Including air-exchange performance in building regulation

Research shows that, despite compliance with building codes, residential ventilation systems do not deliver the requested air exchanges in the individual rooms. One of the reasons for this can be found in the way the building codes are composed. In general building codes only specify the minimum ventilation capacity that need to be installed in the various rooms. The actual performance of the ventilation system is left to the market. Since reality shows that market forces alone do not succeed in securing minimal ventilation performance, the Dutch Standards Committee – when commissioning the revision of the existing standard NEN 1087 (Ventilation for Buildings) – requested that a Performance Assessment method should be incorporated in the new version, in order to guide the market towards better ventilation systems. 
Obviously good IAQ is the actual goal behind ventilation systems. Ventilation systems attempt to influence the IAQ by inducing air exchanges in the various rooms in order to extract and dilute pollutant concentrations. Since type and level of pollutant concentrations is an ongoing research topic and in addition highly dependent on pollutant level of the building itself, the draft Performance Assessment method will not be based on IAQ-metrics (pollutants), but on the primary function the ventilation system itself: ‘its ability to achieve the requested air exchanges in the right place at the right time’. The rapporteurs therefore proposed to follow the methodology that was developed by VHK and U-Gent in consultation with the Residential Working Group of EVIA. The principles of this methodology were presented during the 2017 AIVC conference. The methodology introduces new parameters that indicate the probability of ‘achieving the requested air exchanges in the right place at the right time’, based on the controls that are used, the operating reliability of the ventilation provisions used, and the airtightness of the building. 
Adjustments were necessary to make the methodology suitable for use in building regulations. The coming period will be used to compare results of the Performance Assessment method with the results of field research and multi-zone airflow simulation models, after which the new NEN 1087 and the Performance Assessment method will be published for public consultation.