Irene Poza-Casado
Bibliographic info:
11th International BUILDAIR Symposium, 24- 25 May 2019, Hannover, Germany

Even though air leakage assessment is key towards a better energy performance of buildings, Spain has still not established limitations regarding airtightness. National building regulations in Spain are gathered in the National Building Code (CTE), which was first released in 2006 and updated several times so far.

Airtightness should be considered from two points of view. On the one hand, regarding its energy impact and, on the other hand, regarding its contribution to ventilation, health and comfort of occupants. DB HE 1 on limitation of energy demand (2017) from CTE does not take into account global airtightness. Therefore, there is no standardised procedure for airtightness measurement to be considered for the justification of this document. However, there is a limitation on the permeability of windows depending on the climate zone. DB HS 3 on Indoor air quality (2017) from CTE implements specific ventilation requirements and proceedings to ensure adequate indoor air quality. The equivalent infiltration area can be considered as part of the ventilation inlet area, but it is necessary to justify its estimation. However, the document does not clarify which method should be employed. Since justification is needed during design stage, implementation of pressurization tests does not seem to be an option at this point.

A new update of CTE is expected to be released in 2019. Although measures are taken to implement nZEB following European Directive 2018/844 on the energy performance of buildings and energy efficiency, no update regarding airtightness is expected.

Therefore, it is important to note that no protocols for the determination of air permeability of buildings by means of the fan pressurization method have been implemented so far from a regulatory point of view. However, tests are performed to comply with specific energy programms (Passivhaus, BREEAM, LEED, etc.), by constructors who wish to ensure the quality of construction or as a diagnosis tool in case of poor energy performance of the building or before retrofitting actions.

The current version of the national document that describes the fan pressurization method (UNE-EN 13829), is an outdated adaption of ISO 9972. Although test performance is not required according to regulations, it seems that an update is needed according to the last version of ISO 9972 of 2015, so that tests are performed with unified criteria.


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