Army Sustainability Workshop
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P R ES E N T E D BY L E BA N O N G R E E N B U I L D I N G CO U N C I L ( LG B C )
NOVEMBER 12 – 13 – 19 DECEMBER 1 & 8 Presenter
Mr. Pierre Geara
Mr Pierre Geara
Acoustic Consultant President of the 5th branch at Order of Engineering & Architectural of building. Environmental Noise
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World Health Organization stated that “Noise
World Health Organization stated that Noise must be recognized as a major threat to human well being
must be recognized as a major threat to human well being” What Is Environmental Noise?
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Environmental noise is the summary of noise pollution from outside, transport (i.e traffic planes, trains),
planes trains) construction, industrial
construction industrial and recreational activities.
activities
Noise is frequently described as 'unwanted Sound', and, within this context, environmental noise is generally present in some form in all areas of human activity. i i
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The effects in humans of exposure to environmental noise may vary from emotional to physiological and psychological.
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Sources of noise?
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Comparison of noise (dB) f
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Health Effects From Noise l h ff
Noise pollution is one of the most prevalent sources of environmental complaints in European Union (EU). Especially in densely populated urban areas and residential areas near highways, Union (EU) Especially in densely populated urban areas and residential areas near highways
and Airports…
 According to studies made by W.H.O
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Europeans are exposed to excessive road traffic noise.
 EU cities with population over 250,000 are exposed to harmful annual average noise levels EU i i
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250 000
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(beyond 55 dB during the day and night).
Health Effects From Noise l h ff
Exposure to consistent elevated sound levels can cause hearing impairment, hypertension, heart disease, annoyance, and sleep disturbance.
heart disease annoyance and sleep disturbance
Furthermore, high levels of noise can create stress, increase workplace accidents rates, simulate aggression and other anti‐social behavior.
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The most significant causes are vehicle noise sources, aircraft noise, construction projects, i d
industrial noise, and prolonged exposer to loud music.
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What causes traffic noise?
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The level of traffic noise depends on three things:
 Traffic volumes ‐ Roads with more vehicles are generally louder. Traffic speeds Traffic is louder at higher speeds.
Traffic speeds ‐
Traffic is louder at higher speeds
Percent of heavy trucks on the road ‐ Heavy trucks (e.g., semi‐trucks) What causes traffic noise?
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Traffic noise is a combination of the noises generally produced by:  Vehicle engines, exhaust, and tires.
Traffic noise is also increased by defective mufflers or other faulty equipment. (i.e. Electrical Traffic
noise is also increased by defective mufflers or other faulty equipment (i e Electrical
generators)
How to reduce
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traffic noise?
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Motor vehicle controls, including tire tread designs.
improvements in engine and breaking technologies ‐ cars, buses, and trucks are quieter. Alternative energy advancements are helping to significantly reduce engine noise levels.
 Highway planning and design including the use of newly available quieter asphalts that have Highway planning and design including the use of newly available quieter asphalts that have
the ability to reduce levels by up to 5dB.
 Noise barriers are walls constructed between homes and a roadway to reduce traffic noise y
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levels. barriers can reduce noise levels by 10 to 15 decibels, cutting the loudness of traffic noise in half.
Air plane noise
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What causes air plane noise?
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Different aircraft types have different noise levels and frequencies.
The primary sources of airframe noise are the landing gear and high‐lift devices such as wing flaps and slats.
landing, noise generated by a commercial aircraft airframe is as loud, or even louder, than propulsion noise.
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Aircraft gas turbine engines (jet engines) are responsible for much of the aircraft noise during takeoff and climb, such as the buzz saw noise generated when the tips of the fan blades reach supersonic speeds.
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Aerodynamic noise arises from the airflow around the aircraft fuselage and control surfaces. This type of noise increases with aircraft speed and also at low altitudes due to the density of the air. Air plane noise reduction
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A successful method of reducing noise further, even in ultra‐high bypass ratio engines, is to absorb sound created within the engine. absorb sound created within the engine
Acoustically absorbent material or acoustic ‘liners’ can be placed on the interior surfaces (i.e. the walls of the intakes and bypass ducts).
 Future airplanes will be built with a lighter carbon fiber fuselage and will be powered by new F t
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quieter engines.
Aircraft today are 20‐30dB quieter than first generation of jet aircraft, such as the Boeing 707 and Comet.
Airborne noise between dwellings
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Airborne sound between dwellings
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Airborne Noise, is a sound that reaches a point in a building by propagation from the source through air.
through air
Typically, airborne sound might be generated by:
 Speech.
Television and radio.
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Animal sounds such as dogs barking.
Transport. Sound Insulation d
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Sound insulation materials are used to minimize the transmission of airborne (e.g. from one room to another via sound insulating wall.
room to another via sound insulating wall
Good sound insulating materials are dense heavy materials such as masonry (Brickwork, concrete) and sheet metals. Such materials have a high mass per unit area.
Sound insulating materials are used as noise screens and barriers (e.g. along side roads, as S
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partition walls, floors and ceiling. Minimizing sound transmission between rooms and as enclosures to around noisy machines.
Impact noise between dwellings
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Impact sound (or impact noise) is a form of structure‐borne sound that occurs when an object impacts on another, resulting in the generation and transmission of sound. impacts on another resulting in the generation and transmission of sound
The structural vibration caused by the impact results in sound being radiated from an adjacent vibrating surface.
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A typical example of an impact sound is footsteps on a floor resulting in sound being transmitted through the floor construction and heard in the space below. i d h
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Impact noise can be reduced
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Resilient underlay – can have a similar effect to carpets and pads. Generally, they are made from recycled rubber, rigid fiberglass, foam or other such materials.
from recycled rubber rigid fiberglass foam or other such materials
Resilient mounts – hanging resilient mounts, sound clips or spring ceiling hangers can reduce th t
the transmission of impact sound. i i
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A suspended ceiling system or raised floors can be used to improve impact sound insulation.
Reverberation in buildings
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Reverberation in buildings
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Reverberation is the persistence of sound in a space after a sound source has been stopped. Reverberation time is the time, in seconds, taken for the sound to decay by 60dB after a sound Reverberation time is the time in seconds taken for the sound to decay by 60dB after a sound
source has been stopped.
 The reverberation time of a room is linked to the surfaces that enclose it and the volume of the room.
Speech intelligibility is also a function of reverberation, a high reverberation time causes speech to sound muffled and muddy. Rooms designed for speech therefore typically have a low reverberation time: ≤1 second. A high reverberation time can enhance a music hall by adding richness, depth and warmth to music. A higher level of reverberation within a concert hall is therefore critical. Reverberation time reduction
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Sound Absorption d b
Sound absorption materials are used to minimize reflection of airborne sound by converting sound energy to heat through some frictional process in the absorber.
sound energy to heat through some frictional process in the absorber
Common materials for absorption:
Porous materials such as open‐celled polymer foams
Fibrous materials such as slabs of mineral fiber. Commonly applied to walls and ceilings to improve their absorbing properties.
Please contact CEDRO at:
Thank you
Thank you T/F: +961‐1‐981944
E: info@cedro‐undp.org
www.cedro‐undp.org
Beirut, Maarad Street, Building 287B, 1st floor
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