  We have derived the set of reference scaling parameters yielding collapse of
isentropic acoustic and thermoacoustic (or heat-release-induced) waves across
different pure compressible fluids with an assigned equation of state. The
resulting reference pressure and velocity are consistent with classic acoustic
scaling. The reference temperature and heat release rate need to be expressed
in terms of the isobaric thermal expansion coefficient $\alpha^*_{p_0}$ to
ensure collapse of all thermo-fluid-dynamic fluctuations across all fluids. The
proposed scaling is extended to non-isentropic waves and verified against data
from highly-resolved one-dimensional Navier-Stokes simulations. Conditions
tested include freely propagating isentropic acoustic waves and thermoacoustic
compression waves up to shock strength of 4.27, for six different supercritical
fluids in states ranging from compressible liquid to near-ideal gas, and
spanning seven orders of magnitude of imposed heat release rate.
