Threshold Drainage – Choosing the Right Load Rating

The load rating of a threshold drain is determined by the class, and the class denotes that a product has been tested to be able to safely hold up the required weight. Selecting the right threshold drain with the correct load rating can ensure full and complete safety and security for your project, and avoid the need for costly replacements later down the line.

Pedestrian Areas

If your installation is for a pedestrian area or landscaping project, it's unlikely you'll need a high load rating - a class of A15 (1.5 tonnes) is likely to be suitable. A galvanised steel or polypropylene threshold drain will withstand the loads caused by pedestrians.

Domestic Driveways

Domestic driveways need careful consideration when looking at load ratings. Although the average weight of a car isn't likely to be any more than 1.5 tonnes, the reality is the force exerted through the wheels when the car is turning can often be 3 or 4 times the static weight of the car.

Therefore, we’d recommend you use class B125 (12.5 tonnes) as a minimum, however if you're the owner of a heavy-duty car or van, or are looking to park more than one car on your driveway, it would definitely be worth going to a C250 class (25 tonnes).

Areas of Heavy Traffic

Heavily trafficked roads such at motorways and public car parks are recommended to have threshold drains at D400 class minimum. This is the equivalent of a maximum 40 tonne load rating and is suitable for constant traffic loads, and also heavier traffic loads such as moving vans, commercial lorries and more.

Cargo Yards and Loading Areas

For heavy loading areas, such as docks or transport hubs, it will be worth going even higher with your threshold drain load rating class, all the way up to E600. This can hold up to 60 tonnes of weight, making it ideal for places constantly trafficked by heavy good vehicles.

Airports

Considering the weight of aeroplanes, airports and heavy duty applications will need a class of no less than F900, which provides 90 tonnes of support. threshold drains of this classification usually come with a ductile iron grating and fibre reinforced concrete threshold for added strength.

threshold Drain Grates

Don’t forget, depending on the material your grate is made from, this may slightly affect the performance of your threshold drain – steel grates, for example, may be more resistant to higher pressure than PVC grates.

For more information about threshold drains, take a look through our guides and tips, or if you’re struggling to decide on the class you need, speak to our experts who are always happy to help.