Samuel Jacobs works in a space where engineering decisions are not just about performance, but about risk, reliability, and real-world constraints. As a Senior Mechanical Engineer at WSP in Africa, he focuses on healthcare facilities, where HVAC systems directly impact clinical safety.

With over six years’ experience in the healthcare sector and nearly three years at WSP, Jacobs has been involved in the design of complex hospital environments, including the Roha Advanced Multi-Speciality Hospital in Addis Ababa, where his work offers a practical view of what it takes to deliver high-performance systems in an African context.

What makes HVAC design for healthcare facilities in Africa uniquely challenging?

It is about balance. For ROHA, you are trying to meet international healthcare standards while still designing something that can actually be built, maintained, and operated in the region. We cannot just take a standard and apply it blindly. We need to consider equipment availability, supply chains, local skills, and how systems will be constructed and maintained long after construction is complete.

Those constraints extend beyond design. Equipment may need to be imported, sometimes travelling through multiple countries before reaching the site. Construction programmes may not align with ideal sequencing. Even infrastructure like power and water cannot be assumed. In Africa, you always have to consider power reliability, generator backup, and water storage.

How does targeting EDGE certification influence design decisions?

It introduces a structured approach to reducing energy and water use and overall system demand. For mechanical systems, that often means making deliberate technology choices. It helps us reduce peak loads, lower energy consumption, and improve system efficiency.

The impact is not limited to engineering. Architectural decisions, such as glazing, shading, and insulation, directly affect HVAC performance. If the building envelope, for example, is more efficient, we can install smaller HVAC systems with lower airflow, smaller ducts, and reduced energy demand.

Can you explain the rationale behind combining a central chilled-water plant with VRF systems in this hybrid design?

The hybrid design allows us to separate different types of loads. The central chilled-water system serves air-handling units that manage the external air loads. In critical spaces like operating theatres and MRI suites, those systems handle the full load.

Thermally Activated Building Systems (TABS) are used to address part of the internal load. It is a high temperature chilled-water loop embedded in the concrete slabs that provides radiant cooling and helps manage peak demand. The VRF systems then address the remaining internal loads and provide individual room-level temperature control without the introduction of reheat.

This layered approach enables pressure control and infection management through the central systems, while still maintaining flexibility and comfort in individual spaces.

How do Thermally Activated Building Systems (TABS) contribute to efficiency and resilience in this hospital context?

TABS helps manage peak loads and reduces the demand on the air system. By circulating chilled water through the building structure, it removes heat directly from the space and provides a stable base level of cooling. That reduces reliance on high-airflow systems and improves overall efficiency, particularly in facilities with varying load profiles.

What role does ASHRAE 170 guidance play in shaping system choices for high-risk areas?

ASHRAE 170 is the primary design guide, with other standards such as HTM 03-01 supporting it where required. It defines ventilation rates, filtration, pressurisation, and air distribution strategies across the facility, especially in high-risk clinical spaces.

The way air enters, moves through, and leaves a space is critical. It directly affects infection control and patient safety. In areas like operating theatres, isolation rooms, and sterile processing, incorrect airflow can introduce contamination risks. Managing supply, return, and exhaust air becomes a clinical requirement.

How did coordination with architects, clinicians, and operations teams shape the HVAC strategy?

There was significant coordination with architects and clinicians from the early stages of the design process. The airflow strategy influenced the layout of key spaces such as operating theatres, isolation rooms, and sterile areas.

We needed to create natural paths for air to move from high-pressure sterile areas to lower-pressure zones. That required alignment among the HVAC design, the architectural layout, and the hospital's operating procedures. You cannot always solve these challenges with HVAC alone. Sometimes the building layout itself has to change.

In what ways do pressure zoning and air-flow mapping reinforce infection control and patient safety?

In healthcare, airflow is about containment. Sterile spaces need to be protected from contaminated air. That means maintaining controlled pressure differences and directing airflow in a specific way.

Air moves from areas of high positive pressure to areas of lower or negative pressure. That prevents contaminants from entering critical spaces. It requires precise coordination between systems, layouts, and operational practices.

What are the key benefits of this HVAC solution for patients, staff, and hospital operators?

The system is designed to support a range of clinical functions within a single facility. You have operating theatres, isolation wards, ICUs, maternity spaces, kitchens, laundries, and administrative areas, all with different requirements and operating schedules. The hybrid system provides flexibility, individual control, and clinical safety while maintaining power efficiency.

How does this project demonstrate resilience and sustainability in African healthcare infrastructure?

Resilience comes from the ability to handle different occupancy types and varying load conditions over time. The system can adapt to changes in demand throughout the day, week, and year.

Sustainability is addressed through reduced peak energy demand, improved efficiency, lower water use, and system longevity. At the same time, the design accounts for local realities such as power reliability and long-term maintenance.

What opportunities exist for data-driven monitoring and verification to improve long-term performance?

Building management systems (BMS) play a key role in monitoring and maintaining performance. They allow for ongoing verification against the original design intent.

Over time, that data supports optimisation, early fault detection, and evidence-based maintenance strategies. There is also potential to expand this using digital twin technology, which can support asset management and long-term system planning.

Looking ahead, how might hybrid systems like this evolve to meet Africa’s growing healthcare demands?

There is an opportunity to integrate smart controls and real-time performance analytics more effectively. At the same time, adopting international standards helps establish a consistent baseline for quality, safety, and performance. The challenge is to apply those standards in ways that reflect local operational realities.

With the right balance, these systems can support both high-performance healthcare delivery and long-term sustainability across the region.