A corrosion monitoring device to monitor corrosion in a pipe of a fire sprinkler system, comprising: a sensor assembly including a plug insert , a housing , and at least one sensor portion comprising a plurality of coupon portions coupled with the plug insert, the sensor assembly configured to be disposed in an interior of a pipe in a fire sprinkler system for sensing corrosion of a wall of the pipe, the plurality of coupon portions forming at least part of a plurality of wire loops , the plurality of coupon portions exposed from the housing to the interior of the pipe, the plurality of wire loops having leads that are embedded in the plug insert; and a detector circuit configured to: transmit an electrical signal through the at least one sensor portion; monitor an electrical characteristic of the at least one sensor portion based on the electrical signal; compare at least one of the monitored electrical characteristic and a change in the electrical characteristic of the at least one sensor portion to at least one of a first predetermined value and a previously monitored electrical characteristic; determine a corrosion status indicative of at least one of a corrosion level and a rate of corrosion of the pipe wall based on the comparison indicating corrosion based on the at least one of the monitored electrical characteristic and the change in the electrical characteristic being less than the at least one of the first predetermined value and the previously monitored electrical characteristic; and output an indication of the corrosion status. a sensor assembly including a plug insert , a housing , and at least one sensor portion comprising a plurality of coupon portions coupled with the plug insert, the sensor assembly configured to be disposed in an interior of a pipe in a fire sprinkler system for sensing corrosion of a wall of the pipe, the plurality of coupon portions forming at least part of a plurality of wire loops , the plurality of coupon portions exposed from the housing to the interior of the pipe, the plurality of wire loops having leads that are embedded in the plug insert; and a detector circuit configured to: transmit an electrical signal through the at least one sensor portion; monitor an electrical characteristic of the at least one sensor portion based on the electrical signal; compare at least one of the monitored electrical characteristic and a change in the electrical characteristic of the at least one sensor portion to at least one of a first predetermined value and a previously monitored electrical characteristic; determine a corrosion status indicative of at least one of a corrosion level and a rate of corrosion of the pipe wall based on the comparison indicating corrosion based on the at least one of the monitored electrical characteristic and the change in the electrical characteristic being less than the at least one of the first predetermined value and the previously monitored electrical characteristic; and output an indication of the corrosion status. transmit an electrical signal through the at least one sensor portion; monitor an electrical characteristic of the at least one sensor portion based on the electrical signal; compare at least one of the monitored electrical characteristic and a change in the electrical characteristic of the at least one sensor portion to at least one of a first predetermined value and a previously monitored electrical characteristic; determine a corrosion status indicative of at least one of a corrosion level and a rate of corrosion of the pipe wall based on the comparison indicating corrosion based on the at least one of the monitored electrical characteristic and the change in the electrical characteristic being less than the at least one of the first predetermined value and the previously monitored electrical characteristic; and output an indication of the corrosion status. <EOS>