GB/T 2951.25-1994 Test methods for mechanical and physical properties of wires and cables - Anaerobic bacterial corrosion test for outer sheath

This standard specifies the test equipment, sample preparation, test steps, data processing and result analysis for the anaerobic bacterial corrosion test of the outer sheath. This standard is applicable to the comparative test of the anti-corrosion effect of natural fiber materials such as hemp and paper treated with non-water-soluble preservatives, and can also be used as a comparative test of the bacterial resistance of other fiber materials. The general provisions, definitions and regular calibration of the mechanical and physical properties test of wires and cables are stipulated in GB/T 2951.1. GB/T 2951.25-1994 Test methods for mechanical and physical properties of wires and cables Anaerobic bacterial corrosion test of outer sheath GB/T2951.25-1994 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Test method for determining mechanical and physical properties of electric cables and wiresTest far anaerobe-corrosion of protectrive coverings1 Subject content and applicable scope
GB/T2951.25--94
Replaces GR2951.25-82
This standard specifies the test equipment, sample preparation, test steps, data processing and result analysis for the anaerobic bacterial corrosion test of the outer sheath. This standard is applicable to the comparative test of the anti-corrosion effect of natural fiber materials such as hemp and paper treated with non-water-soluble preservatives, and can also be used for comparative tests of the antibacterial properties of other fiber materials. The general provisions, definitions and regular calibration of test equipment for the mechanical and physical properties of wires and cables are specified in GB/T2951.1. 2 Reference standards
GB/T2951,1---94 General principles for test methods for mechanical and physical properties of wires and cables 3 Test equipment
3.1 Bacteria Anaerobic fiber-decomposing bacteria, cultured from natural bacteria. 3.2 Culture medium
3.2.1 Formula
Sodium ammonium hydrogen phosphate
Potassium dihydrogen phosphate
Dipotassium hydrogen phosphate
Magnesium sulfate
Sodium fluoride
Protein
Calcium carbonate
Distilled water
N.NH,HPO, - 4H.O
K,HPO- 3H,0
MgS0,·7H,0
1000ml
7. 0~7. 4
3.2.2 The culture medium should be sterilized in an autoclave (steam pressure 100~150kPa, 30min) before use. 3.3 Bacterial quantity analysis shall be carried out in accordance with the provisions of Appendix A. 4 Sample preparation
4.1 Sampling quantity and method Randomly sample at least 10 cable paper, each 200mm long; at least 20 cable hemp, each 250mm long. Approved by the State Bureau of Technical Supervision on July 7, 1994 and implemented on January 1, 1995
GH/T 2951.25-94
2 Sample treatment. The sample should be stored in the drying cylinder for at least 48h. 5 Test steps
Weigh 10 fresh soil (preferably fresh pond soil), put it into a frosted specimen bottle, put the sample in after heating, add culture solution to the bottle until full, seal the bottle cap, and move it into a cell culture box at a temperature of 30±5℃. The test time is: 10 days for electric paper and 45 days for cable. Take it out at the appointed time, rinse it with tap water, dry it naturally, and then put it into the drying cylinder for at least 48h. Take out and conduct tensile strength test, the speed is 10cm/min, the tensile strength is in N, and it is accurate to one decimal place. 6 Data processing
6.1 Discarding suspicious observations
When the absolute value d of the difference between the observation value and the arithmetic mean is greater than the &S value, the observation value should be discarded. The value can be found in Table 1 according to the number of samples. S is the sample standard deviation, which can be calculated as follows: (1)
6.2 Numerical discarding should be repeated, that is, after the numerical value is discarded, the arithmetic mean and sample standard deviation are recalculated, and discarded according to the method specified in Article 6.1 until there is nothing to discard. 7 Result analysis
The test results should be checked for t value. The method is as follows: suppose the means of the two normal distributions to be compared are and, and are obtained from and test data respectively, let X, Y represent their sample means, S,, S represent sample variances, then: x-
V(n - 1)s,+(n - 1)S,
when = n;wwW.bzxz.Net
nn(n+n,-2)
ni + nz
According to formula (2) or (3), the t value calculated is compared with the value obtained by looking up Table 2 with degrees of freedom = n1 + n±2 and significance level a = 0.05, and the negation city of the following hypothesis can be determined:. Test slow β-μ negation domain is; b. Test hypothesis> negation domain is:
c. Test hypothesis μ
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