I see the Marlborough Express are reporting that there is progress in the long running dispute over frost fans up the Waihopai valley.
This particular problem area appeared to be mainly concerning the ludicrous (former) district plan rule that allowed fans within 100m of an adjoining neighbours house.
Don't get me wrong, that rule is still in place for existing fans (pre 2010ish). But nowadays the most recent plan change (currently under appeal by the whine growers) is anticipated to be a little more sensible.
I see they (Waihopai Holdings) want to have the fan pretty close still and have employed an acoustic expert to determine how best to achieve the process. As a result they intend to build a large hay bale wall.
That should be quite a sight! I imagine it would be effective in blocking noise, but I'm also imagining it would have to be pretty large. Interesting.
HOWEVER, what's caught my eye was the mention that one of the mitigation methods put in as a condition is INCREASING the speed of the fan!
I quote "Waihopai Holdings' expert witness Jeremy Trevathen said slightly increasing the speed of the fan would raise the noise level, but would reduce annoying special audible characteristics".
Increasing the speed decreases the SAC? At first blush that appears to be something straight from left field.
I honestly don't know how to approach it since it flies in the face of what I accept to be logic.
But I do know one thing.
Any testing that was carried out by Jeremy Trevathan (not 'Trevathen' as reported in the Express) is not independent.
He's a colleague of John Pearse from the University of Canterbury. The same bloke who designed and built the Defender (or at least the original MK1).
Dr Pearses testing relied on simulation of noise via the CONCAWE method, which frankly fiddled the numbers. Trevathan's his mate and he reckons that if you turn up the speed on a Defender the Special Audible Characteristics go down.
That smells.
That smells more that a 35m wall of hay that's beendecomposing too long
Friday, 14 October 2011
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2 comments:
Whilst your case against noise intrusion may be warranted you should only report facts not fiction. The Concawe method is not a simulation but is a recognised way to make adjustments to measured data to account for climatic conditions that are different from those during the measurement period. This correction can make the calculated noise levels higher than measured. Do your homework properly. Also Dr Pearse was the facilitator and project manager, not the designer. Bad reporting leads one to wonder about the veracity of your outpourings so if you want to make a case get the facts right!
Ahh yes, the CONCAWE method. Or more accurately “The propagation of noise from petroleum and petrochemical complexes to neighbouring communities”. Used by the truly desperate to make their noisy activities seem quieter or when their shoddy testing doesn't actually take place in the conditions that it should (Yes, Frost Fan testing) or both :-).
Sorry did I say simulation? I meant prediction. Oh wait, that IS what I said. Perhaps I'm wrong... Perhaps it isn't a prediction method... Oh wait, The CONCAWE method IS a prediction method.
Ahh well that's all sorted out now.
Oh wait “This correction can make the calculated noise levels higher than measured “. But they didn't did they? Applying adjustments using the CONCAWE report made the fan seem quieter didn't it? How convenient. And it avoided all that nasty testing in actual frost conditions. Not pleasant business getting up in the middle of the night and going out in the cold.
So, Dr Pearse was the facilitator and project manager, not the designer? Very interesting. I did not know that. So who did design it? Was the person who designed the MK I Defender, the same as the person who designed the Mk II? Perhaps they took some basic metallurgy classes during the BREAK between the designs.
Anyway, it's great to see the Defender doing so well in the market now. Oh wait... The IP was bought by it's competitor and the remaining units are being serviced by a tractor maintenance firm...
http://www.fmrgroup.co.nz/news/frost-fan-announcement
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