Mechanical Engineer

Mid-Senior Level | Full-time Business Operations | Livermore, CA | 08/06/2026Reference #: REF8674NJob Code: TSS.3 Technical Services & Ops MTS 3 / TSS.4 Technical Services & Ops MTS 4Organization: Project Management OfficePosition Type: Career IndefiniteSecurity Clearance: Anticipated DOE Q clearance (requires U.S. citizenship and a federal background investigation)Drug Test: Required for external applicant(s) selected for this position (includes testing for use of marijuana)Medical Exam: Not applicable Company DescriptionJoin us and make YOUR mark on the World!Lawrence Livermore National Laboratory (LLNL) has turned bold ideas into world-changing impact advancing science and technology to strengthen U.S. security and promote global stability. Our mission spans four critical national security areas nuclear deterrence, threat preparedness, energy security, and multi-domain defense empowering teams to take on the toughest challenges of today and tomorrow. With a culture built on innovation and operational excellence, LLNL is a place where your expertise can make a real impact.Job DescriptionWe have an opening for a Mechanical Engineer. You will provide engineering design solutions for the Laboratory’s mechanical infrastructure, building HVAC systems, building automation and DDC control systems, energy management, laboratory design, and central plant-type equipment in support of projects associated with new construction, remodeling, and modifications to conventional office and laboratory facilities. This position is in the Project Management Office (PMO).The Project Management Office (PMO) provides LLNL with engineering, design, estimating, construction, and project management services. PMO provides infrastructure services to enable cutting-edge research and development in the areas of defense technologies, global security, laser science, bioscience, and more. PMO offers cradle to grave infrastructure services to achieve reliable delivery of completed projects with priority on safety, collaboration, and a workforce working toward our shared vision.This position may offer a hybrid schedule, which includes the flexibility to work from home one or more days per week, after a probationary period. The specifics of the hybrid schedule, including the exact number of days required in the office and virtual work options may vary based on the needs of the team and the organization. This position will be filled at either level based on knowledge and related experience as assessed by the hiring team. Additional job responsibilities (outlined below) will be assigned if hired at the higher level. You willPerform independent technical tasks associated with the engineering, planning, design, and construction of projects associated with LLNL’s mechanical infrastructure.Perform computer-based analyses of heating and cooling load calculations, energy management, and life-cycle cost.Prepare mechanical construction documents, including scoping criteria, construction drawings, specifications, procurement specifications, duct and pipe sizing, HVAC load calculations, and AutoCAD drawings.Provide engineering support during construction by reviewing submittals and shop drawings, responding to contractor questions, evaluating change-order requests, resolving field issues, observing construction activities, and performing inspections. Provide engineering analysis and solutions to a diverse range of moderately complex site building mechanical systems issues and/or problems.Develop approaches to solve moderately complex technical issues associated with specific projects using independent judgment and analysis.Represent the organization in providing engineering solutions to a diverse range of moderate to complex facility mechanical technical issues and/or problems associated with specific projects.Provide engineering support during construction by reviewing submittals and shop drawings, responding to contractor questions, evaluating change order requests, resolving field problems, and performing inspections.Lead assigned internal mechanical projects and serve as the mechanical lead for in-house design projects, with responsibility for technical criteria, budgets, schedules, deliverables, coordination of designers and drafters, and preparation of AutoCAD and Revit models and drawings. Act as the mechanical lead for in-house design projects, and independently provide mechanical designs for said projects, utilizing Revit and AutoCAD.Perform other duties as assigned.Additional job responsibilities at the TSS.4 levelDesign complex building and laboratory mechanical systems for new construction and the renovation and remodeling of existing facilities, including the design of heating, ventilation and air conditioning systems.Prepare designs and engineering studies for conventional mechanical equipment and components in complex building environments supporting highly advanced research activities. Projects include: Design for the installation of air handling equipment, fume hoods, boilers, chillers, DDC control systems, pumps and filter systems, as well as complex mechanical systems in specialized research facilities such as clean rooms, high performance computing facilities, bio-safety labs, semiconductor and electronics fabrication labs, non-reactor nuclear facilities, and laser research facilities.Prepare construction documents for designs, including construction drawings, construction specifications, and procurement specifications for the pre-purchase of LLNL furnished equipment. Use independent judgement to ensure construction documents that have been prepared by both internal staff and external A/E firms are in conformance with applicable Building Codes and LLNL Standards.Prepare procurement documents for the subcontracting of outside consultant Architectural/Engineering (A/E) services to supplement internal engineering capability; manage/direct the outside A/E contracts, including preparing project scopes, technical criteria, engineering design estimates and schedules.QualificationsAbility to secure and maintain a U.S. DOE Q-level security clearance which requires U.S. citizenship.Bachelor’s degree in mechanical engineering, or an equivalent combination of education and at least ten years of mechanical engineering design experience in an architectural/engineering consulting firm.Professional registration as a Mechanical Engineer in the state of California or reciprocity from another state or ability to obtain a California license within 24 months.Experience and knowledge of the professional practice of facility mechanical engineering and construction in areas such as HVAC systems design, piping system analysis and pump selection, building automation and control systems, with a focus on the mechanical design for laboratory tenant improvement (TI) work.Experience in working on projects with multiple stakeholders and complex requirements. The ability to organize and effectively coordinate multiple and sometimes conflicting, concurrent requests and tasks, with accurate follow-through.Experience in plumbing design, and the design of industrial gas systems, and process piping systems for tenant improvement type work.Experience in the preparation of scoping documents for fire protection systems, and in preparing simple fire protection designs for small tenant improvement projects.Experience with mechanical engineering design software for building modeling such as heat load and psychometric analysis, HVAC system modeling, energy management, and/or pipe flow analysis, experience with Microsoft Office software, and Revit and AutoCAD for the preparation of working drawings.Proficient verbal and written communication skills necessary to effectively collaborate in a team environment and present and explain technical information.Additional Qualifications at the TSS.4 LevelSignificant experience and advanced knowledge of the professional practice of commercial, industrial, and laboratory facility mechanical engineering and construction in areas such as HVAC systems design, piping system analysis and pump selection, building automation and control systems, and LEED/sustainable design.Advanced knowledge of applicable state and national construction codes and standards, including California Mechanical & Plumbing Codes, NFPA 1, NFPA 13, and other Fire Codes and Standards, AWWA Standards, and ASHRAE Standards such as 62.1 and 90.1.Significant experience in design management, including project planning, scheduling, professional services estimates, and adherence to completion dates.Qualifications we desireMembership in professional organizations such as ASHRAE, ASME, etc.USGBC LEED AP certification and knowledge of applicable DOE Orders, Federal Standards.Pay Range$154,950 - $235,692 Annually$154,950 - $196,476(TSS.3) Annually$$185,850 - $235,692 (TSS.4) AnnuallyThis is the lowest to highest salary range in good faith we would pay for this role at the time of this posting. An employee’s position within the salary range will be based on several factors including, but not limited to, specific competencies, relevant education, qualifications, certifications, experience, skills, seniority, geographic location, performance, and business or organizational needs.Additional Information#LI-HybridPosition InformationThis is a Career Indefinite position, open to Lab employees and external candidates.Why Lawrence Livermore National Laboratory?Included in 2026 Best Places to Work by Glassdoor!Flexible Benefits Package401(k)Relocation AssistanceEducation Reimbursement ProgramFlexible schedules (*depending on project needs)Our values - visit Security ClearanceThis position requires a Department of Energy (DOE) Q-level clearance. If you are selected, we will initiate a Federal background investigation to determine if you meet eligibility requirements for access to classified information or matter. Also, all L or Q cleared employees are subject to random drug testing. Q-level clearance requires U.S. citizenship. Pre-Employment Drug TestExternal applicant(s) selected for this position must pass a post-offer, pre-employment drug test. This includes testing for use of marijuana as Federal Law applies to us as a Federal Contractor.Wireless and Medical DevicesPer the Department of Energy (DOE), Lawrence Livermore National Laboratory must meet certain restrictions with the use and/or possession of mobile devices in Limited Areas. Depending on your job duties, you may be required to work in a Limited Area where you are not permitted to have a personal and/or laboratory mobile device in your possession. This includes, but not limited to cell phones, tablets, fitness devices, wireless headphones, and other Bluetooth/wireless enabled devices. If you use a medical device, which pairs with a mobile device, you must still follow the rules concerning the mobile device in individual sections within Limited Areas. Sensitive Compartmented Information Facilities require separate approval. Hearing aids without wireless capabilities or wireless that has been disabled are allowed in Limited Areas, Secure Space and Transit/Buffer Space within buildings.How to identify fake job advertisementsPlease be aware of recruitment scams where people or entities are misusing the name of Lawrence Livermore National Laboratory (LLNL) to post fake job advertisements. LLNL never extends an offer without a personal interview and will never charge a fee for joining our company. All current job openings are displayed on the Career Page under “Find Your Job” of our website. If you have encountered a job posting or have been approached with a job offer that you suspect may be fraudulent, we strongly recommend you do not respond.To learn more about recruitment scams: Equal Employment OpportunityWe are an equal opportunity employer that is committed to providing all with a work environment free of discrimination and harassment. All qualified applicants will receive consideration for employment without regard to race, color, religion, marital status, national origin, ancestry, sex, sexual orientation, gender identity, disability, medical condition, pregnancy, protected veteran status, age, citizenship, or any other characteristic protected by applicable laws.Reasonable AccommodationOur goal is to create an accessible and inclusive experience for all candidates applying and interviewing at the Laboratory. If you need a reasonable accommodation during the application or the recruiting process, please use our online form to submit a request. 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