Drainage, Waste & VentQuestion 140 of 360
The air gap for an indirect waste pipe discharging into a receptor must be at least…
a.1/2 inch
b.equal to the pipe diameter
c.3 inches minimum
d.twice the effective opening (diameter) of the indirect waste pipe, and not less than 1 inch
Explanation
An indirect waste air gap must be at least twice the effective opening of the drain pipe, measured vertically, and never less than 1 inch. This physical separation prevents sewage from backing up into the equipment through the indirect drain. It is the same principle used for potable-water air gaps.
Law Reference: 2022 California Plumbing Code (CPC) §801.2Practice all 360 questions free — no signup required.
Related questions on this topic
- Fixtures with flood-level rims located below the elevation of the next upstream manhole cover must be protected from sewer backflow by…
- An installed backwater valve must be…
- Under the CPC, rainwater (storm) drainage and sanitary sewage generally must…
- Food-handling equipment such as a commercial food-prep sink or an ice machine must discharge to the drainage system by means of…
- A domestic dishwasher discharge, before it connects to the drainage system, must be protected against backflow by…
- Which establishment is most likely required to install a grease interceptor or grease trap?
Last reviewed: · editorial process
PrepPass Editorial Team · Verified against California CSLB C-36 Plumbing Trade Examination · How we review