environment.propagation.noise_reducing_devices

Single-number ratings of noise reducing devices (EN 1793, EN 16272).

A barrier beside a road is not judged band by band. It is judged by single numbers, and each is the same operation on a spectrum nobody measures on site: the normalised traffic noise spectrum of EN 1793-3:1997, eighteen one-third octave bands from 100 Hz to 5 kHz carrying relative A-weighted levels $L_{i}$ that stand for what a road sounds like at the roadside.

A barrier beside a railway is judged the same way and by a different spectrum. EN 16272-3-1:2012 prints the normalised railway noise spectrum over the same eighteen bands, and its Clauses 5 and 6 are the two formulas below with that table in place of the other one: rolling noise puts its weight higher up, so the railway spectrum is flat within one decibel from 1,25 kHz to 2,5 kHz where the road one has already begun to fall away. The railway parts carry no category ladder; their annexes are guidance notes, and a rating there is the number and nothing more.

EN 1793-1:2012 rates absorption. What matters to the neighbour is the energy the device sends back across the road, so the rating is what is not absorbed, in decibels (Clause 5):
$D L_{α} = - 10 l g 1 - \frac{\sum _{i = 1}^{18} α _{S i} 1 0 ^{0.1 L_{i}}}{\sum _{i = 1}^{18} 1 0 ^{0.1 L_{i}}}$
A measured $α_{S}$ can exceed one band by band, which can push the weighted ratio past 1 and leave the logarithm without an argument. The clause says so and fixes it: the ratio is limited to 0,99.
EN 1793-2:2012 rates airborne insulation with the same weighting (Clause 5.2), on the transmitted energy rather than the absorbed:
$D L_{R} = - 10 l g \frac{\sum _{i = 1}^{18} 1 0 ^{0.1 L_{i}} 1 0 ^{- 0.1 R_{i}}}{\sum _{i = 1}^{18} 1 0 ^{0.1 L_{i}}}$
EN 1793-5:2016 rates the sound reflection measured in place, the index $R I$ of barrier_reflection, on the same spectrum but from the lowest band the size of the sample makes reliable (Clause 5.8, Formula (12)):
$D L_{R I} = - 10 l g [\frac{\sum _{i = m}^{18} R I _{i} 1 0 ^{0.1 L_{i}}}{\sum _{i = m}^{18} 1 0 ^{0.1 L_{i}}}]$
The clause copies the 0,99 limit on the ratio from EN 1793-1, so a device reflecting more than it receives in the weighted sum rates 0,04 dB.

All three are reported rounded to the nearest integer (EN 1793-1 Clause 6.1, EN 1793-2 Clause 7.1, EN 1793-5 Clause 5.11). The first two have a normative category ladder in their Annex A: A1 to A5 for absorption, B1 to B4 for insulation, with A0 and B0 reserved for “not determined”. The categories are read off the reported integer, which is why the ladders have no gaps between their steps. EN 1793-5 prints no ladder.

Absorption and insulation answer different questions and are not comparable. A device can be a perfect reflector and still keep the noise out (high $D L_{R}$ , low $D L_{α}$ ); a device can be highly absorptive and let sound through (the other way round). The declaration carries both. $D L_{R I}$ answers the first question again, in the direct sound field beside the road rather than the diffuse field of a reverberation room, so it does not convert into $D L_{α}$ either.

Auto-generated from the source docstrings by scripts/generate_api_docs.py (make api-docs). Do not edit by hand.

ABSORPTION_CATEGORIES

Constant (tuple).

ABSORPTION_CATEGORIES = (('A1', -2147483648, 3), ('A2', 4, 7), ('A3', 8, 11), ('A4', 12, 15), ('A5', 16, 2147483648))

ABSORPTION_RATIO_LIMIT

Constant (float).

ABSORPTION_RATIO_LIMIT = 0.99

airborne_insulation_rating

airborne_insulation_rating(
    sound_reduction_index_db: ArrayLike,
    *,
    spectrum: str = 'road',
) -> RoadDeviceRating

DL_R, the single-number rating of airborne sound insulation.

EN 1793-2:2012 Clause 5.2 for a road device, EN 16272-3-1:2012 Clause 6 for a railway one, on the same weighting as the absorption rating above.

Parameters

Name	Description
`sound_reduction_index_db`	$R$ in decibels, in the eighteen one-third octave bands of `TRAFFIC_NOISE_BANDS_HZ`.
`spectrum`	`"road"` (EN 1793-3, the default) or `"railway"` (EN 16272-3-1).

Returns: The rating, its reported integer and, for a road device, its Annex A category.

Raises

Exception	When
ValueError	If the input does not cover the eighteen bands, is not finite, or the spectrum is not one of the two.

INSULATION_CATEGORIES

Constant (tuple).

INSULATION_CATEGORIES = (('B1', -2147483648, 14), ('B2', 15, 24), ('B3', 25, 34), ('B4', 35, 2147483648))

NORMALISED_RAILWAY_NOISE_SPECTRUM_DB

Constant (tuple).

NORMALISED_RAILWAY_NOISE_SPECTRUM_DB = (-27.0, -25.0, -23.0, -21.0, -19.0, -17.0, -15.0, -13.0, -12.0, -11.0, -10.0, -9.0, -9.0, -9.0, -9.0, -10.0, -13.0, -17.0)

NORMALISED_TRAFFIC_NOISE_SPECTRUM_DB

Constant (tuple).

NORMALISED_TRAFFIC_NOISE_SPECTRUM_DB = (-20.0, -20.0, -18.0, -16.0, -15.0, -14.0, -13.0, -12.0, -11.0, -9.0, -8.0, -9.0, -10.0, -11.0, -13.0, -15.0, -16.0, -18.0)

RoadDeviceRating

RoadDeviceRating(
    rating: float,
    reported: int,
    category: str | None,
    quantity: str,
    spectrum: str,
    bands_hz: NDArray[np.float64],
    values: NDArray[np.float64],
    weights: NDArray[np.float64],
    lowest_band_hz: float = 100.0,
)

One single-number rating of a road traffic noise reducing device.

Attributes

Name	Description
`rating`	The rating before rounding, in dB. `DLα` (EN 1793-1), `DL_R` (EN 1793-2) or `DL_RI` (EN 1793-5), depending on `quantity`.
`reported`	The same rating rounded to the nearest integer, which is what a test report carries and what the category is read off.
`category`	The Annex A category of the reported value, `"A1"` to `"A5"` for absorption or `"B1"` to `"B4"` for insulation, or `None` for a railway rating and for reflection, whose standards print no ladder.
`quantity`	`"absorption"`, `"insulation"` or `"reflection"`.
`spectrum`	`"road"` (EN 1793-3) or `"railway"` (EN 16272-3-1).
`bands_hz`	The eighteen band centre frequencies, in Hz.
`values`	The per-band input the rating was weighted from: the sound absorption coefficients, the sound reduction indices in dB, or the sound reflection indices (`nan` allowed below `lowest_band_hz`).
`weights`	The normalised traffic noise spectrum, in dB.
`lowest_band_hz`	The lowest band the rating sums from: 100 Hz for `DLα` and `DL_R`, which sum all eighteen, and the lowest reliable band $m$ for `DL_RI`.

RoadDeviceRating.plot()

RoadDeviceRating.plot(
    ax: Axes | None = None,
    *,
    language: str = 'en',
    **kwargs: Any,
) -> Axes

Plot the per-band input against the spectrum that weights it.

Requires matplotlib (pip install phonometry[plot]); returns the Axes.

RoadDeviceWarning

Raised when a rating is computed on data the standard bounds.

sound_absorption_rating

sound_absorption_rating(
    absorption_coefficients: ArrayLike,
    *,
    spectrum: str = 'road',
) -> RoadDeviceRating

DLα, the single-number rating of sound absorption.

EN 1793-1:2012 Clause 5 for a road device, EN 16272-3-1:2012 Clause 5 for a railway one: the same formula over the same eighteen bands, with the spectrum of the matching part in the weights. Only the road parts print a category ladder, so a railway rating carries none.

Parameters

Name	Description
`absorption_coefficients`	$α_{S}$ in the eighteen one-third octave bands of `TRAFFIC_NOISE_BANDS_HZ`.
`spectrum`	`"road"` (EN 1793-3, the default) or `"railway"` (EN 16272-3-1).

Returns: The rating, its reported integer and, for a road device, its Annex A category.

Raises

Exception	When
ValueError	If the input does not cover the eighteen bands, is not finite, or the spectrum is not one of the two.

Warns

Warning	When
RoadDeviceWarning	If the weighted ratio reaches the 0,99 limit both standards put on it, which means the rating is the limit and not the data.

sound_reflection_rating

sound_reflection_rating(
    reflection_indices: ArrayLike,
    *,
    lowest_band_hz: float = 200.0,
) -> RoadDeviceRating

DL_RI, the single-number rating of sound reflection.

EN 1793-5:2016 Clause 5.8, Formula (12): the sound reflection index weighted by the normalised traffic noise spectrum of EN 1793-3, summed from the lowest reliable band $m$ to 5 kHz. For the qualification sample of 4 m by 4 m that band is 200 Hz (5.5.7), the default; a smaller device starts higher and the report names the range, for example DL_RI (400 - 5 000 Hz) for a 3,5 m barrier. Annex B’s example rates 7,68 dB before rounding on the two-decimal averages of Table B.1 (7,65 dB on its particular values), reported as 8 dB. EN 1793-5 prints no category ladder.

Parameters

Name	Description
`reflection_indices`	$R I$ in the eighteen one-third octave bands of `TRAFFIC_NOISE_BANDS_HZ`; a band below `lowest_band_hz` may be `nan`.
`lowest_band_hz`	The centre of the lowest reliable band, one of the eighteen.

Returns: The rating and its reported integer, category None.

Raises

Exception	When
ValueError	If there are not eighteen values, a band from `lowest_band_hz` up is not a finite non-negative number, the band is not positive or not one of the eighteen, or the weighted ratio is zero.

Warns

Warning	When
RoadDeviceWarning	If the weighted ratio exceeds the maximum of 0,99 Clause 5.8 limits it to; a ratio of 0,99 itself is not limited.

SPECTRA

Constant (mapping).

SPECTRA = {'road': (-20.0, -20.0, -18.0, -16.0, -15.0, -14.0, -13.0, -12.0, -11.0, -9.0, -8.0, -9.0, -10.0, -11.0, -13.0, -15.0, -16.0, -18.0), 'railway': (-27.0, -25.0, -23.0, -21.0, -19.0, -17.0, -15.0, -13.0, -12.0, -11.0, -10.0, -9.0, -9.0, -9.0, -9.0, -10.0, -13.0, -17.0)}

TRAFFIC_NOISE_BANDS_HZ

Constant (tuple).

TRAFFIC_NOISE_BANDS_HZ = (100.0, 125.0, 160.0, 200.0, 250.0, 315.0, 400.0, 500.0, 630.0, 800.0, 1000.0, 1250.0, 1600.0, 2000.0, 2500.0, 3150.0, 4000.0, 5000.0)

Created and maintained by José Manuel Requena Plens ORCID All projects