- Annex 2 Recommended. Flask, beaker and sample basket Appendix 4 Informative. Information data on compliance with GOST 21400-75 ST SEV 1569-79
State standard of the USSR GOST 21400-75 (ST SEV 825-77)
"Chemical-laboratory glass. Technical requirements. Test Methods"
(approved by the Decree of the State Standard of the USSR of December 23, 1975 N 3976)
Chemical and laboratory glass. technical specifications. Test methods
Instead of GOST 9111-59, GOST 7330-55 and OST NKTP 8187/1131,
except for sect. I-III, VI and VIII
This standard applies to chemical laboratory glass (hereinafter referred to as glass) intended for the manufacture of laboratory glassware, instruments and apparatus.
The standard complies with ST SEV 1669-79, ST SEV 825-77 in terms of glass of the TS group (Appendix 4) and recommendations for standardization of SEV PC 1885-69.
The standard takes into account the requirements of ISO 695-84 and ISO 719-85.
(Changed edition, Rev. N 2).
1.1. Glass, depending on the chemical and thermal resistance, should be produced in the following groups:
ХС1 - chemically resistant class 1; ХС2 "" 2nd class; ХС3 "" 3rd class; ТХС1 - thermally and chemically resistant of the 1st class; THS2 - "" "" 2nd class; TS - thermally resistant (borosilicate glass 3.3).
2. Technical requirements
2.1. Glass must be manufactured in accordance with the requirements of this standard according to the normative and technical documentation approved in in due course.
2.2. The chemical resistance of glass to the effects of distilled water, acids and alkalis must comply with those indicated in Table. 1 .
Table 1
|
Consumption rates and losses |
Chemical resistance of glass by groups: |
||||||
|
Distilled water at a temperature of (98+-0.5)°С |
Consumption 0.01 n. hydrochloric acid solution for titration, ml/g (alkali recovery, µg Na2O x r(-1), no more) |
0.1 to 0.2 |
0.2 to 0.8 |
0.1 to 0.2 |
|||
|
20.4% hydrochloric acid solution at boiling for 6 hours |
Weight loss of glass sample, mg/cm2 |
0 to 0.004 |
0 to 0.006 |
0 to 0.005 |
0 to 0.007 |
||
|
1 n. sodium carbonate solution and 1 N. sodium hydroxide solution at boiling for 3 hours |
Weight loss of glass sample, mg/cm2 (mg x dm(-2)), not more than |
||||||
2.3. Thermal resistance and average coefficient of linear thermal expansion of glass must correspond to those indicated in Table. 2 .
table 2
|
glass group |
Thermal stability, °С, not less than |
Average coefficient of linear thermal expansion in the temperature range from 20 to 300°C, alpha x 10(-7) deg(-1) |
|
XC1, XC2, XC3 |
No more than 94 |
|
|
TXS1, TXS2 |
No more than 55 |
|
Note. The value of the coefficient of thermal expansion characterizes only the composition of the glass.
2.2; 2.3. (Changed edition, Rev. N 1).
3. Test methods
3.2. Method for determining the resistance of glass to hydrochloric acid
Acid resistance is determined by the weight loss of the tested glass sample when exposed to a boiling 20.4% hydrochloric acid solution for 6 hours and is expressed as the ratio of weight loss to the unit area of the sample.
3.2.1. To determine the acid resistance, the following equipment and reagents are used:
laboratory analytical scales with a weighing error of mg;
drying cabinet with heating temperature °С;
electric stove;
tripod laboratory;
diamond or glass cutting roller;
platinum wire with a diameter of up to 1.0 mm according to GOST 18389-73;
measuring cylinder with a capacity of 1000 ml according to GOST 1770-74;
a tall glass and a round-bottom flask made of XC1, TXC1 or TS glass. The shape and dimensions of the glass and flask are indicated in Appendix 2;
rubber stopper according to TU 38.1051835-88;
rubber tube with a diameter of 6 mm according to GOST 5496-78;
The reagents used must be analytically qualified. or x. h.
3.2.2. For the test, samples shall be taken in the form of glass tubes with an inner diameter of at least 5 mm or other products whose surface can be easily determined.
The total surface of the samples should be .
It is allowed to take several samples of a smaller size, which add up to the required surface. In this case, the surface of the samples should not differ from each other by more than 5%. The surface of the samples must be smooth, sharp edges must be ground.
Glass specimens must be annealed before testing.
Two samples are taken for testing, one of them is a control. The discrepancies in mass and area of the test and control samples should not exceed 1 g and 10. The lighter sample should be the control.
The samples are measured and the total surface is calculated.
Then the samples are washed in distilled water, rinsed with alcohol and dried in an oven at a temperature of °C for 45 min. The dried samples are cooled in a desiccator to a temperature of °C and weighed. Determine the mass discrepancy between the test and control samples with an error of not more than mg.
3.2.3. To carry out the test, 500-600 ml of a 20.4% hydrochloric acid solution are measured into a glass.
The glass is placed on an electric stove and the solution is brought to a boil. The test sample is placed in a basket of platinum wire and lowered to the bottom of the beaker so that the sample is completely immersed in the solution and does not touch the walls of the beaker. In order to reduce the evaporation of acid, a flask with two outlets is placed on top of the glass. Through one of the outlets, water is passed into the flask for cooling. Between the edge of the glass and the bottom of the flask, a rubber tube, cut along the length, is inserted for sealing. The flask is fixed over the beaker with tripod clamps. The installation scheme is indicated in Appendix 2.
The sample is kept in boiling acid for 6 hours.
After that, the sample is removed from the beaker, rinsed in distilled water and placed in an oven at a temperature of °C and dried for 45 minutes, then cooled in a desiccator to a temperature of °C and weighed with an error of not more than +-0.1 mg.
The tests are repeated on the second pair of samples - the test and control.
3.2.4. Acid resistance of glass () - sample mass loss - is calculated by the formula
where is the difference in mass between the test and control samples before testing, mg;
The difference in mass between the test and control samples after the test, mg;
S is the total surface of the sample, .
From two experiments, the arithmetic mean value and deviations from the mean value are determined. The results are calculated to the third decimal place. The discrepancy between the results in each experiment from the average value should not be more than %.
3.2.5. The acid resistance class, depending on the weight loss of the sample, should be set in accordance with that indicated in Table. 4 .
______________________________
* Tab. 3. (Deleted, Rev. N 2).
3.2.6. The results of the acid resistance test are recorded in a protocol containing:
sample designation;
arithmetic mean of mass loss, ;
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Ending ta and ish and I A TEST METHODS %. At - %. AT, T\« 2 A T j♦ . . . + Yat A TtA T= I, n H i and 2, APPENDIX 2 "Recommended sstI- flask, 2 - cup; 3 - sample basket APPENDICES I.J. APPENDIX 4Reference APPENDIX 4(Introduced additionally. Nam. Le 2). INFORMATION DATA 1. APPROVED AND INTRODUCED BY Decree State Committee standards of the Council of Ministers of the USSR dated December 23, 1975 No. 3976 1-III, VI and VIII 3. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS Designation of NTD. Designation of NTD, Number of paragraph, subparagraph Number of paragraph, subparagraph to which; or reference to which the reference is given GOST 1 6 6 - 8 9 3.2.1 GO ST 10134.3 - S 2 3.3 GOST 1 7 7 0 -7 4 1 8 - 7 7 3.2.1 GOST ST 1 8 3 0 0 -8 7 3.2.1 GOST ST 5 4 9 6 - 7 8 3.2.1 GOST ST 1 8 3 8 9 -7 3 3.2.1 GOST ST 6 7 0 9 - 7 2 -8 2 3.2.1 GOST 1 0 1 3 4 .1 -8 2 3.1 TU 3 8 .1 0 5 1 8 3 5 -8 8 3.2.1 4. The limitation of the period of validity was removed by Decree of the State Standard of the USSR dated 27.12.91 No. 2221 5. EDITION (March 2011) with Amendments No. I, 2, approved in October 1981, July 1986 (IUS 1 -8 2, 1 0 -8 6) 90 GOST 21400-75
M E F G O S U D A R S T V E N N Y S T A N D A R T GLASS CHEMICAL LABORATORY TECHNICAL REQUIREMENTS. TEST METHODS Official publication Moscow Stamdartinform 2011buy napkins UDC 542.26:006.354 Group II M E F G O S U D A R S T V E N Y S T A N D A R T GLASS CHEMI CO-LABORATORY GOST Technical requirements. 21400-75 Test methods Chemical 3rd laboratory glass. technical specifications. Test methods M K S 71.040.20 81.040 Date of introduction 07/01/77 This standard applies to chemical laboratory glass (hereinafter referred to as glass) intended for the manufacture of laboratory glassware, instruments and apparatus. The standard complies with ST SEV 1569-79, ST SEV 825-77 in terms of glass of the TS group (Appendix 4) and recommendations for standardization of SEV PC 1885-69. The standard takes into account the requirements of ISO 695-84 and ISO 719-85. (Revised edition, Rev. No. 2). 1. GROUPS 1.1. Glass, depending on the chemical and thermal resistance, must be produced in the following groups: XCI - chemically resistant 1st class; XC2 * * 2nd class; KhSZ * » 3rd class: ТХС1 - thermally and chemically resistant 1st class; ТХС2 * * * * 2nd class; TS - thermally resistant (borosilicate glass 3.3). (Changed edition. Rev. No. 1). 2. TECHNICAL REQUIREMENTS 2.1. Glass must be manufactured in accordance with the requirements of this standard according to the normative and technical documentation approved in the prescribed manner. 2.2. The chemical resistance of glass to the effects of distilled water, acids and alkalis must correspond to that indicated in Table. 1. T a b l e I Chemical resistance of glass according to Groups Medium Consumption rates and noicpu XCI XC2 XSZ TX C1 TXC2 t s g u t 0 From 0.1 From 0.2 From 0 O r 0.1 From 0 W ater TCMiicpaivpc hydrochloric acid slots TO 0.1 to 0.2 to 0.8 to 0.1 to 0.2 to 0.1 (9 8±0.5) D (alkalin e th e, m kg N a .O g ~ *. ns more) I n m a n n o t i o n o f Reprint prohibited © Standards Publishing House 1975 © STANDARDINFORM 2011 85 S. 2 Ending ta and ish and I Chemical resistance of glass by groups Environment Consumption rates and burns ХС1 ХС2 xes ТХС1 ТХС 2 ТС 20.4% solution Mass loss v From 0 From 0 From 0 From 0 From 0 From 0 hydrochloric acid at different glass, mg / cm 2 to 0.004 to 0.005 to 0.006 to 0.005 to 0.0 07 to 0.004 boiling for 6 h Mixture: Weight loss about b 1 and. a solution of carbon glass glass, mg / cm 2 of acid sodium and 1 n. (mg - dm - 2), ns more than 0.75 1.0 1.1 0.9 1.2 1.5 (150 "heating hydroxide solution at boiling for 3 hours 2.3. Thermal resistance and average coefficient of linear thermal expansion of glass should correspond to those indicated in Table 2. Table 2 Average coefficient of linear thermal thermal stability. 'C , Expansion glass group in the temperature range of at least o r 20 to 300 "C, A 10~7 deg-1 X C I , X C 2. KhSZ 120 N with more than 94 T X C 1. THS2 190 N with more than 55 TS 250 33±1 The value of the coefficient of thermal expansion characterizes only the composition of the glass. 2.2, 2.3. (Revised edition, Rev. No. 1). 3. TEST METHODS 3.1. Water resistance is determined by method A GOST 10134.1. (Revised edition, Rev. .V? 2). 3.1.1 - 3.1.5. (Deleted, Rev. No. 2). 3.2. Method for determining the resistance of glass to hydrochloric acid The resistance to stain is determined by the weight loss of the tested glass sample when exposed to a boiling 20.4% hydrochloric acid solution for 6 hours and is expressed as the ratio of weight loss to unit area of the sample. 3.2.1. To determine acid resistance, the following equipment and reagents are used: - laboratory analytical scales with a weighing error of iO.l mg; - drying cabinet with heating temperature (150±2) ‘С; - electric stove: - laboratory support; - caliper according to GOST 166; - diamond or glass-cutting roller; - tweezers; - platinum wire up to 1.0 mm in diameter according to GOST 18389; - desiccator according to GOST 25336; - measuring cylinder with a capacity of 1000 cm3 according to GOST 1770; - a tall glass and a round-bottom flask made of XCI glass. TXC1 or TS. The shape and dimensions of the glass and flask are specified in Appendix 2; - rubber stopper according to TU 38.1051835; - rubber tube with a diameter of 6 mm according to GOST 5496; - hydrochloric acid according to GOST 3118. 20.4% solution; - rectified ethyl alcohol according to GOST 18300 or rectified hydrolysis alcohol of the highest purity; - distilled water in accordance with GOST 6709. 86 C. 3 The reagents used must have the qualification of analytical grade. or x. part 3.2.2. For the test, samples should be taken in the form of glass tubes with an internal diameter of at least 5 mm or other products, the surface of which can be easily determined. The total surface of the samples should be (400140) cm2. It is allowed to take several samples of smaller size, summing up the required surface. In this case, the surface of the samples should not differ from each other by more than 5 %. The surface of the samples must be smooth, sharp edges must be ground. Glass specimens must be annealed before testing. Two samples are taken for testing, one of them is a control. Differences in mass and area of the test and control samples should not exceed 1 g and 10 cm2. The lighter sample should be the control. The samples are measured and the total surface is calculated. Then the samples are washed in distilled water, rinsed with alcohol and dried in an oven at a temperature of (150-2) "C for 45 minutes. The dried samples are cooled in a desiccator to a temperature of (2015) * C and weighed. 500-600 cm3 of a 20.4% hydrochloric acid solution is placed in a beaker. The beaker is placed on an electric stove and the solution is brought to a boil. The test sample is placed in a basket of platinum wire and lowered to the bottom of the beaker so that the sample is completely immersed in the solution and does not touch the walls of the beaker. In order to reduce the evaporation of acid, a flask with two outlets is placed on top of the beaker. water for cooling. Between the edge of the beaker and the bottom of the flask, a rubber tube, cut along the length, is inserted for sealing. The flask is fixed over the beaker with tripod clamps. The setup diagram is given in Appendix 2. The specimen is kept in boiling acid for 6 hours. desiccator to a temperature (2015) "C and weighed with an error of not more than 10.1 mg. The tests are repeated on the second pair of samples - the test and control. 3.2.4. Stent acid resistance (L-,) - sample mass loss - is calculated by the formula where At - difference between the masses of the test and control samples before testing, mg; Dj1| - difference between the masses of the test and control samples after the test, mg; 5 - total sample surface, cm2. From two experiments, the arithmetic mean and deviations from the mean are determined. The results are calculated to the third decimal place. The discrepancy between the results in each experiment from the average value should not be more than HO %. 3.2.5. Acid-resistant™ class depending on Table 4* sample mass loss should be set in accordance with that specified in Table 4. Class 3.2.6. The results of the test for acid-resistant weight, mg/smkxlogosyukostm bone are recorded in a protocol containing: - designation of the sample; 1 up to 0.007 inclusive - arithmetic mean of weight loss, mg-cm-2; 2 C. 0.007 to 0.015 including part 3 » 0.015 - designation of the acid resistance class; - name of the laboratory that carried out the test; - test date; - designation of this standard. (Introduced additionally. Amendment No. 2). 3.3. Alkali resistance is determined according to GOST 10134.3. (Changed edition. Rev. No. 2). * Tab. 3. (Excluded, I "m. No. 2). 87 p. 4 3.3.1-3.3.5. (Deleted, Rev. No. 2). 3.4. Method for determining the thermal resistance of glass to the maximum temperature difference without breaking Thermal resistance is determined by measuring the temperature difference at which a heated glass sample breaks when it is rapidly cooled in water. 3.4.1. To determine the heat resistance, the following equipment is used: - a vertical tubular electric furnace with a temperature of heating samples up to 250 °C with an accuracy of maintaining a given temperature of ± 1 °C for 15 minutes: - a metal, glass or porcelain vessel for cooling samples with a capacity of 1 dm3; - tongs. 3.4.2. For testing, samples in the form of glass rods (rods) with a length of (30x5) mm and a diameter of (4 ± 0.1) mm should be taken. Samples must be free of cracks, stones and other defects. The ends of the specimens must be melted. Fused specimens must be annealed. The specific difference in the path of the rays should not be more than 0.4 ppm. (Revised edition, Rev. No. 2). 3.4.3. For testing, the samples are placed in an electric furnace, heated to a temperature. equal to the lower limit of the heat resistance of the tested glass, specified in the normative and technical documentation, and kept at this temperature for 15 minutes. After that, the samples are removed from the oven, immersed in a vessel with water, the temperature of which should be from 15 to 20 °C, and then removed from the water. From the tested samples, figurines with cracks of any size are taken and are not used in further tests. The remaining undamaged specimens are reloaded into the furnace. The temperature in the furnace is raised by 10°C and the heating and then cooling in water are repeated. Heating and subsequent cooling are carried out until all the specimens fail. 3.4.4. Thermal resistance of glass AT,*C, calculated by the formula "I D T\« 2 A T j♦ . . . + Yat A TtA T= I, n H i+ ... + "t where d7 "|, dG2, ..., dGt - thermal stability of the sample, * C; l, and 2,..., "t - the number of cracked samples, pcs. 3.5. The coefficient of linear thermal expansion is determined according to GOST 10978. S. 5 APPENDIX 2 "Recommended FLASK, GLASS AND SAMPLE BASKET sstI- flask, 2 - cup; 3 - sample basket APPENDICES I.J.(Excluded, N sh. Le 2). 89 p. 6 APPENDIX 4Reference I N F O R M A T I O N N N Y DATA ON COMPLIANCE WITH GOST 2 1 4 0 0 -7 5 ST SEV 1 5 6 9 -7 9 Clause 3.1 GOST 2 1 4 0 0 -7 5 corresponds to ST SEV 1569-79. APPENDIX 4(Introduced additionally. Nam. Le 2). INFORMATION DATA 1. APPROVED AND INTRODUCED BY Decree of the State Committee for Standards of the Council of Ministers of the USSR No. 3976 dated December 23, 1975 1-III, VI and VIII 3. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS Designation of NTD. Designation of NTD, Number of paragraph, subparagraph Number of the paragraph, subparagraph to which; or reference to which the reference is given GOST 1 6 6 - 8 9 3.2.1 GO ST 10134.3 - S 2 3.3 GOST 1 7 7 0 -7 4 1 8 - 7 7 3.2.1 GOST ST 1 8 3 0 0 -8 7 3.2.1 GOST ST 5 4 9 6 - 7 8 3.2.1 GOST ST 1 8 3 8 9 -7 3 3.2.1 GOST ST 6 7 0 9 - 7 2 -8 2 3.2.1 GOST 1 0 1 3 4.1 -8 2 3.1 TU 3 8.1 0 5 1 8 3 5 -8 8 3.2.1 2, approved in October 1981, July 1986 (IUS 1 -8 2, 1 0 -8 6) 90 GOST 21400-75
TU 38.1051835-88
4. The limitation of the validity period was removed by the Decree of the State Standard of the USSR of December 27, 1991 N 2221
5. EDITION with Amendments No. 1, 2, approved in October 1981, July 1986 (IUS 1-82, 10-86)
This standard applies to chemical laboratory glass (hereinafter referred to as glass) intended for the manufacture of laboratory glassware, instruments and apparatus.
The standard complies with ST SEV 1569-79, ST SEV 825-77 in terms of glass of the TS group (Appendix 4) and recommendations for standardization of SEV PC 1885-69.
The standard takes into account the requirements of ISO 695-84 and ISO 719-85.
1. GROUPS
1.1. Glass, depending on the chemical and thermal resistance, should be produced in the following groups:
ХС1 - chemically resistant class 1;
ХС2 "" 2nd class;
ХС3 "" 3rd class;
ТХС1 - thermally and chemically resistant of the 1st class;
THS2 "" "" 2nd class;
TS - thermally resistant (borosilicate glass 3.3).
(Changed edition, Rev. N 1).
2. TECHNICAL REQUIREMENTS
2.1. Glass must be manufactured in accordance with the requirements of this standard according to the normative and technical documentation approved in the prescribed manner.
2.2. The chemical resistance of glass to the effects of distilled water, acids and alkalis must correspond to those indicated in Table 1.
Table 1
Consumption rates and losses | Chemical resistance of glass by groups |
||||||
Distilled water at a temperature of (98±0.5) °C | Consumption 0.01 n. hydrochloric acid solution for titration, cm/g (alkali recovery, μg NaO g, not more than) | From 0 | From 0.1 | From 0.2 | From 0 | From 0.1 | From 0 |
20.4% hydrochloric acid solution at boiling for 6 hours | Weight loss of glass sample, mg/cm | From 0 | From 0 | From 0 | 0 to 0.005 | From 0 | From 0 |
Mixture: | Weight loss of glass sample, mg/cm (mg dm), no more than | ||||||
2.3. Thermal resistance and average coefficient of linear thermal expansion of glass must correspond to those indicated in Table 2.
table 2
glass group | Thermal stability, °С, not less than | Average coefficient of linear thermal expansion in the temperature range from 20 to 300 °C, 10 degrees |
XC1, XC2, XC3 | No more than 94 |
|
TXS1, TXS2 | No more than 55 |
|
Note. The value of the coefficient of thermal expansion characterizes only the composition of the glass.
2.2, 2.3. (Changed edition, Rev. N 1).
3. TEST METHODS
3.1. Water resistance is determined according to method A GOST 10134.1.
(Changed edition, Rev. N 2).
3.1.1-3.1.5. (Excluded, Rev. N 2).
3.2. Method for determining the resistance of glass to hydrochloric acid
Acid resistance is determined by the weight loss of the tested glass sample when exposed to a boiling 20.4% hydrochloric acid solution for 6 hours and is expressed as the ratio of weight loss to unit area of the sample.
3.2.1. To determine the acid resistance, the following equipment and reagents are used:
- laboratory analytical scales with a weighing error of ±0.1 mg;
- drying cabinet with heating temperature (150±2) °С;
- electric stove;
- laboratory tripod;
- caliper according to GOST 166;
- diamond or glass-cutting roller;
- tweezers;
- platinum wire with a diameter of up to 1.0 mm according to GOST 18389;
- desiccator according to GOST 25336;
- measuring cylinder with a capacity of 1000 cm3 according to GOST 1770;
- a tall glass and a round-bottomed flask made of glass ХС1, ТХС1 or ТС. The shape and dimensions of the glass and flask are specified in Appendix 2;
- rubber stopper according to TU 38.1051835;
- rubber tube with a diameter of 6 mm according to GOST 5496;
- hydrochloric acid according to GOST 3118, 20.4% solution;
- rectified ethyl alcohol according to GOST 18300 or rectified hydrolysis alcohol of the highest purity;
- distilled water according to GOST 6709.
The reagents used must be of analytical grade. or h.h.
3.2.2. For the test, samples should be taken in the form of glass tubes with an internal diameter of at least 5 mm or other products, the surface of which can be easily determined.
The total surface of the samples should be (400±40) cm.
It is allowed to take several samples of a smaller size, which add up to the required surface. In this case, the surface of the samples should not differ from each other by more than 5%. The surface of the samples must be smooth, sharp edges must be ground.
Glass specimens must be annealed before testing.
Two samples are taken for testing, one of them is a control. The discrepancies in mass and area between the test and control samples should not exceed 1 g and 10 cm. The lighter sample should be the control.
The samples are measured and the total surface is calculated.
Then the samples are washed in distilled water, rinsed with alcohol and dried in an oven at a temperature of (150 ± 2) °C for 45 min. The dried samples are cooled in a desiccator to a temperature of (20 ± 5) °C and weighed. Determine the mass discrepancy between the test and control samples with an error of not more than ± 0.1 mg.
3.2.3. To carry out the test, 500-600 cm 3 of a 20.4% hydrochloric acid solution are measured into a glass.
The glass is placed on an electric stove and the solution is brought to a boil. The test sample is placed in a basket of platinum wire and lowered to the bottom of the beaker so that the sample is completely immersed in the solution and does not touch the walls of the beaker. In order to reduce the evaporation of acid, a flask with two outlets is placed on top of the glass. Through one of the outlets, water is passed into the flask for cooling. Between the edge of the glass and the bottom of the flask, a rubber tube, cut along the length, is inserted for sealing. The flask is fixed over the beaker with tripod clamps. The installation diagram is given in Appendix 2.
The sample is kept in boiling acid for 6 hours.
After that, the sample is removed from the beaker, rinsed in distilled water and placed in an oven at a temperature of (150 ± 2) °C and dried for 45 minutes, then cooled in a desiccator to a temperature of (20 ± 5) °C and weighed with an error of not more than ± 0.1 mg.
The tests are repeated on the second pair of samples - the test and control.
3.2.4. Acid resistance of glass () - sample mass loss - is calculated by the formula
where is the difference between the masses of the test and control samples before testing, mg;
- difference between the masses of the test and control samples after the test, mg;
is the total surface area of the specimen, see
From two experiments, the arithmetic mean value and deviations from the mean value are determined. The results are calculated to the third decimal place. The discrepancy between the results in each experiment from the average value should not be more than ±10%.
3.2.5. The acid resistance class, depending on the weight loss of the sample, should be set in accordance with that indicated in Table 4.
Table 4*
_______________
* Table 3. (Deleted, Rev. N 2).
Acid resistance class | Weight loss, mg/cm |
Up to 0.007 incl. |
|
St. 0.007 to 0.015 inclusive |
|
3.2.6. The results of the acid resistance test are recorded in a protocol containing:
- sample designation;
- arithmetic mean of weight loss, mg cm;
- designation of acid resistance class;
- name of the laboratory that carried out the test;
- date of testing;
- designation of this standard.
(Introduced additionally, Rev. N 2).
3.3. Alkali resistance is determined according to GOST 10134.3.
(Changed edition, Rev. N 2).
3.3.1-3.3.5. (Excluded, Rev. N 2).
3.4. Method for determining the thermal resistance of glass to the maximum temperature difference without breaking
Heat resistance is determined by measuring the temperature difference at which the destruction of a heated glass sample occurs when it is rapidly cooled in water.
3.4.1. To determine the heat resistance, the following equipment is used:
- a vertical tubular electric furnace with a heating temperature of samples up to 250 °C with an accuracy of maintaining the set temperature of ±1 °C for 15 minutes;
- a metal, glass or porcelain vessel for cooling samples with a capacity of 1 dm3;
- tongs.
3.4.2. For testing, samples in the form of glass rods (rods) with a length of (30 ± 5) mm and a diameter of (4 ± 0.1) mm should be selected.
Samples must be free of cracks, stones and other defects. The ends of the specimens must be melted. Fused specimens must be annealed. The specific difference in the path of the rays should not be more than 0.4 million.
(Changed edition, Rev. N 2).
3.4.3. For testing, the samples are placed in an electric furnace, heated to a temperature equal to the lower limit of the thermal resistance of the tested glass, specified in the regulatory and technical documentation, and kept at this temperature for 15 minutes.
After that, the samples are taken out of the furnace, immersed in a vessel with water, the temperature of which should be from 15 to 20 ° C, and then removed from the water.
Samples with cracks of any size are taken from the tested samples and are not used in further tests.
The remaining intact samples are reloaded into the furnace. The temperature in the furnace is increased by 10 °C and heating is repeated, followed by cooling in water.
Heating and subsequent cooling is carried out until all samples are destroyed.
The heat resistance tests are repeated on two batches of specimens with the same date of manufacture of the glass.
3.4.4. Thermal resistance of glass, °С, is calculated by the formula
where , , ..., is the heat resistance of the sample, °C;.
________________
* APPENDICES 1, 3. (Excluded, Rev. N 2).
1 - flask;
2 - glass;
3 - sample basket
APPENDIX 4 (informative). INFORMATION DATA ON COMPLIANCE WITH GOST 21400-75 ST SEV 1569-79
APPENDIX 4
Reference
Clause 3.1 of GOST 21400-75 corresponds to ST SEV 1569-79.
APPENDIX 4. (Introduced additionally, Rev. N 2).
The text of the document is verified by:
official publication
Glassware and laboratory equipment.
Specifications. Test methods: Sat. GOSTs. -
M.: IPK Standards Publishing House, 2003
