Partition Mass-Law Transmission Loss

The limp-mass law: a bare single-leaf panel attenuates airborne sound as TL = 20 log10(m f) - 47 dB (field/random incidence; -42 normal), with m the surface mass and f the frequency. Enter m in lb/ft^2 (converted at 1 lb/ft^2 = 4.88 kg/m^2). A single 1/2 in gypsum layer (~2 lb/ft^2) gives about 27 dB at 500 Hz, and the mass law adds +6 dB per doubling of mass or frequency. This is the idealized mass law for comparing bare single-leaf partitions and seeing the mass/frequency trend -- it does NOT capture the coincidence dip, stud/cavity resonances, flanking, or leaks, and it is NOT the ASTM E413 STC rating (which needs the full third-octave spectrum). First-principles acoustics (Bies & Hansen / FHWA); a lab-tested assembly rating and the acoustician govern.

TL = 20 log10(m f) - 47 dB (field/random incidence), or - 42 (normal incidence); m the surface mass in kg/m^2 (lb/ft^2 x 4.88243), f in Hz. +6 dB per doubling of m or f.

First-principles panel acoustics - the limp-mass law - as given in Bies & Hansen, Engineering Noise Control, and FHWA highway-noise guidance, by name.

The mass law TL = 20 log10(m f) - 47 is standard published acoustics (Bies & Hansen; FHWA public highway-noise material); the surface mass and frequency are the user's inputs.

Estimate. AHJ and licensed professional govern.

Field names used by the API: surface_mass_psf, frequency_hz, incidence, surface_mass_kgm2, transmission_loss_db

• Mass law TL = 20 log10(m f) - 47 (field) or - 42 (normal); +6 dB per doubling of m or fBies & Hansen / FHWA
• Idealized single leaf excludes the coincidence dip, stiffness region, cavity/stud resonances, flanking, and leaksscope of this tile
• Not STC the closed-form mass-law TL, not the ASTM E413 STC single-number ratingscope of this tile