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Purpose of the work
The certification of the first Low Energy hospital tested by the Passive House methodology for large-scale buildings in Thessaloniki, Greece.
Method of approach
The Passive House protocol for Airtightness measurement of high-rise buildings was followed and the EN 13829 standard was applied for the measurement. As a medical facility for cancer patients, the maximum efficiency of mechanical ventilation with heat recovery was a basic need to ensure the best hygiene conditions in the new hospital premises. The total volume was 29.830 m³ and the net floor area was 7.259 m² and the target rate to achieve was 1.0 1/h of air change.
Content of the contribution
It was two days of intense work, and the first step was to generate a constant negative pressure of -50 Pa with the help of six BlowerDoor fans. Two more fans were ready to be installed in case the envelope would not reply correctly to the pressure difference. The base camp was installed on the ground floor with all the fans and gauges leading to one central control point. At the same time, the building pressure differences were measured on the windward and leeward sides on the ground floor and additionally controlled on the top 4th floor. The pressure drops from the measurement center on the ground floor to the basement, from the ground floor to the top floor, as well as at four critically assessed points on the ground floor level, were checked to ensure uniform pressure buildup throughout the building.
During the building preparation, some openings were allowed to be closed and covered while a team of about 16 people was spread around the building to check for leakages and possible defective parts of the building. Since it was a very large-scale building, the team was equipped with wireless transceivers (walkie-talkie) and each time a small window or unsealed part of the building was discovered, the controller, who was monitoring the results, could confirm whether the changes were effective or not.
Results and assessment of their significance
Both under- and overpressure measurements were used, and the result was confirmed at 0.98 1/h of air change. It was very critical and of high importance the two days continuing measurement and monitoring every corner of the building by the 16-member team. For instance, by making a detailed inspection of every part of the building, it was discovered that in some bathrooms the showers had not yet been used and the siphons were empty. By simply supplying water to the showers and siphoning them, it was evident to the inspector on the ground floor, the reduction of leakages in the total volume of the building.
Conclusions
Testing the air permeability of the building envelope in a building of this size is the first experience in Greece. It is a bold and vital step towards improving the quality of the building envelope in conjunction with good thermal insulation in order to significantly minimize energy consumption.
Leak detection involved not only the classic thermal anemometer or smoke sticks, but also listening to air whistling through open drains and detecting foul-smelling air from the sewers in rooms where the traps were not yet filled with water. It was very important to have a numerous team checking every single part of the building during the baseline at 50 Pa for a cruise test.
The envelope performed well and most of the airtightness construction techniques were followed by the book and when the instructions are firm and clear, the results reward the effort.
For further information please contact Theo Tountas at: fuv@fuv.gr