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Building service.ppt of neeru and aprajeeta

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Building service.ppt of neeru and aprajeeta

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  2. 2. BUILDING SERVICES Submitted by Name – Neeru and Aprajeeta B.Arch- 5th sem/ 3rd year From – R.T.I.A And D 2
  3. 3. Contents Introduction About the Acoustics Characterstics Acoustic defects Acoustic solution Material Case study of a hotel 3
  4. 4. ACOUSTIC related to the sound or the sense of hearing Introduction :- Acoustic is the science of sound as applied to buildings it deals with the origin propagation and auditory sensation of the sound. Knowledge of the science is used for the design and construction of theaters, cinemas, concert halls, auditorium etc. Proper acoustical conditions also include the sound absorption or dissipation of the exterior noise. 4
  5. 5. Acoustics means to work on these three parameters and improve sound experience. 5
  6. 6. Transmission loss (TM) of sound •When sound is transmitted from source or origin to the adjoining room/ area, reduction in sound intensity takes place. •This is known as transmission loss (TM) •Measured in decibels (dB) 60 decibels 40 decibels TM=60-40=20 DECIBELS. 6
  7. 7. Flanking path: Path between adjacent spaces other than through common partition through which sound or vibration is transferred 7
  8. 8. Sound and vibrations  Sound is a vibration in an elastic medium such as air, water, most building materials, and the earth. (Noise can be defined as unwanted sound, that is, annoying sound made by others or very loud sound which may cause hearing loss). Frequency of sound Frequency is the rate of repetition of a periodic event. The unit of frequency is the hertz (Hz) Wavelength As sound passes through air, the to-and-fromotion of the particles alternately pushes together and draws apart adjacent air particles, forming regions of rarefaction and compression. Wavelength is the distance a sound wave travels during one cycle of vibration. Example-Sound waves in air also are analogous to the ripples (or waves) caused by a stone dropped into still water. The concentric ripples vividly show patterns of molecules transferring energy to adjacent molecules along the surface of the water. In air, however, sound spreads in all directions. 8
  9. 9. Velocity of sound Sound travels at a velocity that depends primarily on the elasticity and density of the medium. In air, at normal temperature and atmospheric pressure, the velocity of sound is approximately 1,130 feet per second (ft/s), or almost 800 mi./h. This is extremely slow when compared to the velocity of light, which is about 186,000 mi./s, but much faster than even hurricane winds. Frequency ranges of audible sounds Hearing ranges for both young and older persons (> 20 years old) A healthy young person is capable of hearing sound energy from about 20 to 20,000 Hz. Hearing sensitivity, especially the upper frequency limit, diminishes with increasing age Even without adverse effects from diseases and noise—a condition called “presbycusis.” Human speech contains energy from about 125 to 8000 Hz. Women’s vocal cords are generally thinner and shorter than men’s, so the wavelengths 9
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  11. 11. CHARACTERSTICS Sound consist of a series of alternate compression and rarefaction that are set by a vibrating body. The sound in the form of wave travel in the direction through any medium. The average velocity of sound in air can be taken as 343 m/s. Flow of sound energy per unit time through unit area is termed as intensity of loudness of sound. Frequency or pitch of audible sound is defined as the no of cycles or vibrations per second that strikes the ears. Good acoustical buildings promote comfortable living, efficiency of work, auditory or public buildings etc. Hence, modern design of buildings and construction should give importance to the improvisional of acoustical conditions and sound insulation so as to exclude of diminish the noise. 11
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  13. 13. ACOUSTIC DEFFECT When the average sound intensity rises in to a suitable level in every part of the room or auditorium with no echoes or disturbances or distortions. This is called acoustic of building. To achieve this, one has to minimize the defects. Following are the main defects of sound- Formation of Echoes Reverberation of Sound Insufficient loudness Sound focl Dead spots Outside or External disturbance 13
  14. 14. FORMATION OF ECHOES- Echoes mainly produced due to the reflection of sound wave(mainly from the surface of walls, roofs, ceilings etc.) Echo is founded when the reflected sound reaches the ear at the same time when a direct sound reaches. Echo causes disturbance and unpleasant hearing. When Not all sound is absorbed, Some of it is reflected, That means sound bounces off the solid matter example- a tennis ball bounces off a wall. Sound reflected back to its source is an echo. 14
  15. 15. This defect can be removed by selecting proper shape of the hall . And by providing rough and porous interior surfaces to disperse the energy of echoes. And by providing rough and porous interior surfaces to disperse the energy of echoes. This defect can be removed by selecting proper shape of the hall . •Echoes are the reflection of sound from relatively flat object that is far enough away that you can discern the time difference. Echoes are used to measure distance, velocity, and the shape of objects. Echoes off gratings result in an unusual pinging sound. •repetition of sound •The sensation of sound persists for 1/15th of a second after the source has ceased. Thus an echo must reach after 1/10th second of the direct sound . 15
  16. 16. Reverberation Is the time interval with in which , the intensity of sound produced or reverberation is the multiple reflection in an enclosed space . The sound persists even when the source of sound has ceased or stopped. This phenomena of sound is called reverberation. 16
  17. 17. 1..Depends on the size of room as if room is small reflections will taken place quickly as waves have to travel less distance, so time will be less. 2.Reverberant sound is the reflected sound , as a result of improper absorption. 3.Reverberation may results in confusion with the sound created next. The time during which the sound persists is called the reverberation time of sound in the hall. reverberation time ‘t’ is given by formula :- t= 0.16V /A where V=volume of room in cubic meters A= total absorbing power of all the surfaces of room/ hall. Reverberation time: Amount of time at a specific frequency that a sound in an enclosed space takes to decrease 60 decibels in level after the source sound has stopped. 17
  18. 18. Reverberation time & quality of sound Reverberation time should remain within limits as per Indian Standard Code: 2526-1963. Sr. No. RECOMMENDED TIME IN SECONDS ACOUSTICS 1 0.50 to 1.50 Excellent 2 1.50 to 2.00 Good 3 2.00 to 3.00 Fairly good 4 3.00 to 5.00 Bad 5 Above 5.0 seconds Very bad 18
  19. 19. INSUFFICIENT LOUDNESS :- In case of theater or large auditoriums the speakers voice or music from the stage should be easily audible in all parts of the hall at the uniform of intensity of loudness. To achieve this, the sound waves should be properly reflected and uniformally spread all over the interior part of the auditorium. But due to the lake of sound reflecting flat surfaces near the sound source or stage and excessive absorption of sound in the hall resulting the defect of insufficient loudness. This defect can be minimized by providing hard surface near the stage absorbent material should be provided as per the requirements. Also the location of loudspeakers should be adjusted. So that there is no dead spots and sound focl. 19
  20. 20. Sound focl Reflecting concave surfaces cause concentration of the reflected sound wave at certain spot, creating a sound of large intensity. These spots are called sound focl. This defect can be remove by :- 1. Geometrical designed shapes of the interior faces, including ceilings. 2. Providing highly absorption materials on focusing areas. 20
  21. 21. Dead spots 1. This defect is an outcome of the formation of sound focl. 2. Because of high concentration of the of reflected sound at spot focl, there is deficiency of reflected sound at some other points. These points are known as dead spots, where sound intensity is so low that is insufficient for hearing. This defect can be remove by Installation of suitable diffuser and reflectors so that there is even distribution of the sound in the hall. 21
  22. 22. Outside or External disturbance External noise from vehicles, traffic engines, factories, cooling plants etc. may enter the hall either through the openings such as doors windows, ventilators etc. or through the walls and other structural elemens having improper sound insulation . Sources of outdoor noises Road traffic. Railways. Climatic conditions. Aero planes. Moving machines. Machines in nearby factories or buildings etc. Sources of in door noises Indoor noises are those which are caused either in the same room or adjacent rooms. And these are due to:- Conversation of peoples. Moving of peoples . Moving of furniture. Crying of babies. Playing of radios/ other musical instruments. Operations of water closets and cisterns. Noise of type writer Banging of doors etc. This defect may be removed by- By using sound insulation material on the walls with respect to the surroundings. 22
  23. 23. Absorptive surfaces are primarily used for the following applications: - Reverberation Control: reduction of reverberant sound energy to improve speech intelligibility and source localization. - Sound Level Control: reduction of sound or noise buildup in a room to maintain appropriate listening levels and improve sound isolation to nearby spaces. - Echo and Reflection Control: elimination of perceived single echoes, multiple flutter echoes, or unwanted sound reflections from room surfaces. - Diffusion Enhancement: mixing of sound in a room by alternating sound absorptive and sound reflective materials. Acoustics solutions 23
  24. 24. Sr. no. Name of acoustics material Characteristic Image 1. Carpet Carpet absorbs airborne noise as efficiently as many specialized acoustical materials. 2. Quiet barrier HD Reducing airborne noise transmission through walls, ceilings and floors. 3. Quiet barrier MD To reduce noise transmission between two spaces. 4. Quiet Batt A premium high-performance acoustical/thermal insulation manufactured from 80% recycled cotton fibers. 5. Tough core Ceiling Tiles Especially well-suited to minimize sound transmission between adjacent spaces sharing a common attic space. 6. Isotrax Blocks and isolates sound, reduces noise from traveling through building 24
  25. 25. Types of sound insulating materials Non porous rigid. Porous rigid materials. Non rigid porous flexible materials. 25
  26. 26. 1.Non porous rigid • Brick masonry • plastered on both sides • Stone masonry structures • Concrete/RCC structures 2.Porous rigid materials. •Light weight concrete •Cellular concrete •Gypsum board partitions 3. Non rigid porous flexible materials •Perforated boards •Compressed fiber boards •Pulp boards •Mineral wool boards •Acoustic tiles /sheets •Glass wool Types of sound insulating materials 26
  27. 27. Absorptive surfaces be any of three basic types of materials: - Porous materials include fibrous materials, foam, carpet, acoustic ceiling tile, and draperies that convert sound energy into heat by friction. Example: fabric-covered 1 in. (2.5 cm) thick fiberglass insulation panels mounted on a wall or ceiling. - Vibrating panels thin sound-reflective materials rigidly or resiliently mounted over an airspace that dissipate sound energy by converting it first to vibrational energy. Example: a 1/4 in. (6 mm) plywood sheet over an airspace (with or without fibrous materials in the airspace). - Volume resonators - materials containing openings leading to a hollow cavity in which sound energy is dissipated. Example: slotted concrete blocks (with or without fibrous materials in the cores). 27
  28. 28. Sound insulating techniques/Solutions There are some construction techniques also which are adopted for sound insulation. Double wall construction. Cavity wall construction. False ceiling. Hollow block construction. Sound insulation in floors. Double pane windows. Baffle blocks, honey combs etc. 28
  32. 32. Hollow block construction. COMPRESSED CONCRETE HOLLOW BLOCKS HOLLOW 32
  33. 33. Sound insulation in floors 33
  34. 34. Sr. no. material name Application co-efficients 1. Brick wall painted 0.023 2. 6mm thick carpet or felt on solid concrete floor 0.65 3. Curtains light, 3kg/sq. m 0.30 4. Curtains medium 0.40 5. Curtains heavy 5.5 kg/sq.m. 0.82 6. Chairs metals or wooden 0.019 7. Chair with leather cushion 0.07 8. Compressed paper board 0.11 9. Floor concrete 0.02 10. Floor timber 0.03 11. Fibre board 12mm thk 0.3 12. Foamed concrete 0.20 13. Glass wool or slag wool 50mm thk fixed on battens secured to solid wall 0.95 14. Plaster, gypsm or line smooth finish or brick 0.04 34
  35. 35. Sr. no. Material name Application co-efficient 15. Plaster, gypsum or lime on lath over solid backing 0.04 16. Perforated fibre board tiles 18mm thk bedded solidly 0.8 17. Plywood panelling fixed on battens keeping about 2mm thk, air gap between the panelling and the solid wall 0.1 18. Brick wall unpainted 0.023 19. Linoleum or asphalt laid on concrete floor 0.03 35
  36. 36. Case study of a hotel 36
  37. 37. Reception of the K. Hotel Wooden use on the wall and on the columns as an decoration purpose which is control the acoustics in the reception area. Co-efficient of wooden .25-.5 1. only one side on the wall method is to be used. Section of the wooden panelling on wall 37
  38. 38. Sound insulation in column and in ceillng 38
  39. 39. Doors of the hotel All doors in k hotel are wooden either washrooms or service areas 39
  40. 40. Wooden as an decorative material but the purpose is same more absorption of sound Wooden panel are also used on the walls for the sound absorption or as an decoration purpose And On the columns also wooden used. Air spaces are to be left in the panelling 40
  41. 41. This was also wooden as an decorative material. It was an hollow an inner part. 41
  42. 42. Furniture in the hotel 42
  43. 43. Sound insulation in ceiling and the flooring 43
  44. 44. Some other material or thing used for the sound insulation, co- efficient of medium curtains 0.40 44
  45. 45. Type of glazing with the wooden frames, co-efficient of glass 0.04 45