Handbook of Asbestos Textiles - Third Edition
Tentative Method of Test for Asbestos content of Asbestos Textile Materials:
This Tentative Method has been approved by the sponsoring committee and accepted by the Society in accordance with established procedures, for use pending adoption as standard. Suggestions for revisions should be addressed to the Society at 1916 Race St., Philadelphia 3, PA.
1. (a) This method covers a procedure for determining the asbestos content of untreated chrysotile asbestos textile materials which are usually blends of asbestos and organic fibers. This method is applicable to treated asbestos textile materials only if the treatment can be completely removed, prior to testing, by appropriate methods, such as boiling in water or solvent extraction.
(b) This test is limited to those asbestos textile materials where asbestos is the only inorganic fiber present, such as continuous filament glass yarns used as reinforcement, can be removed prior to testing.
(c) If carbonates are present in the asbestos they shall be determined separately, and a corresponding correction shall be made to the loss on ignition before the asbestos content is calculated.
Summary of Method
2. (a) If carbonates are not present, a 5-g sample, dried to constant weight, is heated to 800 to 810 C (1470 to 1490 F) for 1hr and the loss in weight is determined. The weight of the ignited sample divided by 0.86 is the weight of the asbestos fiber originally present in the sample. This weight divided by the original sample weight is the asbestos content calculated as a percentage.
(c) If carbonates are present in the asbestos, the weight of the carbon dioxide (CO2) is determined by the Knorr alkalimeter. The asbestos content is determined as described in Paraghraph (a), but the grams of the CO2 from a 1-g sample as determined in Section 9 must be subtracted from the factor 0.86 in calculating the results.
Definitions
3. (a) Standard Atmosphere for Testing Asbestos Textiles, n. - Air maintained at a relative humidity of 50 2 percent and at a temperature of 70 2F (21 1.1 C).
(b) For definitions of other terms used in this method, see Definition of Terms.
Significance
4. The asbestos content of asbestos textile materials is of major significance, as this determines the grade of the textile which in turn indicates the approximate serviceability temperature for such materials.
Apparatus
5. (a) Knorr Alkalimeter, as described in the Appendix and shown in Figs. 1 and 2 for determining carbonates.
(b) Oven, capable of being held at a temperature between 800 to 810 C (1407 to 1490 F).
Test Specimens
6. The number of test specimens shall be as specified in the applicable ASTM specification for the material being tested. If the asbestos textile material has been reinforced with continuous filament glass yarns, the insertion shall be removed before making the determination.
Conditioning
7. Bring all the test specimens to moisture equilibrium for testing in the standard atmosphere for testing asbestos textiles.
Procedure for Preliminary Test for Carbonates in Asbestos
8. (a) Determine if heat decomposable carbonates are present in the asbestos by running the qualitative test described in Paragraph (b).
(b) Place an approximately 0.5-g sample in a test tube (a 30 by 150-mm size is convenient) and wet well with 10ml of distilled water by stirring and tamping with a glass rod, so that no air bubbles are visible in the wet sample. Add 5 ml of concentrated hydrochloric acid (HCl, sp gr 1.19) and again stir and tamp gently with a glass rod, taking care not to introduce any air bubbles. Warm slightly. The formation of gas bubbles on the surface of the submerged asbestos sample is a positive indication that carbonates are present, in which case the amount of CO2 liberated by the carbonates must be determined by the method given in Section 9. If carbonates are not present, follow the procedure described in Section 10.
Procedure for CO2 Liberated by Carbonates in Asbestos
9. (a) Check the Knorr alkalimeter (Fig. 1) to ensure freedom from leaks. Aspirate a current of air through the system at the rate of about two bubbles per minute for a period of 10 min. Stop the air current and remove the absorption tubes. Place the absorption tube G in the balance case and allow it to stand for several minutes. When ready for weighing, open the stopcocks momentarily and close. Weigh and repeat the above procedure. The second weight should agree with the first to within 0.0005g. If it does not, repeat this process until the two successive weighings agree. When a constant weight is reached, replace the absorption tube in the gas train.
(b) Transfer about 1 g of the sample, weighed to the nearest 0.001 g, to the distillation flask. Wash down any adhering particles on the inside neck of the flask with distilled water. Add enough distilled water to the flask so that when the apparatus is reconnected the tip of the dropping funnel will be submerged about 5 to 10 mm. Place 50 ml of HCi (1:1) in the dropping funnel and replace the guard gas-absorption tube at the top of the funnel. Start the flow of water in the condenser and open all the stopcocks, except the one on the dropping funnel. Turn on the aspirator fir medium suction. Adjust the stopcock on the dropping funnel so that the suction will draw the acid slowly into the flask. When all the acid is in the flask, fully open the funnel stopcock and pull air through the system at the rate of two or three bubbles per second. After the reaction in the flask has subsided, heat the contents gently to boiling. When steam starts to condense in the condenser, turn off the heat. Continue to draw air through the apparatus for 30 min. Reweigh the absorption tube G as before. The gain in the weight represents the CO2 in the sample. Record as C1.
(c) Calculate the weight of CO2 as follows:
C2 = C1S
where:
C2 = grams of CO2 from the 1-g sample,
C1 = grams gain in weight of the absorption tube G, and
S = grams of sample used.
(d) Repeat the procedure on another 1-g portion of the sample and calculate the average value of C2. The weight of the absorption tube G after the first determination may be used as the starting point for the second determination without repeating the initial process of obtaining constant weight.
Tentative Method of Test for Asbestos content of Asbestos Textile Materials:
This Tentative Method has been approved by the sponsoring committee and accepted by the Society in accordance with established procedures, for use pending adoption as standard. Suggestions for revisions should be addressed to the Society at 1916 Race St., Philadelphia 3, PA.
1. (a) This method covers a procedure for determining the asbestos content of untreated chrysotile asbestos textile materials which are usually blends of asbestos and organic fibers. This method is applicable to treated asbestos textile materials only if the treatment can be completely removed, prior to testing, by appropriate methods, such as boiling in water or solvent extraction.
(b) This test is limited to those asbestos textile materials where asbestos is the only inorganic fiber present, such as continuous filament glass yarns used as reinforcement, can be removed prior to testing.
(c) If carbonates are present in the asbestos they shall be determined separately, and a corresponding correction shall be made to the loss on ignition before the asbestos content is calculated.
Summary of Method
2. (a) If carbonates are not present, a 5-g sample, dried to constant weight, is heated to 800 to 810 C (1470 to 1490 F) for 1hr and the loss in weight is determined. The weight of the ignited sample divided by 0.86 is the weight of the asbestos fiber originally present in the sample. This weight divided by the original sample weight is the asbestos content calculated as a percentage.
(c) If carbonates are present in the asbestos, the weight of the carbon dioxide (CO2) is determined by the Knorr alkalimeter. The asbestos content is determined as described in Paraghraph (a), but the grams of the CO2 from a 1-g sample as determined in Section 9 must be subtracted from the factor 0.86 in calculating the results.
Definitions
3. (a) Standard Atmosphere for Testing Asbestos Textiles, n. - Air maintained at a relative humidity of 50 2 percent and at a temperature of 70 2F (21 1.1 C).
(b) For definitions of other terms used in this method, see Definition of Terms.
Significance
4. The asbestos content of asbestos textile materials is of major significance, as this determines the grade of the textile which in turn indicates the approximate serviceability temperature for such materials.
Apparatus
5. (a) Knorr Alkalimeter, as described in the Appendix and shown in Figs. 1 and 2 for determining carbonates.
(b) Oven, capable of being held at a temperature between 800 to 810 C (1407 to 1490 F).
Test Specimens
6. The number of test specimens shall be as specified in the applicable ASTM specification for the material being tested. If the asbestos textile material has been reinforced with continuous filament glass yarns, the insertion shall be removed before making the determination.
Conditioning
7. Bring all the test specimens to moisture equilibrium for testing in the standard atmosphere for testing asbestos textiles.
Procedure for Preliminary Test for Carbonates in Asbestos
8. (a) Determine if heat decomposable carbonates are present in the asbestos by running the qualitative test described in Paragraph (b).
(b) Place an approximately 0.5-g sample in a test tube (a 30 by 150-mm size is convenient) and wet well with 10ml of distilled water by stirring and tamping with a glass rod, so that no air bubbles are visible in the wet sample. Add 5 ml of concentrated hydrochloric acid (HCl, sp gr 1.19) and again stir and tamp gently with a glass rod, taking care not to introduce any air bubbles. Warm slightly. The formation of gas bubbles on the surface of the submerged asbestos sample is a positive indication that carbonates are present, in which case the amount of CO2 liberated by the carbonates must be determined by the method given in Section 9. If carbonates are not present, follow the procedure described in Section 10.
Procedure for CO2 Liberated by Carbonates in Asbestos
9. (a) Check the Knorr alkalimeter (Fig. 1) to ensure freedom from leaks. Aspirate a current of air through the system at the rate of about two bubbles per minute for a period of 10 min. Stop the air current and remove the absorption tubes. Place the absorption tube G in the balance case and allow it to stand for several minutes. When ready for weighing, open the stopcocks momentarily and close. Weigh and repeat the above procedure. The second weight should agree with the first to within 0.0005g. If it does not, repeat this process until the two successive weighings agree. When a constant weight is reached, replace the absorption tube in the gas train.
(b) Transfer about 1 g of the sample, weighed to the nearest 0.001 g, to the distillation flask. Wash down any adhering particles on the inside neck of the flask with distilled water. Add enough distilled water to the flask so that when the apparatus is reconnected the tip of the dropping funnel will be submerged about 5 to 10 mm. Place 50 ml of HCi (1:1) in the dropping funnel and replace the guard gas-absorption tube at the top of the funnel. Start the flow of water in the condenser and open all the stopcocks, except the one on the dropping funnel. Turn on the aspirator fir medium suction. Adjust the stopcock on the dropping funnel so that the suction will draw the acid slowly into the flask. When all the acid is in the flask, fully open the funnel stopcock and pull air through the system at the rate of two or three bubbles per second. After the reaction in the flask has subsided, heat the contents gently to boiling. When steam starts to condense in the condenser, turn off the heat. Continue to draw air through the apparatus for 30 min. Reweigh the absorption tube G as before. The gain in the weight represents the CO2 in the sample. Record as C1.
(c) Calculate the weight of CO2 as follows:
C2 = C1S
where:
C2 = grams of CO2 from the 1-g sample,
C1 = grams gain in weight of the absorption tube G, and
S = grams of sample used.
(d) Repeat the procedure on another 1-g portion of the sample and calculate the average value of C2. The weight of the absorption tube G after the first determination may be used as the starting point for the second determination without repeating the initial process of obtaining constant weight.
