Low Frequency Noise Reduction for Water Pump Station

PROJECT:

Paddy Gully Road pump station Wivenhoe to Cressbrook pipeline

INDUSTRY TYPE:

Utilities - Water

CLIENT:

Toowoomba Regional Council (TRC)

LOCATION:

Station Wivenhoe Dam, Qld

Initial project requirements:

Toowoomba Regional Council’s Paddy Gully Road pump station infrequently operated pumps for the Wivenhoe to Cressbrook pipeline. Initially, the noise was not a concern to nearby residence; since the pump station was partially enclosed, the pumps operated infrequently and only emitted a low-frequency sound.

Even though sound in the lower frequency range is around us all the time, people’s sensitivity varies considerably, and many people are not always aware of it. Low-frequency sound is defined loosely as having a frequency below 150 Hz; for example, a rumble of thunder, the noise of a tuba, or sounds like the “oo” in “who.”

A proposed change in the pump station’s operating times meant that the noise levels from the pumps would become an issue for nearby residences since the pump noise levels exceeded the site limits at the boundary by 5 dB.

Flexshield were tasked with creating a design that would meet several challenges: to take advantage of the existing structure, achieve noise reduction, and cater for access for maintenance – not to mention come under the allocated budget!

Duke Environmental referred Toowoomba Regional Council (TRC) to Flexshield. Our team initially worked with Duke Environmental to select suitable products for the project and provide a cost estimate for the submission to TRC.

Project challenges:

Flexshield met with TRC and provided them with product samples and test data certificates to finalise the offer. Once Flexshield was officially awarded the project, our team provided engineered drawings for TRC to approve before manufacture.

A critical factor in Flexshield winning the job was our ability to create a solution where the existing infrastructure didn’t need modification. To do this, we leveraged off the existing steelwork to install V50 Sonic System modular acoustic panels on two interior sides of the structure. These modular acoustic panels have an NRC of up to 1.00 in accordance with ASTM C422-90A and sound attenuation of Rw31 dB in accordance with AS/NZS ISO 717-1-2004.

Flexshield then custom-made concertina sonic curtains to two large doorways to allow truck and crane access for pump maintenance. We also used our versatile sonic curtain as pipe lagging for the pipe that exited the building, extending to where the pipes dip below ground level.

Custom-made sonic curtain pipe lagging for the existing pipe

Flexshield solution:

Since Flexshield is an existing TRC vendor, the project timeframe was reduced as the process was straightforward, eliminating the onboarding and induction required for new contractors. This meant the project took three months to move through the phases of design approval to final project sign-off.

The V50 Sonic System acoustic modular panel and the sonic curtain lagging created positive results for TRC, resulting in:

Reduced environmental impact
Positive relationships with neighbouring residences
The ability to pump water 24/7, and
Protecting the pumps from Australia’s harsh elements.

Toowoomba Regional Council’s Project Manager said of the project,

“The installation went well, and the initial testing has shown a 10dB reduction which is excellent, beating the target by 5dB, so a very good outcome for us. The project team was good to work with too. We will be using Flexshield again on another project at Cambooya very soon.”