Senior Project Engineer – Mechanical U.K; Data Centre Retrofit

About the job

As a Senior Project Engineer – Mechanical, you will play a key role within Ethos’ Data Centre team, with a focus on retrofit projects across mission‑critical data centre environments.

You will lead the design, specification and delivery of mechanical systems, ensuring projects are delivered safely, efficiently and to the highest technical standards. Working within live environments, you will help maintain continuity of operations while delivering high‑quality engineering solutions.

This role will also involve managing project delivery, mentoring junior engineers and acting as a key technical point of contact for clients and contractors across major European data centre markets.

• Lead the design and delivery of mechanical building services upgrades within live data centre environments, including M&E upgrades, capacity increases, technology refreshes, phased refurbishments, and lifecycle replacements.
• Develop and manage retrofit‑specific design strategies, including tie‑ins to live systems, redundancy planning, outage and staging strategies, and resilience design.
• Conduct or oversee technical due diligence of existing data centre facilities, including capacity unlock assessments (power, cooling, and white space).
• Prepare and review detailed design drawings, schematics, schedules, technical reports, and tender documentation.
• Manage project scope, budget, programme, and contracts — identifying and mitigating scope creep, risks, and live‑environment constraints.
• Liaise directly with clients (hyperscale, colocation, and enterprise operators), contractors, and vendors to ensure project goals are achieved with zero operational disruption.
• Drive quality assurance and governance across all assigned projects, adhering to WAP/PTW protocols in live environments.
• Mentor and support the development of junior engineers and graduate staff within the retrofit workstream.
• Support business development by contributing to proposals, client presentations, and technical strategies for retrofit opportunities across EMEA.
• Champion innovation in live‑environment engineering and contribute to the continuous improvement of Ethos’ retrofit delivery model.
• Lead phasing strategy for live cooling and HVAC upgrades, ensuring continuity of critical mechanical infrastructure throughout delivery.

• Strong expertise in mechanical systems design for live data centre environments, including chilled water plant, CRAC/CRAH upgrades, air handling units, in‑row cooling, and fire suppression systems.
• Experience delivering M&E upgrades within operational facilities — including tie‑ins to live plant, outage management, and resilience planning.
• Proficient in AutoCAD, Revit MEP, Bluebeam, and Microsoft Office; working knowledge of IES, HAP, or similar mechanical analysis tools is advantageous.
• Strong knowledge of CIBSE, ASHRAE, BS, IS, and EN standards applied in retrofit and live‑environment contexts.
• Understanding of PUE optimisation and cooling efficiency improvements to meet EU Energy Efficiency Directive targets and client ESG requirements.
• Familiarity with commissioning and integration of mechanical systems within live, mission‑critical facilities.

• Bachelor’s or Master’s degree in Mechanical Engineering or a related discipline.
• Minimum 8 years’ experience in building services engineering, with at least 3 years focused on data centre or mission‑critical projects.
• Demonstrable experience working in live, operational data centre environments — including brownfield upgrades, M&E replacements, or phased refurbishments.
• Chartered Engineer status (or actively working towards Chartership) with Engineers Ireland or equivalent.
• Proven track record managing…