Acoustic Engineer Requirements

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vignesh5

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#239845 7-Aug-2018 14:56

Hi There,

We are looking to buy a property in a new estate which is backed up to the Railway lines.

One of the requirements in the covenants in the Sale and Purchase is there needs to be an Acoustic Engineer Inspection & his recommendations to be Incorporated.

As the Titles are not yet out. We have not received the Instrument. Hence no clarity on this clause.

Has anyone here faced similar case here in the past or in the present. Would like to know how you guys went about the process.

Thanks,

Vig

wellygary

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#2069423 7-Aug-2018 16:51

Is it just land, or a design and build package as well......

If its the latter, you are likely going to have to have any house plans run past the Acoustic people so you don't allow rooms that will have excessive noise from the rail line,

It looks like KR has been moving to internal noise measures lately, rather than more traditionally exterior boundary measures,

see this from KR regarding a plan change in Hamilton ( Page 13)

https://www.epa.govt.nz/assets/FileAPI/proposal/NSP000034/Submissions-and-or-comments/NSP000034-KiwiRail-Holdings-Limited-106919.pdf

You may find its becomes impractical to build bedrooms on the side abuting the rail corridor,

Disrespective

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#2069721 8-Aug-2018 11:30

The council is just making sure what will be built will meet the building code requirements.

You'll need to employ someone during the design phase to provide professional advice on insulation/construction methods that mitigate noise down to the building code acceptable maximum levels. And then after you have finished the build, the same people will probably* have to assess whether the final system meets this. It's quite common for residential units in non residentially zoned areas.

*The council may not ask for this to be done before code compliance is given, but I doubt it.

wsnz

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#2069820 8-Aug-2018 12:54

This condition would have been placed at the behest of KiwiRail who would have been party to the RMA consultation process. The NZTA are adopting a similar position, although they are much more aggressive with the addition of 40m setbacks from state highways, and their every expanding definition of "habitable".

As disrespective mentioned, you'll need to engage an acoustic engineer. We used Marshall Day, who conducted an initial assessment then later a review of the building plans.

MikeAqua

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#2069881 8-Aug-2018 13:35

I also suggest checking what the restrictions on fencing are. Some fence types help significantly with noise, which leaves less sound-attenuation for the actual building to do.

Mike

wellygary

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#2069891 8-Aug-2018 13:54

MikeAqua:

I also suggest checking what the restrictions on fencing are. Some fence types help significantly with noise, which leaves less sound-attenuation for the actual building to do.

They might also want to check with KR on what their requirement for fencing are (they will share the boundary)

http://www.kiwirail.co.nz/in-the-community/boundaries-and-property/fencing-a-boundary-with-rail.html

Bung

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#2070056 8-Aug-2018 14:38

MikeAqua:
I also suggest checking what the restrictions on fencing are. Some fence types help significantly with noise, which leaves less sound-attenuation for the actual building to do.

I suspect that a train could be pounding more vibration into your foundations through the ground and airborne noise will be the lesser part of it.

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mclean

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#2070062 8-Aug-2018 14:47

Until you have the actual wording of the covenant on the title you are only guessing.

It's likely to say that any future complaint you make about the train noise will fall on deaf ears, and that before the council can issue a building consent for a house you will need to prove that noise levels inside the house will be OK when trains are operating. These noise levels are usually set in the councils planning rules for the particular location, or it might be a condition of the resource consent for the subdivision. Apart from affecting the wall and glazing specifications, this sort of thing usually means that you have to meet the building code ventilation requirements with all the windows shut, ie you need mechanical ventilation.

Either way, I'm guessing you won't need the acoustic engineers report until you apply for a building consent, rather then when you purchase the property.

But as I said, only guessing at this stage.

wellygary

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#2070069 8-Aug-2018 14:59

mclean:

Either way, I'm guessing you won't need the acoustic engineers report until you apply for a building consent, rather then when you purchase the property.

But as I said, only guessing at this stage.

Although if there are noise restrictions on the property you need to know what they mean before you buy, rather than getting caught in the position of finding out after you buy that building a compliant dwelling is $$$ more than a comparable section down the road......

Having a understanding of what is or is not possible is a pretty important thing to know when you sign on for the land,

mclean

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#2070147 8-Aug-2018 16:36

wellygary: Although if there are noise restrictions on the property you need to know what they mean before you buy, rather than getting caught in the position of finding out after you buy that building a compliant dwelling is $$$ more than a comparable section down the road......

Having a understanding of what is or is not possible is a pretty important thing to know when you sign on for the land.

Yes, absolutely. And I wonder if the developer is requiring buyers to get a report as part of the disclosure on the property.

vignesh5

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#2070745 9-Aug-2018 15:03

Thanks everyone for the responses. We got access to the guidelines by council and found the necessities to be done for Acoustic Engineer Certificate.

Gib to be 13mm and a Ventialtion system (DVS) which is needed in case we are unable to leave the doors open.

I shall keep posting in case there are additional requirements we get to know in future.

Kickinbac

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#2071581 10-Aug-2018 23:27

vignesh5:
Thanks everyone for the responses. We got access to the guidelines by council and found the necessities to be done for Acoustic Engineer Certificate.

Gib to be 13mm and a Ventialtion system (DVS) which is needed in case we are unable to leave the doors open.

I shall keep posting in case there are additional requirements we get to know in future.

I’m not sure a DVS system will comply. If it’s using air from the roofspace it’s not ‘outdoor’ air and doesn’t comply with NZBC G4 and NZS4303 for ventilation.

I was asked to do a ventilation design/install for some houses next to a motorway offramp with stringent acoustic requirements. It had some obscure NZTA clause with a crazy high ventilation rate for cooling with outdoor air, like having the same ventilation and natural cooling as having your windows wide open in summer. It would have required quite large intake, fan, ductwork and grilles plus needed to be a quiet system so it wasn’t droning away. It was something like minimum fresh air being 30l/s vs. 400l/s just for the lounge. Another option was minimum fresh air plus air conditioning. We gave him various options and the client chose air conditioning using a ducted air conditioning system to all the rooms with a fresh air intake which provided heating, cooling and ventilation all for about 3k more than the fan only option.

Think about sleeping at night in the middle of summer with all the windows closed. You will want air conditioning! Bear that in mind that people get used to the noise after a few months.

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driller2000

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#2071696 11-Aug-2018 10:41

wsnz:

This condition would have been placed at the behest of KiwiRail who would have been party to the RMA consultation process. The NZTA are adopting a similar position, although they are much more aggressive with the addition of 40m setbacks from state highways, and their every expanding definition of "habitable".

As disrespective mentioned, you'll need to engage an acoustic engineer. We used Marshall Day, who conducted an initial assessment then later a review of the building plans.

+1 for Marshall Day - we use them as subbies on many of our projects - knowledgeable, fast and good value.