Source: https://jmrplens.github.io/phonometry/reference/api/power/sound-power-intensity/ Sound power level of a noise source by sound-intensity **scanning**: ISO 9614-2:1996 (engineering, grade 2; survey/control, grade 3). A probe is swept continuously over each segment of a hypothetical surface that encloses the source, reporting the time-averaged signed normal intensity `` and mean-square pressure per segment. The sound power follows from the partial powers `Pi = *Si` summed over the `N` segments (clause 9, equations (5), (6), (12), (13)): ```text Pi = * Si (partial power, Eq. 12) P = sum_i Pi (total power, Eq. 6) LW = 10*lg(P/P0), P0 = 1e-12 W (sound power level, Eq. 13) ``` The method is **not applicable to any band in which P \< 0** (clause 9.2): a strong parasitic source outside the surface makes the net energy flow inward and the determination invalid for that band. Two scanning-method field indicators qualify the determination (Annex A, normative): ```text FpI = [Lp] - LW + 10*lg(S/S0) (Eq. A.1) [Lp] = 10*lg( (1/S) * sum_i Si*10^(0,1*Lpi) ) (area-weighted surface SPL) F+/- = 10*lg( sum_i |Pi| / |sum_i Pi| ) (Eq. A.2) ``` `FpI` is the surface pressure-intensity indicator (equivalent to ISO 9614-1 `F3` for uniform-area segments, Note 14); `F+/-` the negative-partial-power indicator (equivalent to ISO 9614-1 `F3-F2`, Note 15). Because Part 2 weights by segment area `Si` while [`phonometry.field_indicators`](/phonometry/reference/api/power/intensity/#field_indicators) (ISO 9614-1) assumes equal-area positions, the indicators are computed directly here; only the dynamic-capability index `Ld = delta_pI0 - K` is shared with [`phonometry.dynamic_capability_index`](/phonometry/reference/api/power/intensity/#dynamic_capability_index). Qualification criteria per band (Annex B): ```text criterion 1: Ld > FpI Ld = delta_pI0 - K (K = 10 eng / 7 survey, Table 1) criterion 2: F+/- <= 3 dB (mandatory grade 2; optional grade 3) criterion 3: |LWi(1) - LWi(2)| <= s per segment (s from Table 2) ``` A band achieves the **engineering** grade when criteria 1, 2 and 3 hold, the **survey** grade when criteria 1 and 3 hold (clause 8.4), otherwise none. An A-weighted sound power level omits, besides the non-determinable `P <= 0` bands, the bands in which criteria 1 and/or 2 are not satisfied (clause 10.6 b). > Auto-generated from the source docstrings by `scripts/generate_api_docs.py` (`make api-docs`). Do not edit by hand. ## sound_power_intensity ```python sound_power_intensity( normal_intensity: np.ndarray, areas: np.ndarray, *, normal_intensity_2: np.ndarray | None = None, pressure_levels: np.ndarray | None = None, pressure_residual_index: float | np.ndarray | None = None, frequencies: np.ndarray | None = None, band_type: BandType = 'third', grade: Grade = 'engineering', repeatability_limit: float | np.ndarray | None = None, ) -> SoundPowerIntensityResult ``` Sound power level by sound-intensity scanning (ISO 9614-2:1996). `normal_intensity` is an `(N_seg, N_bands)` array (or `(N_seg,)` for a single band) of the signed, segment-averaged normal sound intensity `` (W/m^2), and `areas` the `(N_seg,)` segment areas `Si` (m^2). The partial powers `Pi = *Si` are summed to the band sound power `P` and level `LW = 10*lg(P/P0)` (equations (12), (6), (13)). Bands with `P < 0` are flagged (`negative_band`) and reported as `NaN` (clause 9.2). Supplying `normal_intensity_2` (the second grade-2 sweep) makes `normal_intensity` the first sweep, uses their mean for the partial powers (Eq. 12), and evaluates the repeatability criterion 3. Supplying `pressure_levels` (`Lpi`) evaluates `FpI` (Eq. A.1) and, with `pressure_residual_index` (`delta_pI0`), criterion 1. The per-band achieved grade (clause 8.4) is returned when both a second sweep and `delta_pI0` are available. When criteria 1 and 2 are evaluable (`pressure_levels` and `pressure_residual_index` supplied), the bands failing them are omitted from the A-weighted total and flagged in `a_weighting_omitted_bands` (clause 10.6 b); otherwise every determinable band is summed and a [`SoundPowerWarning`](/phonometry/reference/api/power/sound-power/#soundpowerwarning) notes the missing screening. **Parameters** | Name | Description | | :--- | :--- | | `normal_intensity` | `(N_seg, N_bands)` signed normal intensity, W/m^2. | | `areas` | `(N_seg,)` segment areas `Si`, m^2. | | `normal_intensity_2` | Optional second sweep, same shape (criterion 3). | | `pressure_levels` | Optional `(N_seg, N_bands)` `Lpi` (dB) for FpI. | | `pressure_residual_index` | `delta_pI0` (dB), scalar or per band, for the dynamic-capability index / criterion 1. | | `frequencies` | `(N_bands,)` nominal band centres (Hz), for the A-weighted total and the Table 2 repeatability limits. | | `band_type` | `'octave'` or `'third'` (Table 2 lookup). | | `grade` | `'engineering'` (grade 2) or `'survey'` (grade 3); selects `K` for the reported `Ld` and the criterion-2 warning. | | `repeatability_limit` | Override for the criterion-3 limit `s` (dB), scalar or per band; defaults to ISO 9614-2 Table 2 by `frequencies` for `'engineering'`. For `'survey'` the default is the A-weighted 4 dB reused per band (extrapolated -- non-normative). | **Returns:** [`SoundPowerIntensityResult`](/phonometry/reference/api/power/sound-power-intensity/#soundpowerintensityresult). ## SoundPowerIntensityResult ```python SoundPowerIntensityResult( frequencies: np.ndarray | None, partial_power: np.ndarray, partial_power_level: np.ndarray, sound_power: np.ndarray, sound_power_level: np.ndarray, negative_band: np.ndarray, surface_pressure_intensity_index: np.ndarray | None, negative_partial_power_index: np.ndarray | None, repeatability: np.ndarray | None, dynamic_capability_index: np.ndarray | None, achieved_grade: np.ndarray | None, surface_area: float, sound_power_level_a: float, a_weighting_omitted_bands: np.ndarray | None, grade: str, ) ``` Result of an ISO 9614-2:1996 sound-power-by-scanning determination. `partial_power` is the signed `Pi = *Si` per segment and band (Eq. 12); `partial_power_level` the magnitude level `10*lg(|Pi|/P0)` (Eq. 8), with the sign carried by `partial_power`. `sound_power` is the signed band total `P = sum Pi` (Eq. 6) and `sound_power_level` its level `10*lg(P/P0)` (Eq. 13), `NaN` where `P <= 0` (`negative_band` True, method not applicable, clause 9.2). `surface_pressure_intensity_index` (FpI, Eq. A.1) and `negative_partial_power_index` (F+/-, Eq. A.2) are per band, `None` when the inputs they need are absent. `repeatability` is `|LWi(1)-LWi(2)|` per segment and band (criterion 3), `None` without a second scan; it is `+inf` where the two sweeps reverse the flow direction on a segment (opposite-sign partial powers), a gross non-repeatability that criterion 3 must reject even when the magnitudes happen to match. `dynamic_capability_index` is `Ld` for the requested grade. `achieved_grade` is the per-band class `'engineering'`/ `'survey'`/`'none'` (clause 8.4), `None` when the qualifying inputs (`delta_pI0` and a second scan) are absent. `sound_power_level_a` is the A-weighted total over determinable bands (`NaN` without `frequencies` and more than one band), which omits the bands failing criteria 1 and/or 2 (clause 10.6 b) whenever those criteria are evaluable. `a_weighting_omitted_bands` flags the bands so omitted (per band, `True` = omitted); it is `None` when the criteria inputs (`pressure_levels` and `pressure_residual_index`) are absent, in which case every determinable band is summed and a warning is emitted. ### SoundPowerIntensityResult.plot() ```python SoundPowerIntensityResult.plot( ax: Axes | None = None, *, language: str = 'en', **kwargs: Any, ) -> Axes ``` Plot the LW spectrum; non-positive bands are hatched as unusable. Requires matplotlib (`pip install phonometry[plot]`); returns the `Axes`. ### SoundPowerIntensityResult.report() ```python SoundPowerIntensityResult.report( path: str, *, metadata: ReportMetadata | None = None, engine: str = 'reportlab', verbose: bool = False, language: str = 'en', ) -> str ``` Render an ISO 9614-2 sound-power-by-intensity determination fiche. Writes a one-page sound-power test sheet: the standard-basis line naming the intensity-scanning method and its measurement grade (ISO 9614-2:1996 engineering grade 2 or survey grade 3), an optional metadata header (client, noise source, test environment, instrumentation, climate, date), a per-band table (nominal octave/one-third-octave frequency and the intensity-derived band sound-power level `LW`), the sound-power spectrum `LW(f)` with net-negative bands hatched as unusable, the boxed A-weighted sound power level `LWA` (dB re 1 pW) with the total `LW`, the measurement surface area `S` and the determination grade, an optional verdict row against a declared limit, and a measurement-basis strip stating the partial-power model, the field indicators (`FpI`, `F+/-`) and the Annex B qualification criteria. **Parameters** | Name | Description | | :--- | :--- | | `path` | Destination path of the PDF file. | | `metadata` | Optional [`ReportMetadata`](/phonometry/reference/api/building/insulation/#reportmetadata) supplying the header (`client`, `specimen` the noise source, `test_room` the test environment, `instrumentation`, `temperature`, `relative_humidity`, `pressure`, `test_date`), the footer identity (`laboratory`, `operator`, `report_id`, `notes`) and, via `requirement`, a declared A-weighted sound-power limit the fiche checks the result against (lower is better). | | `engine` | Rendering back end; only `"reportlab"` is supported. | | `verbose` | When `True` the per-band table adds the field indicators `FpI` and `F+/-` and the per-band achieved grade. | | `language` | Fiche language: `"en"` (default) or `"es"`. | **Returns:** The written `path` as a `str`. **Raises** | Exception | When | | :--- | :--- | | ValueError | If `engine` is not `"reportlab"` or `language` is unknown. | | ImportError | If reportlab (or, for the figure, matplotlib) is not installed (`pip install phonometry[report]`). |