Drainage, Waste & VentQuestion 116 of 360
The size of a building drain or sewer:
a.May be reduced after each cleanout
b.May increase then reduce
c.May be reduced after a fixture branch
d.Shall not decrease in size in the direction of flow
Explanation
A drain or sewer must not decrease in size in the direction of flow, because a reduction creates a choke point where solids collect and clog. It may stay the same or increase downstream. Reducing after a cleanout or a branch still violates the no-reduction rule.
Practice all 360 questions free — no signup required.
Related questions on this topic
- A common vent may serve how many fixtures connected at the same level?
- A fixture is 5 feet from its vent, but the trap arm is 1-1/2 inch, which allows only 3 feet 6 inches. The correct fix is to:
- The minimum slope for a 2-1/2 inch horizontal drainage pipe is:
- A vent that terminates through a side wall must be located at least how far from a property line and from openings such as windows?
- A trap primer is installed on a floor drain trap in order to:
- A residential clothes washer standpipe is assigned what DFU value and minimum trap size?
Last reviewed: · editorial process
PrepPass Editorial Team · Verified against California CSLB C-36 Plumbing Trade Examination · How we review