Sound Power Level abbreviated as $SWL$ expresses sound power more practically as a relation to the threshold of hearing - 1 picoW - in a logarithmic scale.
$L_W = 10 \log_{10} \frac{P}{P_0} dB$, where $P$ is sound power and the reference value is $P_0 =1pW$.
Applicable units are those of quantitykind:SoundPowerLevel
Sound Power Level