Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!

Draining Systems - Main Vents

Vents in draining systems protects traps against pressure differences that could cause them to siphon or blow out .

Sponsored Links

Vents protects traps against pressure differences that could cause them to siphon or blow out, leaving occupants unprotected against smell and potential contaminants from the sewer system.

Draining Systems - Main Vents
Pipe Size
Max. Drainage Fixture Units
1 1/4 1
1 /1/2 81)
2 24
2 1/2 48
3 84
4 256

1) No water closets permitted

  • at least one vent should terminate through the roof
  • air admittance valves within the building may be permitted (check local authority)
  • terminating vents in side wall may be permitted (check local authority)
Sponsored Links

Related Topics

  • Dimensions

    Sizes and dimensions of pipes and tubes, and their fittings - inside and outside diameter, weight and more.

Related Documents

Sponsored Links


Search is the most efficient way to navigate the Engineering ToolBox.

Engineering ToolBox - SketchUp Extension - Online 3D modeling!

3D Engineering ToolBox Extension to SketchUp - add parametric components to your SketchUp model

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with older versions of the amazing SketchUp Make and the newer "up to date" SketchUp Pro . Add the Engineering ToolBox extension to your SketchUp Make/Pro from the Extension Warehouse !

Translate this Page

Translate this page to Your Own Language .

About the Engineering ToolBox!

Privacy Policy

We don't collect information from our users. More about


This page can be cited as

  • The Engineering ToolBox (2008). Draining Systems - Main Vents. [online] Available at: [Accessed Day Month Year].

Modify the access date according your visit.

3D Engineering ToolBox - draw and model technical applications! 2D Engineering ToolBox - create and share online diagram drawing templates! Engineering ToolBox Apps - mobile online and offline engineering applications!

Unit Converter


Sponsored Links