Noise control hearing protection

While not possible in some cases, a simple way to protect workers is either to increase their distance from the sound source or to put them in a soundproofed enclosure such as a control room or building. However, it is almost impossible to keep all workers away from high noise sources all the time, so hearing protection will probably be necessary. 

Nixon, G. W., and Berger, E. H. "Hearing Protection Devices." In Handbook of Acoustical Measurements and Noise Control, edited by G. M. Harris, 3rd ed. Woodbury, NY Acoustical Society of America, 1998. 

Many stone processing operations produce high sound levels. Operators exposure to noise is controlled by a combination of reducing/containing it at source, excluding it from control rooms, and the use of remote cameras with monitors in control rooms. Effective personal hearing protection is still required when operators are required to enter noisy areas. 

Hearing protection should not be used as an alternative to controlling noise by technical and organisational means. 

Use of hearing protection in both occupational and non-occupational environments is intended to help reduce noise exposure levels and noise-induced hearing loss (NIHL). In the absence of feasible engineering and administrative noise reduction control methods, use of earplugs or earmuffs is common practice. Unfortunately there are still many myths surrounding the use and effectiveness of hearing protection devices (HPDs). In this article, some of the more common myths and the realities are addressed. 

In fact, when your employees are exposed to more than the Permissible Noise Exposures (PNE) in the table to the left, you must attempt to reduce the level below the PNE with engineering or administrative controls. If that is impossible or inadequate, you must provide workers with hearing protection devices (HPDs). 

Noise problems - wearing of hearing protection, and control of noise at source... 

Hearing protection should not be used as an alternative to controlling noise by technical and organizational means. Employers should consult with their employees or their representatives on the type of hearing protection to be used. 

Noise levels not only change over time, they also vary in different areas of the facility — often so widely that different hearing protection is required for various work areas or, occasionally, various tasks in the same work area. Recognize noisy spots and periodically take readings in these problem areas. Repeat monitoring whenever a change in production, process, equipment or controls increases noise exposures to the extent that additional employees may be exposed or hearing protection device attenuation is inadequate. At a minimum, conduct annual assessments — or even more frequent assessments in previously identified noisy spots. ... 

However, if workers are still exposed to hazardous levels of noise after controls have been put in place, employers must provide hearing protective devices. 

Space limits a complete listing of all 16 questions and, unfortunately, military website restrictions preclude a reference to access. Three of the 16 questions and implementation levels in areas of hazard posting, engineering noise controls and hearing protection are included below for a general sense of this concept. Most military unique references have been deleted and minor reconstruction of some levels was necessary to demonstrate this concept for private sector application. Each level should be understood to contain all positive factors in the level below it. 

Feasible administrative, scheduling, or engineering controls should be utilized to reduce TWA noise exposures to within the limits of Table 4.71. Hearing protection must be provided and used to achieve the TWA noise exposure limits of Table 4.71 whenever administrative, scheduling, or engineering controls fail to do so. 

A prudent rule to follow is that hearing protection should only be considered the final solution when reductions in the noise levels through engineering controls are imfeasible or insufficient to reduce levels below 85 dBA. 

The noise levels in many metal bashing and packaging industries caused low performance and, more seriously, hearing impairment. Today there are established preventive and protective measures of noise control. 

If other means of controls prove to be impossible or infeasible, the use of personal protective equipment by employees may become necessary. Such control methods, however, do not reduce or eliminate the source of the potential hazard and are the least preferred choice for controlling exposure. Personal protective equipment includes air-purifying and air-supplying respirators, hearing protection to reduce noise exposures, eye and face protection and gloves, boots and other impervious clothing. 

The possible adverse effects of excessive noise exposure on hearing have been weU-estabhshed (Sliwinska-Kowalska et al., 2007, Nandi et al., 2008). To prevent occupational noise-induced hearing loss, collective measures can be taken to reduce the overall noise level at the work layout (Bies et al., 2003). Hearing protection is only used when these interventions are insufficient or unfeasible. Noise can be controlled by blocking the noise at the source, along its path from the source to the receiver, and at the end receiver (Hsu et al., 2004). 

Fleischer, 2008. G. Effective protection of the sense of hearing is prevented by IS01999 noise standard. 7th European Conference on Noise Control 2008, EURONOISE 2008, Paris. 3697-3702. 

Reducing the noise exposure to safe levels through engineering controls (preferred), administrative controls, or hearing protection devices... 

Engineering methods of noise control should be used in preference to hearing protection for reduction of exposure to noise. Noise hazard zones must be established and marked where applicable. Local exhaust ventilation must be installed to reduce exposure levels of wood dust, glues, paints and wood treatment chemicals and must be inspected regularly, as required by the COSHH Regulations. Dust extraction equipment must be fitted on all machines which produce dust. Machine guards must be provided as required by the Standards listed, and always used when machines are in motion. 

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