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Plumbing vents are an essential component of home plumbing systems, but many homeowners in Pinehurst, NC, are unaware of these vents. Plumbing systems supply water and remove waste, but the drainage and vent functions are actually two separate systems that work together. A plumbing vent, or vent stack, regulates air pressure in the system. Many problems can occur if this vital component of plumbing infrastructure is compromised.
A plumbing vent removes gas and odors and lets fresh air into the system to help water flow smoothly through pipes. The process is similar to pouring liquid from a can. Liquid flows out of the can very slowly unless a second hole is created as a vent.
Drainage Pipes and Fixtures
Every plumbing fixture in a home needs a vent. Drainage pipes transport sewage waste and greywater out of the home and deliver it to a septic tank or city sewer. A home’s drainage system can not function correctly without functional air vents.
Drain waste vent systems maintain neutral atmospheric pressure inside removal pipes. Equal pressure throughout the length of the pipe lets sewage flow freely through the force of gravity alone. Optimal pressure gradients are essential for everyday functions, such as flushing a toilet or draining a sink.
Many vents are vertical pipes attached to drain lines that run through a home’s roof. Vents are often connected inside an attic to reduce the number of roof penetrations. The vent stack pipe connects to the main roof vent. This pipe guides exhaust gases to be released outside. Vents also let oxygen enter waste pipes, which is necessary for aerobic bacteria to break down sewage. Roof vents are positioned away from air conditioning units and windows so fumes dissipate easily.
Plumbing Vents and Fixture Traps
Plumbing fixtures, such as drains, faucets, and toilets, have traps. A trap is a bend or loop in the pipe. The bend in a section of pipe holds, or traps, water to prevent any noxious gases from entering the home’s interior. Plumbing vents keep air pressure equal on both sides of a trap.
Water moving through a pipe compressed air ahead of it. This creates positive pressure that must be released. Built-up pressure forces wastewater back up through the fixture into the drain. The drain overflows and spreads wastewater and sewer gases into the home.
Negative pressure occurs if air behind the flowing water is not replaced. Negative pressure pulls water out of the trap because water moves into the section of pipe with the lowest pressure. Plumbers install vents inside pipes in strategic positions near fixtures to prevent negative and positive pressure.
Signs of Malfunctioning Vent
Signs of a blocked or improperly installed vent including gurgling sounds in drains, standing water in sinks or bathtubs, and slow drainage in the kitchen or bathroom. The gurgling noise is produced by air siphoned through the trap. Sewer gas may back up into the home as well. Gurgling noises stop when an air vent is completely blocked and forms a vacuum.
Sometimes clearing a drain temporarily restores normal function, but recurring stoppages will continue if a blocked vent caused the original problem. Ongoing stoppages and reduced drainage flows cause sediment build-up in drain pipes. Sediment damages plumbing infrastructure and leads to potentially extensive repairs in the future. Call a professional plumber to examine drains and vents at the first sign of a problem to prevent any additional damage from occurring.
A clogged or malfunctioning toilet vent causes two noticeable anomalies. Air bubbles rise through the water in the toilet bowl, and water levels fluctuate. These anomalies can also be a result of an incorrectly pitched waste pipe or hairline crack in the porcelain trap. Call a professional plumber if you notice these signs.
Plumbing Vent Installation
Plumbing vents are frequently regulated by state and local codes. Professional plumbers know the relevant codes in Pinehurst, NC, but most homeowners do not. It is always best to contact a professional plumber to replace plumbing vents or install vents for new appliances.
Plumbing vents are an important aspect of remodeling projects, especially in kitchens or bathrooms. Vent pipes are usually narrower than drainpipes and do not require a slope. Most vent pipes are installed at an even level unless they need to work around an obstacle. Installing vent pipes can be tricky because they must stay dry. Vent pipes exit from the top of a drainpipe vertically or at an angle, but angles must be no less than 45-degrees horizontally so water can not back up. Plumbers have the appropriate tools and knowledge to determine correct vent pipe positioning and angles.
Common Plumbing Vents
A vent pipe, or auxiliary vent, is attached to a drain line near the fixture. It has a vertical portion that runs straight up and a horizontal portion to connect with a main vent. The horizontal portion should be at least 6-inches higher than the fixture’s flood level, which is the highest point water can rise within the fixture. A sink’s flood level is either the rim or an overflow hole.
A sanitary cross, also known as a common vent, is used for two fixtures on opposite sides of a wall, such as back-to-back sinks. Loop vents are sometimes used for freestanding sinks. Some plumbers try to avoid loop vents, if possible, because they often require separate vent pipes through the roof.
Plumbers may choose to install one of the newest types of vents called air admittance valves, or AAV. AAV vents can be used for multiple fixtures. An AAV vent opens to let air enter drains and closes by gravity to prevent sewer gases from escaping. Sometimes professionals recommend replacing vent lines with admittance valves.
Contact Pride Plumbing if you suspect a plumbing vent in your home may be clogged, obstructed, or damaged. The professional plumbers can also provide assistance with remodeling projects and update or replace plumbing vents in your home.