Wong Mei Yu ES00091 ECH5507. To define what is noise To introduce noise in work station To introduce methods of measuring noise at work To examine.

Noise at work place

Noise at work stationWong Mei YuES00091ECH5507

Objective To define what is noiseTo introduce noise in work station To introduce methods of measuring noise at workTo examine how noise will affect workers and what are the limits and standards.To describe how we can apply these standards at workplacesNoise control and prevention NoiseUnwanted soundMake people annoyNoise is one of the most physical contaminants highly found in the construction sector. Excessive exposure to noise will induce temporary hearing loss or even permanent deafness.

Noise in work stationSource of noise:Equipment (Jet engine, jackhammer)System units (cooling fans, disk drive)Heavy TrucksHuman factors (keyboard, shouting)Machineries

In manufacturing factories, major noise sources come from Machines

List of common noisy machinery 1.Abrasive cutting machinery2. Circular cutting machinery3. Glass grinding machinery4. Marble cutting machinery5. Metal grinding machinery6.Plastic granulating machinery7. Rock/concrete breaking machinery8. Screw/nail making machinery9. Spinning machinery10.Woodworking machinery (such as circular saw, planning machine, spindle molding machine, thickening machine)If a worker is overexposed under high-level noise condition environment , he or she may suffer from Noise-induced hearing loss.Noise-induced hearing loss(NIHL)Noise-induced hearing loss (NIHL) is one of the most common occupational diseases and its effects can be permanent.Caused by Prolonged exposure to loud noiseUnable to hear high pitched soundsDifficulties detecting lower-pitched sounds

As noise at work station is a serious problem, there are some regulations.

IntrepretationDaily personal noise exposure: the level of daily personal noise exposure of an employee ascertained in accordance with the Schedule sectionEmployee: a person employed by a proprietor to perform work in or in connection with an undertakingExposed and exposure: exposed or exposure while at work in an industrial undertaking;First action level: a daily personal noise exposure of 85dB(A);Noise control equipment: includes a damping device, silencer, muffler, acoustic enclosure, anti-vibration mounting and sound-absorbing barrier;Peak action level: noise reaching a peak sound pressure level of 140 dBSecond action level: a daily personal noise exposure of 90 dB(A).

Assessment of noise exposureA proprietor's employee is likely to be exposed to a first action level or above or to a peak action level or above, the proprietor shall ensure that a person who by reason of his training and experience is competent to carry out a noise assessment makes a noise assessment which is adequate for the purposes(a) of identifying which of his employees are likely to be so exposed; and(b) of providing him with information with regard to the noise to which his employees may be exposed that will enable him to comply with his duties under certain regulationWhere there has been a significant change in the work to which the assessment relates or where the proprietor has reason to believe that the assessment is no longer adequate for the purposes the proprietor shall ensure that a further noise assessment is made .The person who carried out the assessment shall prepare an assessment report in the form, and containing the information, that the Commissioner may require.Within 28 days after completing an assessment the proprietor shall send a copy of the assessment report to the Commissioner.The proprietor shall make the assessment report available at all reasonNoise exposure testArrange for a noise assessment wherever an employee is likely to be exposed at or above the first or peak action level. The assessment will need to:(a) identify all employees likely to be so exposed; and(b) provide enough information to enable appropriate action to be taken

How to carry out noise exposure test?To carry out using a sound level meter and a dosimeterTo collect data from workers devoted to different tasks in the construction process. Analysis of the most important levels and indexes have been done with those dataCompare with the limits imposed by the different current regulations.

In general According to some researches, there are high levels of noise for any working environment related to construction. These are so high that between the 60% and 70% of the construction workers are exposed to a noise dose higher than the 100% along their working day.

Review of assessments If the worker is overexposure of noise ,do the following actions:installation or removal of machinerysubstantial changes in workload, work pattern, or machine speedschanges in building structure or machine layoutmachine wear or general deteriorationmodifications to machinery and introduction of automationthe noise control program (such as change in control equipment).Redo the assessment again until no more overexposure of noiseLimit and standardInstruction of controlling noise at work station Hong Kong has established it's own noise at work regulation back in 1986. The regulation is largely based on the UKs regulations which are different from the USs regulations.NOISE EXPOSURE LIMITS

Partial noise dose OSHA has also developed a partial noise dose value (%). It is calculated for each specific Sound pressure level above 80dBA as follow:

Total noise doseIt is calculated by summing all the partial noise dose.

Permissible exposure level (PEL) in different country For OSHA:(1)Set an action level at 50% noise dose value(2) set a PEL at a dose value of 100%.In HK Noise at work regulations (1)First action level at 80 dBA(2)Second action level at 90 dBA.

PreventionThe need for ear protectorsThe employers duty to provide suitable approved ear protectors depends on the exposure level:

(a) Between first and second action levels Where employees are exposed between the first and second action levels, employer need to provide suitable approved ear protectors to employees who request for them.

(b) Second and peak action levels The employer need to provide suitable approved ear protectors to all employees likely to be exposed at or above the second or peak action levels.Ear protection zonesEar protection zone means any part of an industrialundertaking where the employees are likely to beexposed to the second action level or above or to thepeak action level or above. Wherever practicable, theproprietor has to mark ear protection zones with signsshowing that they are areas where suitable approvedear protectors must be worn(figure1)

figure1Some of the actions to control the noise that should be planned in advance are, for instance:

The noisy works should be avoided or reduced during the design stage. The way the construction work will be managed and the risks will be controlled should be planned during the organization stage. The risks should be assessed and eliminated, and the assessment revised during the construction stage. A policy to acquire low-noise machinery and equipment should be considered before the beginning of the construction work, and the action for controlling the noise should be included in the specifications sheet. A planning of the working processes should be done to reduce the noise exposure of the workers to the minimum.End