Shhh, Bay takes look at noise

Otago University associate professor Dr David McBride, monitoring noise levels in Hastings, has conducted an industrial noise study in Hawke's Bay for several years. Photo / Duncan Brown

It quickens the heart, increases blood pressure and stress hormones and makes employers liable, but the noise doctor has a solution.

Otago University associate professor Dr David McBride is studying ways of reducing noise in Hawke's Bay.

He was invited to Hawke's Bay by former OSH inspector-turned-consultant Miles Robinson about four years ago.

"We were keen to keep this initiative going, to see if we could get a couple of noisy industries and make a difference."

Hearing protection was often ineffective and noise generally unhealthy.

"If you look for ways to reduce the noise you always find ways to get it down a little bit. Every little bit helps," Dr McBride said.

"For example with a circular saw there are contributing noises and you can pick them off one at a time and find solutions."

He said one of the best solutions was to enclose a noisy process.

Ear protection often did not work because safety glasses broke the seal, sometimes people wore a beanie under them in cold weather and ear plugs were inconsistent.

"Most people don't wear them properly. Unless they are custom-moulded ear plugs they are prone to be not sitting properly.

"Most left and right ears are different," Dr McBride said. "It is like left and right feet, one ear might be fitted properly but the other is not.

He said under changing health and safety laws employers had to minimise noise.

"If you can't get rid of the noise you have to minimise it by hearing protection, then you have to measure the noise routinely and you have to do everything possible to reduce the noise."

Staff needed to have their hearing tested at regular intervals to ensure protection was working.

Wearing ear plugs under earmuffs was often a good idea, but sometimes ear protection was ineffective, Dr McBride said, "because the noise actually goes through your skull".

Too much ear protection was undesirable because sensory deprivation led to feelings of isolation.

One option was active noise technology, as found in battery-powered earmuffs, but it was expensive and more effective with a consistent noise.

Taking part in the study was Hastings District Council. A representative said staff working with noisy machinery such as tractors, mowers, chippers and chainsaws made mitigation important.

Council saw the opportunity to take part in Dr McBride's study as a win/win, said a council representative. After an initial assessment Dr McBride will make recommendations, and return in a year to see if implementation was effective.

"The results will be made public at the end of the project, giving businesses with similar issues some guidance on how to improve noise in their workplaces."