Plumbing drain trap or interceptor materials of construction:

This article describes the different materials from which plumbing traps (also called plumbing interceptors) are made, such as plastic, brass, cast iron, and we discuss the different properties of each of these plumbing trap materials.

This plumbing traps (interceptors) article series describes plumbing traps (interceptors) and how to diagnose, find, and cure odors in buildings including septic or sewage or sewer gas smells or "gas odors" in buildings with a focus on homes with a private onsite septic tank but including tips for owners whose home is connected to a sewer system as well.

Plumbing Trap Materials: Metal vs PVC Plumbing Traps & Interceptors

Plumbing traps are constructed of any of a number of old traditional materials, principally metals, occasionally wood, or of newer plastic materials.

[Click to enlarge any image]

This photo series will permit you to identify the type of plumbing trap or interceptor material at an installation.

Here we also discuss the leak risks that differ depending on the plumbing interceptor or trap type and material that was used.

Keep in mind that when replacing a plumbing interceptor or plumbing trap, you can usually opt for a material of your choice.

Just be sure that you match the proper size and fittings of the old trap when buying a replacement plumbing trap.

[Click to enlarge any image]

ABS plastic (black plastic) plumbing traps - durable, widespread, 1975-present, shown above.

Brass plumbing traps / interceptors - traditional, widespread use 1900-present, including thicker-walled cast brass (above and in real trouble) or thin-walled brass, possibly chrome plated that we'll show below.

You might note that most of the plumbing interceptors we show here are suffering in some way, askew, broken, loose, corroded, leaky.

Note: At InspectApedia many or our building component photographs were originally taken to document real-world, in-service conditions that are found by trades people, plumbers, for example, or by building inspectors, contractors, home inspectors, or chartered surveyors. These images show conditions rather than showcasing products even when the products are ones we love.

Cast iron plumbing traps (shown above) are more-likely to be found as the house trap or main building drain trap at point at which the sewer piping exits from a building.

You'll recognize cast iron drain/waste/vent piping (DWV) by the thick heavy pipe edges at the pipe hubs and cleanouts [click to enlarge the image] and you can confirm the use of cast iron with a magnet - which will adhere to the pipe surface.

Chrome-plated brass plumbing traps / interceptors - traditional, widespread use world-wide, 1960's - present. Shown above, a leaky chrome-plated brass thin-walled plumbing trap below the author's sink in Mexico. This trap appeared to be leaking but the water was actually from a corroded leaky sink strainer assembly above the trap itself.

[Image needed: galvanized iron plumbing trap] Use the page top or bottom CONTACT link to send us photos for comment or contribution.

Galvanized iron plumbing traps, traditional, 1920 - 1970

Plastic or PVC plumbing traps - widespread, world-wide, 1977 - present. Some plastic plumbing traps are also silver coloured and may be chrome plated. Shown above, first photo: a PVC building sewer line trap providing drain cleanout openings at the foundation wall of a U.S. home. Second photo, a typical white plastic PVC plumbing interceptor or drain trap below a kitchen sink. I'm feeling for wet spots or leaks after having installed new parts.

Below is a photo of a do-it-yourself home-made plumbing interceptor made out of PVC plumbing parts. This trap may not work properly as its dimensions are "non-standard" and also because it's not a P-trap - there is no connection to a plumbing vent.

We discuss this cute home made plumbing trap again at PLUMBING TRAP LEAKS & MISSING INTERCEPTORS.

Below is another home-made or "expedient" plumbing trap that is not a trap.

Rubber plumbing traps (shown above made of an automotive radiator hose) found on some home-made systems didn't work, but rubber traps might be used successfully in other forms. This one, providing no trap, allows sewer gases right up into the building. And it leaks too.

Stainless steel plumbing traps, and nickel plated plumbing traps offer extra corrosion resistance. Some of these are nickel-plated such as the bottle trap ( a small drum trap) I'm holding in the photo above.

Details about where leaks occur on plumbing traps of all types are at PLUMBING TRAP LEAK POINTS.

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

Question: what material should we choose when replacing a leaky plumbing trap

We are in a condo building that is four years old. All of our p-traps are chrome plated.

One of them has already developed a hole in it and caused a leak, damaging our cabinet despite catching it early. We checked the others in our unit and they all show signs of corrosion ...leading us to worry that they will also leak very soon.

Can you please advise on the preferred suggested material for us to replace ours with? The condo board says it is up to us and we want a worry-free situation.

Plumbing supply places are reluctant to advise when it comes to condo buildings so we would appreciate your expertise and guidance. Thanks so much. - Anonymous by private email 2019/08/23

Reply:

You can use new heavier gauge chrome plated brass OR if you like, switch to white PVC plumbing traps. Just measure the trap diameter to be sure you're buying the right replacement - typically 1 1/2" or 1 1/4" diameter.

Plastic P-trap nuts should be tightened only by hand to avoid breaking the joint.

Watch out: don't be fooled: any plumbing trap can leak.

A metal plumbing trap may corrode-through and leak, usually first as a drip later as a worse leak. It may also leak if the trap connectors are not properly tightened or if the internal gaskets or washers are omitted at the connectors.

Examples of heavier duty (thicker 17-gauge) chrome plated metal P-traps:

• Lasco produces a heavy-duty 17-gauge "Plumbers Grade" P-trap in chrome plated brass.
  
  Remember: when considering metal "gauge", the smaller the number, the thicker the metal. So a No. 17-gauge metal P-trap is thicker or heavier-duty than a #22-gauge metal P-trap.
• McGuire Manufacturing produces a chrome plated cast-brass heavy-duty P-trap - shown above - with a 17-gauge sweat extension and a chrome plated steel deep bell flange for use at the wall penetration. Cast brass will be the thickest, heaviest metal trap you might install.

A plastic plumbing trap won't corrode through but it can leak from being over-tightened, especially where lower-quality PVC trap parts are used; Over-tightening leads to snapping a connector ring nut or there can be leaks from being under-tightened too - a problem with any mechanically-attached plumbing trap.

The white plastic plumbing trap shown above on this page is PVC and works just fine. But there's a heaver-duty option too:

• Heavier, thicker ABS (black plastic) P-traps and drain piping are available but might not be compatible with the existing plumbing in your building (that may be metal).
  
  NIBCO produces an ABS P-Trap (shown above) as do other manufacturers.
  
  The advantage of this ABS P-trap is that except by exceptional mechanical damage that cracks the fitting, it's nearly indestructible.
  
  A disadvantage of this ABS P-trap is that if it's glued in place and needed to be replaced (for example because some fool stripped the cleanout nut) your plumber will have to cut it out to re-glue new fittings in place.

In my OPINION I would avoid thin-wall plumbing traps of any material and I would avoid those flexible "accordion" traps (shown below) that seem easier to install and use fewer parts (a plus) but may not flow as well and may be more clog-prone than a smooth-surfaced plumbing drain line and P-trap.

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Continue reading  at PLUMBING S-TRAP CODES & HAZARDS or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see PLUMBING TRAP, INTERCEPTOR FAQs - questions, answers, comments posted originally at this article

Or see these

Recommended Articles

• PLUMBING TRAPS & INTERCEPTORS - home
  • CLOGGED PLUMBING TRAP CAUSE & CURE
  • DEFINITION: PLUMBING TRAPS & PLUMBING INTERCEPTORS
  • DRY PLUMBING TRAP CAUSE & PREVENTION
  • GREASE INTERCEPTORS TRAPS
  • LOOSE TOILETS LEAK SEWER ODORS
  • PLUMBING S-TRAP CODES & HAZARDS
  • PLUMBING TRAP HISTORY
  • PLUMBING TRAPS, ILLEGAL
  • PLUMBING TRAP LEAKS & MISSING INTERCEPTORS
  • PLUMBING TRAP LEAK POINTS
  • PLUMBING TRAP MATERIALS & PROPERTIES
  • SEWER GASES vs PLUMBING TRAPS & VENTS

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PLUMBING TRAP MATERIALS & PROPERTIES at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to PLUMBING SYSTEMS

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