When planning the Spring Hill, Tennessee facility, Saturn’s Hydraulic Selection Committee considered the performance and reliability of fluid power systems in production machinery as the key to achieving their goals of continually increasing uptime, productivity, and quality. To accomplish this, they set fixed requirements for all hydraulic equipment used in the plant. Also, the committee understood a basic concept vitally important to fluid power: system fluid cleanliness directly affects component life and performance.

To this end, Saturn tightened GM's existing standard HSI specification for hydraulic system filtration. They require that all hydraulic systems be equipped with pressure and return line filters having ßx = 200 particle removal efficiency. Also, all fluids added to hydraulic systems first must be filtered through ßx = 200 filters. These filter assemblies must also have visual differential pressure indicators to signal the need for element change before bypass occurs and to maximize element service life.