Insulation design

The pages of the Sound insulation section answer the question what does this building achieve? The pages here answer the one that comes first: what will it achieve, and what should I build? Both halves speak the same language of $R$, $L_n$ and their weighted single numbers, but a prediction is assembled from element data instead of measured in a finished room, so its inputs, its assumptions and its error bars are its own subject.

Predicting Sound Insulation (EN 12354) is the normative model: the airborne and impact flanking transmission between two rooms, path by path, from the direct element and the junction vibration reduction indices $K_{ij}$. It consumes laboratory element data measured per ISO 10140 and junction data measured per ISO 10848, both of which live in Sound insulation beside the field measurement the prediction is checked against, and beside the façade guide that carries the same family across the building envelope.

Detailed Per-Band Prediction (ISO 12354) runs the same standard band by band instead of on single numbers: the laboratory element and junction data are converted to their in-situ values, every path is formed per band, and the result shows which path dominates each band rather than only whether the room passes.

Which of the two do you run? Run the simplified model when what you have is catalogue weighted ratings — $R_w$, $\Delta L_w$, a mass per unit area — and the question is whether the partition meets a limit. Run the detailed one when you have per-band element and junction spectra, or the material properties the standard can calculate them from, and the question is which path to fix in which band. The choice is not about accuracy on the rating: on the standard’s own worked building the two agree well inside their stated spread, and the detailed airborne model carries no bias error and a standard deviation of 1,5 dB to 2,5 dB (Clause 5) against about 2 dB for the simplified one. What the detailed model buys is the spectrum behind the single number.

Predicting Panel Sound Insulation goes one level deeper, to where the element $R$ itself comes from: the mass law and the coincidence dip of a single panel, the plateau shortcut that estimates the whole curve by hand, the coincidence range of a corrugated or ribbed sheet, the mass-spring-mass behaviour of a double wall and the wall-tie bridge that limits a masonry cavity one, transmission through slits and apertures, plate radiation efficiency and point mobilities. It is the physics a catalogue value expresses in one number.

Two pages here carry the floor half of any design, one measuring and one predicting. Floor-Covering Impact Improvement (ISO 16251-1) gives the weighted improvement $\Delta L_w$ of a covering that exists, on a small heavyweight mock-up, and that is the term EN 12354-2 subtracts from the bare-floor level. Predicting Resilient-Layer Performance predicts it for a covering that does not yet exist, from the tapping machine’s own force spectrum, the cut-off frequency of a soft covering, the 30 lg and 40 lg floating-floor laws and the ISO 12354-1 Annex D rating of a wall lining. Both start from the stiffness per unit area $s^{\prime }$ of the resilient layer, measured per EN 29052-1 in Dynamic stiffness of resilient materials over in the materials section, which sets the resonance the whole improvement hangs on.

Building service equipment is a chain of its own, and the two pages only read correctly in order. Structure-borne sound power of equipment (EN 15657) characterises a pump, fan or cistern by the power it injects into the structure, measured on a reception plate of known dissipation and then made plate-independent. Installed structure-borne sound (EN 12354-5) takes that source description, loses part of it to the coupling term the source and receiver mobilities set, and carries the rest to a room that may be several junctions away.

EN 12354 or ISO 12354? One bookkeeping note runs through the whole section. The prediction family was published by CEN as EN 12354-1 to -6 and later reissued by ISO as a second edition, ISO 12354-1:2017 and ISO 12354-2:2017, which is not word for word the earlier text: where a formula changed between the prints, the errata registry records both. Parts 3 to 6 keep their EN designation in the editions used here. Every guide names the edition it was read from — EN 12354-1:2000 and EN 12354-2:2000 for the simplified models on Predicting Sound Insulation, including the tabulated flanking correction $K$ that the 2017 impact part replaced with explicit per-path formulae; ISO 12354-1:2017 and ISO 12354-2:2017 for the per-band models and the Annex L/G worked examples of Detailed Per-Band Prediction; and EN 12354-3:2000 to EN 12354-6:2003 for façades, service equipment and enclosed spaces. Check which edition your regulation calls up before quoting a clause or a correction from either.

And one caveat both parts print, in Clause 5: the models predict the measured performance of buildings assuming good workmanship and high measurement accuracy. A prediction is therefore a statement about a correctly built construction, not about the one that will be built; the standard’s own advice is to vary the uncertain inputs and read the spread in the answer, which ISO 12354-1:2017 Annex K systematises into an uncertainty on the result.

Every prediction here starts from measured data that came from somewhere else, and the design report has to say where. The element $R$ and $L_n$ come from ISO 10140-2 and -3, together with the laboratory structural reverberation time printed in the same report, because the in-situ conversion needs it. The junction indices $K_{ij}$ come from an ISO 10848 measurement or from the EN 12354-1 Annex E catalogue of junction types. The floor-covering improvement $\Delta L_w$ comes from ISO 16251-1 or from a full-size ISO 10140-3 test. The resilient layer’s $s^{\prime }$ comes from EN 29052-1. And for service equipment, the characteristic structure-borne power comes from the EN 15657 reception plate. Two of the pages in this section are themselves such measurements, feeding the others; the built result is finally checked against the ISO 16283 field measurement in Sound insulation.

Pages in this section

• Predicting Sound Insulation (EN 12354): the airborne and impact flanking models between rooms (EN 12354-1/2) with their junction vibration reduction indices and prediction fiches.
• Detailed Per-Band Prediction (ISO 12354): the per-band detailed model of ISO 12354-1/-2 with in-situ element and junction conversion, the flanking indices per band and the per-path contributions behind the rating.
• Predicting Panel Sound Insulation: the mass law, the plateau shortcut and the coincidence dip of a single panel (Sharp, Norton), the coincidence range of a corrugated or ribbed sheet (Vigran/Heckl), double walls and the wall-tie bridge of a masonry cavity wall (Bies, Hopkins), slits and apertures (Gomperts, Wilson-Soroka), radiation efficiency (Leppington/Maidanik) and point mobilities (Cremer).
• Floor-Covering Impact Improvement (ISO 16251-1): the weighted improvement of a soft floor covering measured on a small heavyweight mock-up.
• Predicting Resilient-Layer Performance: the tapping-machine force model, the cut-off frequency of a soft covering, the floating-floor improvement laws and the ISO 12354-1 Annex D rating of a wall lining.
• Structure-borne sound power of equipment (EN 15657): the characteristic power a machine injects into a building element, measured on a reception plate.
• Installed structure-borne sound (EN 12354-5): what that power becomes once the machine is mounted on a real element, and the level it produces in the receiving room.

See also

Pages elsewhere on the site that this section leans on:

• Dynamic stiffness of resilient materials (EN 29052-1): the load-plate resonance measurement, the enclosed-gas term and the floating-floor natural frequency.

What this section does not cover

• A prediction is only as good as the element data you feed it, and the library takes that data as given. The element ratings, the junction indices and the covering improvements are parameters the entry points consume, supplied from measurement or computed with this section’s own estimators — the Annex E junction catalogue, the floating-floor and lining improvement laws, the Annex B homogeneous-element chain and the panel-physics models — and nothing checks the numbers you pass. Only the structure-to-airborne adjustment terms of EN 12354-5 Annexes D and F have no estimator here at all and must come from the standard’s own tables. The simplified prediction page stops at the weighted single numbers by design, and the detailed page is where the per-band models live.

• Every panel model carries a validity range it does not extend past, and the guides flag each: Sharp’s single-panel method is not valid below about 1.5 times the panel’s first resonance, Gomperts’ slit model holds only while the slit is narrow against the wavelength, only Leppington’s method no. 1 is implemented for radiation efficiency, and the orthotropic routes are infinite-panel models that miss the dip real ribbed cladding shows between 2 and 4 kHz. On the resilient-layer side, the tapping-machine force model assumes a frequency-independent driving-point impedance, so a joisted or battened lightweight floor is outside it; soft coverings are treated as linear springs; there is no per-band prediction of a lining’s improvement, because Annex D is a single-number method; and heavy impact sources such as the rubber ball are not covered by any of these models at all — their rating is Heavy and Soft Impact Sources.

• Two edition boundaries: only the 2009 edition of EN 12354-5 is implemented, not the 2023 revision, and the simplified and detailed pages follow different editions of the 12354 family, as the note above says.