All Pipes Are Not Created Equal
Not All Pipes are Created Equal...
Let's talk about the different kinds of pipe plumbing companies install. There have been many times when I am on a job site, and a conversation starts up about the pipe we are putting in the ground. The homeowner is generally clueless about the pipe. He might do two weeks of research on the type of shoes he is going to buy, but doesn't take five minutes to understand what is being installed in his yard. He trusts that the contractor is using quality pipe and leaves it at that. I hope that after reading this post you are equipped with a greater understanding of differences in pipe, because it is really quite important. We want to talk about pipes that were installed in years past, and also the newest pipes that plumbers and excavators install today.
Cast Iron Pipe : This pipe was installed years ago by many contractors. It first came to America in 1817. It was used alot during the 50's through the 80's, and is one of the most problematic pipes we come across. Primarily it was used as a sewer or drain pipe. I don't know of any other uses for it, and I don't recommend having it installed. It is extremely common, and many of the homes and properties we service have cast iron sewer lines. The good thing about cast iron is that it is structurally strong. The weight of dirt and stone will not depress the pipe and make it concave. The bad thing about cast iron is that it is metal, and it rusts and corrodes and collects build up like you would not believe. It forms "barnacles". The diameter of a four inch pipe can be decreased to two inches or less, resulting in a clogged drain. Cast iron pipe as indoor plumbing does not seem to present as big of a problem because there is significant pitch. It is outside, between the house and the septic tank(or sewer) where the clogs will form. It is possible for roots to grow into joints of this pipe. If you want to be proactive about your sewer line not backing up into your house, we recommend changing out this pipe.
Transite or Asbestos Pipe: Not as common as Cast Iron, this pipe was installed pre 1980's. It is actually cement pipe reinforced with asbestos(if you find it, don't eat it). It was used not only as sewer and drain pipe but had a pressure rating which allowed it to be used for water mains. The transite sewer lines we have encountered have for the most part still been in working condition. We have even found ten inch transite water mains that were still in good shape. Most towns are phasing out this pipe because it becomes brittle and springs leaks. If you are sure your sewer line is transite and you have had no problems, I would recommend leaving it alone. If there is a tree anywhere near your septic tank or sewer line, however, I would have pipe installed that is impervious to root intrusion so you have no surprises in your future.
Orangeburg Pipe: This pipe is all too common in older homes. I have only ever seen it used as sewer, drainage, or leach field pipe. Apparently it was used as conduit for telephone lines years ago as well. It is the absolute worst pipe you could have at your residence. It was made from wood pulp and hot pitch, and resembles tar paper. When exposing this pipe with a hand shovel, it is so brittle that you normally dig through it before you realize what you hit. Orangeburg pipe also has a tendency to collapse on the top and the bottom, causing clogs or slow drainage. Roots also love this pipe. If you know your house has orangeburg pipe, we recommend changing it. It will cause headaches down the road.
Thin-wall SDR Pipe: "SDR" stands for "Standard Dimension Ratio". This is a thin, usually white pipe that was installed in the 70's through the 90's. Sadly, I have heard of contractors still using this type of pipe. Thin-wall pipe is not to be confused with SDR-35 gasket pipe. The Thin-wall pipe we are referring to here is only found in sewer and drain(usually gutter) lines. It is absolute garbage. The major problem with this pipe is that it is so thin, just the weight of the ground flattens out the pipe, causing clogs and slow draining. As if that wasn't bad enough, this pipe does not have gaskets. This means root can effortlessly grow into and clog this pipe. We have pulled nine foot root balls out of this thin-wall pipe. Do yourself a favor and have a certified plumber change out your old thin-wall pipe.
<-- SDR-35 Pipe and SDR-21 Pipe -->
SDR 35 and 21 Gasket Pipe: Finally, some good pipe. This pipe has not been around for very long. We are almost never called out to work on someones sewer line where SDR 35 or 21 pipe was used(unless it was installed improperly). This pipe is smooth PVC that allows water and effluent to flow freely through it without clogging. It is also impervious to root intrusion because the joints are completely sealed by rubber gaskets. Our company almost always uses one of these two pipes for sewer or drainage projects. There are no glue-able fittings buried in the ground, which reduces the risk of the pipe separating due to ground movement. Check to make sure your contractor is at the very least using SDR-35 pipe, which is normally green. They do make SDR 35 pipe that does NOT have rubber gaskets, but you need to have the kind WITH gaskets. SDR 21 pipe is even stronger than SDR 35, and is the same thickness as Schedule 40 PVC. Schedule 40 is just normally used as indoor plumbing, because it does not have gaskets. Many times town code will require that if you are not using 21 pipe for a sewer lateral you must encase 35 pipe in stone because it is thinner. All around, one of the best choices for new installs as far as price goes.
HDPE Pipe that our Rochester plumbing team is pulling underneath four homes using a method called "pipe bursting". The HDPE pipe is attached to a "bursting" head which breaks apart old pipe and replaces it with new fusion pipe.
HDPE Pipe: The best pipe you can buy on the market. It stands for "high density polyethylene". You can purchase it in various thicknesses and can be used in pressure systems(water and gas) or sewer and drainage. It is extremely durable and yet flexible. You can almost bend this pipe into a 90 degree angle(\(\(almost). Apparently some HDPE pipe has a 50 year warranty, and manufacturers are considering bumping it up to a 100 year warranty because of the quality of the pipe. The way this pipe is joined together is by a process called "pipe fusion". It literally welds the pipe together, where the joints of the pipe become stronger than the pipe itself. HDPE pipe is primarily used in trenchless applications, because it can be fused to any desired length. Water and effluent flow through this pipe more smoothly than any other pipe on the market. It is obviously impossible for roots to grow into this pipe, and is the best choice for sewer or water lines.
We did not review every pipe under the sun, but now you have a better understanding of different kinds of pipe. You should be able to identify problems based upon your pipe, and also know what your contractor is installing. It is wise to be a homeowner who understands the basics of excavating. The reason is that you can protect yourself from contractors who will cut corners and leave you with more problems than you had before you called them. Remember, the lowest price is not always the cheapest :)