We have a 2 story building in reconstruction (due to fire) with the slab and underground utilities as the starting scenario.  We need to pass city code pressure test of waste system before framing. We are struggling resolving leaks in the 6 inch waste line system under the slab.  The ABS piping system includes Ys, 90s, couplers, and straight pipe sections.  What do you see as options for inner wall repairs at all the sections?  Is there a lining process recommended here?  Other method or process to consider?  Is there a compound or solution we can add with or without water to seal and flush through the system without upsetting authorities or agencies here in CA?

-Tom

Tom, I would recommend sock lining: a felt sock pulled through an existing pipe and then inflated/expanded to fill the width of the old pipe. The sock cures in place and you have a new pipe inside of your old one. I would recommend contacting a reputable trenchless technologies company that offers sock lining services.

-Brian

I hear in the wall what appears to be a pinhole leak in a pipe, but, I have no water leaking anywhere. ( I cut out drywall next to one of the pipes where I hear) It’s DRY! With no water being used in the house, there is minute amt. registering on meter, (next to nothing). With the hot water pressure valve on top of water heater turned off, usage on the meter show NO usage, but, I can still hear hissing in wall.(Hissing stops when I turn off main water valve outside the house.) What’s up??

–Ellen

Ellen, it sounds (no pun intended) like you may have a leak. If you did have a pinhole in your piping system, chances are the water loss is too low to be noticed on a water meter’s readout (dial), and you would also have water showing up somewhere (unless you have lines buried below ground). The best thing to do is call a plumber who can come in and perform a hydrostatic pressure test -which is safer then a compressed air test.

-Brian

Doesn’t adding an epoxy lining to pipes make them narrower? Wouldn’t that mean that there would be less water flowing through and at higher pressure?

-Patrick

Patrick, depending on the diameter of the pipe, the epoxy coating is applied to a thickness between 0.20 and 5 millimeters, resulting in a corresponding reduction in interior pipe diameters. Applied to these specifications, it has never caused velocity or delivery problems in systems. In fact, cured epoxy’s surface is so smooth that it creates less friction than new copper. So even with the reduced diameter caused by the coating, the flow rate is actually greater than an uncoated pipe. We have upgraded over 12,000 suites during the past 10 years, and to date we have not had a velocity or flow problem.

The existing copper pipes in your building may already have a coating of copper oxide (green scale), galvanized steel pipes may have extensive corrosion and buildup. While the corrosion build up in copper pipes may not be as thick as the epoxy lining we apply, the corrosion currently coating your pipes can be extremely rough, causing turbulence and reduced water flow.

By contrast, lined pipes are glassy smooth. This offers little restriction to water flow. Most importantly, unlike new pipes, they remain glassy smooth over the years and never restrict water flow.

-Brian