24/7 Call us on 0402 290 290

Things You Should Know About Plumbing Vents

While some homes have chimneys, others have round roof vents. Still, there are others that have vents for gas-powered appliances. Despite this, all homes have plumbing vent stacks. These keep the water flowing and help keep harmful bacteria and other disease-causing micro-organisms out. Without it, the house will not only end up reeking of sewage and filled with harmful micro-organisms, as it will also be filled with flammable gases. They are, therefore, an essential part of the plumbing systems of homes.


These Need Air, Too
Although these protect the house by allowing the escape of sewer gases into the atmosphere, their primary purpose is to permit the entry of air into drain pipes. In the past centuries, many plumbers, after installing P-traps, noticed that they will empty when water runs in drains, hence rendering them ineffective. Upon the realisation that drains require a direct access to the atmosphere to avoid the development of negative pressure, they started setting up vents on all drain P-traps.

Drains That Do Not Have Vents
As water goes down drainpipes, it creates pressure in front of it, causing a vacuum to be left behind. An effect of the imbalance of pressure is the slowing or stoppage of water, causing clogs to be made in the pipe. A vacuum also sucks out water from P-traps that are connected to the drain. Without vent systems, toilets and drains will remain dry, would not work well, and cause kitchens and bathrooms to be unhygienic. Before vents and P-traps were introduced, municipal sewers were a source of diseases.

The Size and Location of Vents
When plumbers first made vents, there were unsure of how big to make them, and as a result, they were often undersized. However, today’s plumbing codes are clear about the appropriate diameters of vent pipes—they need to be a bit smaller than the drains that they service. Also, vents need to be connected within a short distance away from the P-trap, with the “short distance” dependent on the diameter of the drain.

The Vent System
Vents are part of the drain, waste, and vent (DWV) system of a structure, and while every drain flows out to the sewage system, the vents rise to a stack that goes through the roofs of homes. The stack should be six inches above the roof, and each plumbing fixture should be connected to it. Although vent pipes can horizontally run to the point where they connect, they need to have a slope measuring ¼ inch per foot to the drain that they service. Designing vents is a complex task, since plumbing fixtures are usually close together, and a drain for a fixture might be a vent for another fixture.

The above facts are why only the skilled and licensed plumbers of should handle plumbing vents if they do not function properly. Attempting to fix this problem yourself may result in injuries or the destruction of property.