Drain systems operate via vents and gravity. Vents equalize pressure, while gravity causes all that stuff to flow into the sewer, ultimately to a water reclamation plant and then into a river, lake or ocean. The entire process depends on naturally occurring phenomenon, gravity mostly and pressure equalization. Most all of those pipes that are sticking out of the roof of the home are vents for the drain system.

Plumbing Vent Pipes

Wherever a drain from a sink, washing machine or toilet meet the main drainage systems there is a vent. By penetrating the roof, unpleasant orders are vented to the outside. By allowing air into the system it counteracts any vacuum created by the draining liquids. This allows for the free flow of water through the drains.

Drain & Pipe Slope

Drains are laid at ¼ inch drop per 12 inches or one foot of run for pipes under 2 ½ inches or 2% slope, while pipes of 3 inches or more can be run at 1/8 inch in 12 inches or a 1% slope. Run is the horizontal distance covered. Generally, the pipe size is based on a plumbing unit called the Drainage Fixture Unit of dfu. The total dfu determines the size of pipe. Most codes requires 1 ½ inch inside diameter pipe for most fixtures, i.e. sinks and washing machine drains. Toilets are usually 3 inches diameter as are the main house drain run. If there is no venting, drainage flow can be retarded due to a partial vacuum created by the flow of water. Vents are usually 1 ½ to 2 inch pipe. As the dfu’s add up the pipe must increase in diameter to accommodate the additional volume of liquids. With all that water, condensation is a problem so the vent horizontal runs are set at an angle to allow the condensation to drain back into the drainage system. There is a lot of thought and body of many years’ experience that goes into the design of drains and the selection of materials.

Water & Sewer Supply Pipes Materials

Materials, everything from synthetic tubing through fired clay ceramics to metal can be encountered in drain systems. Anywhere there are high internal or external pressures the material must be able to withstand those pressures without failure and do so for decades. That is why reinforced concrete and cast iron are used in the main systems as they can take the pressure of multiple feet of overburden without collapsing. This is all fine for new installation but what about existing systems. Since plumbing is older than the Roman Empire, a lot of experience has been accumulated. This means that building codes are fairly uniform from generation to generation. But the code does change, particularly as new materials are introduced. Romans used clay for drainage and lead for the water supply. We are dependent mostly on plastic. Of course, any exposure to lead is verboten, even solder used in copper piping is now nonlead based on silver and other low temperature melting metals.

Cleaning & Unclogging Drain Pipes & Sewer Lines in Staten Island, Maspeth, Bronx, Brooklyn, Manhattan, Yonkers, Queens, NYC Boroughs, New York City NY

Understand that your drain system is a marvel of engineering spanning millennia, but it can still fail. When the gunk and water is backed up and refuses to go down, you need the drainage experts at The Original $49.95 Plumber. Drainage is what we do. Contact us today!