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phonometry

Sound insulation

Sound insulation has a life cycle, and the pages of this section follow it. An element (a wall build-up, a floating floor, a window) is first characterised in the laboratory, where suppressed flanking isolates its direct transmission. That laboratory data feeds a prediction of how a whole building will perform, flanking paths included. The finished building is then verified in the field. At every stage the band spectrum is collapsed to the single number regulations quote, and for almost everything that collapse is one shared reference-curve engine rather than a step of any single method. The exception is the heavy-impact rating of ISO 717-2 Annex D, which shifts no curve at all: it sums A-weighted band levels in energy.

Laboratory. Laboratory Insulation Measurement covers the ISO 10140 sound reduction index and normalized impact level with their background-noise correction. Two laboratory methods sit beside it: Sound Insulation by Intensity (ISO 15186) reads the transmitted power off the radiating face when flanking is too high for the pressure method, and Laboratory Flanking Transmission (ISO 10848) measures the junction data the prediction consumes. A third, the floor-covering improvement of ISO 16251-1, is filed with the design pages it feeds.

Prediction. The design-stage half has a section of its own, Insulation design: the EN 12354 flanking model between rooms, the theoretical insulation of a panel, and the two material measurements a floor design consumes.

Field. Field Insulation Measurement (ISO 16283) covers the engineering-grade airborne and impact measurement in the building, its Clause 14 test report and the ISO 12999-1 uncertainty that qualifies it. The same standard specifies two more impact sources, a rubber ball and a bang machine, for the slow low-frequency thumps a tapping machine says nothing about; Heavy and Soft Impact Sources (ISO 16283-2) covers their specification, the Fast-weighted standardization of the maximum level and the Annex D rating. When the question does not deserve that effort, Sound Insulation Survey Method (ISO 10052) trades accuracy for speed with octave bands and a reverberation index.

Ratings and the envelope. Insulation Ratings (ISO 717) is the reference-curve engine every one of those methods ends on, with its spectrum adaptation terms C, Ctr and CI. And Façade Sound Insulation keeps the building envelope in one place: measured per ISO 16283-3, predicted per EN 12354-3, and radiating outwards per EN 12354-4. National building codes restate those ratings in their own global quantities, and Spanish Building Code (CTE DB-HR) implements the Spanish one: the direct Annex A index over eighteen bands, the clause 2 requirement tables and the window-size correction.

Two neighbouring sections complete the picture: the room-side quantities (reverberation time, absorption) live in Room acoustics, and the structure-borne noise of building equipment, predicted by the closely related EN 12354-5, lives in Structure-borne sources.

Pages in this section

Section titled “Pages in this section”

What this section does not cover

Section titled “What this section does not cover”

  • The library starts after the microphone. The field, laboratory, survey and intensity routines that form an insulation index accept per-position spectra and energy-average them for you; the heavy-impact standardization, the flanking indices, the ISO 717 ratings and the background-noise helpers take their per-band input already formed. Either way, nothing verifies how the measurement was made: not the number and placement of the source and microphone positions behind those spectra, not the low-frequency procedures of ISO 16283-1/-2, and not the test-facility and mounting requirements of ISO 10140-1. Those are the operator’s responsibility and the report’s, and they are what makes the numbers here mean something. Background noise is the one correction genuinely left to the caller: field levels must arrive already corrected, their 6 dB signal-to-background floor checked by the operator, while the ISO 10140-4 laboratory helper applies its rule itself, warning when its own floor is broken and capping the correction. Two consequences worth naming: the field and laboratory background corrections are different rules, so that laboratory helper must not be applied to field data; and the intensity route takes both the pressure and the intensity level as inputs, with the scanning probe and its phase-mismatch calibration outside the library.

  • Coverage inside the standards is partial in two places. Of ISO 10848 only the Part 1 formulae are implemented generically, plus the Part 4 modal-overlap validity check, not the facility-specific setups of Parts 2, 3 and 4. Of the Spanish code, only the verification indices are implemented: the simplified option’s solution tables of clause 3, the execution conditions of clause 5 and the maintenance conditions of clause 6 are out of scope, and the general option’s calculation route is Predicting Sound Insulation.

  • And there is no heavy-impact prediction at all. A floor construction can be carried to a tapping-machine level by the models in Insulation design; nothing does the same for the rubber ball, because the complexity of the input force and the use of a time-weighted maximum leave no simple counterpart. The heavy-impact page rates a measurement, and only a measurement.

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