5 research outputs found
Encouraging natural ventilation to improve indoor environmental conditions at schools. Case studies in the north of Spain before and during COVID
The COVID pandemic has strongly affected daily life both in Spanish schools and worldwide. Providing
the best environmental conditions for children allowing face-to-face learning with healthy and safe
indoor spaces is a challenge. In the present study, empirical research about how these environmental
conditions change with COVID is presented comparing the situation from March 2020 to January 2021.
The methodology combines surveys conducted in nine schools with a case study in a selected school
where a detailed monitoring of the building was developed during both heating seasons. This data ana-
lyzes the impact of the new COVID prevention protocols on indoor environmental conditions (especially
those related to natural ventilation). Results show a mean CO2 reduction of 1,400 ppm, having in the sec-
ond term values around 1,000 ppm, although temperatures diminished nearly 2 °C to mean values of
18 °C. Evolution of temperature and CO2 concentration throughout the day was also analyzed, being these
indoor conditions especially important for the children with poorer health. Mechanical ventilation with
heating recovery should complement natural ventilation, at least during the coldest months or hours of
the day, although systems have to be carefully designed and installed to work effectively
Influence of the Water Vapour Permeability of Airtight Sheets on the Behaviour of Facade
The air-tightness of the thermal envelope of buildings is one of the measures to reduce their
energy demands in order to achieve global warming reduction targets. To this end, airtight sheets
with different water vapour permeability characteristics are used. The different products studied are
highly dispersed in terms of equivalent air thickness values, leading to confusion. After the analysis
carried out, it is concluded that all airtight sheets are vapour barriers. To clarify whether or not
these sheets are necessary as vapour barriers, a condensation analysis was carried out on 13 different
facades for 3 climate zones with severe winters as defined in Spanish regulations. The results reveal
that interstitial condensation occurs in only 7 of the 39 case studies, with the traditional facades
of brickwork with render causing the greatest problems if the appropriate products are not used.
In these cases, airtight sheets with water vapour barrier characteristics must be applied on the interior
face of the insulating material. In all other cases (32), the airtight sheets must be permeable to water
vapour if it is looked for a more breathable wall to water vapour and a better control of the interior
humidity conditions