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Can You Hear What I Hear?

Written by building4u on Thursday, 17 May 2012 12:16 in Site Safety
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Exposure to excessive noise in the workplace is one of the most significant health hazards

The Health and Safety in Employment Act 1992 requires employers to take all practicable steps to ensure a safe and healthy place of work, and to identify and appropriately manage significant hazards so that employees and others in the workplace are not harmed.

One of the most significant health hazards in the workplace is exposure to excessive noise. In fact, the number of claims and associated compensation costs for noise-induced hearing loss has doubled in the last five years in New Zealand.

Between July 2007 and June 2008, ACC received 4,865 new claims for noise-induced hearing loss (NIHL). The sectors with the highest claim rates were:

• agriculture, forestry and fishing (1,145 claims)

• manufacturing (1,109 claims)

• construction (851 claims).

The Health and Safety in Employment Regulations 1995 requires that no employee is exposed to noise above the following levels:

• LAeq8h of 85dB(A); and

• LPeak of 140dB.

LAeq8h85dB(A) means the level of daily noise exposure normalised to the average eight-hour working day. Noise level exposure must not exceed the A-weighted sound energy of 85 decibels over an eight-hour period.

A-weighted sound energy measurements ensure that the testing equipment reflects how humans hear noise.

LPeak140dB is the highest frequency unweighted (pure sound) peak sound pressure level. Any noise, even if it is for a short time, must not exceed 140dB because this can cause instantaneous hearing damage.

   Comparative Examples of Noise Levels:

Comparative examples of noise sources, decibels & their effects 

Noise Source

Decibel Level

Decibel Effect

Jet take-off (at 25 meters)


Eardrum rupture

Aircraft carrier deck


Military jet aircraft take-off from aircraft carrier with afterburner at 50 ft (130 dB).


Thunderclap, chain saw. Oxygen torch (121 dB).


Painful. 32 times as loud as 70 dB.

Steel mill, auto horn at 1 meter. Turbo-fan aircraft at takeoff power at 200 ft (118 dB). Riveting machine (110 dB); live rock music (108 - 114 dB).


Average human pain threshold. 16 times as loud as 70 dB.

Jet take-off (at 305 meters), use of outboard motor, power lawn mower, motorcycle, farm tractor, jackhammer, garbage truck. Boeing 707 or DC-8 aircraft at one nautical mile (6080 ft) before landing (106 dB); jet flyover at 1000 feet (103 dB); Bell J-2A helicopter at 100 ft (100 dB).


8 times as loud as 70 dB. Serious damage possible in 8 hr exposure

Boeing 737 or DC-9 aircraft at one nautical mile (6080 ft) before landing (97 dB); power mower (96 dB); motorcycle at 25 ft (90 dB). Newspaper press (97 dB).


4 times as loud as 70 dB. Likely damage 8 hr exp

Garbage disposal, dishwasher, average factory, freight train (at 15 meters). Car wash at 20 ft (89 dB); propeller plane flyover at 1000 ft (88 dB); diesel truck 40 mph at 50 ft (84 dB); diesel train at 45 mph at 100 ft (83 dB). Food blender (88 dB); milling machine (85 dB); garbage disposal (80 dB).


2 times as loud as 70 dB. Possible damage in 8 hr exposure.

Passenger car at 65 mph at 25 ft (77 dB); freeway at 50 ft from pavement edge 10 a.m. (76 dB). Living room music (76 dB); radio or TV-audio, vacuum cleaner (70 dB).


Arbitrary base of comparison. Upper 70s are annoyingly loud to some people.

Conversation in restaurant, office, background music, Air conditioning unit at 100 ft


Half as loud as 70 dB. Fairly quiet

Quiet suburb, conversation at home. Large electrical transformers at 100 ft


One-fourth as loud as 70 dB.

Library, bird calls (44 dB); lowest limit of urban ambient sound


One-eighth as loud as 70 dB.

Quiet rural area


One-sixteenth as loud as 70 dB. Very Quiet

Whisper, rustling leaves




Barely audible

Duties of Suppliers

The Health and Safety in Employment Regulations 1995 specify the duties of designers, manufacturers and suppliers of hearing protectors. They must design and manufacture protective clothing and equipment, including hearing protection, so that it will give adequate protection from the harm the clothing or equipment is intended to protect. Manufacturers and suppliers must also provide comprehensive and readily understandable information about:

• what the protective clothing and/or equipment has been designed for; and

• how to use, wear, clean and maintain it.

Duties of Employers

The law requires employers to take all practicable steps to eliminate, isolate or minimise the hazards of excessive noise in the workplace. However, if all practicable measures have been taken and noise still exceeds 85dB(A), employees and others in the workplace exposed to the noise will be required to wear hearing protection.

If the employer has to minimise excessive noise hazards, and determines that hearing protection must be used as part of safe practice, the employer must:

• Supply the hearing protection to employees

• Provide information to employees about how to use the hearing protection, why it is necessary to wear it, how to keep it clean (if reusable, like earmuffs or reusable earplugs), where replacements are located (if disposable, like one-use earplugs), how to assemble or disassemble it (if applicable)

• Monitor employees' exposure to the noise hazards

• Take all practicable steps to obtain consent to monitor employees' exposure to the hazards (e.g. audiometry testing)

• Give results of any monitoring undertaken to exposed employees

• Train and adequately supervise employees in the safe execution of their work, including by wearing hearing protection.

Duties of Employees

Employees are legally required to wear or use the protective clothing and equipment that the employer issues to them, including hearing protection.

Employees can also refuse to perform work that is likely to cause serious harm, for example: employees expected to work in an environment known to contain noise in excess of 140dB without having access to hearing protection, could - after trying to work with the employer in good faith to resolve the issue - refuse to do the work.

Note: the refusal only applies to work that is known to be unsafe and likely to cause serious harm. If other, safer work is available, it must be conducted.


The Department of labour has recently reviewed and updated its publication Classified Hearing Protectors. The information contained in this publication is intended to assist employers and employees to choose hearing protectors that will give suitable protection against excessive noise levels. It is based on AS/NZS 1269:2005 Occupational Noise Management.

CLICK HERE to read this publication


Last modified on Thursday, 17 May 2012 14:08