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GB/T 38498-2020 English PDF (GBT38498-2020)

GB/T 38498-2020 English PDF (GBT38498-2020)

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GB/T 38498-2020: Evaluation method for determining metal corrosion of disinfectant

This Standard specifies evaluation method for corrosion of disinfectants and disinfection equipment to metals under the conditions of aerosol spray, ultrasonic atomization, vaporization, gas, constant spray, wiping, immersion or washing disinfection. This Standard is applicable to evaluation on corrosion of metals by disinfectants that come into contact with various metal and alloy materials during the disinfection process and disinfection instruments that use chemical factors to disinfect.
GB/T 38498-2020
GB
NATIONAL STANDARD OF THE
PEOPLE REPUBLIC OF CHINA
ICS 11.080
C 50
Evaluation method for determining metal corrosion of
disinfectant
ISSUED ON: MARCH 06, 2020
IMPLEMENTED ON: OCTOBER 01, 2020
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 ... 4
4 Evaluation principle ... 5
5 Test methods ... 6
6 Calculation and report of metal corrosion rate ... 11
Evaluation method for determining metal corrosion of
disinfectant
1 Scope
This Standard specifies evaluation method for corrosion of disinfectants and disinfection equipment to metals under the conditions of aerosol spray, ultrasonic atomization, vaporization, gas, constant spray, wiping, immersion or washing disinfection.
This Standard is applicable to evaluation on corrosion of metals by disinfectants that come into contact with various metal and alloy materials during the disinfection process and disinfection instruments that use chemical factors to disinfect.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 700, Carbon structural steels
GB/T 1173, Casting aluminium alloys
GB/T 1175, Casting zinc alloys
GB/T 1176, Casting copper and copper alloys
GB/T 1220, Stainless steel bars
GB/T 2481.1, Bonded abrasives - Determination and designation of grain
size distribution - Part 1: Macrogrits F4 to F220
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply. 3.1 corrosion
Table 2 -- Disinfectant metal corrosion classification
Corrosion rate (R) / (mm/a) Level
< 0.0100 Basically no corrosion
0.0100~< 0.1000 Mild corrosion
0.1000~< 1.0000 Moderate corrosion
???1.0000 Severe corrosion
5 Test methods
5.1 Main test equipment
5.1.1 Metal and alloy material samples
5.1.1.1 Appearance requirements
Round. Diameter is 24.00mm. Thickness is 1.0mm. Penetrate a small hole with a diameter of 2.0mm. The total surface area is about 9.80cm2 (including the upper, lower, peripheral surface and the side of the small hole).
5.1.1.2 Material and quality requirements
5.1.1.2.1 Carbon steel shall meet the requirements of GB/T 700. Carbon steel is easy to oxidize and rust and shall be stored in oil.
5.1.1.2.2 Copper shall meet the requirements of GB/T 1176.
5.1.1.2.3 Aluminum shall meet the requirements of GB/T 1173.
5.1.1.2.4 Stainless steel shall meet the requirements of GB/T 1220.
5.1.1.2.5 Zinc shall meet the requirements of GB/T 1175.
5.1.1.3 Selection requirements
5.1.1.3.1 The size and thickness (specifications) of the metal sheets used shall be consistent. The surface shall be polished.
5.1.1.3.2 Metal samples can only be used once. It shall not affect the accuracy of the test.
5.1.2 Sandpaper
The sandpaper for removing the metal oxide layer is 120 grit water sandpaper. Sandpaper shall meet the requirements of GB/T 2481.1. Each piece of
sandpaper can only grind one metal material.
5.1.3 Test water
density is 1.19gcm-3) at room temperature for 1min~3min;
b) Carbon steel sheet: Soak in 75??C~90??C ammonium citrate solution (200g of ammonium citrate is added with purified water to 1000mL) for 20min;
c) Aluminum sheet: Soak in nitric acid solution (100mL of 66%~68% nitric acid is added with purified water to 1000mL; nitric acid density is 1.42gcm- 3) at room temperature for 1min~5min;
d) Stainless steel: Soak in 60??C nitric acid solution (100mL of 66%~68% nitric acid is added with purified water to 1000mL; density of nitric acid is
1.42g??cm-3) for 20min;
e) Zinc: Soak in 70??C ammonium chloride solution (100g of ammonium
chloride is added with purified water to make 1000mL of solution) for
2min~5min.
5.2.2.2 After removing the corrosion products and cleaning the metal sample, use coarse filter paper to absorb moisture. Place in a petri dish with filter paper. Put into a 50??C incubator. Dry 1h. Use a plastic tweezer to clamp. Take out and store in a desiccator. Place at room temperature and weigh.
5.2.3 Sample measurement
5.2.3.1 Use a Vernier caliper to measure the diameter, thickness and aperture of the sample before the test (to the nearest of 0.1mm). Calculate the total surface area of the sample.
5.2.3.2 Use an analytical balance to respectively weigh the sample before and after cleaning. Zero the balance. Weigh each metal piece 3 times, to the nearest of 0.1mg. Take the average value as the weight before and after the test. 5.2.3.3 When performing operations such as measuring size and weighing, clean gloves shall be worn. The measuring tools used shall be clean and free of oil. Use a plastic tweezer to clamp the sample. Do not touch the sample directly with your hands.
5.3 Aerosol corrosion test
5.3.1 Test preparation
For a pair of adjacent aerosol cabinets (1m3) or aerosol chambers (20m3), one is used for test and the other for control. The environment (including
temperature, humidity, light, airtightness and ventilation conditions) of a pair of aerosol cabinets or aerosol chambers shall be consistent. The cabinet (or chamber) shall be constructed of stainless steel or aluminum alloy and glass. Temperature and humidity adjustment devices, as well as ventilator devices and corresponding pipes shall be installed.
test needs to be interrupted for a long time, the test samples of the test group and the control group shall be taken out of the aerosol cabinet (or chamber) at the same time. Perform sample treatment in the same way as the sample after the test is completed. Store in a desiccator after processing until the test is resumed.
5.3.4 Test control
In the control group, except for replacing the disinfectant with test water or turning off the disinfection factor of the disinfector, the rest of the test steps and processes are the same as the test group. After the cycle is over, remove the metal piece. Use the same method to clean, chemically treat, rinse, dry, and weigh the samples of the test group. Calculate its average weight loss. 5.4 Full immersion corrosion test
5.4.1 Disinfectant replacement
For disinfectors with volatile or unstable active ingredients, such as chlorine dioxide, acid potential water and oxidizing disinfectants, the disinfectant used to soak the sample is changed once a day. When replacing the disinfectant, the operation shall be rapid. The sample shall not be exposed to the air for too long. For disinfectors with stable active ingredients, such as guanidine, phenols, quaternary ammonium salts, aldehydes, there is no need to change the
disinfectant used to soak the sample.
5.4.2 Test steps
5.4.2.1 Soaking method: Prepare the disinfectant for testing according to the highest concentration of disinfectant. Use it to soak the test sample. When soaking, each metal piece needs to be soaked in at least 200mL of disinfectant. 5.4.2.2 Continuous flushing method: Adjust the generator disinfection factor to the highest concentration. Insert the outlet pipe (non-metallic) into the bottom of the soaking container. Turn on the generator. Adjust the flow to make the disinfectant overflow continuously and the sample metal sheet not swing significantly.
5.4.2.3 The disinfectant in a container can only soak or rinse the same metal. 5.4.2.4 Tie a label with plastic thread for metal sample. Indicate the number and date and hang in the disinfectant. Continuously soak or rinse for 72h.
5.4.2.5 Place 3 samples per test for each metal. When soaking or rinsing, if each sample of the same metal is separated by more than 1cm, it can be carried out in the same container (it contains 600mL of disinfectant for soaking method). 5.4.2.6 After soaking or rinsing for the specified time, remove the metal piece.

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