A premier Boston-based university was building a state of the art academic research complex. The facility required a central ultrapure water system to feed laboratory equipment, lab points-of-use, and humidification equipment on multiple floors throughout the building. The university hired an engineering firm to design the plumbing systems, and Atlas was approached to assist with the design of the central ultrapure water system.
The university opted to pursue ASTM type III water quality, which requires resistivity to be held at approximately 4 megohms. Water would be polished at points of use if ASTM Type II or greater were required for individual laboratories in the building. The engineering team specified a flow rate of 30 gallons-per-minute (GPM) of reverse osmosis (RO) “make-up” and 90 GPM of distribution flow. An Allen Bradley PLC with customized alarms and outputs was also required.
Atlas High Purity designed an ultrapure water system to meet the facility’s quality and flow requirements. Atlas utilized a Suez E8 57K RO to feed a 5000 gallon storage tank. The storage tank would be filled through a series of deionization (DI) vessels in order to meet the ASTM Type III water quality.
Surprisingly, designing an ultrapure water system to consistently achieve the lower resistivity target specified in ASTM Type III can be more challenging than achieving maximum resistivity (18 megohms) as specified in ASTM Type I. Once deionized water enters an atmospheric storage tank for recirculation, it will degrade as it absorbs CO2 to form carbonic acid. Controlling this process to meet a lower resistivity requirement is much harder than simply polishing with DI on the loop distribution, which ensures that resistivity is held around 17-18 megohms for all points of use. Atlas addressed this challenge by designing a side-stream recirculation system that automatically recirculates a lower flow stream of water from the storage tank back through the DI tanks if resistivity drops below 4 megohms. This ensures that the desired ASTM Type III quality is consistently delivered to all points of use.
Atlas worked with a local Allen Bradley partner to program a PLC to meet all end user requirements. Equipment was assembled and skid-mounted at Atlas’s facility in Braintree, MA, and connected on-site by Atlas’s expert team of installers. The result is a durable and reliable system that consistently meets end user quality and flow requirements. The system’s vitals can be monitored by the facility’s BMS.