2018-11-1_PR Comm Packet - Laserfiche WebLink

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Ammonia Detection System The ammonia detection system is original, has reached its useful life and should be replaced. New and better technology exists that would provide improved safety, reliability, and more sophisticated alarming levels. Brine Pumping System The brine pumping system pumps the chilled brine from the refrigeration plant to the rink slab then back to the refrigeration plant to be rechilled. The system consists of brine, insulated transmission mains, brine pumps, and expansion tanks all performing a critical function in this important component of the cooling process. Brine The brine in the system was originally a 1.26 CaCl/Water mix. Much of the brine is original and some has been supplemented over the years for brine leaks and system repairs. The operator of the system indicated that they were noticing a lot of residual iron in the system. This could be due to several conditions including low pH and a low level of inhibitor in the brine. We have noted low pH levels in the brine over the past several years. Residual iron sludge tends to neutralize the inhibitor which then can then accelerate the development of more iron. We understand the City has been filtering residual materials from the brine over the past ten years, however it has been challenging, given some of the shortfalls of the retrofit equipment, it’s location, and time challenges with this maintenance effort. The City has been filtering during the summer months whenever it can, however it appears that the amount of residual iron is still quite high. The brine is typically sampled twice a year. Once, around the beginning of the calendar year near the beginning of the ice skating season, and again about the time the ice system is shut down for the year, around March. We did receive detailed bine tests from the past 13 years which indicate ongoing issues with residual metals, low pH, lack of brine clarity which was also confirmed in a discussion with Frank Garber, the City’s brine treatment consultant for the facility. The City installed a coupon sampling system in 2005 to measure steel corrosion impacts of the brine by measuring metal loss on the coupons. The coupon testing is done at approximately the same frequency as the brine testing and it has consistently provided acceptable levels of corrosion. Frank Garber indicated that their approach to treatment has been if the coupon test results are less than 2 mpy (mils per year) and there is a residual level of inhibitor present then they leave the brine alone. They did originally recommend the filtration of the brine but that has not been effective due to operational problems with the equipment. Stantec has concerns with the current condition of the brine. There is not clarity to the brine, residual metals are present, pH is low, and we are uncertain how effective the inhibitor is functioning given the high residual iron that is currently in the system. While it does not appear that the residual iron is plugging up the cooling pipes in the ice rink floor, we have concerns that 141414