The module 8A SILDIS®[0][1] software (in Excel format) enables the predictive calculation of noise attenuation in Heating Ventilation Air Conditionning (HVAC) air ducts and stacks-chimneys, as illustrated by an example (numbered 8.4.1 in the User's manual).
Problem statement for the predictive calculation of noise attenuation in Heating Ventilation Air Conditionning (HVAC) air ducts and industrial stacks-chimneys using SILDIS® software (example)
One wish to calculate the attenuation for the 63 Hz center-frequency octave band of a lightly fouled brick chimney [1] with a height of 135 m [2] and a diameter of 6 m [3], considering:
- for the conveyed fluid: air at a temperature of 129.8 °C [4], a pressure of 101325 Pa [5], and a mass flow rate of 96.4 kg/s [6]
The language used is English [7].
Input data for the predictive calculation of noise attenuation in Heating Ventilation Air Conditionning (HVAC) air ducts and industrial stacks-chimneys using SILDIS® software (example)
The input data required for the calculation are listed below, referencing the information provided earlier (cf. the figures in brackets in the preceding section, which serve as references for explaining the selection below). The input cells are identified by their Excel coordinates (column/row) in the following excerpt from the User' manual.
Input data to be entered into the "in COALA" Excel sheet for the predictive calculation of noise attenuation in Heating Ventilation Air Conditionning (HVAC) air ducts and industrial stacks-chimneys using SILDIS® software (example)
| Item | Cell for input | Foreseen action | Input | Landmark / comment |
| Langage | AF2 | For English, select E; for French, select F | E | [7] |
| Temperature (°C) | D5 | Enter a real number | 129.8 | [4] |
| Pressure (Pa) | D6 | Enter a positive real number | 101325 | [5] |
Input data to be entered into the "in COSIL" Excel sheet for the predictive calculation of noise attenuation in Heating Ventilation Air Conditionning (HVAC) air ducts and industrial stacks-chimneys using SILDIS® software (example)
| Item | Cell for input | Foreseen action | Input | Landmark / comment |
| Mass flow rate | D66 | Entrer un nombre réel | 96.4 | [6] |
Input data to be entered into the "in COSTDU" Excel sheet for the predictive calculation of noise attenuation in Heating Ventilation Air Conditionning (HVAC) air ducts and industrial stacks-chimneys using SILDIS® software (example)
| Item | Cell for input | Foreseen action | Input | Landmark / comment |
| Model for insertion loss | S5 | Select a model (in a drop-down menu) | 3733b-B-L | [1] |
| Duct length (m) | X5 | Enter a positive real number | 135 | [2] |
| To get D = (m) | E23 | Enter a positive real number | 6 | [6] |
| Biggest dimension a (m) | P23 | Enter a positive real number | 5.317 | cf. cell H23 |
| Smallest dimension b (m) | P24 | Enter a positive real number | 5.317 | cf. celle H24 |
Output data: result of the predictive calculation of noise attenuation for Heating Ventilation Air Conditionning (HVAC) air ducts and industrial stacks-chimneys using SILDIS® software (example)
For the example under consideration, the results of the predictive calculation for noise attenuation in Heating Ventilation Air Conditionning (HVAC) air ducts and industrial stacks-chimneys can be viewed:
- in the "in-out COSTDU" Excel sheet
- tables: by octave frequency band
Result: the attenuation is 2.2 dB for the octave band with a center frequency of 63 Hz
remarks:
- also displayed in the "in-out COSTDU" sheet are:
- the attenuation in other frequency bands centered from 31 Hz to 16 kHz
- the sound power level of the flow noise
- the sound power level downstream of the duct/stack-chimney section under consideration (when the sound power level upstream is known)
[0] Sound Impact Limitation - Design for Industrialized Solutions