HITESH PATEL Faculty Of Civil engineering department MGITER,NAVSARI. PRESENTED BY: SR.NO.NAMEENROLLMENT NO. 1 GAJERA BRIJESH R GHAVA ASHISH G MANGANI JATIN J PARMAR KRUPAL P GUIDED BY:- GROUP ID : 9 B.E. – II, SEM- III

Acoustics Acoustics “ is the interdisciplinary science that deals with the study of all mechanical waves in gases, liquids, and solids including vibration, sound, ultrasound and infrasound. The word "acoustic" is derived from the Greek word ἀ κουστικός (akoustikos), meaning "of or for hearing, ready to hear". The scientific study of the propagation, absorption, and reflection of sound waves is called acoustics.”

S OUND WAVE PROPERTIES AND CHARACTERISTICS …….. A musical tone is a steady periodic sound. A simple tone, or pure tone, has a sinusoidal waveform. A compound tone is any musical tone that is not sinusoidal, but is periodic, such that it can be described as a sum of simple tones with harmonically related frequencies. A noise results from non-periodic vibrations (statistically random vibration)

Objective sound wave characteristics Frequency, or its inverse, the period Harmonic Content (Harmonic spectrum) Intensity Amplitude Waveform Wavelength Speed (velocity vector) Direction (wave vector)

Sound Intensity. Sound Pressure

Intensity and loudness of sound 7 Loudness of a sound corresponds to the degree of sensation depending upon the intensity of sound and sensitivity of ear drums. It may also happen that the same listener might give different judgments about the loudness of sound of the same intensity but of different frequencies as the response of the ear is found to vary with the frequency of vibration.

Frequency and pitch of sound 8 The audio range falls between 20 Hz and 20,000 Hz. This range is important because its frequencies can be detected by the human ear. A frequency is expressed in terms of Hz(Hertz) and it determines pitch of sound source. They can be categorized as: Low tones –sound of urban road traffic. Mild tones –sound of piano notes. High tones –sound of single tea kettle.

Subjective sound perception Sounds may be generally characterized by pitch, loudness, and quality.loudness quality E QUAL L OUDNESS C URVES

Reflection of sound waves. Reflection of sound waves is exactly the same as that of light waves. That is angle of incidence is equal to the angle of reflection. *c *c INCIDENT WAVE REFLECTED WAVE REFLECTING SURFACE.

Reflection of sound waves. Sound waves reflected at a convex surface are magnified and are considered bigger. They are attenuated and therefore weaker. So convex surface may be used with advantage to spread the sound waves throughout the room. WAVE FRONTCONVEX REFLECTOR SOUND SOURCE

Acoustical design of halls The initial sound from the source should be of adequate intensity so that it can be heard throughout the hall. For halls of big sizes suitable sound amplification system should be installed. The sound produced should be evenly distributed so that there is no dead spots and sound foci.

Physical Design Principles for halls

Acoustics materials QUIET BARRIER HD A flexible, 2lb per sq./ft. 1/4 in. thick, high density material with a smooth surface designed to reduce noise transmission between two spaces. Applications include reducing airborne noise transmission through walls, ceilings and floors.

A COUSTICS MATERIALS QUIET BARRIER MD A flexible, 1lb per sq./ft. 1/8 in. thick, high density material with a smooth surface specially engineered to reduce noise transmission between two spaces. PRESENTATION BY MANISH KUMAR LEC. ARCHITECTURE AT PATIALA

Acoustics materials QUIET BATT Insulation A premium high-performance acoustical/thermal insulation manufactured from 80% recycled cotton fibers. QUIET BATT® offers superior noise reduction versus typical fiberglass, cellulose and foam insulations. PRESENTATION BY MANISH KUMAR LEC. ARCHITECTURE AT PATIALA

Acoustics materials Tough core Ceiling Tiles High-performance composite ceiling panel. Especially well-suited to minimize sound transmission between adjacent spaces sharing a common attic space. Available in a variety of finish options and edge details. PRESENTATION BY MANISH KUMAR LEC. ARCHITECTURE AT PATIALA

Acoustics materials damping tiles used for noise absorption. PRESENTATION BY MANISH KUMAR LEC. ARCHITECTURE AT PATIALA

Sound insulation ( effects of noise) It creates discomfort. It has adverse effect on blood pressure, sleep and causes muscular strains. It leads to fatigue and decreases the efficiency of a person. It takes away essence of music and speech. It disturbs concentration. Prolonged exposure to noise may result in temporary deafness or even nervous breakdown. PRESENTATION BY MANISH KUMAR LEC. ARCHITECTURE AT PATIALA

Types of sound insulating materials Non rigid porous flexible materials Perforated boards Compressed fiber boards Pulp boards Mineral wool boards Acoustic tiles /sheets Glass wool PRESENTATION BY MANISH KUMAR LEC. ARCHITECTURE AT PATIALA

Sound insulating techniques Double wall construction. BOARDS WOODEN STUDS SOUND ABSORBING BLANKET BOARDS WOODEN STUDS PRESENTATION BY MANISH KUMAR LEC. ARCHITECTURE AT PATIALA

Sound insulating techniques 22 Cavity wall construction. EXTERNAL WALL 13MM PLASTERED 5CM CAVITY BRICK WALL 10CM CELOTEX OR OTHER INSULATING BOARD METAL FLY PRESENTATION BY MANISH KUMAR LEC. ARCHITECTURE AT PATIALA

Sound insulating techniques 23 False ceiling. REINFORCED CONCRETE ROOF SUSPENDERS FALSE CEILING PRESENTATION BY MANISH KUMAR LEC. ARCHITECTURE AT PATIALA

Sound insulating techniques Hollow block construction. COMPRESSED CONCRETE HOLLOW BLOCKS HOLLOW PRESENTATION BY MANISH KUMAR LEC. ARCHITECTURE A

Anti-termite Treatment The termites are popularly known as white ants and they are found in abundance in tropical and sub-tropical countries. These insects live in a colony and they are very fast in eating wood and other cellulosic materials as food. The also damage non-cellulosic materials like plastic, leather, etc. Anti-termite treatment may be divided into two categories: (a)Pre-construction treatment (b)Post-construction treatment

(a) Pre-construction treatment : This treatment is started right at the initial stage of construction of building. This treatment can be divided into three operations. (1) Site preparation (2) Soil treatment (3)Structural barries

(1) Site preparation : This operation consists of removal of stumps, roots, logs, waste wood etc. from the soil at the construction site. This is essential since the termites thrive on these materials. ChemicalConcertration by weight DDT5% BHC0.5% Aldrin0.25% Heptachlor0.25% Chlordane0.5%

(2) Soil treatment : Chemical treatment to the soil at the time of construction of the building is the best and only reliable method of protect the building agains termites. An insecticide solution consists of any one of the following chemicals in water emulsion. Another chemical, aldrex 30 E.C. has also proved to be the most effective. ChemiclasConcentration by weight Aldrin0.5% heptachlor0.5% chlodane1%

(3) Structural barries : To prevent the entry of termites through walls, impenetrable physical structural barriers may be provided continuously at plinth level. Such structural barrier may be in the form of a cement concrete layer or metal layer at plinth level. Cement concrete layer may be 5 to 7.5 cm thick. Metal barrier may consists of no-corrodible sheets of copper or G.I. of 0.8 mm thick.

(b)Post- construction treatment : It is a maintenance treatment for those buildings which are already under attack of termites. It is essential to carry out inspection to estimate the magnitude of spread of termites in the building and to detect the points of entry of termites in the building. The points may be in near vicinity of columns, basements, bathrooms, lavatories, leaking pipes, drains etc.

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