Vineyard’s noisy fans infuriate neighbours

Neighbours of a Masterton vineyard say its new frost fans sound louder that ‘‘a fleet of Iroquois helicopters’’.

And, in fact, Matahiwi Estate used to use conventional choppers for its frost protection, but the neighbours said they were much more bearable than the new twobladed fan towers installed next door.

Erica Kinder lives on the Loopline opposite the vineyard and has formed an action group of residents who are ‘‘frustrated and angry’’ about the noise of the fans.

‘‘It’s like an Iroquois helicopter – that really deep, whoop, whoop, whoop sound. Imagine nine of those out there.

‘‘Even through the double-glazing it’s like your head is expanding. All the windows are shaking and the whole house is vibrating.’’

The fans were automatically set to start up at a certain temperature which could mean they were operating from midnight until dawn on some frosty nights.

Kinder said there were 28 members of the Matahiwi Frost Fan Action Group, which met earlier this month to discuss how to combat the noise.

The residents believe a solution could be for the vineyards to use quieter four or five-blade fans, than the two-blade options currently installed.

Matahiwi Estate owner and former Wairarapa MP Alastair Scott said he had invested in the fans because using helicopters had become increasingly expensive.

Scott said he realised the fans were noisy, but they were a necessary protection measure for the vineyard, which could lose a harvest if frost killed the buds.

‘‘Whatever I use is going to be noisy, helicopters are noisy and five-bladed fans will wake them up even though they are less noisy than the two-bladed fans.’’

Last year the vineyard needed frost protection on more than 12 nights during spring.

He said water frost protection was not a viable option on his vineyard because the volume of water needed was not available.

Chris Kay of New Zealand Frost Fans said two-blade fans were about 10 decibels louder than those with four blades, which seemed like ‘‘double the sound’’ to the listener due to the nature of the decibel scale.

‘‘A frost fan with more blades and a reduced diameter can run at lower rpm, whilst producing the same or better wind momentum as a faster two-blade fan,’’ Kay said.

‘‘And because the blade tip speed is slower, due to the lower rpm and smaller blade diameter, the fan produces a lot less noise.’’

He also said the nature of the sound of fans with more blades was more of a constant hum than the deep whoop-whoop sound made by Iroquois helicopters, famously used by the US in Vietnam.

Kinder said the Masterton District Council refused to monitor the noise levels of the Matahiwi fans because ‘‘they say they don’t have to’’ as it’s a permitted activity.

The council said under the Wairarapa Combined District Plan there were no noise level limits on frost fans in the Rural Primary Production Zone.

‘‘Frost protection devices are specifically excluded from having to comply with the noise level limits.’’

A plan change in 2010 restricted maximum fan noise to 55 decibels, measured from 300 metres away or a nearby house.

Kinder bought a noise monitor and measured the sound outside the house at more than 65 decibels in the early hours.