Exterior/Interior Smoke Testing

Cross Connection	Broken Sewer Main	Roof Leaders
	Foundation Drain

Exterior Smoke Testing

Exterior smoke testing is known to be a relatively inexpensive and quick method of detecting inflow/infiltration sources in sewer systems. Using a gas driven fan, a safe and non toxic petroleum distillate (liquid smoke) is forced into the storm or sanitary sewer system. Lighter than air liquid smoke passes through the storm or sanitary system and rises through any openings that exist within the system.

Exterior smoke testing is best used to detect:

• Inflow sources such as storm sewer inter-connections.
• Point source inflow leaks in drainage paths or ponding areas.
• Roof leaders.
• Area drains.
• Foundation drains.
• Abandoned building sewer laterals.

The system configuration is also proven by locating hidden manholes and identifying any new construction that has not been updated on drawings.

Interior Smoke Testing

Smoke testing may also be used to locate air quality and sewer system integrity problems in buildings. Smoke is generated by the same methods as exterior smoke testing, however, smoke is usually injected into the building or residence through a sewer main, or a sewer plumbing vent or fixture. Smoke will travel through sewer vent systems and through the air spaces in sewer lines, and will emanate from any leaks in the system. Smoke has the ability to travel through wall cavities and annular floor/ceiling spaces. By visually tracking the flow of smoke through the system, integrity problems could be identified.

Typical findings from an indoor smoke testing program may include:

• Dry traps in floor drains.
• Improperly capped sewer lines or vents.
• Broken sewer lines or vents.
• Leaking fixture seals.
• Cross connected sewer vents and drains.
• The drawing of air emanating from sewer vents into air intakes of air exchange systems.