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[DUNBAR PLUMBING]

A repeat customer of ours contacted us to address a leak in the garage of their home on sylvan drive. Sylvan drive is located in independence kentucky. Dunbar Plumbing has done numerous plumbing tasks at this location and the house was built in the 1970 era.

Given the age of this home, Cast Iron was the majority of drain stacks inside this home with the rest of the branches done in copper drain piping. Copper drain work was something that simplified the installation of plumbing and due to the cost of piping in 3" or 4" copper, the use of cast iron was the preferred method. However over time what results in the aging of copper piping, the piping has a predetermined "life" before issues result in its use.
When we arrived at the home, first inspection of the piping arrangement led to the majority of the drainage system piped in the garage area. This along with minor removal of the ceiling revealed what was leaking onto the floor. A 2" copper drain line that connected into the main 4" cast iron stack had evidence of pinholes in the piping in the last foot of piping before transitioning into cast iron. Here is a brief explanation of what to expect on piping systems where cast iron drain piping and copper drain piping are mixed:
 
Most if not always when copper drain piping is used in older homes, a brass ferrule is utilized in the cast iron hub that connects to the larger piping. This, over time creates a situation where the transition itself starts to corrode and close up the inside diameter of the pipe. When this problem occurs, the waste matter that is travelling through the piping system is slowed down and causes buildup in the copper piping leading to the cast iron hub.
 
This area right before the copper enters the cast iron hub is where pinholes, or thinning of the piping occurs. Back in the day when copper drain lines were introduced, the actual thickness of the copper drain piping is paper thin to begin with, roughly 1/16" of an inch. With products such as detergents, acidic food waste, urine, and any other mixtures of household chemicals and products provides a cocktail of fluids/gels/liquids that travel through the copper drain lines and eventually become lodged in the piping whether it is a coating or clumps, gathering in turns or directions of the piping.
 
Over time, this collection of products serves as the problematic issues that lead to pinholes or deterioration of copper piping inside the system, leading to replacement.  It is common to see homeowners using electrical tape, wrapping the piping where the holes are found to be leaking to 'buy time' before finally replacing the piping. This surely is not the correct way to fix a plumbing problem, but nonetheless it is a method that provides a temporary fix until the piping is replaced correctly and according to code.

[DUNBAR PLUMBING]

The piping with the holes on this job involved roughly less than 10 feet of piping and there was plenty of evidence that the pipe was not only leaking but heavily clogged at the connection to the cast iron stack.  Our first step was to cut the cast iron wye directly below the hub serving the 2" copper drain. We chose to go this route because right where we cut the cast iron hub off was signs of deterioration that spelled trouble for attempting to extract the lead pour, oakum and brass ferrule from the hub. If the cast iron hub was decent, a service weight gasket would be utilized to put back inside the hub along with new 2" PVC pipe.
 
Using a diamond blade angle grinder along with a bi metal sawzall blade we were able to safely remove the hub leaving a short jot of cast iron piping leading directly into the 4" cast iron stack. In removing the hub, we found that the short jot of piping was completely clogged with black waste matter. Quick use of a piece of wire scraped out the pipe back to its original diameter, allowing for uninterrupted flow. At the other end of the pipe, the copper drain piping was cut roughly 2" from the intersecting wye that veers off to carry the waste of a nearby tub. The condition of the copper drain piping was in satisfactory shape from that point forward, limiting the amount of pipe removal.
 
Now that both ends of the drain piping was removed, the next step involved utilizing the correct mechanical fittings that rejoin dissimilar materials together. Cast Iron to PVC - PVC to Copper. The mechanical coupling for each end of this joining of new PVC pipe consists of a rubber type connector with a pair of stainless steel hose clamps and a stainless steel covering to secure the rubber connection from expanding. This is a code requirement in most states in the country and provides the best connection design for this type of repair. This also allows for easy removal of connections if the need for drain cleaning when there is no access.
 
Once the rubber connection (No Hub Mission Coupling) was installed on the short piece of 2" cast iron pipe, from there the transition of pvc pipe is introduced and the direction of the pipe and fittings in pvc generally follow that of the existing. Keep in mind though that pvc pipe fittings will be different than copper and have longer sweeps. This will prevent the ability to cut piping lengths the same size of the copper drain piping that is removed.

[DUNBAR PLUMBING]

It's always best to dry fit your assembly of pvc pipe and fittings to make sure that your installation goes smoothly and without error, preventing any issues that affects the fall or "tilt" of your drain piping. It is very important that your drain piping between your two fixed positions are kept in the equation of determining your amount of fall. Fall or "Pitch" is based on a basic rule of 1/8" per foot fall. 1/4" per foot fall can be used as well if the situation warrants. Having "fall" on the piping is necessary to remove the waste water waste matter from the fixture to the drain line leading to the point of disposal. Sewage disposal can be of a septic system or city sewer. Installing drain piping without proper fall or backpitched, piping that is falling the wrong direction can cause buildup in the newly installed drain piping resulting in a smaller area of the pipe's interior area. This also allows for the new drain to collect waste matter which further worsens the chance for a clogged piping system.
 
Once you measure your pipe to fit into your turns of direction, your pvc fittings, it is then safe to clean and glue your pvc pipe together to complete the task of the drain repair. Remember that it is wise to mark your pipe against the fittings by the hubs making sure your pipe fully enters the hub of your fittings. If this isn't done properly what happens is your measurements of pipe will be incorrect causing the distance between fittings to change, resulting in mistakes. Pencil a line on your pipe in a dry fit equation to make sure that when gauging your pipe before installing that the pipe has travelled fully into the hub of your fittings. It is then safe to glue the pipe to the fittings after this is accomplished.
 
Once your piping is installed by the use of glue and mechanical couplings, make sure that the new piping you erected is properly supported by the use of bracing or strapping in the necessary intervals required for the size of pipe installed. Failure to do this can result in sagging of the pvc pipe. PVC pipe has vulnerabilities when it comes to temperature variances. Extreme heating of the pipe caused by the discharge of heated water, for example a dishwasher utilizing 120F temperature. If the piping is not supported within the necessary distances this plastic piping can begin to sag between fixed positions and cause problems with buildup, creating a 'belly' or low spot that can collect waste matter sealing off the path of flow.
 
Once the piping is strapped, make sure that your mechanical couplings are tightened at the clamps by use of a torque wrench to 60 foot pounds of torque. This is the proper measurement that ensures that the coupling is indeed tight to both sides of the dissimilar materials without leakage. Once this is accomplished then you can operate the plumbing fixtures associated with this drain to test for leaks, making sure that the installation of your new piping is done correctly and without error.  Dunbar Plumbing offers partial or complete drain piping replacement in your home. Please contact us at 859-359-4833 to schedule your replacement by our company to get the job done right.
 
 

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Tags: copper  drain line  sylvan drive  independence  kentucky cast iron copper pipe brass ferrule