Air-gap types and their ratings, tap-gap sizes over basins and baths, where a gap is measured from, and what can bridge or drown it.
An air gap is a physical break: water falls from the outlet through open air, so there is no continuous path back into the supply and no moving seal to stick or wear. That makes it the protection relied on for category 5, but only for the right type, correctly installed.
Read the full Water Regulations note with Premium
You’re reading the free preview. PlumbRevise Premium unlocks the complete write-up, the worked detail for every Water Regulations note — plus timed tests on every module.
Plenty of modules are free to read in full.