GB/T 38979-2020 PDF English
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| Standard ID | Contents [version] | USD | STEP2 | [PDF] delivery | Name of Chinese Standard | Status |
| GB/T 38979-2020 | English | 230 |
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GB/T 38979-2020: Sanitary wares - Test method for flushing noise of toilet---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GBT38979-2020
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 91.140.70
Q 31
Sanitary wares - Test method for flushing noise of
toilet
Issued on. JULY 21, 2020
Implemented on. JUNE 01, 2021
Issued by. State Administration for Market Regulation;
Standardization Administration of the People’s Republic of
China.
Table of Contents
Foreword... 3
1 Scope... 4
2 Normative references... 4
3 Terms and definitions... 5
4 Facility conditions and measuring instruments... 5
5 Sample installation and commissioning... 6
6 Sound pressure level measurement... 7
7 Result calculation... 10
8 Uncertainty of measurement... 14
9 Test report... 19
Foreword
This Standard was drafted in accordance with the rules given in GB/T 1.1-2009.
This Standard was proposed by China Building Materials Federation.
This Standard shall be under the jurisdiction of National Technical Committee
249 on Building and Sanitary Ceramics of Standardization Administration of
China (SAC/TC 249).
The drafting organizations of this Standard. Tangshan Customs
Comprehensive Technical Service Center, Xianyang Research & Design
Institute of Ceramics, Taizhou Product Quality and Safety Testing Research
Institute, Huida Sanitary Ware Co., Ltd., Xiamen R&T Plumbing Technology Co.,
Ltd., Xiamen Kitchen Industry Association.
The drafters of this Standard. Li Wenjie, Wang Bo, Wu Yinan, Weng Xiaowei,
Zhang Yihan, Zhang Xuesong, Wang Bing, Ye Ying, Zhao Jiangwei.
Sanitary wares - Test method for flushing noise of
toilet
1 Scope
This Standard specifies the facility conditions and measuring instruments,
sample installation and commissioning, sound pressure level measurement,
result calculation, uncertainty of measurement and test report for flushing noise
detection of toilets (not including toilets and smart toilets that use pressure
flushing devices).
This Standard applies to the flushing noise detection of toilets (not including
toilets and smart toilets that use pressure flushing devices).
2 Normative references
The following documents are indispensable for the application of this document.
For dated references, only the dated version applies to this document. For
undated references, the latest edition (including all amendments) applies to this
document.
GB/T 3768-2017, Acoustics - Determination of sound power levels and
sound energy levels of noise sources using sound pressure - Survey method
using an enveloping measurement surface over a reflecting plane
GB/T 3785.1, Electroacoustics - Sound level meters - Part 1.Specifications
GB/T 6952, Sanitary wares
GB/T 15173, Electroacoustics - Sound calibrators
GB/T 26730, Sanitary ware - Gravity water flushing devices and supports
JC/T 764, WC seats
JC/T 932, Drainage fittings for sanitary wares
ISO 3744, Acoustics - Determination of sound power levels and sound
energy levels of noise sources using sound pressure - Engineering methods
for an essentially free field over a reflecting plane
3 Terms and definitions
Terms and definitions determined by GB/T 3768-2017, GB/T 6952, and the
following ones are applicable to this document.
3.1 Measurement time interval
It is used to determine the time of integration of the sound level meter for the A-
weighted cumulative percentage sound pressure level of the flushing noise of
the to-be-tested toilet sample.
3.2 Standard test operator
The personnel who are required to operate the to-be-tested toilet sample to
complete the flushing process.
4 Facility conditions and measuring instruments
4.1 Test room
The test room should be a semi-anechoic room or a rigid-wall room; the
background noise on the hemispherical measurement surface shall be more
than 3 dB(A) lower than the average value of the A-weighted equivalent sound
level LAeq of the flushing noise of the to-be-tested toilet sample.
4.2 Measuring instruments
The sound level meter for measurement shall meet the requirements for Grade-
2 instrument in GB/T 3785.1; it is recommended to use a Grade-1 instrument.
The sound calibrator shall meet the Grade-1 accuracy requirements in GB/T
15173.
5 Sample installation and commissioning
5.1 Sample quantity and specifications
Take a toilet sample.
5.2 Toilet matching requirements
5.2.1 For matching products, install the to-be-tested toilet sample in accordance
with the manufacturer's instructions; conduct a connection tightness test under
the test static pressure of 0.14 MPa ± 0.01 MPa, to ensure that the toilet and its
flushing devices have the overall tightness in good condition.
5.2.2 For non-matching products, the to-be-tested toilet sample can be
equipped with a gravity flushing device that meets the requirements of rated
water consumption, has an anti-siphon function and meets the requirements of
GB/T 26730; the working water level of the flushing tank shall meet the needs
of the normal flushing process.
5.3 Installation and orientation of the toilet sample
Place the to-be-tested floor-type toilet sample or the sanitary ware support that
contains the wall-mounted toilet sample on the floor of the semi-anechoic room
or rigid-wall room; make the distance between the center and any wall not less
than 1.5 m.
6 Sound pressure level measurement
6.1 Determination of size of the sound source reference body
Use the to-be-tested toilet sample as the sound source reference body; put
down the toilet seat; lift the cover.
6.4 Sound pressure level measurement procedures
6.4.1 In a semi-anechoic room or a rigid-wall room that meets the requirements,
locate each measurement point according to the microphone position
coordinates on the hemispherical measurement surface. Then, move the sound
level meter to the position of each measurement point in turn; ensure that the
orientation of the microphone is the same as the incident angle of the sound
wave when it is calibrated and it perpendicularly points to the measuring surface.
Position number
6.4.4 Before testing the flushing noise of the toilet sample, it shall meet the
requirements for water consumption in GB/T 6952.
6.4.5 Under the specified test static pressure, start the flushing device and time
it in the normal way (generally no more than 1 s); use the A-weighted fast-time
weighting characteristic "F" of the sound level meter to respectively measure
the A-weighted cumulative percentage sound pressure levels LpAi(50) and LpAi(10)
of the toilet flushing noise on the hemispheric measurement surface and record
them.
7 Result calculation
7.1 Calculation of the average value of A-weighted cumulative percentage
sound pressure level
7.2 Background noise correction
The background noise correction values K1A(50) and K1A(10) of the A-weighted
cumulative percentage sound pressure level are calculated according to
Formula (5) and Formula (6) respectively.
7.3 Test environment correction
Calculate the environment correction value K2A according to Formula (7).
7.5 Calculation of the sound power level
During the normal flushing cycle, the sound power levels LWA (50) and LWA (10)
under the meteorological conditions of the test site are calculated according to
Formula (10) and Formula (11) respectively.
8 Uncertainty of measurement
8.1 Combined standard uncertainty uLWA of the A-weighted sound power
level measurement
The uncertainty uLWA of the toilet flushing noise sound power level that is
measured according to this Standard is characterized by its total standard
deviation σtot; it’s calculated according to Formula (12).
8.2 Determination of σomc
Under the test static pressure of 0.14 MPa ± 0.01 MPa, the same standard test
operator uses the same sound level meter, and, according to the test
procedures that are specified in Chapter 6, uses the point that is numbered 10
on the hemispheric measurement surface as the microphone position
coordinate,
8.3 Determination of σR0
8.3.1 Reproducibility standard deviation σR0
Reproducibility standard deviation σR0 includes measurement method,
repeatability of sound pressure level measurement, measurement surface area,
background noise correction, test environment correction, meteorological
condition correction, sound level meter performance, number of measurement
points, angle difference between the noise source acoustic emission direction
and the measurement surface normal, frequency spectrum shape and tuned
sound and other uncertainty components; it’s calculated according to Formula
(15).
8.3.7 Uncertainty caused by the meteorological condition correction
The uncertainty, which is caused by the reference quantity difference that is
used for sound pressure level and sound power level, and the change of sound
power level with temperature and pressure, is umet = 0.3 dB; the sensitivity
coefficient is cmet = 1.When the altitude of the test site is less than 1 500 m, no
meteorological condition correction is required; when the altitude is greater than
1 500 m, perform the meteorological condition correction in accordance with
ISO 3744.
8.3.10 Uncertainty caused by the angle difference between the sound
source acoustic emission direction and the measurement surface normal
In a semi-anechoic room, the uncertainty which is caused by the angle
difference between the acoustic emission direction of the toilet flushing noise
and the hemispherical measurement surface normal is uangle = 0.25 dB; the
sensitivity coefficient is cangle = 10-0.1K2A. For a rigid-walled room, it is
recommended to analyze the influence of the sound source and its directivity,
measurement distance and other factors to determine the standard uncertainty
reasonably.
9 Test report
The test report shall include the following.
......
Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al.
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