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There are two main factors that determine what is used:
ABS and PVC are the cheapest, however there can be limitations with their use in larger buildings due to fire code requirements.
Where fire codes requirements limit the use of plastics, either cast-iron or DWV copper is used for the piping above ground switching to either Chrome or Brass p-traps for the sinks. However depending on the authority having jurisdiction (usually the local inspector), PVC or ABS p-traps may be permitted within the sink cabinet.
XFR-PVC is a kind of fire resistant PVC, and does meet flame and smoke spread requirements and, depending on the project, may be allowed to be used instead of Cast-iron or DWV copper where metal is typically required.
Also made of chrome-plated metal, wall-mounted sinks leave the p-trap exposed.
Labs that use chemicals and acids typically use either glass or special acid resistant plastic pipe and p-traps.
I think new sink drainpipes are almost all PVC. A corroded metal kitchen sink pipe was recently replaced with a PVC one, but while shopping, I noticed that metal downpipes are still offered.
Theoretically, metal should be more heat resistant while PVC should be more resistant to chemicals and rust. However, the majority of drain cleaners no longer contain lye, and no one in their right mind would pour 500°F fluid into a sink. Rust, however, is still a problem.
Yes, I believe that incoming water contamination is more of a lead concern than outgoing water contamination. In addition, plumbers occasionally still fix damaged drain tile junctions with molten lead. However, given that I doubt most municipal water treatment facilities are set up to remove a significant amount of heavy metals, it is probably preferable to remove lead from the water wherever possible.
To be aware of, almost all codes permit metal, but some require you to use only PVC or ABS. Again due to codes, there may occasionally be a stronger availability of one plastic type over the other, so you may want to select the more widespread (“regional availability”). Another aspect is that one kind might be less expensive in your area. You might be required by code to use metal for larger buildings.
PVC (at least sched. 40 thickness is required):
Lasts “about forever,” resists corrosion, cheap. Doesnt sag as much as ABS (on very long horizontal pipes, for instance). Requires both a primer and glue, which is more work to install). Fittings may hold up better. Typically white. Is said to be slightly quieter than ABS. If on rooftop (i.e. vent) might degrade more quickly than ABS. Its rumored to be more brittle than ABS in cold climates (shatter more easily), though typically your sink drain pipes might be exposed to temperature extremes (vents on the roof might though). Temperature rating is max 180 °F (typically high enough for typical drain use). Might be more resistant to chemicals, if its a laboratory. Might shatter more easily after being exposed to cold a lot.
ABS:
Lasts “about forever,” resists corrosion, cheap. Can glue without a primer (faster install/labor). Typically black. Apparently it can deform if left in the sun for short periods of time, though PVC and ABS both become brittle if left in the sun for long, so be careful there, possibly painting vents, etc. Is said to have better impact strength (read “smash it with a hammer”) than PVC, though hopefully youre not accidentally smashing pipes anyway. It is said to “continue burning” after the flame is extinguished, therefore sometimes disallowed in commercial buildings. Is said to have worse fittings over time than ABS. Temperature rating -40 °F to 180 °F.
In the end, ABS is excellent because it was “made for” DWV. PVC also works great. Be aware that ABS and PVC pipes cannot be simply connected (i.e., glued) together, and that certain codes call for the use of a special joining connector. Since you’re screwing it into the wall rather than gluing it together, this isn’t as big of a deal with sink drains, but it is with regular pipe lines. Sticking with what’s already there, like what’s in the wall, might be worthwhile if it adds stability. Some people seem to prefer ABS, some PVC. Since the drain is inside, there are fewer temperature extremes and shorter pipes, so they will likely both function underneath the sink.
Cast Iron:
More fire safe. Less noisy (frequently used for vertical pipes because of that). Can gets lime deposit build-up, etc over time, especially on smaller pipes. You can chrome plate it for looks.
Copper:
More fire safe. Susceptible to chemicals poured down it and corrosion over time causing it to weaken. You can chrome plate it for looks.
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PVC, or polyvinyl chloride, drain pipes are common in modern bathrooms. This substance carries nonpotable water through drains and other plumbing components. The P-trap, which joins the drain to the home plumbing, is included in PVC pipes found under sinks. Such pipes can be joined together with glue or with pieces that are threaded. Your PVC pipes will be held much more firmly and permanently by glue, which can only be broken by severing the pipes. No matter how many pieces you use under a sink or what kind of pieces you use, using a two-step process of priming and gluing your pipes will produce the best connection possible.
For a number of Colorado newspapers, Heath Roberts has experience as a professional reporter. He has written features and covered breaking news for the Denver Post and other regional publications. Roberts holds bachelor’s degrees in political science and journalism.
Call a Plumber When You Get a Clogged DrainIf and when a clog in a home drain pipe does occur, the best remedy is to
Typically, clogs result from inappropriate items being flushed down the wrong pipe. For instance, food particles could simply build up at the j-bend in a kitchen sink without a garbage disposal if food particles are rinsed down the drain in that sink. Over time, these particles could result in a clog. When hair strands are flushed down shower drains or anything other than human waste and toilet paper is flushed down toilets, a similar process takes place. Typically, the clogging process develops over time as a result of drain abuse. In the worst-case scenarios, a major clog results from allowing something large and insoluble to slip down.