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HyMix rapid roll acoustic door

Reasons for Installing Rapid Roll Acoustic Doors

Background Due to the ‘up before the sparrows’ starts and...


Due to the ‘up before the sparrows’ starts and the machinery-intensive process of mixing cement, gravel, sand and water, concrete batching plants are very noisy workplaces.

Just ask anyone who lives near one. The nearby residents will tell you about the infuriating din of concrete trucks driving in and out, revving their motors to mix the concrete before delivering it, as well as associated noises such as high-pressure water cleaning, and forklifts reversing.

It would be bad enough during the day, but at dawn when noise travels so quickly and carries much further, it’s a nightmare.

Such was the case for neighbours living reasonably close to the Hymix concrete batching plant at Springwood, in Brisbane’s south.

The business was so brisk, early starts were called for (usually 4.30 am or earlier), extra shifts were running, and the fleet of 13 concrete trucks based at the plant was barely able to cope with the speedy turnaround.

On hectic days, up to 20 trucks an hour were in the mixing/ batching process – with the mixing all done inside the concrete truck.

To ensure each batch of concrete mixed thoroughly, the trucks needed to operate at full revs for considerable periods originally out in the open with no sound barriers whatsoever.

The result was the noise was consistently going over 6 dB above background noise at the boundary even though sirens and reversing buzzers on the trucks were automatically disabled before 7 am.

The neighbours were not happy. And justifiably so.

On paper, this needn’t have bothered HyMix; they had a DA to virtually make as much noise as was deemed necessary, 365 days a year, with no restrictions.

However, being a good corporate citizen, HyMix voluntarily sought information and advice from Brisbane City Council and acoustic experts about the best way to quieten noise at a concrete batching plant.


Acoustic Rapid Roll Doors – a unique soundproofing solution for concrete batching plants

With the door down, you can stand behind the truck and have a normal conversation… instead of having to yell at the top of your voice over the engine!”

Dave, HyMix Plant Manager


Flexshield’s Acoustic Rapid Roll Doors were the ideal solution to quieten the noise at the HyMix concrete batching plant.

Interestingly, to our knowledge, no Rapid Roll Doors of this exact type have ever been installed before.

As the name implies, its rapid roll is what sets it apart.

As opposed to a manual door, which would involve the driver having to stop, get out of the truck, open the door, get back in, drive forward, get out and close the door, the whole process is streamlined and allows for fast access.

The high-speed door features a state-of-the-art German motor & electronics and incorporates an integrated motion sensor, similar to a radar.

For HyMix, the opening cycle is set by speed actuator at approximately 3 seconds (2m every 1.7 seconds), so it doesn’t slow the process.

Some applications (such as those requiring thermal fidelity) have programming for faster opening cycles – up to 2.5m per second – but this pace was deemed appropriate for this application to reduce maintenance and prolong the service life.

Even though the sensor works very well, the concrete batching plant often opts to use the manual operation as it is so easy.

In manual mode, the driver radios in and the controller press a remote key fob or induction loop, and the door rises and shuts behind the truck.

The Acoustic Door, by the way, is only needed at the back of the shed because that is the side that faces the neighbours – the front of the shed is entirely open.

It just keeps on working and hasn’t missed a beat.

Dave, HyMix Plant Manager



Technical considerations of this unique Acoustic Door

The Noise Control Rapid Door construction was 4kG/m2 Sonic Curtain.

Fitted to a semi-enclosed sound absorptive shed, to test the Acoustic Door, noise readings were taken during normal operations and using Pink Noise as a noise source. Testing of the noise levels was complete at a distance of 3 metres with the door opened and closed.


Rapid Roll Acoustic Doors for every application.

Regardless of whether you run a concrete batching plant, or any manufacturing plant, if you need the door to operate quieter, faster, smarter and safer, Flexshield’s Rapid Roll Doors are the way to go.

Designed and sustainably manufactured in Australia, they can be customised to suit your individual requirements in terms of:

  • Size & specification
  • Colour
  • Capacity of motor
  • Integration to building design
  • Climatic conditions
  • Specific functionality (eg visibility through doorway),
  • and much more.


Meticulously constructed with few wearing parts, they are so robust and reliable the efficient opening and closing will be in operation thousands of cycles later, almost irrespective of the environment in which they are installed.

In fact, they come complete with a 1-year/100,000 or 3-year/300,000 Warranty (conditional) and parts availability is guaranteed Australia wide.

Furthermore, they are fully crash-tested and designed to recover automatically recover from an impact to the door during operation.

Super energy-efficient, they can be configured to open faster, be closed for longer and be sealed around the perimeters when closed.

This is important in thermal-centric industries to effectively reduce energy loss through doorways, and in food production to ensure hygiene requirements and reduce cross contamination.

Flexshield’s Rapid Roll Doors are ideal in facilities with significant-to-high traffic movements, to maintain closed doors without serious disruption to operations.

For more information about Rapid Roll Doors contact us or download our complete product catalogue.