Detailed Engineering and Design services are required on projects where clients need to exercise a high degree of design control and manage the details of materials selection; mechanical, electrical and structural design; HMI; process instrumentation; automation and control design; preferred equipment; and contractor, subcontractor and/or vendor selection. The detailed design package will include process, mechanical, electrical, and structural drawings and may also include architectural and civil drawings, depending on project requirements. The detailed design package will also include a detailed specification package covering all construction services and requirements. The specification package will define required contractor submittals (fabrication drawings, as-built drawings, 3D design drawings, O&M manuals, start-up and commissioning plans, safety plans, quality assurance plans, etc.). Detailed design services normally require additional Construction Management, or “services during construction”, in order to manage client support requirements, requested changes, project schedule, and budgets, and to manage and review required contractor submittals.