ASTM D1122 for density or relative density of engine coolant concentrates
ASTM D1122 standard test method for density or relative density of engine coolant concentrates and engine coolants by the hydrometer
7. Procedure
7.1 If the coolant has a small amount of separated upper layer, remove it before determining the relative density of the lower layer. To separate, pour the sample into a 500-mL separatory funnel, allow to stand for 3 h at room temperature but not below 20°C (68°F), and then draw off the lower layer.
7.2 If the original coolant is homogeneous, no separation will be required.
7.3 Cool the homogeneous sample or the separated lower layer sample to about 14°C (57°F). Pour the sample into the clean, dry hydrometer cylinder without splashing, so as to reduce to a minimum the formation of air bubbles (see Note 1). Place the cylinder vertically in the water bath and let the temperature of the sample reach 15.0 +/- 0.3°C (59 +/- 0.5°F). Slowly and carefully lower the hydrometer into the sample to a level two smallest scale divisions below that at which it will float and then release the hydrometer. When the hydrometer has come to rest and floats freely away from the walls of the cylinder and the temperature has reached 15.5 +/- 0.3°C (60 +/- 0.5°F), read the hydrometer.
NOTE 1 - When handling the sample (that is, mixing, transferring, or stirring) be careful to avoid formation of air bubbles. Remove any air bubbles by touching them with a clean, dry glass rod.
7.4 The hydrometer is read in the following ways: If the sample is sufficiently transparent, place the eye slightly below the level of the liquid and slowly raise it until the surface of the sample changes from a distorted ellipse to a straight line cutting the hydrometer scale. If the sample is opaque, read the point on the hydrometer scale to which the sample rises above the main surface of the liquid with the eye placed slightly above the plane of the surface of the sample. Correct this reading by an amount equal to the height to which the sample rises on the hydrometer stem above the main liquid surface. This height will vary for different coolants and different hydrometers, and the correction will depend upon the width of the hydrometer scale graduations. Determine the correction factor for the hydrometer used by observing the height above the main surface of the liquid to which the coolant rises on the hydrometer scale when the hydrometer is immersed in a transparent liquid, such as an ethylene or propylene glycol solution, having a surface tension similar to that of the sample under test.
