In modern pipelines, sewerage (or DWV) is part of a system that removes waste and greywater from buildings, and regulates air pressure in the waste system pipeline to aid free flow. Wastes are produced in equipment such as toilets, wash basins, and bathrooms, and out of equipment through traps, dipped pipes that always contain water.
Video Drain-waste-vent system
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The DWV system maintains neutral air pressure in the waterways, enabling free flow of water and sewerage and through sewage pipes by gravity. It is important that sufficient downward slope is maintained throughout, to keep the fluid and entrained solid flowing freely into the main channel of the building. In relatively rare situations, the downward slope of the building to the drain can not be made, and a special collection hole is required and a "waste disposal" removal pump. In contrast, drinking water supply systems operate under pressure to distribute water through buildings, and do not require a continuous downward slant in their piping.
Every equipment is required to have internal or external traps; double traps are prohibited by the pipeline because of their vulnerability to plugging. Each plumbing fixture must also have an installed vent. The top of the pile should be removed too, through a pile of holes , sometimes called odor pipe .
All pipe waste equipment uses traps to prevent exhaust gases from leaking into the house. Through the trap, all the fixtures are connected to the sewer line, which in turn brings waste to the "pile of soil", or "ground ventilation pipe". At the lowest point of the building drain system, the sewer pit is installed, and rises (usually inside the wall) to and out of the roof. Trash comes out of the building through the main canal of the building and flows through the sewer, leading to a septic system or a public sewer. Cesspits are generally prohibited in the developed area.
The ventilation system, or plumbing , consists of a number of pipes leading from the waste pipe to the outside of the house, usually through the roof. Ventilation provides a means to release exhaust gases outside instead of inside the house. Ventilation also recognizes oxygen to the waste system to allow digestion of aerobic waste, and to prevent dangerous anaerobic decomposition. Ventilation provides a way to equalize the pressure on both sides of the trap, thereby allowing the trap to hold the water necessary to maintain the effectiveness of the trap, and avoiding any possible "trap pitfalls".
Maps Drain-waste-vent system
Operation
The sewer pipe is usually at a neutral air pressure compared to the surrounding atmosphere. When a column of wastewater flows through a pipe, it compresses the air in front of it in a pipe, creating positive pressure that must be removed so as not to push back the waste stream and trap water downstream. seal. When the water column passes, air must flow freely behind the waste stream, or negative the pressure result. The extent of this pressure fluctuation is determined by the volume of fluid from waste disposal.
Excessive negative air pressure, behind the dried "snails" of water, can suck water from traps in pipe fittings. Generally, the toilet outlet has the shortest trap seal, making it most vulnerable to being emptied by induced siphonase. An empty trap can allow dangerous exhaust gases into the building.
On the other hand, if the air pressure inside the channel suddenly becomes higher than the ambient, this positive transient can cause the wastewater to be pushed into the fixture, breaking the seal of the trap, with serious health and hygiene consequences if it is too strong. Tall buildings of three or more stories are particularly vulnerable to this problem. Ventilating pot is installed parallel to the pile of garbage to allow proper ventilation in tall buildings.
External vents
Most of the drainage systems of residential buildings in North America are released directly through the roof of the building. DWV pipes are typically ABS or PVC DWV-rated plastic pipes equipped with flashing in roof penetration to prevent rain water from entering the building. Older homes can use copper, iron, tin or clay pipes, in rough order to enhance the beauty.
Under many older building codes, the ventilation pipe (the pipe leading to the main roof vents) should be within a 5 feet (1.5 m) radius of the drying fixtures it serves (sink, toilet, shower stall, etc.). To allow only one ventilation hole, and thus one roof penetration permitted by local building codes, sub-ventilation can be tied together inside the building and out through common ventilation holes. One additional requirement for ventilation stack connections occurs when there is very long horizontal drainage running with very little slope to run. Adding a ventilation connection in the run will help the flow, and when used with cleaning it allows for better serviceability over the long run.
Clogged blockages are a relatively common problem caused by anything from leaves, dead animals, ice dams in very cold weather, or the horizontal part of the ventilation system, tilted in the wrong direction and filled with water from rain or condensation. Symptoms range from bubbles in the toilet when watered, to slow drainage, and all the way to suck (empty) traps that allow gas gutters to enter the building.
When the fixture traps are properly ventilated, the "sucking" sound is often heard when the equipment loudly empties during normal operation. This phenomenon is harmless, and differs from "trap traps" caused by pressure variations caused by wastewater motions elsewhere in the system, which should not allow interaction from one fixture to another. Toilets are a special case, as they are usually designed to suck themselves to ensure a complete evacuation of its contents; they are then automatically recharged by a special valve mechanism.
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Island fixture vent
island hole , sometimes colloquially called "Chicago Loop" is an alternative way to set up traps which is installed in island sinks under counter or other similar applications where conventional vertical ventilation piles or inlet air valves are not feasible or permitted.
Like all water courses, ventilation should be provided to allow the wastewater to flow to replace the sewer gas in the sewer, and then to allow air (or other liquids) to fill the vacuum that will form when water flows down the pipe.
Island supply vents provide an elegant solution to this need: when the channel is opened, water moves the exhaust gas to the sanitary tee, the water flows downward while the gutter is moved upward and towards the vent. Ventilation can also provide air to fill the vacuum made.
The key to ventilation of functional island equipment is that the upper elbow should be at least as high as "flood level" (the peak may drain the water in the sink). This ensures that the vents never get soaked.
Cost
Installation costs are high because of the large number of elbows and small pieces of pipes required. The biggest expense with modern plastic pipe disposal is labor. The use of street elbow is helpful.
Alternately if moving to the island sink, set the P-trap below the island floor and pour out the top of the sewer. Attach it to the trap and turn 180 degrees so that the water in the vent hole flows into the drain. The slope flows down, steep slope, and plugs into existing ventilation from previous equipment that is now abandoned. Patch the previously existing channel into a vent. In Canada, the national pipeline requires minimum trap arm minimum 2 times the diameter of the pipe, (for example, 1.25-inch pipe requires 2.5-inch trap arm, 1.5 pipe requires 3-inch trap arm, etc.) and that pipe ventilation becomes one size larger than the channel it serves, also cleaning is needed both on ventilation and sewer. The reason is that if the sink is installed, the wastewater will go back up and down to the ventilation, maybe plugging in the vents (because it is under the table), and cleaning will allow pipe cleaning.
Fittings
The drainage and ventilation system not only requires pipes, but also many special fittings that greatly increase the cost of construction. Special access fittings like "cleaning" increase long-term maintenance of the system, and are required by most plumbing codes.
See also
References
Further reading
- Fink, Justin (September 16, 2015). "Sewerage System-Waste-Vent". Fine Homebuilding . Taunton Press. 154 : 18-19 . Retrieved 2015-09-25 .
External links
Source of the article : Wikipedia
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