Equipment / Tools
- Channel-lock pliers
- Tape measure
- PVC pipe cutter or hacksaw
- Air admittance valve
- Sanitary tee fitting
- PVC pipe
- PVC primer
- PVC solvent glue
- Pipe-seal tape
- Additional PVC fittings
A vent is a necessary part of the drain system for any plumbing fixture. Its purpose is to equalize pressure in the pipes and prevent a vacuum from forming as the fixture drains. Without venting, the negative pressure caused by the flow of draining water can potentially suck water out of the drain trap and allow sewer gases to enter the home. The vents allow air into the drain pipes to help keep the drain flowing properly. In some instances, though, properly venting a drain can be difficult to do.
In most houses, the drain line for each sink extends horizontally back into a wall, where it fits into a sanitary tee. One outlet on the tee extends downward into a vertical drain line, and the other extends upward into a vent system that is open to outside air. This exposure to fresh air releases sewer gases and allows fresh air into the system to help water drain quickly.
Sometimes, though, it is difficult to connect fixture drains to an external vent pipe. In mobile homes, for example, there may be no external vents at all. And in homes with island sinks with no cabinetry above the island, it can be difficult to find a route for linking the sink drain to an external vent. In these instances, an alternative method of equalizing air pressure is required. This is where the AAV comes in.
An air admittance valve (AAV), sometimes called an auto vent, is a device attached to the fixture drain line. It has a mechanism that opens up to admit room air into the drain under the force of the negative pressure caused by water flowing through the drain. With this negative pressure dissipated, the water in the drain trap cannot be siphoned off. Once the water stops flowing and the negative pressure ends, the AAV device automatically closes to prevent sewer gases from entering the room.
Rules on the use of AAVs vary widely from state to state. While the trend seems to be toward gradual acceptance of these devices, some state building codes still do not allow air admittance valves as a replacement for traditional vents. Other states limit the number of AAVs that a single home can use. Always check with your local building inspections office for advice on what venting strategies are allowed.
Where allowed by code, AAVs can be used with any type of sink or fixture. Some sinks will give hints that an AAV is necessary. A sink that gurgles loudly, for example, or one that drains very slowly even though there are no clog issues, might be doing so because of negative air pressure in the lines. Adding an AAV often resolves these issues. Especially where there is no direct connection to the vent system, as is often the case in sink island situations, installing an AAV may improve the function of the drain. If the drain already has an AAV, such symptoms might indicate that the valve needs to be replaced.
Installing an AAV to vent a sink is fairly easy, whether you are replacing an old existing vent or putting one in for the first time. It basically involves tapping into the existing drain trap configuration to install an AAV via a new sanitary tee fitting and a short upward extension pipe. While it is possible to install an AAV hidden inside walls during remodeling work, it is more common to install them right under the sink cabinet as an adaptation of the pipe joining the drain trap to the branch drain.
With each sink and each drain configuration slightly different, you should be ready to adapt while installing an AAV. As every home plumber knows, it’s not uncommon for additional adapter fittings and other parts to be necessary to fit unique circumstances.
The World Health Organization has declared plumbers the most important front-line health workers around the globe. Most people know from seeing the basins, taps and toilets that of what they are seeing, much of the work is behind the scenes. This “hidden” work meets the essential requirements of our daily lives especially when living in close communities.
Among the objectives upon which the World Plumbing Council was founded is promoting awareness of the plumbing industry’s role in protecting the environment by providing safe, fresh water and sanitation through proper management, care, reuse and conservation of natural resources. The industry also plays a major role in the installation of technologies that address concerns about the depletion of fossil fuels and work toward reducing harmful emissions.
Freshwater is infinite supply on Earth and as the key to life is, without question, our planet’s most precious natural resource. The plumbing industry recognizes the tenuous balance mankind must maintain to guarantee its very existence and embraces efforts to ensure we are preserving every drop possible.
Many of these efforts are well-publicized and countless others go largely unnoticed. Part of the reason for establishing 11 March as World Plumbing Day is to educate the general public about the work the plumbing industry performs every day to conserve the world’s increasingly overstretched sources of drinking water and promote energy efficiency and the increased use of renewable sources of energy.
The professional plumbing industry is poised to make significant contributions to all aspects of water conservation and water reuse. This skill set already exists and can be enhanced through additional training of the young professionals. But a different paradigm must be enacted to include these valuable resources in the solution.
Alter historical approaches to water expansion with new strategy comprised of an integration of conservation and reuse.
If we do not alter our historical approaches to water supply expansion, we will only be able to provide a fraction of the world’s water demand in the next few decades. By 2050, the world population is estimated to increase by 3 billion people, with 100 percent of this growth expected to be concentrated in urban areas. Within 20 years, the projected demand for water will increase between 40 and 50 percent. Although it was universally agreed that the water challenges ahead of us are daunting, the good news is it is not insurmountable.
Conservation and reuse must be done thru a combination of centralized and decentralized approaches.
The strategy must integrate water/wastewater conveyance, water and wastewater treatment, river and surface water cleanup, wastewater and gray water reuse, rainwater harvesting, desalination, and climate change adaptation. With 100 percent of the world population growth occurring in urban areas in the next 30 years, most of the focus was on needed changes to urban water management. The key component of this strategy is to minimize consumption while maximizing recovery through a move toward a hybrid approach of conservation and a combination of centralized and decentralized water reclamation and reuse. The concept applies to all urban areas whether they are rapidly developing cities in Asia or fully developed urban systems in North America.
Plumbing industry largely responsible for the advancing de-centralized conservation and water reuse.
Governing bodies around the world need to make the tough decisions, recognize change is needed, adjust water rates to match real overall costs, implement policies, and inspire the populace to work cooperatively toward solutions. There is enough water to go around and the water technology needed to accomplish our demand goals is already available, proven and widely accessible. The biggest obstacle we have in front of us is the lack of recognition that change is needed. A sustainable water supply is only achievable if all stakeholders in the water loop, including the plumbing industry, are working together.
The plumbing industry will play an essential role in helping stakeholders understand the importance of implementing a key component of the integrated strategy. There will be a need to accelerate the development and installation of high efficiency plumbing systems and components, and standardize the use of decentralized (onsite) alternate water sources, such as rainwater and gray water, in order to offset the need to expand water generation and …