The existence of water and sewer maintenance pit lids and access covers is not something most people think about – until you drive over one that’s sunken or not level with the road. Then their presence is noticed!

When pit covers aren’t installed correctly or have been corroded by weather and use over time, they can sink into roadways causing traffic hazards or, more significantly, can corrode, become leaky and allow water from the surrounding environment to seep into underground infrastructure. In some instances, manhole structures that aren’t watertight can allow millions of extra gallons of water to enter the system annually. All of the water that moves through urban water infrastructure requires treatment, and these huge additional quantities add massive costs to cities, to utilities and ultimately to us all.

Repairing and upgrading manhole structures, including pit risers, manhole frames and access lids, is an important part of urban renewal. It ensures safety as well as optimal urban infrastructure and water industry operations.

Roads pose unique challenges for water and sewer pit covers

Until recently, ductile iron and concrete infill manhole covers have been the most commonly used product for water and sewers in road situations. These conventional covers can weigh hundreds of kilos and are extremely difficult to move once in place. They are also vulnerable to rust, which degrades the seal, allowing water to leak in and gas to leak out over time. However, they have been the best option so far to meet the unique requirements where access to underground infrastructure is required.

This is why leading manhole repairer, Mr. Manhole, have teamed up with Terra Firma to install our leading E400 composite pit lids when removing and replacing water and sewer manhole infrastructure in roadways.

Water and Sewer cover retrofit to meet Australian standards

Mr. Manhole is an Aussie company that rebuild and repair manholes with unique cutting machine technology. Their specialised technology is engineered for quickly removing and replacing manhole frames and covers.

Mr. Manhole previously partnered with Terra Firma to complete the Bolte Bridge onramp retrofit. This project took place in a busy highway situation and required the removal and replacement process to be completed quickly and efficiently with minimal shutdown to traffic. Due to the success of the Bolte Bridge project, Mr. Manhole and Terra Firma have teamed up again to complete an urban road renewal project in Tasmania.

Terra Firma composites – the perfect fit

Due to the unique challenges of infrastructure, coupled with the ongoing need for quick, safe and easy infrastructure access, Terra Firma E400 Composite lids were used in both the Bolte Bridge and Tasmanian Mr Manhole projects. These lids provide the following benefits:

  • Non-corrosive materials that won’t rust when in contact with H2S, sand, salt and all chemicals met in sewer and road environments.
  • Covers that lock into position.
  • Provides a permanent, leak-free, gas-tight seal.
  • Weigh approximately one-third of cast iron.
  • Quick and easy to install and access
  • Significantly reduces the risk of injury to workers by eliminating the need to lift heavy objects manually.
  • Rated Class E under the AS3996:2019 standards

A streamlined approach

To successfully replace a pit lid, the old fixtures including the lid, the frame and the riser pipe that give access to the sewer or drain are removed. These components are then replaced, and new covers are fitted. You can watch a video here that shows the process in action. Once upgraded, there are significantly reduced OH&S injuries to workers when removing pit lids. With the Mr. Manhole process, repairs cost as little as $521 compared with the traditional $1640 (excluding the pit lid).

Successful project with infrastructure that will stand the test of time

Mr. Manhole’s cutting technology works with Terra Firma’s E400 100% watertight/gas-tight composite covers to address corrosion and surface water infiltration and inflow issues. In conjunction, these two products provide a comprehensive solution for leaking water and sewer covers and frames.

Upgraded utility pits now have the following:

  • No seepage, either water in or gas out
  • Unaffected by chemicals and gasses found in this environment
  • No rust or corrosion
  • Reduces injury to workers from moving traditional lids
  • Eliminates pit-cover potholes
  • Repairs that are completed quickly with minimal shut-down

Partnerships like this make us genuinely excited about the future of our urban landscapes and the role of innovation in creating safer and more sustainable cities.

As an Australian owned and managed company, we specialise in composite products designed specifically to meet the unique demands of Australian civil infrastructure. We can also develop custom access solutions for almost any challenge.

If you’d like to know how composite access covers including our Terra Firma E400 and Terra Firma smart covers could benefit your next project or would like to discuss our composite solutions more broadly, you can contact us here to start a conversation.

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