ASTM D5482 Standard Test Method for Vapor Pressure of Petroleum Products (Mini Method - Atmospheric)
6. Apparatus
6.1 Vapor Pressure Apparatus - The type of apparatus suitable for use in this test method employs a small volume test chamber incorporating a transducer for pressure measurements and associated equipment for thermostatically controlling the chamber temperature.
6.1.1 The test chamber shall be designed to contain between 2 and 50 mL of liquid and vapor and be capable of maintaining a vapor-liquid ratio between 3.95 and 1.00 and 4.05 and 1.00.
6.1.2 The pressure transducer shall have a minimum operational range from 0 to 172 kPa (0 to 25.0 psi) with a minimum resolution of 0.1 kPa (0.01 psi) and a minimum accuracy of +/- 0.3 kPa (+/- 0.05 psi). The pressure measurement system shall include associated electronics and readout devices to display the resulting pressure reading.
6.1.3 A thermostatically controlled heater shall be used to maintain the test chamber at 37.8 +/- 0.1°C (100 +/- 0.2°F) for the duration of the test.
6.1.4 A platinum resistance thermometer shall be used for measuring the temperature of the test chamber. The minimum temperature range of the measuring device shall be from ambient to 75°C (167°F) with a resolution of 0.1°C (0.2°F) and accuracy of 0.1°C (0.2°F).
6.1.5 The vapor pressure apparatus shall have provisions for introduction of the test specimen into the test chamber and for the cleaning or purging of the chamber following the test.
6.2 Syringe, if required, gas tight, 1 to 20 mL capacity with a +/- 1 %, or better, accuracy and a +/- 1 %, or better, precision. The capacity of the syringe shall not exceed two times the volume of the test specimen being dispensed, and shall be chosen so as to provide maximum accuracy and resolution for the volume to be injected.
6.3 Iced-Water Bath or Air Bath, for chilling the samples and syringe to temperatures between 0 and 1°C (32 and 34°F).
6.4 Pressure Measuring Device, capable of measuring ambient and above ambient pressures with an accuracy of 0.20 kPa (0.03 psi) or better at the same elevation relative to sea level as the apparatus in the laboratory.
6.4.1 When a mercury manometer is not used as the pressure measuring device, the calibration of the pressure measuring device employed shall be periodically checked (with traceability to a nationally recognized standard) to ensure that the device remains within the required accuracy specified in 6.4.
6.5 Pressure Source, clean, dry compressed gas or other suitable compressed air capable of providing pressure for calibration of the transducer and cleaning of the cell.
NOTE 2 - A vacuum source is an alternate means for cleaning of the cell.
7. Reagents and Materials
7.1 Purity of Reagents - Use chemicals of at least 99 % purity for quality control checks (see Section 11). Unless otherwise indicated, it is intended that all reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such specifications are available. Lower purities can be used, provided it is first ascertained that the reagent is of sufficient purity to permit its use without lessening the accuracy of the determination.
7.2 Cyclohexane, (Warning - Cyclohexane is flammable and a health hazard).
7.3 Cyclopentane, (Warning - Cyclopentane is flammable and a health hazard).
7.4 2,2-Dimethylbutane, (Warning - 2,2-dimethylbutane is flammable and a health hazard).
7.5 2,3-Dimethylbutane, (Warning - 2,3-dimethylbutane is flammable and a health hazard).
7.6 2-Methylpentane, (Warning - 2-methylpentane is flammable and a health hazard).
7.7 Toluene, (Warning - Toluene is flammable and a health hazard).
