Sterilizer Chemical Emissions Solution

A plant in the Midwest is one of 31 across the country that employs ethylene oxide (EtO) techniques to perform the important job of sterilizing a wide variety of medical equipment, including surgical kits, masks, face shields and gloves. However, issues had arisen about emissions of the chemical used in the sterilization process. Plant management asked Stanley Consultants engineers to devise a solution that would allow it to scrub discharge of the chemical.

The existing plant had controls that monitored EtO but had no functional capability. The new system controlled variable speed fans that drew air out of different areas of the plant, as well as monitoring other parts of the system, such as air pressure in the dozens of dry bed air cleaners where air is cooled before being circulated through a cleansing media. Other piping conducts air through a new scrubber process before exiting the building’s tower. A new system of sensors and alarms were part of the design, which added another screen in the control room.

The most creative part of the controls engineering was working with the controls vendor to set up system parameters without knowing the inputs and outputs of the system after being built due to the short design timeline.

The system was operating by the end of 2019 with ongoing adjustments. It enabled the plant to play a critical role in safely sterilizing medical equipment for use during the prolonged COVID-19 pandemic.