Noise control

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  • THERE ARE MANY TYPES OF VIBRATION ISOLATION MOUNTS. THE TOP TWO ARE VERSIONS OF AIR BAGS, WHILE THE BOTTOM USE SPECIAL RUBBER COMPOUNDS TO PREVENT METAL TO METAL FRICTION THESE MOUNTS SHOULD BE SELECTED FOR EACH SPECIFIC APPLICATION THE PURPOSE OF EITHER TYPE IS TO DE-COUPLE VIBRATING MACHINERY FROM THE BUILDING. THE RESULT IS A SIGNIFICANT REDUCTION IN STRUCTURE BORNE NOISE
  • THE CONCEPT OF PLACING A BARRIER ADJACENT TO A NOISE SOURCE (e.g. A MILL, A CRUSHER, OR A SCREEN) IS TO ESTABLISH AN ACOUSTICAL SHADOW ZONE WHERE THE NOISE LEVELS ARE SIGNIFICANTLY LOWER). THIS AREA MAY BE THE LOCATION OF A WORK STATION OR A PART OF THE PLANT THAT IS FREQUENTLY TRAVELED
  • ONE METHOD OF BLOCKING THE AIRBORNE PATH OF SOUND IS TO BUILD A WALL SEPARATING AREAS OF THE PLANT. SEVERAL STYLES OF CONCRETE BLOCK ARE AVAILABLE THAT NOT ONLY ACT AS A BARRIER BUT ALSO HAVE OPENINGS TO ALLOW THE SOUND TO ENTER THE CAVITY OF THE BLOCKS AND BE ABSORBED BY MINERAL WOOL OR FIBERGLASS.
  • THE USE OF VINYL STRIP CURTAINS TO SEPARATE AREAS OF PLANTS AND MILLS ARE VERY COMMON. IT IS IMPORTANT TO REMEMBER THAT TO BE EFFECTIVE THE STRIPS NEED TO HAVE A 30 TO 50 % OVERLAP. IN SOME CASES THESE STRIPS MAY NEED TO BE DOUBLES
  • THEY ALSO NEED TO BE OF SUFFICIENT SIZE, ENVIRONMENTALLY CONTROLLED AND STRUCTURALLY ISOLATED IF NECESSARY
  • Noise control

    1. 1. NOISE CONTROLNOISE 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 RAJYASHWANT RAJ VERMAVERMA (MECHANICAL)(MECHANICAL)
    2. 2. 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.
    3. 3. Source of noiseSource of noise
    4. 4. SOURCE PATH RECEIVERSOURCE PATH RECEIVER
    5. 5. HOW CAN WE CONTROLHOW CAN WE CONTROL NOISE?NOISE? Control the source. Block the path. Enclose the receiver.
    6. 6. 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.
    7. 7. 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 CONTROLHOW CAN WE CONTROL NOISE AT SOURCE?NOISE AT SOURCE?
    8. 8. 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.
    9. 9. BY RESILIENT SCREENBY RESILIENT SCREEN DECKINGDECKING The use of resilient screen decking reduces the impact of rock on metal
    10. 10. VIBRATION ISOLATEDVIBRATION ISOLATED MOUNTEDMOUNTED
    11. 11. 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 CONTROLHOW CAN WE CONTROL NOISE ALONG PATH?NOISE ALONG PATH?
    12. 12. Barrier ConceptBarrier Concept Shadow Zone Diffracted Propagated Reflected Noise Source Barrier
    13. 13. ACOUSTICALACOUSTICAL BLOCKWALLSBLOCKWALLS
    14. 14. STRIP CURTAIN BARRIERSSTRIP CURTAIN BARRIERS
    15. 15. 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
    16. 16. Allowable Boundary NoiseAllowable Boundary Noise LimitsLimits Affected Day Evening Night Premises 7 am – 7 pm 7 pm – 11 pm 11 pm- 7am Noise 65 dBA 60 dBA 55dBA Sensitive Residential 70 dBA 65 dBA 60 dBA Commercial/ 75 dBA 70 dBA 65 dBA Industrial
    17. 17. 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 CONTROLHOW CAN WE CONTROL NOISE AT RECEIVER?NOISE AT RECEIVER?
    18. 18. OPERATOR’S BOOTH MUSTOPERATOR’S BOOTH MUST PROVIDE ADEQUATEVISIBILITYPROVIDE ADEQUATEVISIBILITY
    19. 19. Central Building Plan Unit 30.11.1999

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