Environmental exposures in health facilities

Indoors at workplaces, adverse thermal conditions can lead to errors, reduced work performance, and even accidents. Heat may have particularly serious consequences in healthcare with patients who may be vulnerable and therefore rely on staff to be vigilant and careful.

Currently, energy used for space cooling accounts for 20% of the global CO₂ emissions from buildings. With increasing temperatures caused by climate change, the energy used to cool buildings is projected to more than triple by 2050. It is, therefore, crucial to emphasise sustainable practices in the building sector. This includes more widespread use of solutions that can moderate indoor environments at low energy use, preferably by passive means, using renewable energy, and using sustainable materials.

This deliverable contains two sections: 1) one on the measurement of thermal exposures in the maternity wards of four healthcare facilities in Zimbabwe, South Africa, and Sweden, and 2) a section that evaluates through numerical simulations the effect on the indoor thermal conditions, energy use, and sustainability of selected building-related mitigation interventions in a maternity ward at the Mt. Darwin Hospital in Zimbabwe - under a current and a projected future climate scenario.

Measurement devices recording air temperature, globe temperature and air humidity were located in selected rooms in the healthcare facilities. Based on the measured parameters, different indices were used to assess indoor thermal comfort (Sweden) or heat exposure (Zimbabwe and South Africa). Measurements in Sweden represented autumn/winter (October-January), in Zimbabwe spring/summer (September-December), and in South Africa the summer period (December and January).

In Sweden, the recorded temperatures were mainly within the highest comfort quality categories. In contrast, in the facilities in both Zimbabwe and South Africa, temperatures were well above the recommended limits for comfortable indoor conditions. However, the relative air humidity (RH) in Sweden was lower than 20% RH in 25% of the recordings and lower than 40% RH in around 90%. This may affect the staff’s perception of dry air and cause symptoms such as dry mucous membranes in the eyes, nose, mouth, and dry skin. In contrast, in South Africa and Zimbabwe, the relative air humidity was higher than 40% RH in around 75% of the recordings. In combination with a high operative temperature, the air humidity may reduce the evaporation of sweat, which is required to sustain the body’s heat balance.

In South Africa, the Wet Bulb Globe Temperature (WBGT) was below the reference limit for unacclimatised persons performing work at low or moderate metabolic rates almost all the time. In contrast, the reference limit for moderate work in Zimbabwe exceeded 7% of the measurements. Reference limits reflect unacclimatised persons, as healthcare workers may not be acclimatised to heat. Even though air temperatures reached relatively high levels, the air humidity during these periods was moderate, preventing excessively high WBGTs.

A virtual model of the maternity ward at Mt Darwin District Hospital was created based on observations in the hospital case building. The model was used for a year-long simulation of the indoor environment and energy use with a weather file representing the location of the hospital with the current climate and with a projection to 2080. Different refurbishment solutions were tested alone and in combination. The solutions included reflective roof paint, ventilation grilles in exterior walls, ceiling and exterior walls insulation, new windows, shading overhangs, a split-type air conditioning unit and a central air handling unit. The feasibility of the refurbishment solutions was evaluated based on their influence on the indoor environment, energy use, global warming potential, and life cycle costing.

It was possible almost to eliminate time with temperatures above 32°C when several of the refurbishment solutions were combined. As the associated costs and environmental impacts were considerably higher with the active than with the passive solutions, photovoltaics should be implemented with active solutions.

The projection for the year 2080 showed a 15-percentage point increase in yearly hours with indoor temperatures higher than 32°C with the current building. However, implementing the studied combinations of refurbishment measures diminished future overheating. Combinations incorporating active measures demonstrated minimal change compared to the current achievable indoor environment, though consuming significantly more energy.