The drain-waste-vent system transports all the used water and waste from the house to the septic or sewer system. It’s a network of drain pipes that runs to all the sinks, toilets, baths, showers, and washer. These pipes drain the waste from the house.
Older homes use cast iron pipes. However, most newer waste systems use rigid plastic PVC (polyvinyl chloride) or ABS (acrylonitrile butadiene styrene) pipe that are sealed with glue. It wasn’t until the late 1960′s or early 1970′s that plastic PVC sewer pipe was introduced. Once introduced the PVC pipe quickly became the choice for sewage pipe on new home construction. PVC provided much easier installations, cheaper materials, and easier production. Cast iron waste water piping was still being installed during the early PVC years and can be found in early 1970′s homes. Cast iron waste piping is still used in many commercial, industrial and municipal applications, and even in some residential structures.
If your home has cast iron pipe sealed with lead solder, it can be very hard to work on your Waste systems. Cast iron pipes have been manufactured and used in the United States since the early 1800′s. The first usage was for water distribution but eventually also expanded to waste water disposal (soil pipes also called sewage pipes). By the 1890′s an actual cast iron soil pipe industry took shape and was recognized. Cast iron waste water piping was not the only product used over the years but it did provide a highly reliable and durable pipe that lasted much longer periods than other materials.
A good quality cast iron pipe, installed under ideal conditions, has a life expectancy of 75 – 100 years, and possibly even more. Cast iron does rust but when it does the rust actually forms a barrier layer over the remainder of the pipe which helps protect it from further rusting. Since most cast iron pipes were thick walled to begin with even with some rusting inside they can handle the lower pressures of waste water disposal quite well and last a long time. Cast iron also provides many other benefits in home waste systems that still makes it a good choice for homes. However it is more expensive to purchase and install. Also many plumbers of residential structures do not have the experience it takes to properly install and maintain it. As a result PVC has taken over for the majority of home installations today.
Cast Iron pipes used to carry waste are more susceptible to rust and leaks than cast iron pipes used to carry water. If you see rust on the outside of your pipes – unless there is deep pitting – there isn’t usually a reason to worry. Underground waste lines very rarely fail because of external rust, usually the problem is out of sight, on the inside of the pipe.
The contents of waste lines can create hydrogen sulfide gases. When these gases oxidize, they produce sulfuric acid and the acid will corrode cast iron pipes.
You can expect to see two different kinds of cast iron pipe failure:
Problems at the Pipe Seams – Seams are created when pipes are formed during the casting process. In this case, the hydrogen sulfide gas has collected in the pipe and attacked a weakened seam.
Pinhole Cracks – These cracks are very small and will not be visible during an inspection. What you will see are blobs of rust under the horizontal sections of the pipe. These blobs can be very tiny or up to the size of walnuts. These rust blobs are often overlooked because there are no obvious leaks. As the leaks form, rust will expand over the pinholes and seal off the water.
When cast iron pipes are formed, they are “pit-casted”; this means the internal pipe walls are not all the same thickness. The thinner portions of the pipe wall will show the cracks and pinholes first, so be on the lookout for patches of rust in different areas of the pipes.
However, today’s homes may utilize cast iron pipe sealed with neoprene in some places as a way to avoid the noise plastic creates when water is draining through it.
The soil stack is the main component of the waste drain. It’s a vertical “stack” of pipes that starts in the basement/crawlspace floor or wall where it’s connected to the outbound sewer or septic line.
The top end of the stack acts as a vent. It extends vertically out through the roof, allowing gases to escape outside and also helps promote drain flow by drawing air inward.
A plugged vent can trap dangerous gases and inhibits drainage; similar to plugging a drinking straw with your thumb to hold liquid.
Make sure the vent doesn’t terminate in the attic. Trapped sewer gases can be dangerous, stink and cause serious structural problems. And a system without a vent may actually suck water out a sink’s trap, or do the reverse and fill the sink with water when another fixture drains.
A trap blocks sewer/septic gases. Without one, sewer gases can flow up the stack, drain pipes and come out wherever there’s a drain. A trap looks like an “U” and is installed below the drain.
When water drains, the trap’s shape causes a small amount of water to remain in the bend. That water blocks any gases from moving up the pipe and entering the room.
Drain Waste Vent Plumbers Help
No comments:
Post a Comment