory windows which can
be opened to release some of the hot air when it rises. Glazing should be greatly
reduced on the east and west walls and should be virtually eliminated on the north
side of the home because most cold winds in winter come from the north and
west (Desbarats 1980, 56). Because the house needs as much protection from these
winds as possible, and glazing cannot provide this protection, windows should be
eliminated. (Desbarats 1980, 28).


Glass
The amount as well as type of glass windows used in a house are very important
considerations in terms of thermal comfort, cost and efficiency. There are many
different types of windows available: single, double and triple paned (Button 1993,
164)
A single pane is simply one pane of glass. These are generally the worst types of
windows
to use. Although they are the cheapest windows available, they are not energy
efficient
and they allow more heat gain in summer and heat loss in winter than either the
double
or triple paned windows do. Double pane windows are much more energy efficient.
The reason is the cold winter air passes through the first pane but then must pass
through a gap of either air or Argon gas before it reaches the second pane. The
reason
this is helpful is because air or Argon gas provide excellent insulation and do not
allow
the cold to penetrate nearly as much as it would if there were only one pane. Triple
paned windows work on the same principal as double paned but they are even more
energy efficient because there is even an additional layer of insulation (Button 1993,
166). It is
also possible to get windows with coatings such as low emissivity coatings (low-E)
which help to block the suns harmful rays but still allow visible light to pass through
(Button 1993, 173).

(Hibshman 1983, 29)
R-Values for Different Types of Glass

Thermal Mass
Thermal mass is another important concept to keep in mind when dealing with
energy
efficient housing. It is important for these types of homes to be built with materials
that have a large amount of thermal mass (Hibshman, 1983, p.48). Such materials are
brick,
stone and concrete. These materials are ideal because materials with a large thermal
mass
absorb much of the energy they receive from the sun. These materials absorb and
release energy
completely, but slowly. Because it takes a long time for the energy to be released
after it is absorbed, a phenomenon known as lag, warm sunlight that is absorbed
during the day is finally released over time at night. This is another natural
phenomenon
which proves helpful because it provides warmth at night when the house is the
coldest and
heat is necessary. Because all of the heat is released at night the floor is then cool for
the
next day and consequently this helps to cool the rest of the house. It is also important
leave
the concrete floors on the south side of the house exposed. If they are carpeted, they
lose most
all of their thermal mass properties. However, carpeting would be acceptable on the
north side of the house because there should be almost no windows there
anyway (Hibshman, 1983, p.32).


(Hibshman, 1983, p.32)
How Thermal Mass Works

Affordability in Sustainability Using Passive Solar Heating
Cost is a very important factor for designing sustainable architecture. Aside from
creating
enviornmentally friendly architecture, sustainable architecture allows lower building
and
maintenance costs. Affordability goes hand in hand with sustainablity and is
something which
we, as designers, should concentrate on when designing the housing in East St. Louis.
One way
to create affordable homes is by using everyday, affordable materials to replace
expensive and
wasteful mechanical ones. One way this can be achieved is by using 55-gallon drums
filled with
water to create thermal mass, a very necessary element for passive solar heating. By
placing these
drums in direct sunlight, they will absorb the sun's energy and, because lag also
occurs in water,
they will have the same effect on the house that materials like concrete or masonry
would, but
without the cost (Hibshman, 1983, p.50). Another, affordable solution is to use these
drums
filled with water to replace water heaters. They can be placed in the roof or any other
place
where they will receive a lot of direct sunlight (see figure on "Sustainable Design"
page).
The owner can then use that water which has been naturally heated for bathing or
cooking,
replacing a mechanical hot water heater and greatly reducing cost (Hibshman, 1983,
p.53).
Another way to create affordable yet sustainable architecture is by using
unconventional
building techniques. One way is to use post-and-beam units instead of conventional
stick
framing. The posts are then anchored into the concrete. This creates a very stable
framing
system and also reduces costs because no 2"x4" studs are used and therefore, less
wood is
used. However, the most important money saving factor in this construction is the use
of
prefabricated wall systems. These systems are cut into 4'x8' sheets and can then
be placed right in between the posts on the construction site with no wated materials
used
(Hibshman, 1983, p.71). This is also a faster method of construction so the labor
costs
will also be reduced. While these are just a few ideas more specific examples using
these
techniques can be found in the sited material.

Diagram showing good passive solar design
(Hibshman, 1983, p.71)

Previous - Next

Passive solar building design
From Wikipedia, the free encyclopedia


Elements of passive solar design, shown in a direct gain application


Active and passive solar systems are used in the Solar Umbrella house to achieve nearly 100%energy neutrality.
In passive solar building design, windows, walls, and floors are made to collect, store, and distribute solar energy in the form of heat in the
winter and reject solar heat in the summer. This is called passive solar design or climatic design because, unlike active solar heatingsystems,
it doesn't involve the use of mechanical and electrical devices.
[1]

The key to designing a passive solar building is to best take advantage of the local climate. Elements to be considered include window
placement and glazing type, thermal insulation, thermal mass, and shading. Passive solar design techniques can be applied most easily to
new buildings, but existing buildings can be adapted or "retrofitted".
Contents
[hide]
 1 Passive energy gain
 2 As a science
 3 The solar path in passive design
 4 Passive solar thermodynamic principles
o 4.1 Convective heat transfer
o 4.2 Radiative heat transfer
 5 Site specific considerations during design
 6 Design elements for residential buildings in temperate climates
 7 Efficiency and economics of passive solar heating
 8 Key passive solar building design concepts
o 8.1 Direct solar gain
o 8.2 Indirect solar gain
o 8.3 Isolated solar gain
o 8.4 Heat storage
o 8.5 Insulation
o 8.6 Special glazing systems and window coverings
o 8.7 Glazing selection
 8.7.1 Equator-facing glass
 8.7.2 Roof-angle glass / Skylights
 8.7.3 Angle of incident radiation
o 8.8 Operable shading and insulation devices
o 8.9 Exterior colors reflecting - absorbing
 9 Landscaping and gardens
 10 Other passive solar principles
o 10.1 Passive solar lighting
 10.1.1 Interior reflecting
o 10.2 Passive solar water heating
 11 Comparison to the Passive House standard in Europe
 12 Design tools
 13 Levels of application
o 13.1 Pragmatic
o 13.2 Annualised
o 13.3 Minimum machinery
o 13.4 Zero Energy Building
 14 See also
 15 References
 16 External links
Passive energy gain[edit]
Passive solar technologies use sunlight without active mechanical systems (as contrasted to active solar). Such technologies convert
sunlight into usable heat (water, air, thermal mass), cause air-movement for ventilating, or future use, with little use of other energy sources.
A common example is a solarium on the equator-side of a building. Passive cooling is the use of the same design principles to reduce
summer cooling requirements.
Some passive systems use a small amount of conventional energy to control dampers, shutters, night insulation, and other devices that
enhance solar energy collection, storage, and use, and reduce undesirable heat transfer.
Passive solar technologies include direct and indirect solar gain for space heating, solar water heating systems based on
the thermosiphon or geyser pump, use of thermal mass and phase-change materials for slowing indoor air temperature swings, solar
cookers, the solar chimney for enhancing natural ventilation, and earth sheltering.
More widely, passive solar technologies include the solar furnace and solar forge, but these typically require some external energy for
aligning their concentrating mirrors or receivers, and historically have not proven to be practical or cost effective for widespread use. 'Low-
grade' energy needs, such as space and water heating, have proven, over time, to be better applications for passive use of solar energy.
As a science[edit]
The scientific basis for Passive Solar Building Design
[2]
has been developed from a combination of climatology, thermodynamics (
particularly heat transfer: conduction (heat), convection, andelectromagnetic radiation ), fluid mechanics / natural convection (passive
movement of air and water without the use of electricity, fans or pumps), and human thermal comfort based on heat
index, psychrometrics and enthalpy control for buildings to be inhabited by humans or animals, sunrooms, solariums, and greenhouses for
raising plants.
Specific attention is divided into: the site, location and solar orientation of the building, local sun path, the prevailing level
of insolation ( latitude / sunshine / clouds / precipitation (meteorology) ), design and construction quality / materials, placement / size / type of
windows and walls, and incorporation of solar-energy-storing thermal mass with heat capacity.
While these considerations may be directed toward any building, achieving an ideal optimized cost / performance solution requires
careful, holistic, system integration engineering of these scientific principles. Modern refinements through computer modeling (such as the
comprehensive U.S. Department of Energy "Energy Plus"
[3]
energy simulation software), and application of decades of lessons learned
(since the 1970s energy crisis) can achieve significant energy savings and reduction of environmental damage, without sacrificing
functionality or aesthetics.
[4]
In fact, passive-solar design features such as a greenhouse / sunroom / solarium can greatly enhance the
livability, daylight, views, and value of a home, at a low cost per unit of space.
Much has been learned about passive solar building design since the 1970s energy crisis. Many unscientific, intuition-based expensive
construction experiments have attempted and failed to achieve zero energy - the total elimination of heating-and-cooling energy bills.
Passive solar building construction may not be difficult or expensive (using off-the-shelf existing materials and technology), but the scientific
passive solar building design is a non-trivial engineering effort that requires significant study of previous counter-intuitive lessons learned,
and time to enter, evaluate, and iteratively refine the computer simulation input and output.
One of the most useful post-construction evaluation tools has been the use of thermography using digital thermal imaging cameras for a
formal quantitative scientific energy audit. Thermal imaging can be used to document areas of poor thermal performance such as the
negative thermal impact of roof-angled glass or a skylight on a cold winter night or hot summer day.
The scientific lessons learned over the last three decades have been captured in sophisticated comprehensive energy simulation computer
software systems (like U.S. DOE Energy Plus, et al.).
Scientific passive solar building design with quantitative cost benefit product optimization is not easy for a novice. The level of complexity has
resulted in ongoing bad-architecture, and many intuition-based, unscientific construction experiments that disappoint their designers and
waste a significant portion of their construction budget on inappropriate ideas.
The economic motivation for scientific design and engineering is significant. If it had been applied comprehensively to new building
construction beginning in 1980 (based on 1970's lessons learned), America could be saving over $250,000,000 per year on expensive
energy and related pollution today.
[citation needed]

Since 1979, Passive Solar Building Design has been a critical element of achieving zero energy by educational institution experiments, and
governments around the world, including the U.S. Department of Energy, and the energy research scientists that they have supported for
decades. The cost effective proof of concept was established decades ago, but cultural assimilation into architecture, construction trades,
and building-owner decision making has been very slow and difficult to change.
[citation needed]

The new terms "Architectural Science" and "Architectural Technology" are being added to some schools of Architecture, with a future goal of
teaching the above scientific and energy-engineering principles.
[citation needed]

The solar path in passive design[edit]


Solar altitude over a year; latitude based on New York,New York
Main articles: Sun path and Position of the Sun
The ability to achieve these goals simultaneously is fundamentally dependent on the seasonal variations in the sun's path throughout the
day.
This occurs as a result of the inclination of the Earth's axis of rotation in relation to its orbit. The sun path is unique for any given latitude.
In Northern Hemisphere non-tropical latitudes farther than 23.5 degrees from the equator:
 The sun will reach its highest point toward the South in the Northern Hemisphere and the North
in the Southern Hemisphere (in the direction of the equator)
 As winter solstice approaches, the angle at which the sun rises and sets progressively moves
further toward the South and the daylight hours will become shorter
 The opposite is noted in summer where the sun will rise and set further toward the North and
the daylight hours will lengthen
[5]

The converse is observed in the Southern Hemisphere, but the sun rises to the east and sets toward the west regardless of which
hemisphere you are in.
In equatorial regions at less than 23.5 degrees, the position of the sun at solar noon will oscillate from north to south and back again during
the year.
[6]

In regions closer than 23.5 degrees from either north-or-south pole, during summer the sun will trace a complete circle in the sky without
setting whilst it will never appear above the horizon six months later, during the height of winter.
[7]

The 47-degree difference in the altitude of the sun at solar noon between winter and summer forms the basis of passive solar design. This
information is combined with local climatic data (degree day) heating and cooling requirements to determine at what time of the year solar
gain will be beneficial for thermal comfort, and when it should be blocked with shading. By strategic placement of items such as glazing and
shading devices, the percent of solar gain entering a building can be controlled throughout the year.
One passive solar sun path design problem is that although the sun is in the same relative position six weeks before, and six weeks after, the
solstice, due to "thermal lag" from the thermal massof the Earth, the temperature and solar gain requirements are quite different before and
after the summer or winter solstice. Movable shutters, shades, shade screens, or window quilts can accommodate day-to-day and hour-to-
hour solar gain and insulation requirements.
Careful arrangement of rooms completes the passive solar design. A common recommendation for residential dwellings is to place living
areas facing solar noon and sleeping quarters on the opposite side.
[8]
A heliodon is a traditional movable light device used by architects and
designers to help model sun path effects. In modern times, 3D computer graphics can visually simulate this data, and calculate performance
predictions.
[4]

Passive solar thermodynamic principles[edit]
Personal thermal comfort is a function of personal health factors (medical, psychological, sociological and situational), ambient air
temperature, mean radiant temperature, air movement (wind chill, turbulence) and relative humidity (affecting
human evaporative cooling). Heat transfer in buildings occurs through convection, conduction, and thermal radiation through roof, walls, floor
and windows.
[9]

Convective heat transfer[edit]
Convective heat transfer can be beneficial or detrimental. Uncontrolled air infiltration from poor weatherization / weatherstripping / draft-
proofing can contribute up to 40% of heat loss during winter;
[10]
however, strategic placement of operable windows or vents can enhance
convection, cross-ventilation, and summer cooling when the outside air is of a comfortable temperature andrelative
humidity.
[11]
Filtered energy recovery ventilation systems may be useful to eliminate undesirable humidity, dust, pollen, and microorganisms
in unfiltered ventilation air.
Natural convection causing rising warm air and falling cooler air can result in an uneven stratification of heat. This may cause uncomfortable
variations in temperature in the upper and lower conditioned space, serve as a method of venting hot air, or be designed in as a natural-
convection air-flow loop for passive solar heat distribution and temperature equalization. Natural human cooling
by perspiration and evaporation may be facilitated through natural or forced convective air movement by fans, but ceiling fans can disturb the
stratified insulating air layers at the top of a room, and accelerate heat transfer from a hot attic, or through nearby windows. In addition,
high relative humidity inhibits evaporative cooling by humans.
Radiative heat transfer[edit]
The main source of heat transfer is radiant energy, and the primary source is the sun. Solar radiation occurs predominantly through the roof
and windows (but also through walls). Thermal radiation moves from a warmer surface to a cooler one. Roofs receive the majority of the
solar radiation delivered to a house. A cool roof, or green roof in addition to a radiant barrier can help prevent your attic from becoming hotter
than the peak summer outdoor air temperature
[12]
(see albedo, absorptivity, emissivity, and reflectivity).
Windows are a ready and predictable site for thermal radiation.
[13]
Energy from radiation can move into a window in the day time, and out of
the same window at night. Radiation uses photons to transmit electromagnetic waves through a vacuum, or translucent medium. Solar heat
gain can be significant even on cold clear days. Solar heat gain through windows can be reduced byinsulated glazing, shading, and
orientation. Windows are particularly difficult to insulate compared to roof and walls. Convective heat transfer through and around window
coverings also degrade its insulation properties.
[13]
When shading windows, external shading is more effective at reducing heat gain than
internal window coverings.
[13]

Western and eastern sun can provide warmth and lighting, but are vulnerable to overheating in summer if not shaded. In contrast, the low
midday sun readily admits light and warmth during the winter, but can be easily shaded with appropriate length overhangs or angled louvres
during summer and leaf bearing summer shade trees which shed their leaves in the fall. The amount of radiant heat received is related to the
location latitude, altitude, cloud cover, and seasonal / hourly angle of incidence (see Sun path and Lambert's cosine law).
Another passive solar design principle is that thermal energy can be stored in certain building materials and released again when heat gain
eases to stabilize diurnal (day/night) temperature variations. The complex interaction of thermodynamic principles can be counterintuitive for
first-time designers. Precise computer modeling can help avoid costly construction experiments.
Site specific considerations during design[edit]
 Latitude, sun path, and insolation (sunshine)
 Seasonal variations in solar gain e.g. cooling or heating degree days, solar insolation, humidity
 Diurnal variations in temperature
 Micro-climate details related to breezes, humidity, vegetation and land contour
 Obstructions / Over-shadowing - to solar gain or local cross-winds
Design elements for residential buildings in temperate climates[edit]
 Placement of room-types, internal doors & walls, & equipment in the house.
 Orienting the building to face the equator (or a few degrees to the East to capture the morning
sun)
[8]

 Extending the building dimension along the east/west axis
 Adequately sizing windows to face the midday sun in the winter, and be shaded in the summer.
 Minimising windows on other sides, especially western windows
[13]

 Erecting correctly sized, latitude-specific roof overhangs,
[14]
or shading elements (shrubbery,
trees, trellises, fences, shutters, etc.)
[15]

 Using the appropriate amount and type of insulation including radiant barriers and bulk
insulation to minimise seasonal excessive heat gain or loss
 Using thermal mass to store excess solar energy during the winter day (which is then re-
radiated during the night)
[16]

The precise amount of equator-facing glass and thermal mass should be based on careful consideration of latitude, altitude, climatic
conditions, and heating/cooling degree day requirements.
Factors that can degrade thermal performance:
 Deviation from ideal orientation and north/south/east/west aspect ratio
 Excessive glass area ('over-glazing') resulting in overheating (also resulting in glare and fading
of soft furnishings) and heat loss when ambient air temperatures fall
 Installing glazing where solar gain during the day and thermal losses during the night cannot be
controlled easily e.g. West-facing, angled glazing, skylights
[17]

 Thermal losses through non-insulated or unprotected glazing
 Lack of adequate shading during seasonal periods of high solar gain (especially on the West
wall)
 Incorrect application of thermal mass to modulate daily temperature variations
 Open staircases leading to unequal distribution of warm air between upper and lower floors as
warm air rises
 High building surface area to volume - Too many corners
 Inadequate weatherization leading to high air infiltration
 Lack of, or incorrectly installed, radiant barriers during the hot season. (See also cool
roof and green roof)
 Insulation materials that are not matched to the main mode of heat transfer (e.g. undesirable
convective/conductive/radiant heat transfer)
Efficiency and economics of passive solar heating[edit]
Technically, PSH is highly efficient. Direct-gain systems can utilize (i.e. convert into "useful" heat) 65-70% of the energy of solar radiation that
strikes the aperture or collector.
Passive solar fraction (PSF) is the percentage of the required heat load met by PSH and hence represents potential reduction in heating
costs. RETScreen International has reported a PSF of 20-50%. Within the field of sustainability, energy conservation even of the order of
15% is considered substantial.
Other sources report the following PSFs:
 5-25% for modest systems
 40% for "highly optimized" systems
 Up to 75% for "very intense" systems
In favorable climates such as the southwest United States, highly optimized systems can exceed 75% PSF.
[18]

For more information see Solar Air Heat
Key passive solar building design concepts[edit]
There are six primary passive solar energy configurations:
[19]

 direct solar gain
 indirect solar gain
 isolated solar gain
 heat storage
 insulation and glazing
 passive cooling
Direct solar gain[edit]
Direct gain attempts to control the amount of direct solar radiation reaching the living space. This direct solar gain is a critical part of passive
solar house designation as it imparts to a direct gain.
The cost effectiveness of these configurations are currently being investigated in great detail and are demonstrating promising results.
[20]

Indirect solar gain[edit]
Indirect gain attempts to control solar radiation reaching an area adjacent but not part of the living space. Heat enters the building through
windows and is captured and stored in thermal mass(e.g. water tank, masonry wall) and slowly transmitted indirectly to the building
through conduction and convection. Efficiency can suffer from slow response (thermal lag) and heat losses at night. Other issues include the
cost of insulated glazing and developing effective systems to redistribute heat throughout the living area.
Isolated solar gain[edit]
Isolated gain involves utilizing solar energy to passively move heat from or to the living space using a fluid, such as water or air by natural
convection or forced convection. Heat gain can occur through a sunspace, solarium or solar closet. These areas may also be employed
usefully as a greenhouse or drying cabinet. An equator-side sun room may have its exterior windows higher than the windows between the
sun room and the interior living space, to allow the low winter sun to penetrate to the cold side of adjacent rooms. Glass placement and
overhangs prevent solar gain during the summer. Earth cooling tubes or other passive cooling techniques can keep a solarium cool in the
summer.
Measures should be taken to reduce heat loss at night e.g. window coverings or movable window insulation
Examples:
 Thermosiphon
 Barra system
 Double envelope house
 Thermal buffer zone
[21]

 Solar space heating system
 Solar chimney
Heat storage[edit]
The sun doesn't shine all the time. Heat storage, or thermal mass, keeps the building warm when the sun can't heat it.
In diurnal solar houses, the storage is designed for one or a few days. The usual method is a custom-constructed thermal mass. This
includes a Trombe wall, a ventilated concrete floor, a cistern, water wall or roof pond. It is also feasible to use the thermal mass of the earth
itself, either as-is or by incorporation into the structure by banking or using rammed earth as a structural medium.
[22]

In subarctic areas, or areas that have long terms without solar gain (e.g. weeks of freezing fog), purpose-built thermal mass is very
expensive. Don Stephens pioneered an experimental technique to use the ground as thermal mass large enough for annualized heat
storage. His designs run an isolated thermosiphon 3 m under a house, and insulate the ground with a 6 m waterproof skirt.
[23]

Insulation[edit]
Main article: Building insulation
Thermal insulation or superinsulation (type, placement and amount) reduces unwanted leakage of heat.
[9]
Some passive buildings are
actually constructed of insulation.
Special glazing systems and window coverings[edit]
Main articles: Insulated glazing and Window covering
The effectiveness of direct solar gain systems is significantly enhanced by insulative (e.g. double glazing), spectrally selective glazing (low-
e), or movable window insulation (window quilts, bifold interior insulation shutters, shades, etc.).
[24]

Generally, Equator-facing windows should not employ glazing coatings that inhibit solar gain.
There is extensive use of super-insulated windows in the German Passive House standard. Selection of different spectrally selective window
coating depends on the ratio of heating versus coolingdegree days for the design location.
Glazing selection[edit]
Equator-facing glass[edit]
The requirement for vertical equator-facing glass is different from the other three sides of a building. Reflective window coatings and multiple
panes of glass can reduce useful solar gain. However, direct-gain systems are more dependent on double or triple glazing to reduce heat
loss. Indirect-gain and isolated-gain configurations may still be able to function effectively with only single-pane glazing. Nevertheless, the
optimal cost-effective solution is both location and system dependent.
Roof-angle glass / Skylights[edit]
Skylights admit harsh direct overhead sunlight and glare
[25]
either horizontally (a flat roof) or pitched at the same angle as the roof slope. In
some cases, horizontal skylights are used with reflectors to increase the intensity of solar radiation (and harsh glare), depending on the
roof angle of incidence. When the winter sun is low on the horizon, most solar radiation reflects off of roof angled glass ( the angle of
incidence is nearly parallel to roof-angled glass morning and afternoon ). When the summer sun is high, it is nearly perpendicular to roof-
angled glass, which maximizes solar gain at the wrong time of year, and acts like a solar furnace. Skylights should be covered and well-
insulated to reduce natural convection ( warm air rising ) heat loss on cold winter nights, and intense solar heat gain during hot
spring/summer/fall days.
The equator-facing side of a building is south in the northern hemisphere, and north in the southern hemisphere. Skylights on roofs that face
away from the equator provide mostly indirect illumination, except for summer days when the sun rises on the non-equator side of the
building (depending on latitude). Skylights on east-facing roofs provide maximum direct light and solar heat gain in the summer morning.
West-facing skylights provide afternoon sunlight and heat gain during the hottest part of the day.
Some skylights have expensive glazing that partially reduces summer solar heat gain, while still allowing some visible light transmission.
However, if visible light can pass through it, so can some radiant heat gain (they are both electromagnetic radiation waves.
You can partially reduce some of the unwanted roof-angled-glazing summer solar heat gain by installing a skylight in the shade
of deciduous (leaf-shedding) trees, or by adding a movable insulated opaque window covering on the inside or outside of the skylight. This
would eliminate the daylight benefit in the summer. If tree limbs hang over a roof, they will increase problems with leaves in rain gutters,
possibly cause roof-damaging ice dams, shorten roof life, and provide an easier path for pests to enter your attic. Leaves and twigs on
skylights are unappealing, difficult to clean, and can increase the glazing breakage risk in wind storms.
"Sawtooth roof glazing" with vertical-glass-only can bring some of the passive solar building design benefits into the core of a commercial or
industrial building, without the need for any roof-angled glass or skylights.
Skylights provide daylight. The only view they provide is essentially straight up in most applications. Well-insulated light tubes can bring
daylight into northern rooms, without using a skylight. A passive-solar greenhouse provides abundant daylight for the equator-side of the
building.
Infrared thermography color thermal imaging cameras ( used in formal energy audits ) can quickly document the negative thermal impact of
roof-angled glass or a skylight on a cold winter night or hot summer day.
The U.S. Department of Energy states: "vertical glazing is the overall best option for sunspaces."
[26]
Roof-angled glass and sidewall glass are
not recommended for passive solar sunspaces.
The U.S. DOE explains drawbacks to roof-angled glazing: Glass and plastic have little structural strength. When installed vertically, glass (or
plastic) bears its own weight because only a small area (the top edge of the glazing) is subject to gravity. As the glass tilts off the vertical
axis, however, an increased area (now the sloped cross-section) of the glazing has to bear the force of gravity. Glass is also brittle; it does
not flex much before breaking. To counteract this, you usually must increase the thickness of the glazing or increase the number of structural
supports to hold the glazing. Both increase overall cost, and the latter will reduce the amount of solar gain into the sunspace.
Another common problem with sloped glazing is its increased exposure to the weather. It is difficult to maintain a good seal on roof-angled
glass in intense sunlight. Hail, sleet, snow, and wind may cause material failure. For occupant safety, regulatory agencies usually require
sloped glass to be made of safety glass, laminated, or a combination thereof, which reduce solar gain potential. Most of the roof-angled glass
on the Crowne Plaza Hotel Orlando Airport sunspace was destroyed in a single windstorm. Roof-angled glass increases construction cost,
and can increase insurance premiums. Vertical glass is less susceptible to weather damage than roof-angled glass.
It is difficult to control solar heat gain in a sunspace with sloped glazing during the summer and even during the middle of a mild and sunny
winter day. Skylights are the antithesis of zero energy building Passive Solar Cooling in climates with an air conditioning requirement.
Angle of incident radiation[edit]
The amount of solar gain transmitted through glass is also affected by the angle of the incident solar radiation. Sunlight striking glass within
20 degrees of perpendicular is mostly transmitted through the glass, whereas sunlight at more than 35 degrees from perpendicular is
mostly reflected
[27]

All of these factors can be modeled more precisely with a photographic light meter and a heliodon or optical bench, which can quantify the
ratio of reflectivity to transmissivity, based on angle of incidence.
Alternatively, passive solar computer software can determine the impact of sun path, and cooling-and-heating degree
days on energy performance. Regional climatic conditions are often available from local weather services.
Operable shading and insulation devices[edit]
A design with too much equator-facing glass can result in excessive winter, spring, or fall day heating, uncomfortably bright living spaces at
certain times of the year, and excessive heat transfer on winter nights and summer days.
Although the sun is at the same altitude 6-weeks before and after the solstice, the heating and cooling requirements before and after the
solstice are significantly different. Heat storage on the Earth's surface causes "thermal lag." Variable cloud cover influences solar gain
potential. This means that latitude-specific fixed window overhangs, while important, are not a complete seasonal solar gain control solution.
Control mechanisms (such as manual-or-motorized interior insulated drapes, shutters, exterior roll-down shade screens, or retractable
awnings) can compensate for differences caused by thermal lag or cloud cover, and help control daily / hourly solar gain requirement
variations.
Home automation systems that monitor temperature, sunlight, time of day, and room occupancy can precisely control motorized window-
shading-and-insulation devices.
Exterior colors reflecting - absorbing[edit]
Materials and colors can be chosen to reflect or absorb solar thermal energy. Using information on a Color for electromagnetic radiation to
determine its thermal radiation properties of reflection or absorption can assist the choices.
See Lawrence Berkeley National Laboratory and Oak Ridge National Laboratory: "Cool Colors"
Landscaping and gardens[edit]
Main article: Energy-efficient landscaping
Energy-efficient landscaping materials for careful passive solar choices include hardscape building material and "softscape" plants. The use
of landscape design principles for selection of trees,hedges, and trellis-pergola features with vines; all can be used to create summer
shading. For winter solar gain it is desirable to use deciduous plants that drop their leaves in the autumn gives year round passive solar
benefits. Non-deciduous evergreen shrubs and trees can be windbreaks, at variable heights and distances, to create protection and shelter
from winter wind chill.Xeriscaping with 'mature size appropriate' native species of-and drought tolerant plants, drip irrigation, mulching,
and organic gardening practices reduce or eliminate the need for energy-and-water-intensive irrigation, gas powered garden equipment, and
reduces the landfill waste footprint. Solar powered landscape lighting and fountain pumps, and covered swimming pools and plunge
pools with solar water heaters can reduce the impact of such amenities.
 Sustainable gardening
 Sustainable landscaping
 Sustainable landscape architecture
Other passive solar principles[edit]
Passive solar lighting[edit]
Main article: Passive solar lighting
Passive solar lighting techniques enhance taking advantage of natural illumination for interiors, and so reduce reliance on artificial lighting
systems.
This can be achieved by careful building design, orientation, and placement of window sections to collect light. Other creative solutions
involve the use of reflecting surfaces to admit daylight into the interior of a building. Window sections should be adequately sized, and to
avoid over-illumination can be shielded with a Brise soleil, awnings, well placed trees, glass coatings, and other passive and active
devices.
[19]

Another major issue for many window systems is that they can be potentially vulnerable sites of excessive thermal gain or heat loss. Whilst
high mounted clerestory window and traditionalskylights can introduce daylight in poorly oriented sections of a building, unwanted heat
transfer may be hard to control.
[28][29]
Thus, energy that is saved by reducing artificial lighting is often more than offset by the energy required
for operating HVAC systems to maintain thermal comfort.
Various methods can be employed to address this including but not limited to window coverings, insulated glazing and novel materials such
as aerogel semi-transparent insulation, optical fiberembedded in walls or roof, or hybrid solar lighting at Oak Ridge National Laboratory.
Interior reflecting[edit]
Reflecting elements, from active and passive daylighting collectors, such as light shelves, lighter wall and floor colors, mirrored wall sections,
interior walls with upper glass panels, and clear or translucent glassed hinged doors and sliding glass doors take the captured light and
passively reflect it further inside. The light can be from passive windows or skylights and solar light tubes or from active daylighting sources.
In traditional Japanese architecture the Shōji sliding panel doors, with translucent Washi screens, are an original precedent. International
style, Modernist andMid-century modern architecture were earlier innovators of this passive penetration and reflection in industrial,
commercial, and residential applications.
Passive solar water heating[edit]
Main article: Solar hot water
There are many ways to use solar thermal energy to heat water for domestic use. Different active-and-passive solar hot water technologies
have different location-specific economic cost benefit analysis implications.
Fundamental passive solar hot water heating involves no pumps or anything electrical. It is very cost effective in climates that do not have
lengthy sub-freezing, or very-cloudy, weather conditions. Other active solar water heating technologies, etc. may be more appropriate for
some locations.
It is possible to have active solar hot water which is also capable of being "off grid" and qualifies as sustainable. This is done by the use of a
photovoltaic cell which uses energy from the sun to power the pumps.
[citation needed]

Comparison to the Passive House standard in Europe[edit]
Main article: Passive house
There is growing momentum in Europe for the approach espoused by the Passive House (Passivhaus in German) Institute in Germany.
Rather than relying solely on traditional passive solar design techniques, this approach seeks to make use of all passive sources of heat,
minimises energy usage, and emphasises the need for high levels of insulation reinforced by meticulous attention to detail in order to
address thermal bridging and cold air infiltration. Most of the buildings built to the Passive House standard also incorporate an active heat
recovery ventilation unit with or without a small (typically 1 kW) incorporated heating component.
The energy design of Passive House buildings is developed using a spreadsheet-based modeling tool called the Passive House Planning
Package (PHPP) which is updated periodically. The current version is PHPP2007, where 2007 is the year of issue. A building may be
certified as a 'Passive House' when it can be shown that it meets certain criteria, the most important being that the annual specific heat
demand for the house should not exceed 15kWh/m
2
a.
Design tools[edit]
Traditionally a heliodon was used to simulate the altitude and azimuth of the sun shining on a model building at any time of any day of the
year.
[30]
In modern times, computer programs can model this phenomenon and integrate local climate data (including site impacts such
as overshadowing and physical obstructions) to predict the solar gain potential for a particular building design over the course of a
year. GPS-based smartphone applications can now do this inexpensively on a hand held device. These tools provide the passive solar
designer the ability to evaluate local conditions, design elements and orientation prior to construction. Energy performance optimization
normally requires an iterative-refinement design-and-evaluate process. There is no such thing as a "one-size-fits-all" universal passive solar
building design that would work well in all locations.
Levels of application[edit]
Pragmatic[edit]
Many detached suburban houses can achieve reductions in heating expense without obvious changes to their appearance, comfort or
usability.
[31]
This is done using good siting and window positioning, small amounts of thermal mass, with good-but-conventional insulation,
weatherization, and an occasional supplementary heat source, such as a central radiator connected to a (solar) water heater. Sunrays may
fall on a wall during the daytime and raise the temperature of its thermal mass. This will then radiate heat into the building in the evening.
This can be a problem in the summer, especially on western walls in areas with high degree day cooling requirements. External shading, or a
radiant barrier plus air gap, may be used to reduce undesirable summer solar gain.
Annualised[edit]
An extension of the "passive solar" approach to seasonal solar capture and storage of heat and cooling. These designs attempt to capture
warm-season solar heat, and convey it to a seasonal thermal store for use months later during the cold season ("annualised passive solar.")
Increased storage is achieved by employing large amounts of thermal mass or earth coupling. Anecdotal reports suggest they can be
effective but no formal study has been conducted to demonstrate their superiority. The approach also can move cooling into the warm
season.
Examples:
 Passive Annual Heat Storage (PAHS) - by John Hait
 Annualized Geothermal Solar (AGS) heating - by Don Stephen
 Earthed-roof
Minimum machinery[edit]
A "purely passive" solar-heated house would have no mechanical furnace unit, relying instead on energy captured from sunshine, only
supplemented by "incidental" heat energy given off by lights, computers, and other task-specific appliances (such as those for cooking,
entertainment, etc.), showering, people and pets. The use of natural convection air currents (rather than mechanical devices such as fans) to
circulate air is related, though not strictly solar design.
Passive solar building design sometimes uses limited electrical and mechanical controls to operate dampers, insulating shutters, shades,
awnings, or reflectors. Some systems enlist small fans or solar-heated chimneys to improve convective air-flow. A reasonable way to analyse
these systems is by measuring their coefficient of performance. A heat pump might use 1 J for every 4 J it delivers giving a COP of 4. A
system that only uses a 30 W fan to more-evenly distribute 10 kW of solar heat through an entire house would have a COP of 300.
Zero Energy Building[edit]
Passive solar building design is often a foundational element of a cost-effective zero energy building.
[32][33]
Although a ZEB uses multiple
passive solar building design concepts, a ZEB is usually not purely passive, having active mechanical renewable energy generation systems
such as: wind turbine, photovoltaics, micro hydro, geothermal, and other emerging alternative energy sources.
See also[edit]

Renewableenergy portal

Energy portal

Sustainabledevelopment portal
 Architecture 2030
 Daylighting
 Energy plus house
 List of low-energy building techniques
 List of pioneering solar buildings
 Low energy building
 Low-energy house
 Earthship
 PlusEnergy
 Solar architecture
 The 2010 Imperative
Energy Rating systems
 House Energy Rating (Aust.)
 Home energy rating (USA)
 EnerGuide (Canada)
 National Home Energy Rating (UK)
References[edit]
1. Jump up^ Doerr, Thomas (2012). Passive Solar Simplified (1st ed.). Retrieved October 24,
2012.
2. Jump up^ "U.S. Department of Energy - Energy Efficiency and Renewable Energy - Passive
Solar Building Design". Retrieved 2011-03-27.
3. Jump up^ "U.S. Department of Energy - Energy Efficiency and Renewable Energy - Energy
Plus Energy Simulation Software". Retrieved 2011-03-27.
4. ^ Jump up to:
a

b
"Rating tools". Archived from the original on September 30, 2007. Retrieved
2011-11-03.
5. Jump up^ http://www.srrb.noaa.gov/highlights/sunrise/fig5_40n.gif
6. Jump up^ http://www.srrb.noaa.gov/highlights/sunrise/fig5_0n.gif
7. Jump up^ http://www.srrb.noaa.gov/highlights/sunrise/fig5_90n.gif
8. ^ Jump up to:
a

b
Your Home - Orientation
9. ^ Jump up to:
a

b
Your Home - Insulation
10. Jump up^ "BERC - Airtightness". Ornl.gov. 2004-05-26. Retrieved 2010-03-16.
11. Jump up^ Your Home - Passive Cooling
12. Jump up^ "EERE Radiant Barriers". Eere.energy.gov. 2009-05-28. Retrieved 2010-03-16.
13. ^ Jump up to:
a

b

c

d
"Glazing". Archived from the original on December 15, 2007. Retrieved
2011-11-03.
14. Jump up^ Springer, John L. (December 1954). "The 'Big Piece' Way to Build". Popular
Science 165 (6): 157.
15. Jump up^ Your Home - Shading
16. Jump up^ Your Home - Thermal Mass
17. Jump up^ "Introductory Passive Solar Energy Technology Overview". U.S. DOE - ORNL
Passive Solar Workshop. Retrieved 2007-12-23.
18. Jump up^ "Passive Solar Design". New Mexico Solar Association.
19. ^ Jump up to:
a

b
Chiras, D. The Solar House: Passive Heating and Cooling. Chelsea Green
Publishing Company; 2002.
20. Jump up^ "Zero Energy Buildings". Fsec.ucf.edu. Retrieved 2010-03-16.
21. Jump up^ "Two Small Delta Ts Are Better Than One Large Delta T". Zero Energy Design.
Retrieved 2007-12-23.
22. Jump up^ Earthships
23. Jump up^ Annualized Geo-Solar Heating, Don Stephens- Accessed 2009-02-05
24. Jump up^ Shurcliff, William A.. Thermal Shutters & Shades - Over 100 Schemes for Reducing
Heat Loss through Windows 1980. ISBN 0-931790-14-X.
25. Jump up^ "Florida Solar Energy Center - Skylights". Retrieved 2011-03-29.
26. Jump up^ "U.S. Department of Energy - Energy Efficiency and Renewable Energy - Sunspace
Orientation and Glazing Angles". Retrieved 2011-03-28.
27. Jump up^ "Solar Heat Gain Through Glass". Irc.nrc-cnrc.gc.ca. 2010-03-08. Retrieved 2010-
03-16.
28. Jump up^ "[ARCHIVED CONTENT] Insulating and heating your home efficiently : Directgov -
Environment and greener living". Direct.gov.uk. Retrieved 2010-03-16.
29. Jump up^ "Reduce Your Heating Bills This Winter - Overlooked Sources of Heat Loss in the
Home". Allwoodwork.com. 2003-02-14. Retrieved 2010-03-16.
30. Jump up^ [1]
[dead link]

31. Jump up^ "Industrial Technologies Program: Industrial Distributed Energy". Eere.energy.gov.
Retrieved 2010-03-16.
32. Jump up^ "Cold-Climate Case Study for Affordable Zero Energy Homes: Preprint" (PDF).
Retrieved 2010-03-16.
33. Jump up^ "Zero Energy Homes: A Brief Primer" (PDF). Retrieved 2010-03-16.
External links[edit]
 www.solarbuildings.ca - Canadian Solar Buildings Research Network
 www.eere.energy.gov - US Department of Energy (DOE) Guidelines
 www.climatechange.gov.au - Australian Dept of Climate Change and Energy Efficiency
 www.ornl.gov - Oak Ridge National Laboratory (ORNL) Building Technology
 www.FSEC.UCF.edu - Florida Solar Energy Center
 www.ZeroEnergyDesign.com - 28 Years of Passive Solar Building Design
 [2] - Prefabricated Passive Solar Home Kits
 Passive Solar Design Guidelines
 http://www.solaroof.org/wiki
 www.PassiveSolarEnergy.info - Passive Solar Energy Technology Overview
 www.yourhome.gov.au/technical/index.html - Your Home Technical Manual developed by the
Commonwealth of Australia to provide information about how to design, build and live in
environmentally sustainable homes.
 amergin.tippinst.ie/downloadsEnergyArchhtml.html- Energy in Architecture, The European
Passive Solar Handbook, Goulding J.R, Owen Lewis J, Steemers Theo C, Sponsored by the
European Commission, published by Batsford 1986, reprinted 1993
[show]Error: Page does not exist
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o Controlling temperature with passive design: an introduction
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Passive Design
Designing the building and the spaces within it to benefit from natural light, ventilation and even temperatures.

o
o


Passive Design
Passive design is the key to sustainable building.
It responds to local climate and site conditions to maximise building users’ comfort and health while minimising energy use.
It achieves this by using free, renewable sources of energy such as sun and wind to provide household heating, cooling, ventilation and
lighting, thereby reducing or removing the need for mechanical heating or cooling. Using passive design can reduce temperature fluctuations,
improve indoor air quality and make a home drier and more enjoyable to live in.
It can also reduce energy use and environmental impacts such as greenhouse gas emissions.
Interest in passive design has grown, particularly in the last decade or so, as part of a movement towards more comfortable and resource-
efficient buildings.
Key features of passive design
The key elements of passive design are: building location and orientation on the site; building layout; window design; insulation (including
window insulation); thermal mass; shading; and ventilation. Each of these elements works with others to achieve comfortable temperatures
and good indoor air quality.
The first step is to achieve the right amount of solar access – enough to provide warmth during cooler months but prevent overheating in
summer. This is done through a combination of location and orientation, room layout, window design and shading.
Insulation and thermal mass help to maintain even temperatures, while ventilation provides passive cooling as well as improving indoor air
quality.
All of these elements work alongside each other and therefore should be considered holistically. For example, large windows that admit high
levels of natural light might also result in excessive heat gain, especially if they cast light on an area of thermal mass. Similarly, opening
windows that provide ventilation will also let in noise.
Alongside passive design features, designers should also consider other factors such as views, covenants and local authority restrictions, and
building owners’ preferences.
Passive design in new and existing buildings
It costs little or nothing to incorporate passive design into a new building. The benefits are greatest when passive design principles are
incorporated into the entire design and build process, from site selection onwards.
Once a building is completed, some passive design features can be incorporated during later upgrades – for example, insulation can be
improved, and it may be possible to alter room layout to improve orientation and solar access.
But it may be difficult to achieve the full benefits. For example, it will not be practical to turn a completed house around on the site to take
better advantage of sun or cooling breezes.

Controlling temperature with passive design: an introduction

Location, orientation and layout

Insulation

Thermal mass

Shading

Ventilation

Daylighting

Glazing and glazing units

Controlling indoor air quality

Controlling noise

Climate change
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5. Acoustical Properties of Building Materials
Acoustical Properties of Building Materials
By Jagg Xaxx, eHow Contributor
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Wood is a building material that absorbs sound.
It's common to consider the durability, cost and aesthetic appeal of building materials when building a new home,
but builders and homeowners often neglect acoustics. A beautiful home can become a headache if sound carries
through it too easily, or if every sound has an echo. You can control the acoustics of your new home to some extent
by considering what materials to use during the design process. Have a question? Get an answer from a Handyman now!
Other People Are Reading
 Acoustic Properties of Materials
 List of Acoustic Materials
1. Principles
o Vibrations in the air and in materials carry sound through a room. When these vibrations hit a flat, hard surface, they
rebound into the room, causing an echo. When sound waves hit a surface that is susceptible to vibration, the material
in the wall transfers the sound into the next room rather than stopping or reflecting it. Thus, a solid concrete room
will be prone to echoes while a room framed with wood and sheathed with drywall will not be soundproof. Providing
an absorbent, roughly textured surface such as a wall full of books decreases both sound transfer and echoes.
Materials
o Concrete is very effective at reducing sound transfer from one room to another, but will create echoes within a room if
left in its natural state. Wood reduces both sound transfer and echoing, unless it is installed in large, flat walls with
nothing breaking it up. You can make a hardwood floor more acoustically pleasing by placing a thick wool carpet in
the middle to absorb ambient sound. Wool and other carpets, soft and upholstered furniture and textile wall hangings
all contribute to an aurally pleasing environment.
o
Echoes
o Most people have had the experience of walking through a brand new house with nothing in it and listening to the
strange echoes. In a lived-in house, the shapes, materials and surfaces break up sound waves and create an
environment in which vibrations can't bounce back and forth, which is why you don't hear echoes in your home. If
you have large rooms that feature concrete walls, concrete floors and concrete ceiling surfaces and very few
possessions, then you may notice echoes.
Soundproofing
o Some types of wall insulation are made specifically for soundproofing. These acoustic batts are installed inside of
framed walls in the same way as heat insulation, but are designed to dampen sound vibrations. You can further
soundproof walls by sheathing them with plywood and screwing drywall over the plywood. This greatly reduces the
vibrational characteristics of the drywall and eliminates sound passing from one room to another. For a truly
soundproofed room, build a double row of studs with insulation in between them. Most sound that passes between
rooms is carried through the wall studs.
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Acoustical properties of building materials
APRIL 03, 2013 SAJAN NO COMMENTS
Acoustical properties of building materials
Sound – it is anything that can be heard. In other words, it is the sensation caused by a vibrating medium acting on the air. Source
of sound is most often vibrating solid body. The medium conveying sound to ear can be gas, liquid or solid. It is transmitted as the
longitudinal wave motion. i.e. successive compression- rarefaction of molecules. In solid body, the transmission is by lateral motion.
Wave length determines pitch of sound. Higher the frequency, higher would be pitch. Frequency is the waves per unit time. Sound is
the product of frequency and wave length. Loudness depends on distance from vibrating body.
Ranges of hearing frequency are 20 Hz to 20 kHz.
1. Infra sound –frequency less than 20 Hz
2. Audible sound – frequency ranges between 20 Hz t- 20kHz
3. Ultra sound – frequency greater than 20 kHz

 Reactions produce by sound
1. Reflections – from walls, floors, ceiling etc.
2. Absorption – by floors, by ceiling, by furniture etc.
3. Transmission – to adjacent room
 Sound classification
1. Air borne sound – sound through air to air.
2. Impact of structure borne sound – sound through direct contact, such as footsteps, hammering or vibration etc. it is very sharp
and troublesome.
Acoustics
Acoustic is the science of sound
It assures the optimum conditions for producing and listening to speech and music
The panning of acoustical design has to provide for dissipation of noise and insulation against sound
Noise and its effect
1. Annoyance- irritation
2. Disturbance of sleep
3. Interface of disturbing conversation
4. Damage of ear
Measurement of annoyance is subjective attitude and depends upon with mental and physical well being of listeners with their
experience
 Magnitude of noise level
Types of
sounds
Noise
level (dB)
Effects
Light road
trafficMedium
road
trafficsHeavy
road
trafficsRail
trafficsAir
traffics
60-7070-
8080-
9090-
100>130
 Physiological effect
(annoyance)
 Physiological effect
(annoyance)
 Prolonged exposure
causes permanent
hearing loss
 Prolonged exposure
causes damage to
auditory organ
 Causes pain
 Instantaneous loss of
hearing

 Defects due to reflected sound
1. Echoes
2. Reverberation
Echo is the reflected sound and heard just after the produced as a repetition
Reverberation is the continuous reflection of produced sound waves (reflection, inter-reflection etc) until they are gradually faded out
Certain amount of reverberation is necessary to enhance the sound, but excessive is damaging to clarity.
 Reverberation time
It is the time taken for sound energy to decay by below annoyance level (60dB) after the sound source has stopped. It depends on,
volume of room, absorption in walls roofs and floors etc. it has to be minimized using sound absorbing materials.
 Sound insulation
1. Sound absorption (prevention of reflection)
2. Sound insulation (prevention of transmission)
 Sound absorbents
1. Porous materials
2. Resonant panel
3. Cavity resonators
4. Composite types
In porous materials, the sound waves on striking its surface enter to the pores, vibrate inside and die-out there. Normally these
materials are soft and have large pores with interconnected channels.
Resonant panels are semi-hard in the form of porous fiber boards that acts as sound absorbent. These boards are fixed on timber
frame with air gap between and also with wall backing. In the resonant panels, the sound pressure waves cause vibration and this
vibration is absorbed by air gap (space) called damping. Porous materials may also be put in the gap between boards. It is suitable
for low frequency waves.
Cavity resonators are the chambers with the narrow openings. The absorption of sound takes place in the case by the resonance of
air.
Composite types are the perforated panels fixed with air space containing porous absorbents. The panels may be of metal, plywood,
hard board, plaster board etc. the perforation should be at least 10 percent of area high frequency sounds are absorbed in this
perforated panel.

Acoustic insulation materials
Incoming search terms:
 Porous absorbents in buildings
 sound properties of building materials

Posted in: 2nd Semester, B.E Civil, Building Construction, Notes Tags: Acoustical,Building, materials, of, Properties
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Noise control and constructional precautions to reduce noise
APRIL 05, 2013 SAJAN NO COMMENTS
The Noise control and constructional precautions to reduce noise are as follows :-
 General consideration
1. Isolate sound source
2. Proper orientation of building , i.e. no opening towards noise
3. Properly planned rooms in building
4. Furnishing materials in room helps sound absorption
5. Partitions – Ridge and Movable
6. Control of impact sound i.e. sue of resilient materials as carpets in floor
7. Discontinuing the path of vibration by using sound absorbing materials
8. Use of headphones and air plugs in case of high sound.
 Construction materials
1. Wall partitions
Absorbents in the Wall partitions act as the barriers to air borne sound transmission
Types
 Rigid and homogeneous partitions
Insulation in this case depends on the weight of the partition per unit area and increases with thickness.
Following table illustrates the insulation properties for different walls.
S.
No.
Types of wall Approx.
wt. of
wall
kg/m²
Average
sound
reduction dB
1. One brick wall
plastered in both
side
490 50
2. One and half brick
wall plastered in
both side
710 53
3. Cavity (50mm) with
half brick in both
leaves
490 50-53
4. Half brick or
concrete with
plaster both side
170 45
5. 200 mm concrete
wall
185 45
6. Gypsum board
partition on timber
frame
70 45
7. 75mm hollow clay
block with plaster
both side
36

Hard reflecting surface outside partition increases insulation
 Partition of porous material
Insulation increase to 10% or higher
Material may be rigid or flexible
 Hollow and composite partition
Cavity is better
Filling of cavity with resilient material is preferred
2. Floors/Ceilings
There is the horizontal barrier to noise
They act as barrier to airborne an impact sound, but offer poor insulation for structure borne or impact sounds or insulation in floor,
resilient surface materials, and floating floors.
 Resilient surface materials on floors
Cotton, wooden, carpets, asphalt mastic’s, PVC carpets, corks, etc.
Softer the material used greater would be the insulation value
 Floating floor construction
Provides insulation from any other parts of structure
It is made to rest on float over existing floor by means of resilient materials such as, glass, wool, quilt, hair felt, cork rubber, etc.
Impact sound do not transmits.
On concrete floor, partition is constructed off the structural floor and it is independent
Types of floating floors
 Concrete floor with floating concrete screed: it is the PCC of 1:1-5:3 on resilient materials above concrete floor.
 Concrete floor with floating wooden raft: it is wooden nailed to battens forming raft on resilient quilt (20mm)
 Heavy concrete floor with soft floor (resilient) finish or covering

 Wooden floors
It has the problem of impact sound
3. Windows and doors
It should be
- Air tight
- Double glazed
- Thickness of glass to be increased
- Increase weight of shutter
4. Insulating sanitary fitting
- WC be insulated, pan to rest upon thin pad of felt, cork, rubber, etc.
- Cisterns not on wall of bed rooms, brackets be fixed with insulating materials (clips)
5. Machine mounting and insulation of machinery
Machine resting on resilient materials as steel spring, rubber, corks, etc.
Brush holders is a spring is typically used with the brush, to maintain constant contact with the commutator. As the brush and
commutator wear down, the spring steadily pushes the brush downwards towards the commutator. Eventually the brush wears small
and thin enough that steady contact is no longer possible or it is no longer securely held in the brush holder, and so the brush must
be replaced.

Active Noise Controller
Incoming search terms:
 NOISE PRECAUTIONS
 pvc floor

Posted in: 2nd Semester, B.E Civil, Building Construction, Notes Tags: and,constructional, Control, Noise, precautions, reduce, to
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DECEMBER 2013
S M T W T F S
« Jul
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8 9 10 11 12 13 14
15 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31
 RECENT POSTS
o Radial and Transverse component
o Curvilinear Motion of Particle
o Rectilinear Motion of Particle
o Nichol Prism
o Letter Proposal
o Brewster’s Law of Polarization of Light
o Diffraction through double slit
o Diffraction through single slit
o Diffraction And Its Types
o Jesus Christ
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