For the calculation of internal specific fan power, SFPint,:
- In cases where internal pressure measurements can be performed, the internal fan efficiency is to be used as defined and described in draft Commission communication VERSION OF 21/12/2015 Section 5.2.
- Alternatively, in cases where internal pressure measurements cannot be performed, the external fan efficiency is to be used for SFPint determination for NRVU, as defined and described under Section 5.2 in draft Commission communication VERSION OF 21/12/2015.
In the case of UVUs, the Regulation distinguishes between general and UVUs intended to be used with a filter. UVUs intended to be used with a filter must fulfil requirements concerning maximum internal specific fan power SFPint_limit.
All UVUs (intended to be used with or without a filter) must fulfil the minimum fan efficiency of ventilation units, ηvu. The fan efficiency of a UVU is determined as described in draft Commission communication VERSION OF 21/12/2015, at the declared (nominal) flow and pressure of the reference configuration. This way, pressure loss attributed to the casing is taken into account. Please note that the operational point is not by definition the best efficiency point of the fan, but the nominal conditions of the ventilation unit as stated in Annex 1, 2 (2).
Disclaimer: Please note that the European Commission cannot provide a legally binding interpretation of the EU legislation, as this is the sole competence of the European Court of Justice. Any remarks from the European Commission services are without prejudice to the position the Commission might take should related cases arise in a procedure before the Court of Justice.