Fan Peformance Curves
The performance curves for these fans have been established using the inlet test method in a test rig according to DIN 24 163, mounting position D (connected on both sides). The curves indicate the static pressure rise Δ pst, for direct-driven fans and the total pressure increase Δ pt, for belt driven fans as a function of the volume flow. The dynamic pressure rise Δ pd2 shown in the performance curves refers to the outlet cross-sectional area of the fan.
Sound Levels
The figures given in the performance curves are the A-weighted sound power levels LWA6 in decibels at the outlet side in ducted 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 (see below) or is obtained approximately as follows:
LWA5 ≈ LWA6 - 6 dB
The A-weighted sound power level LWA2 according to DIN 45 635, part 38, can be calculated via the relative sound power levels (see below) or is obtained by the following approximation formula: LWA2 ≈ LWA6 - 25 dB
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
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.
The A-weighted octave sound power level is important for the choice of suitable sound attenuators. It is obtained as follows: LWAokt = LWA6 + LWArel