Division 1 Definitions for the purposes of Annex I

‘Measurement category’ means a test, measurement or usage arrangement that defines the inlet and outlet conditions of the fan under test.

‘Measurement category A’ means an arrangement where the fan is measured with free inlet and outlet conditions.

‘Measurement category B’ means an arrangement where the fan is measured with free inlet and with a duct fitted to its outlet.

‘Measurement category C’ means an arrangement where the fan is measured with a duct fitted to its inlet and with free outlet conditions.

‘Measurement category D’ means an arrangement where the fan is measured with a duct fitted to its inlet and outlet.

‘Efficiency category’ means the fan gas output energy form used to determine the fan energy efficiency, either static efficiency or total efficiency, where:

1. (a)

   ‘fan static pressure’ (p_sf) has been used to determine fan gas power in the efficiency equation for fan static efficiency; and

2. (b)

   ‘fan total pressure’ (p_f) has been used to determine fan gas power in the efficiency equation for total efficiency.

‘Static efficiency’ means the energy efficiency of a fan, based upon measurement of the ‘fan static pressure’ (p_sf).

‘Fan static pressure’ (p_sf) means the fan total pressure (p_f) minus the fan dynamic pressure corrected by the Mach factor.

‘Stagnation pressure’ means the pressure measured at a point in a flowing gas if it were brought to rest via an isentropic process.

‘Dynamic pressure’ means the pressure calculated from the mass flow rate, the average gas density at the outlet and the fan outlet area.

‘Mach factor’ means a correction factor applied to dynamic pressure at a point, defined as the stagnation pressure minus the pressure with respect to absolute zero pressure which is exerted at a point at rest relative to the gas around it and divided by the dynamic pressure.

‘Total efficiency’ means the energy efficiency of a fan, based upon measurement of the ‘fan total pressure’ (p_f ).

‘Fan total pressure’ (p_f ) means the difference between the stagnation pressure at the fan outlet and the stagnation pressure at the fan inlet.

‘Efficiency grade’ is a parameter in the calculation of the target energy efficiency of a fan of specific electric input power at its optimum energy efficiency point (expressed as parameter ‘N’ in the calculation of the fan energy efficiency).

The ‘target energy efficiency’ (η_target) is the minimum energy efficiency a fan must achieve in order to meet the requirements and is based on its electrical input power at its point of optimum energy efficiency, where η_target is the output value from the appropriate equation in Section 3 of Annex II, using the applicable integer N of the efficiency grade (Annex I, Section 2, Tables 1 and 2) and the electrical power input P_e(d) of the fan expressed in kW at its point of optimum energy efficiency in the applicable energy efficiency formula.

‘Variable speed drive (VSD)’ means an electronic power converter integrated — or functioning as one system — with the motor and the fan, that continuously adapts the electrical power supplied to the electric motor in order to control the mechanical power output of the motor according to the torque-speed characteristic of the load being driven by the motor, excluding variable voltage controllers where only the supply voltage for the motor is varied.

‘Overall efficiency’ is either ‘static efficiency’ or ‘total efficiency’, whichever is applicable.