Why would a sewer project in Los Angeles matter to building owners and facility managers in Virginia, Maryland and Washington DC? Because it shows, at very large scale, the decision every owner of aging drainage piping eventually faces: dig it up, or renew it from the inside.
In 2013, Los Angeles was spending more than $10 million to repair approximately 9,000 feet of severely corroded reinforced concrete wastewater pipe sized from 57 to 66 inches, and the Los Angeles County Sanitation District chose cured-in-place pipe (CIPP) to do it.
Four reasons CIPP made sense, and why they apply inside buildings
- Structural integrity. CIPP creates a new structural pipe inside the old one. A resin-saturated liner is pressed against the host pipe wall and cured into a hard, continuous, jointless pipe. A properly installed liner has a 50-year design service life, and our installations carry a 10-year workmanship warranty.
- Keeping water and roots out. Cracked and offset joints let water in and invite root intrusion. A continuous, jointless liner closes those paths, which is why the recognized installation standards, ASTM F1216 and F1743, require the liner to run continuous with no gaps at branch or service connections.
- Better flow. A cured liner reduces internal diameter slightly but typically improves hydraulic capacity in aged pipe. In building drainage, the jointless epoxy surface is far smoother than tuberculated cast iron or offset clay.
- Lower total cost. Trenchless rehabilitation typically costs 40 to 75 percent less than excavating and replacing the same line, before counting the restoration and disruption it avoids. In a city those costs are closed roads and lost business. In a building they are opened walls, damaged finishes and displaced residents or operations.
The same technology at building scale
Municipal mainline rehabilitation and building rehabilitation share the same technologies and standards. Inside occupied buildings, CIPP installs in pipes from 2 to 84 inches in diameter and in continuous runs from 4 to 1,000 feet, through bends and diameter transitions, working from cleanouts, roof vents and small access openings. One difference matters indoors: the styrene-based polyester resins common in municipal mainline work are generally avoided in occupied buildings in favor of low-odor epoxy.
Start with the condition of the pipe
For a building, the first step is CCTV inspection of the lines, with each segment graded on the NASSCO 1-to-5 condition scale and a prioritized plan behind the grades. Not every segment is a lining candidate. A collapsed or badly deformed line needs replacement, and a good evaluation says so before anyone proposes a price.
