Lauxes Grates offers a customisable range of anodised aluminium grates that can be tailored to meet your specific drain flow requirements. This means you can drill as many holes as you need for multiple waste outlets on a single grate. However, how do you determine how many outlets you will need for your project?

To begin with, you need to know the flow rate of each waste outlet size. Naturally, the bigger the hole, the larger the volume of water can be drained per minute, so we recommend using the largest possible size of waste outlet. 

Below is a list of waste outlet sizes and the corresponding flow rates:

  • 40mm: 18 litres per minute
  • 50mm: 24 litres per minute
  • 72mm: 43 litres per minute
  • 80mm: 68 litres per minute

For most indoor applications, a single 80mm waste outlet may be more than sufficient to handle the water volume from, for instance, a bathroom with double showerheads.

However, for outdoor applications it is more complex as the water levels can vary significantly. A Lauxes linear grate, several metres in length, on a fully covered balcony, might be just fine with a single outlet. But a driveway grate at the end of a slope may need more outlets to comfortably handle heavy rainfall.

One last factor to consider is the plumbing connected to linear grates, as it will set up the limit for the overall flow rate. Adding an extra waste outlet to the grate will not increase the flow rate of drainage.

If in doubt, contact your local plumber for an accurate recommendation based on your state/territory laws and application type.