Download - Noise control
NOISE CONTROL NOISE CONTROL AT SOURCE, AT SOURCE, ALONG PATH,ALONG PATH,AT RECEIVERAT RECEIVER
SUBMITTED TO:-SUBMITTED TO:- SUBMITTED BY:- SUBMITTED BY:-ER. DHEERAJ SONIER. DHEERAJ SONI YASHWANT RAJ YASHWANT RAJ
VERMAVERMA (MECHANICAL) (MECHANICAL)
INTRODUCTIONINTRODUCTION
Noise is unwanted sound. It can cause hearing loss, disturb verbal communication or cause nuisance. The most common sources are industrial noise and traffic. Vibrations can cause damage to assets, radiate noise or cause discomfort to people.
Noise control or noise mitigation is a set of strategies to reduce noise pollution or to reduce the impact of that noise, whether outdoors or indoors.
Source of noiseSource of noise
SOURCE PATH SOURCE PATH RECEIVERRECEIVER
HOW CAN WE CONTROL HOW CAN WE CONTROL NOISE?NOISE?
Control the source.
Block the path.
Enclose the receiver.
WHY NOISE AT SOURCE?WHY NOISE AT SOURCE?
Mechanical shock between two machine parts.
Friction between two machine parts.Unbalance rotating and
reciprocating parts.Vibration of large parts.Loose fitting.Irregular fluid flow.Improper maintenance.
Vibration damping:- Applicable for large vibrating surfaces. The damping mechanism works by extracting the vibration energy from the thin sheet and dissipating it as heat. A common material is sound deadened steel.
Vibration isolation:- Reverts transmission of vibration energy from a source to a receiver by introducing a flexible element or a physical break. Common vibration isolators are springs, rubber mounts, cork etc.
HOW CAN WE CONTROL HOW CAN WE CONTROL NOISE AT SOURCE?NOISE AT SOURCE?
Judicious sitting of the mechanical equipment.
Proper maintenance.Proper material of machine part (For
example:-nylon gears can be used instead of metal gears.).
Choice of low noise mechanical equipment.
BY RESILIENT SCREEN BY RESILIENT SCREEN DECKINGDECKING
The use of resilient screen decking reduces
the impact of rock on metal
VIBRATION ISOLATED VIBRATION ISOLATED MOUNTEDMOUNTED
Noise insulator:- Prevent the transmission of noise by the introduction of a mass barrier. Common materials have high-density properties such as brick, thick glass, concrete, metal etc.
Noise absorber:- A porous material which acts as a ‘noise sponge’ by converting the sound energy into heat within the material. Common sound absorption materials include decoupled lead-based tiles, open cell foams and fiberglass.
HOW CAN WE CONTROL HOW CAN WE CONTROL NOISE ALONG PATH?NOISE ALONG PATH?
Barrier ConceptBarrier Concept
Shadow
Zone
Shadow
Zone
DiffractedDiffracted
PropagatedReflected
Noise Source
Barrier
ACOUSTICAL ACOUSTICAL BLOCKWALLSBLOCKWALLS
STRIP CURTAIN STRIP CURTAIN BARRIERSBARRIERS
VINYL STRIP CURTAINS can be used TO SEPARATE AREAS OF PLANTS AND MILLS.
THE STRIPS NEED TO HAVE A 30 TO 50 % OVERLAP.
IN SOME CASES THESE STRIPS MAY NEED TO BE DOUBLES
Allowable Boundary Allowable Boundary Noise LimitsNoise Limits
Affected Day Evening Night
Premises 7 am – 7 pm 7 pm – 11 pm 11 pm- 7am
Noise 65 dBA 60 dBA 55dBASensitive
Residential 70 dBA 65 dBA 60 dBA
Commercial/ 75 dBA 70 dBA 65 dBA Industrial
Use head sets and ear plugs in industry.Doors and windows should be well sealed.Ventilation opening should be provided
with acoustic attenuators.Internal surface should be made of
absorptive materials.Innovative building design may be used to
prevent or reduce the intrusion of noise. For example, no window openings facing noise source.
HOW CAN WE CONTROL HOW CAN WE CONTROL NOISE AT RECEIVER?NOISE AT RECEIVER?
OPERATOR’S BOOTH MUST OPERATOR’S BOOTH MUST PROVIDE ADEQUATE PROVIDE ADEQUATE
VISIBILITYVISIBILITY
Central Building Plan Unit 30.11.1999