You already know that Lauxes Grates are made from anodised aluminium therefore they are a breeze to customise as you can drill as many holes for as many waste outlets you require. However, how many outlets do you need for your project?
First 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. The flow rates for each outlet size are listed below:
40mm — 18 litres per minute
50mm — 24 litres per minute
72mm — 43 litres per minute
80mm — 68 litres per minute
An 80mm waste outlet
has a flow rate of
68 litres per minute.
In practical terms, that means that for most indoor applications one 80mm outlet may be capable to handle the water volume (for example, more than sufficient for a bathroom with double shower heads).
However, for outdoor applications it is more complex as the water levels can vary significantly. A several-metre-long Lauxes grate, on a fully covered balcony, might be just fine with the one outlet. Although, 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 the grate, 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.