The different type of attenuations and benefits of each one

Are you new to the world of stormwater attenuation crates and don’t know where to start? With five main variations to choose from, each offering different features and benefits, it can be overwhelming. In this article, we’ll take a closer look at the different types of stormwater attenuation crates and their key benefits.

  • Single Piece Crates: These crates contain everything in one piece, including the flow control compartment. This simplifies the installation process and makes it easier to manage, as there are fewer components involved. The crates are also pre-fabricated and fully assembled, making them ready to use and be installed straight away.

  • Stackable Crates: Stackable stormwater attenuation crates offer a modular design that provides more flexibility during installation. The installation process can be completed faster and without the need for heavy equipment. These crates are best suited for areas that can’t accommodate a long row of connected crates, and they are stacked on top of each other to retain large storage capacities.

  • Light Duty Crates: Light duty crates are designed to accommodate pedestrian loads, as well as domestic vehicular loads. They are commonly used in gardens and landscaping areas, with a load limit of around 20 tonnes. The installation location, depth of cover, tank depth, top surface cover, ground type, and usual loading traffic must be taken into consideration when using these crates.

  • Heavy Duty Crates: These crates are built to handle large weight loads at ground level, with a load capacity of over 60-70 tonnes. The exact load capacity is determined by factors such as cover depth, soil type, surface finish, and others. Heavy duty crates are typically used in areas with high amounts of traffic, or for car parking areas accommodating multiple domestic vehicles.

  • Inspectable Crates: Inspectable stormwater attenuation crates make maintenance easier, as they are designed with inspection in mind. They include inlets and outlets for assessment of the system’s condition. With increased calls for better sustainability, inspectable crates are becoming more common.

Stormwater attenuation crates are used below ground to manage surface water levels after heavy rainfall. Once installed, they work by capturing water during storms, retaining it in the tank, and redirecting it to a local body of water or storm drain at a controlled rate to avoid flooding.

show attenuation crates heavy duty

These crates are used in various environments, such as roads, car parks, shopping centres, sports stadiums, pavements, and more. The number of crates required depends on the storage size needed and can vary based on factors such as flow rate and soil type. Installation depth should be at least 2 meters below the ground to maintain proper filtration levels. It is important to be aware of regulations, such as a minimum of 2.5 meters away from boundaries and 5 meters away from nearby buildings, when installing stormwater attenuation crates. A percolation test should be carried out before installation, and the size should be based on a drainage calculation.

2m down attenuation

Here at Polycon, we supply the Polycrate. Below is an outline of the models and where they are best used.

PolyCrate HP and HPR – Underground drainage basins with PolyCrate HP and HPR have a basin depth of up to 20ft and allow the overlying surfaces to be used for the following purposes:

HS 25 rated surfaces access ramps for heavy goods vehicles access roads to industrial areas parking areas for special vehicles (truck mixers, fire engines)

PolyCrate STR – Underground drainage basins with PolyCrate STR have a basin depth of up to 14ft allow the overlying surfaces to be used for the following purposes:

HS20 / HGV 30 rated surfaces access roads to residential areas parking areas for cars and light vehicles cycling tracks

For more information on our different PolyCrates systems visit here.

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