Source: https://jmrplens.github.io/phonometry/buildings/insulation/insulation-survey/ # Sound Insulation Survey Method (ISO 10052) Not every question deserves a full engineering measurement. When a dispute needs a number this afternoon, ISO 10052 trades accuracy for speed: octave bands, a hand-held meter and one correction index instead of per-band reverberation times. This guide covers the survey (control) method: the reverberation index and its room-class estimate, the airborne, impact, façade and service-equipment quantities, and the survey fiches. The engineering-grade methods live in [Field Insulation Measurement (ISO 16283)](https://jmrplens.github.io/phonometry/buildings/insulation/insulation-field/); the single-number engines behind the survey ratings in [Insulation Ratings (ISO 717)](https://jmrplens.github.io/phonometry/buildings/insulation/insulation-ratings/). ## Octave bands and the reverberation index The [engineering methods](https://jmrplens.github.io/phonometry/buildings/insulation/insulation-field/) buy accuracy with effort: swept microphones, per-band reverberation times, careful background correction. For a quick check in a dwelling, ISO 10052 defines a **survey (control) method**: octave bands, a hand-held meter, and a single quantity, the **reverberation index** $k = 10\log_{10}(T/T_0)$ ($T_0 = 0.5\ \text{s}$), to carry the receiving-room correction. Every survey quantity is then just an addition of $k$: the standardized level difference $D_\mathrm{nT} = D + k$, the normalized $D_\mathrm{n} = D + k + 10\log_{10}(A_0 T_0/(0.16\,V))$, the apparent $R' = D + k + 10\log_{10}(S T_0/(0.16\,V))$ (using $V/7.5$ for $S$ where that is larger), and, for impacts and façades, $L'_\mathrm{nT} = L_\mathrm{i} - k$ and $D_{2\mathrm{m,nT}} = D_{2\mathrm{m}} + k$. The clause references follow ISO 10052:2021; the formulas and the reverberation-index table are identical in the harmonized EN ISO 10052:2004+A1:2010. The reverberation index is either **measured** (feed the reverberation time to `reverberation_index(T)`) or, in a control survey, **estimated** from the room type and volume with `estimate_reverberation_index(V, room)` (Table 4: furnished `"kitchen"` / `"bathroom"` / `"furnished"`, or the unfurnished construction classes `"a"`–`"h"` and the mixed `"a+e"`…`"d+h"`). A fourth quantity unique to this method is **service-equipment noise** $L_{XY}$: the energy average of three A- or C-weighted positions. ```python import numpy as np from phonometry import building # Octave-band levels (125-2000 Hz) and the measured receiving-room T. l1 = np.array([88.0, 90.0, 92.0, 92.0, 90.0]) l2 = np.array([55.0, 51.0, 47.0, 41.0, 35.0]) k = building.reverberation_index([0.70, 0.60, 0.50, 0.45, 0.40]) # k = 10 lg(T/0.5) res = building.survey_airborne_insulation(l1, l2, k, volume=50.0, area=12.0) print(np.round(res.d_nt, 1)) # [34.5 39.8 45. 50.5 54. ] DnT = D + k print(res.rating.rating, res.rating.c) # 49 -1 -> DnT,w (C) print(res.r_prime_rating.rating) # 48 -> R'w # No reverberation time measured? Estimate k from Table 4 (heavy walls, hard # floor, 35-60 m3 -> class "g"). k_est = building.estimate_reverberation_index(50.0, "g") print(k_est) # [4.5 5. 5.5 5.5 5.5] # Service-equipment noise: energy average of three A-weighted positions. se = building.survey_service_equipment_level([35.0, 30.0, 32.0], 3.0, volume=50.0) print(round(float(se.l_xy), 1), round(float(se.l_xy_nt), 1)) # 32.8 29.8 res.plot() # DnT vs shifted ISO 717-1 reference (needs matplotlib) ``` *The reverberation index $k = 10\log_{10}(T/T_0)$ shifts the raw level difference $D$ into the standardized $D_\mathrm{nT}$: up where the room is live ($T > T_0$), down where it is dead. The automatic rating is formed only for exactly 5 octave (or 16 one-third-octave) values.*

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```python import matplotlib.pyplot as plt import numpy as np from phonometry import building # Octave-band levels (125-2000 Hz) and the measured receiving-room T. bands = [125, 250, 500, 1000, 2000] l1 = np.array([88.0, 90.0, 92.0, 92.0, 90.0]) l2 = np.array([55.0, 51.0, 47.0, 41.0, 35.0]) k = building.reverberation_index([0.70, 0.60, 0.50, 0.45, 0.40]) # k = 10 lg(T/0.5) res = building.survey_airborne_insulation(l1, l2, k, volume=50.0) x = np.arange(len(bands)) fig, ax = plt.subplots() ax.fill_between(x, res.d, res.d_nt, alpha=0.2, label="k = 10 log10(T/T0)") ax.plot(x, res.d, "--o", label="D (level difference)") ax.plot(x, res.d_nt, "-s", label="DnT (standardized)") ax.set_xticks(x, [str(b) for b in bands]) ax.set(xlabel="Frequency [Hz]", ylabel="Level difference [dB]", title=f"ISO 10052 survey method: DnT,w = {res.rating.rating} dB") ax.legend() plt.show() ```

### `survey_airborne_insulation()` and friends: parameters | Parameter | Type | Units | Range / default | Notes | | :--- | :--- | :--- | :--- | :--- | | `l1` / `l2` | 1D or 2D array | dB | one/band, or `(positions, bands)` | Source / receiving (or outdoor `l1_2m`) levels | | `li` | 1D or 2D array | dB | one/band, or `(positions, bands)` | Impact levels (energy-averaged over positions) | | `reverberation_index` | scalar or 1D array | dB | one per band | $k$ from `reverberation_index` or `estimate_reverberation_index`; `survey_service_equipment_level()` also accepts a scalar $k$ | | `volume` | float | m³ | > 0 | Receiving-room $V$ (for $D_\mathrm{n}$ / $L'_\mathrm{n}$ / $R'$ / normalized) | | `area` | float | m² | > 0 | Common-partition $S$ (airborne $R'$; $V/7.5$ rule applied) | | `measurements` | array | dB | exactly 3 | Service-equipment positions (`survey_service_equipment_level`) | | `room` | str | — | `"kitchen"`/`"bathroom"`/`"furnished"`/`"a"`–`"h"`/`"a+e"`… | `estimate_reverberation_index` room class (Table 4) | `survey_airborne_insulation()` returns a `SurveyAirborneResult` (`d`, `d_nt`, `d_n`, `r_prime`, `rating`, `r_prime_rating`); `survey_impact_insulation()` a `SurveyImpactResult` (`l_i`, `l_nt`, `l_n`, `rating`); `survey_facade_insulation()` a `SurveyFacadeResult`; `survey_service_equipment_level()` a `SurveyServiceEquipmentResult` (`l_xy`, `l_xy_nt`, `l_xy_n`). What the functions do not do is police the survey. They consume band levels wherever they came from: nothing verifies the sweep, the source corner, the tapping-machine positions or the one-corner-plus-two-central service-equipment recipe, and nothing checks the 6 dB signal-to-background floor of Clause 6.2.1 — nor applies a correction when it was not met, which is the method's own rule (record the level, and note that the result was affected by an unknown amount). The ± 2 dB agreement with the engineering method is the standard's own estimate (Clause 6.6 NOTE), not something the library models or propagates: no survey result carries an uncertainty, and when the stakes rise the step up is [Field Insulation Measurement (ISO 16283)](https://jmrplens.github.io/phonometry/buildings/insulation/insulation-field/), whose ISO 12999-1 machinery does produce one. Annex A's report form and Annex B's operating cycles for service equipment are outside the library too. ## ISO 10052 survey reports (`.report()`) The airborne, impact and façade survey results each carry a `.report(path)` that writes the one-page ISO 10052 survey (control) method field report: the standard-basis line naming ISO 10052 (octave bands), an optional metadata header, the octave-band table beside the measured-versus-shifted-reference curve, the boxed field rating ($D_\mathrm{nT,w}$/$R'_\mathrm{w}$, $L'_\mathrm{nT,w}$ or $D_{2\mathrm{m,nT,w}}$), the survey-method statement, an optional requirement verdict (level differences pass at or above it, the impact level at or below it) and a footer. The airborne result reports `quantity="dnt"` (default) or `"r_prime"`; `verbose=True`, `metadata` and `language="es"` behave as in the fiches above. ```python import numpy as np from phonometry import building, ReportMetadata res.report("DnTw_survey.pdf", metadata=ReportMetadata(requirement=40.0)) # DnT,w (C; Ctr) # Impact and façade surveys reuse the same k; li is the tapping-machine level # in the room below, l1_2m the level 2 m in front of the façade. li = np.array([66.0, 64.0, 62.0, 60.0, 55.0]) impact = building.survey_impact_insulation(li, k, volume=50.0) impact.plot() # L'nT vs the shifted ISO 717-2 reference (needs matplotlib) impact.report("LnTw_survey.pdf") # L'nT,w (CI) l1_2m = np.array([76.0, 78.0, 79.0, 79.0, 77.0]) facade = building.survey_facade_insulation(l1_2m, l2, k, volume=40.0) facade.report("D2mnTw_survey.pdf") # D2m,nT,w (C; Ctr) ``` *The impact survey applies the reverberation index with the opposite sign, $L'_\mathrm{nT} = L_\mathrm{i} - k$: a live receiving room ($T > T_0$) **lowers** the standardized impact level. As in the airborne case, the automatic rating appears for exactly 5 octave (or 16 one-third-octave) values.*

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```python import matplotlib.pyplot as plt import numpy as np from phonometry import building # Octave-band tapping-machine levels below the floor, and the measured T. bands = [125, 250, 500, 1000, 2000] li = np.array([66.0, 64.0, 62.0, 60.0, 55.0]) k = building.reverberation_index([0.70, 0.60, 0.50, 0.45, 0.40]) impact = building.survey_impact_insulation(li, k, volume=50.0) # One line — L'nT vs the shifted ISO 717-2 reference: impact.plot() plt.show() # By hand, showing the sign flip of the correction: x = np.arange(len(bands)) fig, ax = plt.subplots() ax.fill_between(x, impact.l_i, impact.l_nt, alpha=0.2, label="-k = -10 log10(T/T0)") ax.plot(x, impact.l_i, "--o", label="Li (impact level)") ax.plot(x, impact.l_nt, "-s", label="L'nT (standardized)") ax.set_xticks(x, [str(b) for b in bands]) ax.set(xlabel="Frequency [Hz]", ylabel="Impact sound pressure level [dB]", title=f"ISO 10052 survey method: L'nT,w = {impact.rating.rating} dB") ax.legend() plt.show() ```

Rendered examples of the survey fiches, regenerated with `make reports`, are kept in the repository. Click a preview to open the PDF: [](https://raw.githubusercontent.com/jmrplens/phonometry/main/.github/reports/iso10052_airborne_example.pdf) *Survey airborne fiche (`SurveyAirborneResult.report`), DnT,w (C; Ctr).* [](https://raw.githubusercontent.com/jmrplens/phonometry/main/.github/reports/iso10052_impact_example.pdf) *Survey impact fiche (`SurveyImpactResult.report`), L'nT,w (CI).* [](https://raw.githubusercontent.com/jmrplens/phonometry/main/.github/reports/iso10052_facade_example.pdf) *Survey façade fiche (`SurveyFacadeResult.report`), D2m,nT,w (C; Ctr).* ## References - Vigran, T. E. (2008). *Building acoustics*. CRC Press. ISBN 978-0-415-42853-8. [doi:10.1201/9781482266016](https://doi.org/10.1201/9781482266016). The building-acoustics context of the field quantities the survey method approximates. - International Organization for Standardization. (2021). *Acoustics — Field measurements of airborne and impact sound insulation and of service equipment sound — Survey method* (ISO 10052:2021). [iso.org catalogue](https://www.iso.org/standard/76560.html). The survey method this page implements: the reverberation-index correction, the four survey quantities and their reports. ## Standards ISO 10052:2021 (harmonized as EN ISO 10052:2004+A1:2010), which defines the field survey method: the reverberation-index correction, the standardized/normalized airborne, impact and façade quantities, and service-equipment noise. The single-number ratings reuse ISO 717-1 and ISO 717-2. ## See also - [Field Insulation Measurement (ISO 16283)](https://jmrplens.github.io/phonometry/buildings/insulation/insulation-field/): the engineering-grade airborne, impact and façade measurements this method approximates, and their ISO 12999-1 uncertainty. - [Insulation Ratings (ISO 717)](https://jmrplens.github.io/phonometry/buildings/insulation/insulation-ratings/): the reference-curve engines behind the survey ratings. - [Room Acoustics](https://jmrplens.github.io/phonometry/buildings/rooms/room-acoustics/): the measured reverberation times behind the reverberation index. - [Levels](https://jmrplens.github.io/phonometry/signals/levels/levels/): the energy averaging behind the octave-band levels. - API reference: [`building.measurement.survey_insulation`](https://jmrplens.github.io/phonometry/reference/api/building/survey-insulation/).