Senior Engineer - Mechanical Design

Together We Build – Partnership, Innovation, Excellence, and Safety

At Kelso Industries, 5,000+ employees across 40+ companies work together to deliver exceptional HVAC, mechanical, plumbing, refrigeration, and electrical solutions nationwide. Join us to grow your career, make an impact, and be part of a team where innovation, excellence, and safety come first.

Recruiter Notice: We respectfully ask external recruiters and staffing agencies not to submit candidates. We only accept direct applications.

Senior Engineer

About NDBS

National Design Build Services (NDBS) is a mechanical design/build firm based in St. Louis, MO. We design and deliver HVAC, refrigeration and process systems for commercial, industrial and mission-critical facilities, including food processing, manufacturing, data centers, and refrigerated warehouses. NDBS is part of the Kelso Industries family of MEP+ companies, which shares the core values of Partnership, Innovation, Excellence and Safety. We take projects from design through fabrication and field installation, using off-site prefabrication partners where it improves schedule, quality and job-site safety. NDBS offers an excellent benefits and compensation program and strong career development opportunities.

Position Description

The Senior Engineer supports the Lead Engineer on data centers, mission-critical facilities and large industrial plants delivered through design-build and design-assist. You will own the day-to-day mechanical design on assigned projects: running calculations, selecting equipment, developing drawings and models, and coordinating with other disciplines, so design becomes complete, accurate construction documents. You will also supervise and mentor Design Engineers, assigning work, reviewing it for quality, and helping that engineer grow. This role is a direct path toward a Lead Engineer position.

Position Information

Position Type: Full Time

Travel Required: 15%

Department: Engineering

Reporting: Lead Engineer

Direct Reports: Yes

Location: St. Louis, MO 63146 OR Remote, United States

Skills & Responsibilities (including but not limited to):

• Adhering to NDBS Core Values
  • Safety
  • We Answer Our Phones
  • Always Innovating
  • Collaborative Partnerships
  • Reputation
  • Entrepreneurship

• Design:
  • Develop the mechanical design on assigned projects from the basis of design and P&IDs through milestone reviews and issued-for-construction (IFC) drawings.
  • Perform heat load, hydraulic, psychrometric and pipe sizing calculations, and select equipment such as chillers, air handlers, pumps and CDUs.
  • Prepare drawings, schedules, details and Revit models, and run Navisworks clash detection with other disciplines.
  • Coordinate day-to-day with plumbing, structural, electrical, civil and controls designers and sub-consultants, and bring open issues to the Lead Engineer.
  • Draft sequences of operation and support controls partners on PLC logic and Building Management Systems.
  • Track deliverables, engineering hours and review comments on assigned work, and report status to the Lead Engineer.

• Mission-Critical and Industrial Design:
  • Design data center cooling systems, including chilled water plants, CRAH/CRAC units and fan walls, economizers and containment, applying the redundancy (N+1, 2N, concurrent maintainability) set in the basis of design.
  • Support liquid cooling design for high-density and AI workloads, including CDUs and technology cooling system (TCS) and facility water loops.
  • Design HVAC, process exhaust, compressed air, boiler and hot water systems, and size natural gas, process and utility piping for industrial facilities.
  • Prepare RFIs to close gaps in owner and process-equipment data.

• Supervision of Design Engineer:
  • Assign and schedule work for the Design Engineer, and set clear expectations for scope, quality and deadlines.
  • Check calculations, drawings and models
  • Coach the Design Engineer on design methods, codes, software and NDBS standards, and give regular feedback on performance and development.

• Prefabrication Coordination:
  • Identify where prefabricated pipe spools, skids and modules add value and design them for constructability and repeatability.
  • Confirm design concepts early so prefabricated piping can be released without rework.
  • Review and witness factory acceptance tests and support commissioning and integrated systems testing.

• Project Execution:
  • Take part in internal turnover meetings and help define scope, schedule and resources for assigned work.
  • Support preconstruction with design quantities and scope reviews for estimating.
  • Review trade-partner submittals and draft RFI responses for Lead Engineer approval.
  • Attend coordination meetings with owners, general contractors and trade partners, and use Procore and Autodesk Construction Cloud to manage documents.
  • Support quality control through site visits, field verification and punch lists.

Qualifications and Education Requirements

• Bachelor's degree in an engineering field; mechanical preferred.
• Minimum 5+ years of HVAC/R design experience; data center, mission-critical or industrial experience preferred.
• Professional Engineer (PE) license preferred, or EIT with the ability to obtain a PE.
• Hands-on experience with chilled water, hydronic and process piping design.
• Working knowledge of ASHRAE, International Codes, NFPA, and ASME piping codes.
• Experience guiding or mentoring junior engineers or designers.
• Ability to work to deadlines while juggling several projects and changing priorities.
• Self-motivated, with excellent time and task management skills.
• Strong organization and communication skills, and the ability to work well in a team.

Preferred Experience and Tools

• Industrial process experience: process exhaust, compressed air, boilers and natural gas systems.
• Liquid cooling and high-density (AI/HPC) data center experience.
• Experience with design-build and design-assist delivery, and with Procore and Autodesk Construction Cloud.
• Experience with prefabricated mechanical systems such as skids, pipe spools or utility racks.
• Fluency in Revit MEP and AutoCAD; experience with Navisworks clash detection.
• Experience with load software such as Trane TRACE or Carrier HAP

Work Environment:

The role is mostly office or remote design work, with regular time on active construction sites and in fabrication shops. Site and shop visits require standard PPE and following NDBS and client safety programs.

NDBS is an equal opportunity employer and all qualified applicants will receive consideration for employment without regard to race, color, religion, sex, national origin, disability status, protected veteran status, or any other characteristic protected by law.

Why Join Kelso Industries?

Join us and be part of a team dedicated to creating efficient, sustainable, and high-performance environments that make a lasting impact across the industrial, commercial, and institutional sectors.

Here you will experience:

Growth Opportunities: Develop new skills, take on exciting challenges, and advance your career in meaningful ways.

Company Culture: You’ll thrive in an environment that supports your growth, values your contributions, and makes work fulfilling and enjoyable.

Impact: Your work directly contributes to meaningful outcomes, allowing you to see the difference you make and feel a sense of purpose every day.

Competitive Compensation & Benefits: You’ll be rewarded fairly for your contributions while enjoying perks that enhance your financial security, health, and overall well-being.

Kelso Industries celebrates diversity and is committed to creating an inclusive environment for all employees. We do not discriminate in any aspect of employment based on race, color, religion, national origin, ancestry, gender, sexual orientation, gender identity and/or expression, age, veteran status, disability, or any other characteristic protected by federal, state, or local employment discrimination laws where Kelso does business