The Opportunity We are seeking an experienced Senior Mechanical Design Engineer with a strong background in mission-critical environments, specifically data centres. This is a key technical role within a multidisciplinary team, focused on the design, coordination, and delivery of high-performance mechanical systems for hyperscale and enterprise-level data centre projects across the UK and Ireland. Key Responsibilities Lead or support the detailed design of mechanical systems including: HVAC and close-control cooling (CRAC/CRAH, DX, chilled water) LTHW/CHW systems, pipework sizing, and plant selection Hot/cold water services, ventilation, and smoke extract Renewable energy and heat recovery systems (where applicable) Integration of BMS and control strategies tailored to data centre operations Produce coordinated layouts, schematics, schedules, and specifications using Revit and AutoCAD. Perform critical calculations (load analysis, pressure loss, fan/pump sizing) using tools such as Hevacomp and IES VE. Engage with clients, design teams, and contractors to ensure compliance, efficiency, and resilience. Support delivery through RIBA stages and provide site-based technical input where required. Requirements Degree in Mechanical or Building Services Engineering. CEng or working towards (CIBSE/IMechE). 5-8+ years in mechanical building services design, with recent data centre experience. Strong knowledge of UK Building Regulations, CIBSE guides, BSRIA, and sustainability principles. Proficient in Revit MEP, MagiCAD, AutoCAD, Hevacomp, IES VE, and BMS interface design. Desirable Experience with Tier III / Tier IV data centre standards (Uptime Institute, ASHRAE TC9.9). Understanding of BIM Level 2 / ISO 19650 standards. Familiarity with commissioning processes and on-site coordination. Important This role is only open to applicants with full, unrestricted right to work in the UK. Unfortunately, we cannot consider applicants requiring visa sponsorship now or in future. This is a rare opportunity to join a high-performing team at the forefront of critical infrastructure design, working on some of the most technically complex and energy-intensive projects in the built environment. If you're ready to take your career forward in the data centre sector, we'd love to hear from you.