Strutt|Mechanical Services|Regenerated Noise|Attenuator (NAP Silentflow) inserts sound power levels into the active row of the worksheet.
NAP Attenuator regenerated noise has been provided in graphs, specific for each type of attenuator, by the manufacturer. From these graphs, the following formula has been used to calculate the overall sound power level according to the type of attenuator selected:
`L_W = 50log V + 10log A + 2`
`V` is the volume flow rate through the attenuator (m3/s)
`A` is the attenuator face area (m2)
Input required is type of attenuator (series), model, attenuator length, V and A.