Perform various aspects of mechanical engineering design as directed by more experienced engineers or designers, including conceptual studies, program requirements, design analysis, calculations, equipment selection and layout, and system selection and layout for building design, upgrades, and retrofits. Position Summary: Clark Nexsen is seeking a Mechanical Engineer III who will be responsible for design, engineering, analysis, equipment selection, and system layout of HVAC, plumbing, piping, and related mechanical building systems for Commercial and Government facilities.