Going underground with boundary boxes
August 2022

Boundary boxes are a common feature on our residential streets, designed to house the water meter at the boundary between the water main and the domestic supply. However, when it comes to their installation, there are numerous factors to consider in order to ensure a long-lasting service life. Here, Rich Pedley at Aliaxis explores more.

While boundary boxes are a staple part of urban infrastructure, they can present asset owners with a bit of a headache. Indeed, a common and costly issue involving boundary boxes is ground sinkage around the boundary box location cover. This sinkage can be due to a number of reasons, from ground settlement to the weight of passing traffic over time. As well as being unsightly, sunken ground can also present numerous safety risks, from potential trip hazards for pedestrians to causing damage to vehicles.

For asset owners and contractors, this can lead to costly callouts, rework and repeat maintenance. This in itself can be a convoluted and complex process, with the boundary box presenting something of a ‘no mans land’ when it comes to ownership and responsibility. However, this can all largely be avoided if the correct solution is chosen at the early specification and planning stage of a project.

Load-bearing capabilities

While both the backfill material and the backfilling technique used will also have a role to play in the longevity of the installation, looking at the boundary box’s load-bearing capabilities is another key factor for consideration. Boundary boxes can often be manufactured with an adjustable top section, enabling installers to easily adjust the height of the box to be in perfect alignment with the adjacent pavement or road surface. Commonly featuring a telescopic adjustment mechanism, there is the danger that - over time and with the constant loads from passing traffic - the box and cover can sink.

Consider instead opting for a boundary box that is manufactured with a screw adjustment mechanism. Offering the assurance of a stronger, more robust hold and reliable load-bearing capabilities, this in turn can reduce the likelihood of depression during the product’s lifetime. The Adjusta boundary box range from Aliaxis UK is the only load-bearing adjustable boundary box available on the market, providing Grade B load-bearing capabilities with a range of screw adjustable top units available.

Watertight vs non-watertight

Another consideration for asset owners, contractors and housebuilders is to decide whether a watertight or non-watertight boundary box is required. While this may sound counter-productive, given the box’s purpose to house a water meter, there are certain applications where a watertight boundary box is essential. For example, if the installation is within an area with a known high water-table. Here, without the installation of a watertight boundary box, water from the ground could penetrate inside the box and the internal unit, causing issues with the meter and leading to more callouts.

The right connection for the job

With so many possible applications and scenarios, from installations on new-build developments to repairs and retrofits to contaminated brownfield land; it’s important to look for a boundary box product range with a variety of inlet and outlet connection options.

Each application will have slightly different installation requirements and sequences, whether connecting to a new pipework system that’s being laid at the same time as the box is being installed or retrofitting a new boundary box to existing pipework. For example, for new installations, a boundary box that offers a push-fit pipe connection can be the ideal choice, enabling contractors to easily and efficiently connect the boundary box to the new water supply. Alternatively, for retrofit projects, boundary boxes are available with pipe tails, whereby sections of pipe are already installed within the box ready for jointing with the existing network, offering additional flexibility.

There are also boundary boxes available specifically for use on contaminated land – key as more housebuilders and housing associations are looking towards brownfield land developments. The BS8588 approved Adjusta boundary box range from Aliaxis UK can offer peace of mind into these applications, with both a plastic and brass manifold option.

The Adjusta range of boundary boxes also offers a variety of inlet and outlet connection options to suit different applications and project requirements, providing the utility and construction sector with a highly versatile solution.