Workers’ protection aim of noise cuts

Press, 27 October 1977, Page 3

Workers’ protection aim of noise cuts

PA Wellington The acceptable noise level for a normal eight-hour working day has been cut by the Health and Labour Departments from 90 to 85 decibels, to protect workers’ hearing.

The departments say that at noise levels over 85 decibels people have to shout to make themselves heard by people one metre distant. Where the new acceptable level is exceeded, conservation measures will have to be instituted, they say. The reduced permitted noise level followed similar action in several other countries, because research had shown that the previously recommended maximum level of 90 decibels did not afford sufficient protection for many workers, the departments said yesterday. If Labour Department inspectors find a factory where noise levels are high, the local medical officer of health is called in to determine whether noise is excessive.

If so, the inspectors go back to see whether noise can be reduced by redesigning equipment, isolating

noisy machinery, or by installing insulation. Where this is not possible, a hearing conservation programme is set up. This includes educating the workers on the need to protect their hearing, the use of ear plugs or muffs and, where noise levels are very high, periodic hearing tests are made.

People exposed to high noise levels in their occupations who also have noisy hobbies—such as trail-bike riding or shooting—may run the risk of damaging' their hearing. The Employers’ Federation has strongly attacked the new maximum permissible noise levels. The federation’s research director (Mr R. Taylor) said he was disturbed that the departments had not sought the federation’s views before the change was announced. “Regardless of the five-year phase-in period, the new requirement would put impossible demands on many industries,” he said. “It is not technically feasible to reduce noise on many machines because of their design and operating capacities.”

Overseas studies showed it was not the intensity of noise

that damaged hearing so much as the frequency levels, said Mr Taylor. “A recent study of 250,000 employees in the United States indicated that noise levels of 82 to 92 decibels continuous through the working day had little effect on hearing at speech levels. “So there is little to be gained by reducing the noise to 85 decibels, as proposed by the departments. It is imposing a considerable amount of effort and cost for little value.”

An Auckland ear specialist. Mr P. W. Eisdell-Moore, said the reduction would save considerable potential ear damage, but he would like to see the level as low as 75 decibels.

“For every three decibels of sound round the danger level you double the potential damage than can occur in the ear,” he said. “It used to be accepted internationally that 90 decibels was an acceptable level for eight hours a day over a 40-year working life, but it was found that if you worked in an area of 93 decibels the same amount of damage would occur after a fourhour working day.”