Fan performance curves
The performance curves of these fans have been established using a test chamber according to DIN 24 163, mounting position D (connected at both sides). The curves indicate the static pressure increase ∆ pst as a function of the volume flow. The dynamic pressure increase ∆ pd2 shown in the performance curves refers to the flange cross-sectional area of the fan housing.
Sound levels
The figures given in the performance curves represent the A-weighted sound power levels LWA6 in decibel at the outlet side in duct systems. The A-weighted sound power level at the inlet side LWA5, according to DIN 45 635, part 38, can be calculated via the relative sound power levels or can be obtained by the following approximation calculation:
LWA5 ≈ LWA6 - 6 dB(A)
The A-weighted sound power level radiated from the casing LWA2, according to DIN 45 635, part 38, can be calculated via the relative sound power levels (see below) or is obtained approximately as follows:
LWA2 ≈ LWA6 - 17 dB(A) - for EKN or DKN
LWA2 ≈ LWA6 - 25 dB(A) - for EKNS or DKNS
The A-weighted sound pressure level LPA at a distance of 1 metre is obtained approximately by deducting 7 dB(A) from the A-weighted sound power level.:
LPA(1m) ≈ LWA2 - 7 dB(A)
It is important to note that reflexion and environmental characteristics as well as resonant frequencies influence the sound pressure levels in different ways. In order to avoid structure-borne noise transfer to a connected duct system we recommend the use of flexible connections EVK/EVKN (see page 28). The A-weighted octave sound power level is important for the choice of suitable sound attenuators. It is obtained as follows:
LWAokt = LWA6 + LWArel