Senior Mechanical Engineer

At Salas O’Brien we tell our clients that we’re engineered for impact. This passion for making a difference applies just as much to our team as it does to our projects. That’s why we’re committed to living our values every day: inspiring, achieving, and connecting as shared owners of our success with a focus on a sustainable future.

Building for the long-term means that all of our team members can expect to work on amazing projects with a people-first approach to problem solving. It also means that each member of our team has truly limitless potential to build a unique, meaningful, and high‑impact career—and they’ll receive great total rewards along the way.

We are seeking a Senior Mechanical Engineer who can develop and lead HVAC and process ventilation design for complex, secure, high-hazard federal facility programs. We are currently working on projects and have openings available to support the modernization of Department of Energy and National Nuclear Security Administration facilities contributing to the mission of defending the United States and supporting the nation's nuclear security enterprise.

Job Summary:

The Senior Mechanical Engineer works in a fast-paced, multidisciplinary team environment leading HVAC and process ventilation design for new facilities, additions, and renovation projects, with particular emphasis on hazardous occupancy (e.g., IBC H-2) and secure facility environments where mechanical system design carries direct life‑safety and mission‑critical consequences. The position's responsibilities primarily focus on providing technical leadership for the creation of construction drawings and specifications, existing system studies, and facility master planning efforts, including base building HVAC systems as well as specialized process ventilation, fume/smoke exhaust, and gas-monitoring systems required in high-hazard processing environments.

Qualified candidates will meet with clients, project teams, code officials, contractors, and others to address mechanical and process ventilation issues and develop effective working relationships across a program's full design lifecycle. The project clientele includes Federal Government (DOE/NNSA), Department of Defense, national laboratory‑adjacent programs, Higher Education, Commercial, Health Care, Science and Technology, and other municipal and institutional facilities.

Duties and Responsibilities:

• Meet with clients to determine and document HVAC and process ventilation requirements.
• Develop HVAC and specialized process ventilation system designs based on project scope, client RFPs, and hazardous occupancy classification requirements.
• Provide engineering design, evaluation, and planning of mechanical systems for a variety of building types, including base building HVAC and specialty systems (fume/smoke exhaust, gas detection/monitoring, chemical treatment systems) for high‑hazard process environments.
• Perform load/energy calculations using software such as Trace 700/3D, IES, and similar programs.
• Conduct existing building surveys and documentation of existing HVAC systems, including comparative analysis between an existing reference facility and a target facility.
• Develop system design calculations and equipment selection for use in buildings.
• Evaluate material compatibility and equipment durability for mechanical systems operating in chemically aggressive or corrosive process environments
• Prepare detailed design documents, reports, and studies.
• Complete code compliance research, including hazardous occupancy classification requirements.
• Coordinate work with other disciplines, including structural, electrical, fire protection, process, and security systems.
• Provide engineering services during construction (ESDC), including RFI…