This step performs the calculation for the efficiency of MV fans and calculates the points. It also checks the North and South window openings for NV spaces. Note that for a window to count as a North or South opening, it needs to have the right orientation (+ or – 22.5 degrees), but also to be defined as openable (cf. Natvent Design section). The points between NV and MV are then area pro-rated, which is the second line points in the Results section. The first line gives those points pro-rated according to the air-conditioned/non air-conditioned areas.
Example:A building of 10,000m2 has 6,000m2 air conditioned, 3,000m2 naturally ventilated and 1,000m2 mechanically ventilated. Under NRB 1-4, 8 points were scored for the natural ventilation section part, and 3 points under the mechanical ventilation part. The total number of points for NRB 1-4 before pro-rating is 8*(3,000/4,000)+3*(1,000/4,000) = 6.75 points. After pro-rating between air-conditioned and non air-conditioned spaces, the total number of points for this section is: 6.75*(4,000/10,000) = 2.7 points.
This point computation is fully automated in the report, this example is only for the user’s understanding, but no further action or such calculation is required to be performed.
