Express Plumbing Heating & Air Blog
One of the most confusing aspects of plumbing, for the average person, One of the most confusing aspects of plumbing, for the average person is where, how, and what is a vent. Let me start by simply telling you that the pipe or pipes penetrating your roof. Most likely is a plumbing vent. There may be a similar pipe up there that could be an exhaust for your furnace or water heater, but most likely it is a vent for your plumbing system. To be safe and legal every you need a vent. The main purpose of the vent or vents within your house, or any other building, is to prevent the possible siphonage of the P traps that keep the sewer gases out of the structure.
The U-shaped pipe under your plumbing fixture is the P-trap. This is designed to stay full of water. Therefore “trap” the sewer gas behind it and not allow it to enter your home. Sewer gas can be anywhere from a stinky annoyance, to as much as a toxic danger. Without properly placed and installed vents. It is very possible that these traps can either be siphoned out by other fixtures.
Vents must be installed properly and at a precise location. Vents also serve other functions in the system, such as allowing fixtures to drain better. They also regulate positive and negative pressure balances. Especially in a larger building with very tall waste stacks.
The air admittance valve is a little device that can serve as a vent but does not have to penetrate the roof. These will allow air to enter when needed but they will not allow the sewer gas to escape. They have a very real drawback though, and that is they cannot relieve positive pressure. These devices were invented and designed with the intent of solving some very tricky plumbing venting dilemmas. A real vent through the roof is always the best way to install a plumbing system.
is where, how, and what is a vent. Let me start by simply telling you that the pipe or pipes penetrating your roof. Most likely is a plumbing vent. There may be a similar pipe up there that could be an exhaust for your furnace or water heater, but most likely it is a vent for your plumbing system. To be safe and legal every you need a vent. The main purpose of the vent or vents within your house, or any other building, is to prevent the possible siphonage of the P traps that keep the sewer gases out of the structure.
The U-shaped pipe under your plumbing fixture is the P-trap. This is designed to stay full of water. Therefore “trap” the sewer gas behind it and not allow it to enter your home. Sewer gas can be anywhere from a stinky annoyance, to as much as a toxic danger. Without properly placed and installed vents. It is very possible that these traps can either be siphoned out by other fixtures.
Vents must be installed properly and at a precise location. Vents also serve other functions in the system, such as allowing fixtures to drain better. They also regulate positive and negative pressure balances. Especially in a larger building with very tall waste stacks.
The air admittance valve is a little device that can serve as a vent but does not have to penetrate the roof. These will allow air to enter when needed but they will not allow the sewer gas to escape. They have a very real drawback though, and that is they cannot relieve positive pressure. These devices were invented and designed with the intent of solving some very tricky plumbing venting dilemmas. A real vent through the roof is always the best way to install a plumbing system.
