Smoke testing consists of injecting non-toxic smoke, mixed with large volumes of air, into a sanitary sewer line, typically through a manhole.
The smoke travels the path of least resistance and quickly shows up at sites that allow surface water inflow. Smoke testing is a great way to identify broken manholes, illegal connections such as roof drains, sump pumps and yard drains, and uncapped lines. It will even reveal cracked mains and laterals, provided there is a passageway for the smoke to travel to the surface.
Although video inspection and other techniques certainly are important components of any I&I (Inflow & Infiltration) survey, research has shown that approximately 65 percent of all extraneous storm water inflow enters the system from somewhere other than the main line. Surface water that enters a sewer system can lead to increased wastewater treatment costs and severe overflow issues during wet weather events. Smoke testing is a method of inspecting both the main lines and laterals. Smoke travels throughout the system, identifying problems in all connected lines—even sections of line that were not known to exist or thought to be independent or unconnected.
Smoke testing is as important now as it ever has been as growing municipalities increase demands on aging and often deteriorating collection systems. Used extensively for more than 50 years, smoke testing has proven to be a vital ingredient of successful inflow and infiltration (I&I) studies. American Underground, Inc.’s experienced and trained professionals will enter and detail any defects found during smoke testing in a detailed report.
Smoke Test Diagram