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Antimicrobial and cleaning function of household and similar electrical appliances - Part 4: Particular requirements for refrigerator
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Antibacterial and cleaning function for household and similar electrical appliances -- Particular requirements of refrigerator
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GB/T 21551.4-2024: PDF in English (GBT 21551.4-2024) GB/T 21551.4-2024
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 97.040.30
CCS Y 61
Replacing GB 21551.4-2010
Antimicrobial and Cleaning Function of Household and
Similar Electrical Appliances - Part 4.Particular
Requirements for Refrigerator
ISSUED ON. DECEMBER 31, 2024
IMPLEMENTED ON. JANUARY 1, 2027
Issued by. State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword... 3
Introduction... 5
1 Scope... 7
2 Normative References... 7
3 Terms and Definitions... 8
4 Technical Requirements... 8
5 Test Methods... 9
6 Marking and Instructions for Use... 11
Appendix A (normative) Test Method for Microbial Reduction... 12
Appendix B (normative) Test Method for Cleaning / Deodorization... 17
Bibliography... 19
Antimicrobial and Cleaning Function of Household and
Similar Electrical Appliances - Part 4.Particular
Requirements for Refrigerator
1 Scope
This document specifies the hygiene and safety, and functional requirements for refrigerators,
refrigerator-freezers and freezers for household and similar purposes with the antimicrobial,
microbial reduction and cleaning functions, as well as the marking requirements, and describes
the corresponding test methods.
This document applies to the production, inspection and sales of refrigerators, refrigerator-
freezers and freezers (hereinafter referred to as “refrigerators”) for household and similar
purposes that have one or more functions of antimicrobia, preventing mildew, microbial
reduction, cleaning / deodorization, etc.
2 Normative References
The contents of the following documents constitute indispensable clauses of this document
through the normative references in the text. In terms of references with a specified date, only
versions with a specified date are applicable to this document. In terms of references without a
specified date, the latest version (including all the modifications) is applicable to this document.
GB 4789.2 National Food Safety Standard - Microbiological Examination of Food. Aerobic
Plate Count
GB/T 8059 Household and Similar Refrigerating Appliances
GB/T 18883 Standards for Indoor Air Quality
GB 19489 Laboratories - General Requirements for Biosafety
GB/T 21551.1 Antimicrobial and Cleaning Function of Household and Similar Electrical
Appliances - Part 1.General Requirement
GB/T 21551.2 Antimicrobial and Cleaning Function of Household and Similar Electrical
Appliances - Part 2.Particular Requirements for Material
GB 44498 Household and Similar Electrical Appliances - Health Technical Specification
HJ 1042 Ambient Air and Waste Gas - Determination of Trimethylamine - Solvent Absorption
- Headspace/gas Chromatography
4.1.2 Inhibition ring
The inhibition ring shall meet the requirements of GB/T 21551.1.
4.1.3 Hygiene toxicology
For refrigerators with materials that are explicitly stated to have the antimicrobial function or
components and parts containing antimicrobial materials, the toxicology shall comply with the
requirements of GB/T 21551.1.
4.2 Requirements for Antimicrobia, Microbial Reduction and Cleaning
4.2.1 Antimicrobia
The antimicrobial rate of refrigerator materials or components and parts that are explicitly stated
to have the antimicrobial function shall comply with the requirements of GB/T 21551.2.
4.2.2 Preventing mildew
For refrigerator materials or components parts that are explicitly stated to have the preventing
mildew function, the preventing mildew level shall comply with the requirements of GB/T
21551.2.
4.2.3 Microbial reduction
For refrigerators that are explicitly stated to have the microbial reduction function, the microbial
reduction state shall not be lower than 90.0%.
4.2.4 Cleaning / deodorization
For refrigerators that are explicitly stated to have the cleaning / deodorization function, the
cleaning rate / deodorization rate shall not be lower than 90.0%.
5 Test Methods
5.1 Test Conditions
5.1.1 General conditions
Except for tests with specific provisions on test environmental conditions, all tests shall be
carried out indoors with an ambient temperature of (25 2) C, a relative humidity not
exceeding 75%, and without external air flow, strong sunlight or other radiation.
The test power supply is an AC sine wave, and the fluctuation range of voltage and frequency
shall not exceed 1% of the rated value.
5.1.2 Measurement instruments
The general measurement instruments for the test shall satisfy the following requirements.
a) The accuracy class of electrical measurement instruments used for type tests, except
for those specified in specific provisions, shall not be lower than Class 0.5, and the
accuracy class of exit-factory tests shall not be lower than Class 1.0;
b) Thermometer. with a maximum allowable error of 0.5 C;
c) Hygrometer. with a maximum allowable error of 2%;
d) Timing instrument. with a maximum allowable error of 1 s/24 h;
e) Ultraviolet radiation meter. with a resolution of not lower than 0.1 W/cm2;
f) Ozone analyzer. with a resolution of not lower than 0.001 mg/m3.
5.2 Hygiene and Safety Test
5.2.1 Hygiene and safety test of the whole machine
5.2.1.1 General conditions
The test result of harmful substance leakage test of refrigerators shall be the test value minus
the background concentration value in the laboratory environment. The laboratory background
environment shall comply with the requirements of GB/T 18883.
The appliance shall be stably operated for at least 30 minutes before starting the test.
5.2.1.2 Ozone leakage
With the refrigerator door or lid closed, in accordance with the ultraviolet photometry method
specified in GB/T 18883, test at a vertical distance of 5 cm from the plane of the refrigerator.
The sampling frequency is 1 time/min and the test time shall not be less than 20 min. The
average value of each sampling point is taken as the final result.
5.2.1.3 UV leakage
When testing for UV leakage, the refrigerator needs to be placed in a dark room (paint the walls
black). With the refrigerator door or lid closed, use a UV radiation meter to test at a vertical
distance of 5 cm from the center of the plane where the door crack is located. Respectively take
one point at the center of each door crack, measure the ultraviolet light with a main wavelength
of 253.7 nm, and take the average value. If the manufacturer explicitly states that the main
wavelength of ultraviolet light is another value, then, additional tests shall be carried out for
that wavelength.
NOTE. the sampling points are set in accordance with the actual installation situation.
5.2.2 Inhibition ring
Appendix A
(normative)
Test Method for Microbial Reduction
A.1 Test Principle
This method is to inoculate the test bacteria on the test carrier agar, respectively place it for a
certain period of time under two conditions. the refrigerator microbial reduction program is
turned on and turned off. Calculate the microbial reduction rate by the count of viable bacteria
remaining after the end.
A.2 Test Environment
The test shall adopt aseptic operation techniques, and the laboratory environment shall comply
with the requirements of GB 19489.
A.3 Test Bacteria, Materials, Instruments and Equipment
A.3.1 Test bacteria
The test bacteria are as follows.
a) Staphylococcus aureus subsp. aureus CGMCC 1.2910, which is equivalent to ATCC
6538P;
b) Escherichia coli CGMCC 1.2463, which is equivalent to ATCC 8739.
If necessary, other bacterial species may also be selected as test bacterial species. All bacterial
species or strains shall be provided by corresponding national bacterial species preservation and
management institutions, and the names of the test bacterial species and strain numbers shall
be clearly stated in the report.
Laboratories shall use test microorganisms in accordance with relevant national safety
regulations. If other test pathogens are selected, the laboratories shall have a biosafety
protection level that is compatible with the hazards and shall not involve the first and second
categories of pathogenic microorganisms in the Catalogue of Pathogenic Microorganisms
Transmissible to Humans.
The various culture medium components used to culture bacterial species shall comply with the
requirements of the bacterial species preservation and management institutions.
A.3.2 Culture media and reagents
The culture media and reagents used during the test are as follows.
7.2 ~ 7.4, dispense into conical flasks, use sealing films to seal them, and at 121 C, sterilize
them in a pressure steam sterilizer for 20 min.
If commercial culture medium is used, it shall be prepared and sterilized in accordance with the
preparation method and sterilization conditions specified on the culture medium.
A.4.2 Preparation of nutrient agar (NA) medium
Beef extract 5.0 g
Peptone 10.0 g
Sodium chloride 5.0 g
Agar 15.0 g
Preparation method. take the above-mentioned components, add them to 1,000 mL of distilled
water, and heat to dissolve them. Use 0.1 mol/L sodium hydroxide solution to adjust the pH
after sterilization to 7.2 ~ 7.4.Add agar and dissolve it. At 121 C, sterilize it in a pressure steam
sterilizer for 20 min.
If commercial culture medium is used, it shall be prepared and sterilized in accordance with the
preparation method and sterilization conditions specified on the culture medium.
A.4.3 Preparation of inoculation culture solution
The inoculation culture solution is prepared with a physiological saline solution of NB. The
inoculation culture solution for the culture of Escherichia coli is added with 0.2% (volume
fraction) NB, and the inoculation culture solution for the culture of Staphylococcus aureus
subsp. aureus is added with 1.0% (volume fraction) NB. To facilitate bacterial dispersion, a
small amount of surfactant Tween-80 may be added. To prevent the test bacteria from
inactivating in a low temperature environment, an appropriate amount of protective agent, for
example, glycerol, may be added to the bacterial culture solution. Use 0.1 mol/L sodium
hydroxide solution to adjust the pH after sterilization to 7.2 ~ 7.4, divide the contents into
portions, and at 121 C, sterilize them in a pressure steam sterilizer for 20 min.
A.4.4 Preservation of bacterial species
Inoculate the standard strain onto a NA slant, at (37 1) C, culture it for (24 1) h, and then,
preserve at 5 C ~ 10 C (shall not exceed 1 month) as slant-preserved bacteria
A.4.5 Activation of bacterial species
Transfer the slant-preserved bacteria to a NA plate, at (37 1) C, culture it for (24 1) h.
Transfer once a day. During the test, the 3rd ~ 5th generation of fresh bacterial culture transferred
within 24 hours shall be used.
A.4.6 Preparation of bacterial suspension
Use an inoculation loop to scrape 1 ~ 2 loops of fresh bacteria from the fresh culture of A.4.5,
add them to the inoculation culture solution, and successively prepare 10-fold gradient diluents.
Select the diluent with a bacterial solution concentration of 5.0 103 CFU/mL ~ 1.0 104
CFU/mL as the test bacterial solution, and in accordance with the method of GB 4789.2,
determine the concentration of the bacterial solution.
A.4.7 Preparation of test carrier agar
Take 8.5 g of sodium chloride and 20 g of agar, add them to 1,000 mL of distilled water, and
heat to dissolve them. Use 0.1 mol/L sodium hydroxide solution to adjust the pH after
sterilization to 7.2 ~ 7.4.At 121 C, sterilize in a pressure steam sterilizer for 20 min. Pour
about 15 mL of sterilized agar into a sterilized culture dish and let it solidify for later use.
A.5 Test Steps
The test is carried out in accordance with the following steps.
a) Use a transfer pipette to pipette an appropriate amount of the bacterial suspension
prepared in A.4.6 and dropwise add it onto the culture dish containing the test carrier
agar, and evenly spread the bacterial suspension;
b) The refrigerators in the test group and the control group run at no load for 24 hours at
an ambient temperature of (25 2) C and a relative humidity of not exceeding 75%.
The temperatures of each compartment of the refrigerators are set in accordance with
the test procedures explicitly stated by the manufacturer. If there is no explicit
statement, then, the temperature of the refrigerating compartment is set at 5 C, the
temperature of the freezing compartment is set at 18 C, and the temperature of the
alternating-temperature compartment is set at 0 C. Before the test, use 75% (volume
fraction) ethanol to wipe the inner surface of the compartment to be tested and the
surfaces of the accessories in the compartment, and dry them. During no-load
operation, try not to turn on the microbial reduction program;
c) Respectively place culture dishes in the center of the test compartment of refrigerators
in the test group and the control group, open the cover of the culture dishes, for the
test group, turn on the microbial reduction program, and for the control group, do not
turn on the microbial reduction program, and run for 24 hours;
NOTE 1.if the test compartment is a refrigerating compartment, then, place the culture dishes in
the center of the upper, middle and lower shelves.
NOTE 2.if the test compartment is a drawer, then, place the culture dishes at the left, middle and
right positions of the drawer.
NOTE 3.if the microbial reduction program of the refrigerator cannot be turned off, place the
culture dishes of the control group in an environment that can achieve the internal and
external temperature conditions specified in b). In the internal environment, the
temperature fluctuation is controlled within 1 C. Before the test, the internal
Appendix B
(normative)
Test Method for Cleaning / Deodorization
B.1 Test Principle
Introduce a certain concentration of chemical gas into the designated compartment of the
refrigerator and run the designated cleaning / deodorization program. Based on the change in
chemical gas concentration before and after the program, calculate the cleaning rate /
deodorization rate.
B.2 Test Gas, Instruments and Equipment
B.2.1 Test gas
Trimethylamine (purity. 99.5%, when used, diluted to a suitable concentration with high-purity
nitrogen), which is used to evaluate the deodorization program.
NOTE 1.if evaluating the conventional cleaning function, ethylene is recommended as the test gas,
and the test steps shall refer to this Appendix.
NOTE 2.when other gases are selected in accordance with the use conditions, the final test result
shall explicitly state the name of the selected gas.
B.2.2 Instruments and equipment
Gas chromatograph. with split / splitless injection port, equipped with hydrogen flame
ionization detector (FID) or / and nitrogen phosphorus detector (NPD).
Air sampler. with a flow rate of 0.1 L/min ~ 1.0 L/min.
NOTE. if other gases are selected, the instruments and equipment shall comply with the
corresponding standard test methods.
B.3 Test Preparation
Use an electric drill to drill two holes on the horizontal center line of the door of the refrigerator
to be tested. The positions of the two holes shall be evenly distributed. If the holes need to pass
through components and parts or panels in the refrigerator that hinder the drilling, the positions
may be appropriately deviated.
Take out all the partitions and drawers in the refrigerator, first, use 75% (volume fraction)
ethanol, and then, distilled water to wipe the inside of the refrigerator, and after cleaning, place
it in operation at room temperature for 24 hours.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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