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Recent wildfire events in California and Oregon have resulted in localized water contamination. A potential cause is the heating of polymer-based water service lines and mains in these communities. Identifying the source of contamination can be a huge burden on municipalities, taking significant resources and time. The investigation in Santa Rosa and Paradise, California took months and millions of dollars, and delayed their recovery. These contamination events highlighted the need for a quicker, more efficient way to check water lines in affected areas. Previous research has shown that the threshold temperatures that result in contamination are 194° C for polyvinyl chloride (PVC) and 250° C for high-density polyethylene (HDPE) pipes, respectively. The objective of this work is the development of a low-cost sensor system to identify potentially damaged pipelines and sources of water contamination. The proposed solution is a radio frequency identification (RFID) based temperature sensor to indicate once a certain temperature is reached. Passive, ultra-high frequency RFID tags are used in conjunction with a trigger mechanism that disconnects after the threshold temperature is reached over a meaningful duration. Passive RFID will allow for the tags to operate without the use of batteries, and are very affordable. The design and characterization of the sensor utilizes two experimental frameworks: (1) benchtop testing, (2) small-scale tests in a more realistic environment. The benchtop testing identifies the trigger temperature, mechanism, and reliability of the sensor design. The small-scale testing installs the sensors on buried pipes subjected to a realistic fire load. The resulting design and characterization will be presented in terms of accuracy, durability, and reliability. Additionally, the heat flux of the benchtop testing will differ from a more realistic environment, so the results will be compared to isolate how the heat flux might impact future wildland-urban interface (WUI) based sensor development.
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