An air break is used to indirectly connect a drainage pipe to another drainage pipe. This is commonly used to protect fixtures that are used to prepare food, drinking fountains, ice makers and many other devices that cannot be contaminated.
"The idea behind the air break is to prevent contaminated water from getting sucked back up into the pipe and or appliance, therefore contaminating the potable water within the water system. If there is a negative pressure within the home plumbing system, most of the water within the system will automatically be drained to the area of least resistance, therefore creating a potential negative pressure, and potentially siphoning dirty/contaminated water into the system. An air break prevents this from happening."
An air break is created by leaving an unobstructed vertical gap from the discharge of a fixture and the receptacle that receives it. This distance must be at least 25mm (1") or the size of the pipe.
- if the drain from an ice machine was 3/4" the minimum air break would be 1" (25mm)
- if the drain from a steam cooker was 2" the minimum air break distance would be 2" (50mm)