1. PURPOSE
1.1 This fabrication and erection specification defines the minimum requirements for two different methods of determining the pH value for mineral wool.
2. scope
2.1 This specification applies to mineral wool in metal ducts and cold boxes for service temperatures between -254° to +315°C (-425° to +600°F).
3. related documents
3.1 Air Products Engineering Documents 4WCB-50002 Mineral Wool for Cold Box Insulation
4. DEFINITIONS
4.1 Random sample: A sample taken without bias, so that every item has an equal chance of inclusion. For the purpose of this document, a random sample consists of one portion of the mineral wool extracted from the center of one shipping package or from the production line immediately preceding the packaging operation. Care must be taken to ensure that the sample includes a proportional amount of shot and any other particles that separate while extracting the sample.
4.2 Representative samples: A sample resulting from planned action taken to ensure that specified portions of its contents are drawn from different subportions. For the purpose of this document, a representative sample shall mean a quantity of mineral wool composed of a minimum of three random samples. The total quantity shall be thoroughly mixed.
4.3 Specimen: A suitably-sized portion of a representative sample.
5. APPLICATION
5.1 A supplier who has previously supplied mineral wool in accordance with this specification and who can also furnish a test certificate indicating compliance with the requirements of this specification shall be considered as having met the necessary requirements if both requirements are met: The mineral wool previously provided has met the specification in full The constituent materials met the requirements of 4WCB-50002.
5.2 A supplier who has not previously supplied mineral wool to this specification and 4WCB-50002 shall proceed with the pH determination as outlined in Section 7.
6. TESTING APPARATUS
6.1 Four 200-milliliter Pyrex glass beakers Two glass funnels Two glass stirrers A balance capable of weighing 5 grams of specimen A thermometer capable of measuring 100°C Deionized or distilled water Whatman No. 41 filter papers Controlled heating means A timer A mortar and pestle Representative samples pH measurements may be taken with either of the following equipment options:
6.2 Orbeco-Hellige (No. 605-AHT) Pocket Comparator manufactured by ORBECO ANALYTICAL SYSTEMS, INC., 185 Marine St., Farmingdale, NY 11735 Tel: (516) 293-4110. Color disk number 190-D supplied with the Pocket Comparator. Thymol Blue Indicator supplied with the Pocket Comparator.
6.3 pH/ion measuring equipment (Beckman Zeromatic or equal). Small quantity of reagent grade Potassium Chloride (KCl).
7. PROCEDURE
7.1 Acid wash four 200 milliliter Pyrex glass beakers, two glass funnels, and two glass stirrers with a 5% nitric acid solution.
7.2 Thoroughly rinse the glass beakers, funnels, and stirrers with deionized water.
7.3 Separately grind five specimens of 5 grams each from coarse to fine, using a mortar and pestle or other mechanical means.
7.4 Combine the specimens and mix.
7.5 To an acid-washed beaker, add 5 grams of the specimen obtained in Step 7.4.
7.6 Heat the deionized or distilled water to boiling [generally 100°C (215°F)].
7.7 Add 100 milliliters of the 100°C (212°F) water to the beakers in Step 7.5.
7.8 Stir the contents of the beaker for 10 minutes and allow to cool to room temperature.
7.9 Pour the contents of the beaker through a Whatman No. 41 filter and funnel into an acid-washed Pyrex glass beaker.
7.10 Measure the pH value of the specimen in Step 7.9 using either of the methods specified in Section 8.
8. MEASUREMENTS
8.1 pH Measurements Using the Pocket Comparator
8.1.1 Record the temperature before measurement of samples.
8.1.2 Add 5 milliliters (ml) of the solution prepared in Step 7.9 to a clean, dry, No. 6000-T13 precision tube included with the Pocket Comparator (the tube is graduated to 5 ml).
8.1.3 Add ½ ml of the Orbeco-Hellige Indicator Solution (Thymol Blue) to the precision tube in Step 8.1.2 and mix.
8.1.4 Fill a second precision tube with 5 ml of solution prepared in Step 7.9.
8.1.5 Place the precision tube with the blank solution in the left holder of the comparator and the precision tube with the indicator in the right holder of the comparator (with the comparator held in the viewing direction).
8.1.6 With a viewing distance of about 245 mm (10 in) and the eye at the center of the lens, rotate the color wheel until a match is determined. Indirect lighting shall be used in the path of the prism.
8.1.7 Record the pH that is in the upper right hand corner.
8.2 pH Measurements Using an Electrode and Ion Meter
8.2.1 Add approximately 1 gram of potassium chloride (KCl) to the contents of the beaker prepared in Step 7.9 and mix. The action of the potassium chloride is to avoid any measuring problems when the leached fluid is measured against a standard buffer fluid.
8.2.2 Measure the pH value by submersion of the pH electrode and read the associated indicator.
8.2.3 Record the measured pH value.
8.2.4 Repeat the procedure (Steps 7.5 through 7.10) using 5 grams of the specimen already ground in Step 7.3.