Traps are commonly installed on fixtures, suchas lavatories, sinks, and urinals. At times, theP-trap may also be suitable in shower baths andother installations that do not require wasting oflarge amounts of water.VentsA VENT (pipe) allows gases in the sewagedrainage system to discharge to the outside. It alsoallows sufficient air to enter, reducing the airturbulence in the system. Without a vent, oncethe water is discharged from the fixture, themoving waste tends to siphon the water from theother fixture traps as it goes through the pipes.This means that the vent piping must serve thevarious fixtures, as well as the rest of the sewagedrainage system. The vent from a fixture or groupof fixtures ties in with the main vent. A MAINVENT is the principal artery of the venting systemto which vent branches maybe connected and runundiminished in size as directly as possible fromthe building drain to the open air above (fig. 8-19).The MAIN SOIL AND WASTE VENT orVENT STACK, installed in a vertical position,refers to the portion of the stack that extendsabove the highest fixture branch, through theroof, and to the exterior of the building.Various types of vents are used in the ventila-tion of fixtures. The selection of a particular typedepends largely on the manner in which theplumbing fixtures are to be located and grouped.An INDIVIDUAL VENT, also known as aBACK VENT, connects the main vent with theindividual trap underneath or behind a fixture.This method of venting is shown in figure 8-19.Figure 8-19.-Typical stack and vent installation.8-15
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business