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An Experiment On Effectiveness of different materials on sound insulation<br />CC2007 Environmental Science (Group Presentation)<br />Group Members:<br /><ul><li>Wong Wai Sum , Sum (09081555A)

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Li Hong Bin , Ben (10034164A)

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LukWai Man , Ray (10094530A)

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Lau CheokHei, Jeff (09090889A)

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KanKaHim , Ken (10022177A)</li></li></ul><li>Content<br />Background Introduction<br />Experiment Objective<br />Experiment Procedure<br />Result <br />Analysis<br />Further development<br />Q & A<br />

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What is noise?<br />Noise can be a very Loud sound<br />Low-level sound but annoying<br />

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Loud Noise in Hong Kong<br />The main concern of noise :Traffic Noise<br />It affects more than one million people<br />655 roads generate noise greater than 70 dB<br /> But only 101 of these roads applied barriers<br />

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What can we do personally?<br />Choose some good sound insulating materials to build your flat.<br />Today, we are going to test which materials (commonly seen in our daily lives) are good at insulating sound !<br />

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Sound Insulation Experiment<br />Objective <br />To compare the sound insulation ‘s effectiveness of different materials under different frequencies in term of Sound Reduction Index(R) and Transmitted coefficient (T).<br />

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Materials to be tested…<br />(1)the Expandable Polystyrene (EPS) foam<br />(2)stainless steel<br />(3)wood<br />(4)A4 paper<br />

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What is sound??<br />Sound is a mechanical wave <br /><ul><li>also a kind of longitudinal wave which does not have Polarization(偏震)</li></ul>produced by vibrations of objects<br />require medium for propagation<br /> example: air, water<br />cannot travel in vacuum<br />

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Where the sound from?<br />Can be found easily in our daily life<br />For example,<br />Musical instrument<br />Car<br />Talking<br />Aircraft take-off<br />

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Sound Insulation<br />Insulate the sound we don’t want to hear<br />The ability for the material to reduce the sound energy transmitted into an adjoining air space.<br />Type of sound insulation:<br />Airborne Sound Insulation<br />Impact Sound Insulation<br />

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Airborne Sound Insulation<br />the insulation against noise originating in air, e.g. voices, music, motor traffic, wind.<br />Impact Sound Insulation<br />the insulation against noise originating directly on a structure by blows or vibration <br />

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Insulated the sound by mean of …<br />reflection<br />absorption<br />Sound would reflect at the surface of material so that only a part of sound energy will be transmitted. <br />Also, material will absorbs the sound energy and dissipates in form of heat making the reduction of transmission of sound.<br />result in reduction in sound level<br />

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Decibel meter<br />using a decibel meter, we can measure the sound level (in dB) of different sound source. <br />sound level (L)<br /> L = 10 log10 [ I/I0 ]…………………(1)<br />sound reduction index (R):<br /> R = 10 log10 [ 1 / T ] (dB)…………(2)<br /> T: Transmitted sound energy / Incident sound energy<br />

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Sound Insulation Experiment<br />Apparatus:<br />

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<ul><li>Dimension of the shoe box = 29cm x 19cm x11cm = 6061cm3

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Area of the opened part = 19cm x 11cm = 209cm2</li></li></ul><li><ul><li>Frequencies chosen:

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Materials used:</li></li></ul><li>Sound Insulation Experiment<br />Procedure:<br />Cut out one side of the shoe box and place the cloths inside the box.<br />Set up the apparatus following the sequence from A to D as shown in Fig. 1.1.<br />

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3. Turn on the speaker and generate a frequency of 125Hz (f1).<br />4. Measure the sound level (L0) using the sound meter and record it in Table 1.1.<br />5. Put the Expandable Polystyrene (EPS) foam (material 1) in front of the shoe box to cover the opened part of the box.<br />6. Measure the sound level (L1) for three times using the sound meter and record them in Table 1.1.<br />

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7. Repeat steps 2 to 5 for the remaining measurements using other frequency and material.<br />8. Calculate the average sound level (Laverage= (L1+L2+L3)/3), Sound Reduction Index (R) and transmitted coefficient (T) for different material under different frequency using equation (2).<br />9. Draw bar charts to show the relation between R/T and different frequencies for different materials.<br />

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Result and Discussion:<br />

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So, the greater the R, <br />the greater the Sound <br />Reduction Level is.<br />

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So, the smaller the T, <br />the greater the<br />Sound Reduction <br />Level is.<br />

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Analysis:<br /><ul><li>Assumption:

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The unique sound source for the experiment is the frequency generator.

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The background noise during the experiment is kept constant.

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The reflection and refraction effects of sound are negligible.</li></li></ul><li><ul><li>Sources of error:

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Unstable readings of decibel meter

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Impact sound can transmit through the ground to the box due to the vibration of speaker.

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For the sound transmitted through the material , the sound wave can be reflected inside the shoe box, which may be noise, and it may affect the reading.</li></li></ul><li><ul><li>The background noise may not be constant though out the experiment.

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Maximum possible error of the measurement = 0.05dB x 2 = 0.1dB</li></li></ul><li>In Our Experiment<br />Conclusion:<br /><ul><li>The greater the R, the greater the Sound Reduction Level is. </li></ul>( R↑->Reduction Level↑)<br /><ul><li>The smaller the T, the greater the Sound Reduction Level is.</li></ul>( T↓-> Reduction Level↑)<br /><ul><li>The most effective sound insulation material :</li></ul>Steel board (2mm)<br /><ul><li>The least effective sound insulation material :</li></ul>EPS foam (18mm), A4 paper - 50pcs (5mm)<br />

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Some Professional Insulation Materials<br />features & benefits:<br /><ul><li>high performance soundproofing material for reducing airborne noise.

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may be used behind drywall in wall and ceiling assemblies or sandwiched between existing and new drywall.

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use in flooring systems to increase sound transmission class.

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used for both residential and commercial soundproofing applications.</li></ul>QUIET BARRIER® HDSuperior soundproofing material for blocking noise for residential and commercial use.<br />

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features & benefits:<br /><ul><li>cost-effective, low-profile sound blocking barrier

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designed to reduce noise transmission in wall, floor & ceiling assemblies

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replaces lead sheeting

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available in sheets, rolls and "peel & stick" versions</li></ul>QUIET BARRIER® MDEconomical soundproofing material for blocking noise for residential and commercial use.<br />

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Comparison on QUIET BARRIER® HD & QUIET BARRIER® MD<br />

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features & benefits:<br /><ul><li>blocks and absorbs noise while reducing structural vibrations

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great for engine compartments and equipment closures where moderate noise blocking is required

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easy to cut for custom installations

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may be used behind drywall

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available with peel and stick adhesive backing</li></ul>QUIET BARRIER® LD CompositeAcoustical vinyl barrier composite for blocking sound.<br />

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features & benefits:<br /><ul><li>blocks and absorbs noise while reducing structural vibrations

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great for engine compartments and equipment enclosures

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available with peel and stick adhesive backing</li></ul>QUIET BARRIER® MD CompositeAcoustical vinyl barrier composite.<br />

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features & benefits:<br /><ul><li>heavy duty noise blocking, decoupling and sound absorption in one composite material

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available with peel and stick adhesive backing for easy installation

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excellent material for machine and engine enclosures and compressor rooms</li></ul>QUIET BARRIER® HD CompositeMost effective acoustical vinyl barrier composite for blocking sound.<br />

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Comparison on LD Composite, MD Composite, HD Composite<br />

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Other insulation materials<br />

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Examples of floor system<br />

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Examples of wall system<br />

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Measures of soundproofing at home<br />Paints the wall with latex paints<br /><ul><li>reduce sound</li></ul>Install carpets on the floor<br /><ul><li>absorb sound</li></ul>Install drapes or shutters on the windows<br /><ul><li>absorb sound</li></ul>Soft furniture<br /><ul><li>dampen sound waves</li></li></ul><li>Solid doors<br />keep sound out of individual rooms<br />install a clear window film<br />provide a soundproofing buffer<br />rearrange furniture<br />E.g. place a filled bookshelf <br /> against a particularly noisy wall<br />decorate room with rough <br /> surface finishings<br />effect multiple distortion to the propagation of the wave<br />

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Q & A<br />

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Reference<br />“How to Soundproof: Basic Principles”. Noise Help. 22 February, 2011<br /> <http://www.noisehelp.com/how-to-soundproof.html><br />“Frequency-Dependent Sound Absorption”. Science Buddies. 28 February,2011<br /> <http://www.sciencebuddies.org/science-fair-projects/project_ideas/Phys_p029.shtml><br />“Transmission of Sound” City University of Hong Kong. 1 March,2011<br /> <http://personal.cityu.edu.hk/~bsapplec/transmis.htm><br />“Explore... Home Improvement: How Sound Insulations Work” Trans4mind Ltd.<br /> 1 March , 2011<br /> < http://www.trans4mind.com/explore/home-improvement/19620.html ><br />The Sound Solution – Soundproofing Materials & Sound Proofing Products<br /> <https://www.noisestopsystems.co.uk/><br />How to soundproof a room<br /> <http://www.howtoall.com/Homefiles/howtosoundproofaroom8.htm><br />How to Soundproof Rooms in a House<br /> <http://www.ehow.com/how_1000181_soundproof-a-room.html#ixzz1FyklcYCp><br />

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Reference<br />“Sound Blocking Products – QUIET BARRIER® HD” . Soundproof Foam. 9 March, 2011<br /> <http://www.soundprooffoam.com/quiet-barrier.html><br />“Sound Blocking Products – QUIET BARRIER® MD” . Soundproof Foam. 9 March, 2011<br /> <http://www.soundprooffoam.com/econo-barrier.html><br />“Sound Blocking Products – QUIET BARRIER® LD Composite” . Soundproof Foam. 11 March, 2011<br /> <http://www.soundprooffoam.com/value-barrier.html><br />“Sound Blocking Products – QUIET BARRIER® MD Composite” . Soundproof Foam. 11 March, 2011<br /> <http://www.soundprooffoam.com/dura-barrier.html><br />“Sound Blocking Products – QUIET BARRIER® HD Composite” . Soundproof Foam. 11 March, 2011<br /> <http://www.soundprooffoam.com/ultra-barrier.html><br />

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~ The End ~Thank You !<br />