Public Health Engineering for Climate Resilience: A Systems Approach to Water Safety, Legionella Prevention, and Hybrid Heat Pump Efficiency in LEED Gold Healthcare

This paper outlines the integrated engineering design for a Long-Term Care Centre (LTCC) in Dubai, demonstrating a systems approach that achieves rigorous public health outcomes and LEED Gold sustainability in a hot, arid climate. The design synthesizes demanding standards, including NFPA 99, ASHRAE 90.1, and DHA Guidelines. The core technical achievement is the synergistic use of energy and water systems. Sustainability targets are met by a Hybrid Heat Pump System (HPS) that reclaims thermal waste from mandatory cooling—a major regional energy liability—to generate the facility's Domestic Hot Water (DHW) at high efficiency. Public health is ensured by a multi-barrier water safety strategy focused on Legionella prevention. This involves layered controls: Thermal Control: A Cooled Cold Water System (CCWS) actively maintains cold water below $20^\circ\text{C}$ to inhibit growth, while DHW is circulated hot for disinfection. Disinfection: Pre-filtration and primary UV treatment are complemented by Copper-Silver Ionization, which provides a crucial, long-lasting residual disinfectant throughout the distribution network, penetrating and disrupting biofilm.