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6 Steps to Performing a Smoke Test

Posted By Brad Robertson on October 09, 2014

In this video Wessler Engineering is on site smoke testing a sanitary sewer system to locate and identify defects that are contributing to inflow infiltration. The theory behind smoke testing is: where smoke's getting out, water is getting in.

6 Steps to Performing a Smoke Test

1. Identify test areas: Identify areas of the sanitary sewer system that experience inflow during wet weather. In our video, the primary sources of inflow that we target are storm inlets that are directly or indirectly connected to the sanitary sewer system.

2. Prepare: Two days prior to smoke testing, we distribute door hangers to each of the residents and answer any questions that they might have. We provide a detailed list of precautions to take to eliminate smoke from getting into the home. Most commonly, we see dry traps and plumbing fixtures that have not been used in a while. We suggest putting water or low-grade vegetable oil in the traps to prevent smoke or unpleasant odor from entering the house.

We ensure that all our crews wear the proper safety clothing and safety vests for quick and easy identification. We also train our crews to observe all maintenance of traffic, heed any homeowner concerns, and comply with all safety regulations.

3. Look for smoke: While we smoke test, we are looking for smoke coming out of a home’s roof vent. That tells us that the home is tied on to the sanitary sewer system. The most common defects on the private side are: broken clean-out caps, downspouts, broken service laterals, sump pumps, and crawl spaces. We are also looking for defects on the public side such as sanitary manholes with open pick holes, manholes that lie in low areas, and broken main lines.

If smoke is observed in the home, the homeowner is advised to contact a licensed plumber for a more detailed investigation. The most common defects within the home include: a bad wax ring around the toilet, an unidentified drain without a trap, or defective plumbing.

4. Identify defects: The next step in smoke testing is to identify defects that need to be rehabilitated or corrected. We use a non-toxic liquid smoke that is in compliance with the Substance Control Act. We use remote plugs that can be inflated from above grade without entering the sewer. This eliminates confined space entry and keeps our crews efficient and productive. This also helps isolate segments of sewers without affecting other areas.

5. Document defects: We identify smoke-testing defects by flags or marking with paint, and then the proper documentation will be recorded on our tablet. The tablet allows us to place a marker on a digital aerial map and record all pertinent data for a given defect. This increases accuracy and efficiency compared to traditional pen-and-paper methods. The data can also be reviewed in real time anywhere an internet connection is available.

6. Report: We gather all the data and photos together and generate a list estimating the amount of inflow and infiltration along with cost estimates to correct the defects and recommend the rehabilitation methods.

Thanks for watching our smoke testing video. We hope this video has been very beneficial to you and your community. If you have any questions, please feel free to contact us.

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