La certificazione parte terza

Torna alla lista
Certification manual
Certification Manual
OM (Operational Manual)
RS (Rating Standard)

Scope of the programme

The programme scope covers all the fans types that are intended to be used as Air Handling Units components.

Fan components listed in the Operational Manual OM-22 have to be taken into account in the fan performance ratings that appear in the technical documentation (see definition in Certification Manual) in order to comply with the “wire-to-air” approach.


The full list of useful definitions can be consulted in RS 1/C/001. Some are presented hereafter.


A power electronic device that regulates the speed of a motor. Speed can be varied either continuously or in steps by a variable-speed motor, variable-speed coupling, convertors (inverters), voltage control or by use of electronically commutated or switched reluctance motors. The controller can notably be on/off, 2-speed, multi-speed drive or variable speed drive.

Direct drive

Drive arrangement for a fan where the impeller is fixed to the motor shaft, either directly or with a co-axial coupling, and where the impeller speed is identical to the motor’s rotational speed.

Drive/control (electrical) input power

The drive/control (electrical) input power Ped [W] is the electric power input measured at the main terminals of the controller.

Fan air power

Conventional output power Pu [W] which is the product of the mass flow-rate by the fan work per unit mass, or the product of the inlet volume flow, the compressibility coefficient and the fan pressure.

Fan impeller efficiency

The fan impeller efficiency ηr [%] is the fan air power Pu divided by the impeller power Pr.

Fan impeller power

The fan impeller power Pr [W], is the mechanical power supplied to the fan impeller.

Fan range

A family of fans of different sizes grouped under the same designation and using the same operating software/DLL (see RS 1/C/001 for further details).

Fan static efficiency

The fan static efficiency is the energy efficiency of a fan based upon the measurement of the fan static pressure psf.

Fan static pressure difference

Difference Δps-static [Pa] between the static pressure at the fan outlet and the total pressure at the fan inlet.


The part of the fan that is imparting energy into the gas flow and is also known as the fan wheel.

Maximum fan speed 

Maximum rotational speed Nmax in rotations per minute [rpm] for which there is no risk of blade damage.

Motor (electrical) input power

The motor (electrical) input power Pe [W] is the electric power input measured at the main terminals of the motor.

Octave band sound power level 

Sound power level in an octave band with a defined centre frequency, noted LWfc, expressed in [dB] and defined as 10 times the logarithm to the base 10 of the ratio of the sound power in watts to a reference value of 1 picowatt (10-12 W).

Overall efficiency

The overall efficiency [%] stands for static efficiency when the fan is tested in the measurement/installation category “A” (free inlet, free outlet and a partition between inlet and outlet zone).

Shaft power

The fan shaft power Pa [W], is the mechanical power supplied to the fan shaft, including bearings.

Variable speed drive

The Variable speed drive (VSD) is an electronic controller, integrated or functioning as one system or as a separate delivery with the motor and the fan, which continuously adapts the electrical power supplied to the motor in order to control its mechanical power output according to the torque-speed characteristic of the load being driven.

Wire-to-air approach

The Wire-to-Air approach consists in assessing the fan performance from the electric wire to the air discharge, accounting for all the components involved in the air stream generation that affect the performance data.

All the components listed in §II of OM-22 that appear in the applicant/participant product catalogue have to be included in the tested fan assembly.

Whenever a given component (see components list in §II of OM-22) is not included in the applicant/participant catalogue, a recommended component is to be specified in the declaration file and its influence on the certified performance values is to be accounted for in the DLL/software ratings in accordance with the rating requirements (see RS 1/C/001 for further details).

Certified performance items and associated tolerances

When tested in the laboratory the obtained performance data shall not differ from the declared values by more than the following tolerance values:

Static pressure difference -4 % or -15 Pa
Shaft power, including bearings +3 %
Impeller efficiency -5 percentage points
Maximum fan speed -5 %
Motor (electrical) input power +3 %
Drive/control (electrical) input power +3 %
Overall (static) efficiency   -5 percentage points
Inlet/outlet LWfc by octave bands at 125 Hz +5 dB
Inlet/outlet LWfc by octave bands for 250 Hz - 8000 Hz +3 dB


vedi articoli correlati