The critical role that a roof vent pipe plays in the plumbing system demands care in its design and features. You might end up with sewer gases in your home or building without proper installation. Is it, therefore, advisable to have an elbow on your roof vent pipe? Scroll down.

Yes, an elbow is necessary for a roof vent pipe to keep the flow of water at a consistent speed. However, there are cases when you cannot use the vent elbow when the join is below the water level.

This article will scrutinize whether vent pipes have to be straight or not and the number of elbows required in a plumbing vent. Using our expertise and years of dealing with plumbing systems, we will dissect these aspects and more, step by step. If you are thinking of a DIY plumbing system, you cannot afford to skip this article.

The Role of A Roof Vent Pipe

Every home has a plumbing system responsible for removing waste and water. Although the vent and drainage systems are different, these two work together to ensure that your home is habitable. That is where vent pipes come in to supply fresh air to the various plumbing fixtures in the house.

Whenever you flush your toilet or drain your sink, that odor does not remain in your toilet or kitchen because of the vent pipes. These vent pipes are mostly located away from air conditioning units or windows to dissipate the fumes easily. That is why you will find them on the roofs.

They also serve the following functions:

  • Preventing sewer gases from entering your home
  • Allowing wastewater gas and odor to escape

With this background in mind, we will move on to understand the role of an elbow in a vent pipe. Maybe this is why your plumbing air vents are not working properly.

Does A Plumbing Vent Pipe Have To Be Straight?

Plumbing experts recommend straight vent pipes to maintain proper airflow into the plumbing system. It is always proper to make them straight on the vertical. Doing this prevents the occurrence of vapor locks in the drainage systems.

Bends cause moisture to accumulate and get trapped in the vent pipes. Remember that the vent pipe is always warm, and any moisture trapped in a bend can cause a vapor lock. The result of this is a malfunctioning vent pipe and an uncomfortable house.

However, other bends do not cause these airlocks, such as the ’90s or 45s. These bends are always necessary when connecting to other piping systems. If the vent pipe is at the proper 90-degree mark, you do not need to worry about airlocks.

With the right materials and measurements, you can still make a bend in your vent pipe and have a functional venting system. You can only achieve this with the help of a professional, and it is not recommended for DIY home makeovers.

How Many Elbows Can A Plumbing Vent Have?

Having identified the implications of bends on a plumbing system, considering the number of elbows is important. The more elbows you have, the higher the chance of experiencing air locks in your plumbing system.

The number of elbows depends on how high or low you want the venting system to be in your house. It is advisable to use more straight sections instead of elbows whenever possible. Doing this reduces the chances of water getting stuck at different points of the plumbing system.

It is preferable to have one elbow, but this depends on the code your state recommends. Factors to consider when determining the number of elbows for a plumbing vent include:

  1. Local building code
  2. The type of building
  3. How high above ground the vent goes
  4. The topography of the area

Using national or international standards may not be convenient as they may differ from what works best in your country. The standard practice is one elbow with 90-degree angles.

That is why it is important to do background research on your home country’s building requirements, topography, and desired length before installing elbows in your vent pipe. Most professional plumbers have this information and would be in a proper place to advise you accordingly.

Tips For Fitting Elbows On Vent Pipes

It is important to note that vent pipes come in different sizes and shapes. These determine the type and design of elbows you can use.

The standard pipe fittings for elbows are 45 degrees and 90 degrees. The 90-degree elbow is best for the long and short radius elbow fittings.

The elbow allows the flexibility to change the pipe in any direction. Depending on your plumbing system needs, you can cut it to any degree. The elbows come in short radius (1D) and Long Radius (1.5D).

Experts recommend long radius elbows because they have less pressure loss than the short radius elbow. Most plumbers use the short radius elbows under limited space applications. The sudden change in direction leads to a high-pressure drop in the short radius elbows.

Final Words

An elbow is necessary for a roof vent pipe when properly conducted due diligence. Any miscalculation in installing an elbow may cause more damage to your drainage system and home at large. Ensure that you have all your facts right before opting to have an elbow in your roof vent pipe or not.