BHI partnered with Dartmouth Thayer School of Engineering to create a design guide of alternative ventilation strategies to reference when laying out future hospitals in Haiti and other under-resourced nations.

The project found that natural ventilation alone cannot be relied on to sufficiently ventilate isolation rooms, but, if positioned properly, the ceiling fans already used by BHI for patient comfort can. The resulting guide provides design solutions that promote proper ventilation and prevent the spread of airborne disease, while also relying on minimal mechanical elements, providing cooling effects, staying within budget, and maintaining its feasibility in low-resource settings. The guide also contains recommendations on optimizing building layout for passive airflow (as a supplement to the mechanical system) by including a central courtyard, sloped ceilings, roof overhangs, and outdoor corridors.

Testing conducted by the Dartmouth team centered on optimizing exhaust airflow from ceiling fans. Computational Fluid Dynamics (CFD) software can model how ceiling fans move air within structures. Forty-eight isolation room designs were simulated in a Design of Experiment (DOE) to determine which construction factors allow the ceiling fan to exhaust air most effectively.
Roof shape is the most important factor in promoting airflow, while more openings and lower ceilings also help. A cupola, or roof pop-up, placed above the ceiling fan provides over 200 air changes per hour (ACH) when the fan is on maximum power, significantly more than the minimum 12 ACH. Open windows and furniture in the room either increase or do not affect airflow. With the exception of the flat roof models, most of the models tested easily achieve the minimum ACH. Therefore, BHI has flexibility in the future when choosing a design based building location, minimizing cost, optimizing mechanical airflow, or maximizing natural ventilation.

The guide also includes a full architectural model of an isolation ward that uses these principles to maximize mechanical and natural ventilation, while also minimizing costs. Although this project focused on ventilating isolation rooms in Haiti, the principles presented in the design guide can be applied to ventilate different rooms in other settings. When BHI plans their next facility, they can consult this design guide to minimize costs, maximize patient comfort, and reliably prevent the spread of airborne disease.