ASTM D5800 method for evaporation loss of lubricating oils by the Noack method
Procedure C Selby-Noack Volatility Test
25. Apparatus
25.1 Selby-Noack Instrument, (see Fig. 13) including glassware and other parts as follows:
25.1.1 Reaction Flask Bottom, capable of heating a sample quickly to test temperatures of 250°C.

25.1.2 Reaction Flask Top.

25.1.3 Coalescing Filter.

25.1.4 Pump Filter.

25.1.5 Orifice Tube.

25.1.6 Orifice Cap, of a set of incremental sizes.

25.1.7 Thermocouple Sheath.

25.1.8 Magnetic Stir Bar.

25.1.9 Thermocouple.

25.1.10 Measuring Rod, of known length.

25.1.11 Viton O-rings.

25.1.12 Coalescing Filter Cartridges.

25.1.13 Pump Filter Cartridges.

25.2 Balance, capable of weighing at least 300 g to the nearest 0.01 g.

25.3 Beaker, 600 mL.

25.4 Cork Ring, capable of supporting collection flask during weighing.

25.5 Digital Timer.

25.6 Tapered Glass Adapter.

26. Reagents and Materials
26.1 Cleaning Solvent, such as VarCleen, capable of removing varnish from glassware

26.2 Hydrocarbon Solvent, such as hexane.

26.3 Average Volatility Reference Oil.

26.4 High Volatility Reference Oil.

26.5 Pump Oil, suitable for vacuum pump installed in instrument.

27. Preparation of Apparatus
27.1 Locate the instrument on a laboratory bench if possible (rather than a hood) to minimize atmospheric pressure fluctuation. Vent the vacuum pump outlet provided on the back of the instrument with a metal or plastic tube leading to a suitable exhaust outlet. Whether the instrument is placed on the bench or in a hood, make sure the instrument's built-in door (which serves as both draft control and safety shield) is firmly closed and latched for all calibrations and tests as illustrated in Fig. 13.

27.2 Set the height of the outlet of the orifice tube 11.4 cm above the inside bottom of the reaction flask.

27.2.1 Measure the length of the measuring rod and the length of the orifice tube (without the cap) in centimetres.

27.2.2 Add the measured length of the orifice tube without the orifice cap to 11.4 cm.

27.2.3 Use the value obtained in 27.2.2 to set the length of the measuring rod by affixing the collar at that height. This will give the desired value from the lower tip of the measuring rod up to the bottom of the collar.

27.2.4 Turn the tapered plastic piece on the orifice tube toward the top of threaded section and be sure the orifice cap is removed.

27.2.5 Temporarily assemble the top and bottom pieces of the reactor and put the orifice tube in position.

27.2.6 Insert the measuring rod through the orifice tube. When the lower end of the rod is in contact with the reactor bottom, the lower surface of the collar should be above the upper end of the orifice tube.

27.2.7 Adjust the tapered plastic piece on the orifice down to achieve very light contact between the upper end of the orifice tube and the lower surface of the collar on the measuring rod to establish the proper position.

27.3 Insert the two thermocouple connectors into the thermocouple receptacles on the cabinet.

27.4 Insert the heater cable into the heater connection on the cabinet.

27.5 Be sure that the inside of the reactor bottom is clean (see 30.5) and that the other glassware, hardware, and tubing are free of any oil residue.

27.6 If collection of the volatilized oil is desired, clean the coalescing filter housing with a hydrocarbon solvent, dry, and install new filter cartridge.

27.7 Turn on the main power switch located on the front panel.

27.8 Before operating the instrument close the shield door.

28. Calibration
28.1 Calibrate the thermocouple at 100°C or higher against a certified thermometer or other standard temperature measuring device and, if necessary, adjust the calibration offset on the temperature controller according to the manufacturer's instructions.

28.2 Preheat reaction flask bottom by placing the clean flask (with magnetic stirrer inside) on the reaction flask platform. Place the thermocouple inside the flask and be sure that the tip is firmly touching the inside wall. Set the temperature controller for 100°C and turn on the heater switch. When the temperature reaches 100°C, start the timer for 5 min.

28.3 After the 5 min has expired, turn off the heater switch and wait for the flask to cool below 50°C. After cooling, check the dry weight of the reaction flask bottom against the weight of previous weighings.

NOTE 14 - The sequential weighings should be reasonably constant (that is, within more or less 0.02 g) although the weight will decrease in a regular way over days and months of use. Any sudden increase in weight or erratic fluctuation is an indication that the outside insulating coating of the bottom reaction flask has been contaminated and the flask should be repeatedly baked according to 28.2 until constant weight is reestablished.

28.4 Weigh the flask with the stirring bar and record the value to the nearest 0.01 g.

28.5 Pour 65 g more or less 0.02 g of reference oil into the reaction flask. Record the mass of the oil to the nearest 0.01 g.

28.6 Insert the appropriate orifice cap size into orifice tube making certain there is a good seal. Insert the orifice tube (with the orifice cap) into the center glass tapered joint on the reaction flask top and make certain it has seated properly.

28.7 Insert the thermocouple sheath, without the thermocouple, into the thermocouple connection on the reaction flask top with the bend facing away from the glass sidearm.

28.8 Join the reaction flask top and bottom and insert the assembly into the flask clip provided.

28.9 Raise the stirrer platform to stabilize the reaction flask bottom.

28.10 If collection of volatiles is desired, weigh the clean coalescing filter assembly including the filter cartridge and record the results to the nearest 0.01 g.

28.11 Mount to bracket with the arrow pointing in the direction of air flow (toward the vacuum pump).

28.12 Connect the inlet coalescer tubing to the barbed end of the tapered glass adapter (which will be later connected to the reaction flask top sidearm).

28.13 Connect the tubing to the input side of the coalescing filter and connect the tapered glass adapter to the reaction flask top sidearm and secure with a glass joint clamp.

28.14 Connect the vacuum hose from the pump filter (above the coalescing filter) to the output connection on the coalescing filter.

28.15 Connect the hose from the pressure sensor to the barbed connection on the reaction flask top next to the sidearm. After connections are made, check that the reaction flask top is horizontal with the reaction flask bottom and that the O-ring seal between them is in proper position.

28.16 Slide the thermocouple into the thermocouple sheath in such a manner that the plastic tubing seals the joint between the thermocouple and the thermocouple sheath. This will ensure no leaks.

28.17 Make certain that the thermocouple contacts the wall. This can be viewed by looking down through the top of the reaction flask top. It is important that the thermocouple touches the inside wall of the reaction flask at least 0.5 in below the surface of the oil for proper results.

28.18 With the vacuum control Open/Close switch set to the middle or Flow position, turn on the Vacuum On/Off switch on the upper console.

28.19 Press down the Gauge Factor/Flow/Set Pt. switch and, using the Set Point dial, adjust the vacuum to 2.00 cm (20 mm) of water on the meter readout. When at a reading of 2.00, release the Gauge Factor/Flow/Set Pt. switch.

28.20 Press one flnger tightly over the hole in the orifice cap and toggle the vacuum control Open/Close switch to the closed position. The vacuum reading should increase to a stable value (this must be below 19.00 cm of water). Once stabilized and with finger still in place, turn the vacuum pump off and monitor the vacuum to observe how well it maintains the vacuum. Remove finger from the orifice cap and again monitor the vacuum; it should quickly decrease to a zero reading.

28.21 If there is a leak, recheck all of the glass fittings, the orifice tube and the thermocouple sheath for proper seating. Repeat step 28.20. If there is no leak then continue to 28.22.

NOTE 15 - High temperature vacuum grease may be used to seal leaks, if necessary. Vacuum grease should not be used on components that are weighed during the test procedure.

28.22 With the vacuum switch already on and controlling at 2.00 cm of water, turn on the stirrer. Visually verify the stirring.

28.23 Set the temperature controller to 250°C and turn on the heater switch. An automatic timer will activate when the heater switch is turned on. The timer will turn off the heater, vacuum, and stirring motor after 1 h.

28.24 Allow the unit to cool down to a temperature safe for handling (approximately 20 min). Gloves may be used to handle while hot.

28.25 Weigh the volatilized oil (if desired).

28.25.1 Remove the tubing from the coalescing filter assembly and remove the assembly from the bracket.

28.25.2 Weigh the entire coalescing filter assembly and record the results to the nearest 0.01 g. Subtract previous dry assembly weight from 28.10 to obtain the weight of volatilized oil.

28.25.3 Save the volatilized oil, if desired, by draining out through the petcock in the bottom of the coalescing filter housing.

28.26 Remove the pressure sensor tube and the thermocouple, and then remove the reaction flask top. The orifice tube and thermocouple sheath may be left in position during cleaning and reassembly. (If any oil is clinging to the sheath tip, touch it to the side wall of the reactor bottom to return it to the reaction flask.)

28.27 Weigh and record the reaction flask bottom plus remaining residual oil to the nearest 0.01 g and either discard or save the residual oil for further analysis.

28.28 Clean all glassware and hardware as described in 30.1-30.7.

28.29 Calculate the percent volatility loss of the reference fluid to the nearest 0.1 % (see Section 31).

28.30 Compare the result to the given value of the reference fluid. If results are within limits, proceed to the Sample Procedure.

28.31 If the result is not within the limits of the reference fluid check that the procedure has been followed and that the apparatus is set up properly with no leaks. Check the calibration of the temperature controller and pressure sensing device.

NOTE 16 - Procedures for calibration of the temperature controller and pressure controller can be found in the Operations Manual for the Selby-Noack Volatility test.

28.32 If no errors in setup or procedure are identified, proceed to changing the size of the orifice cap. The size should be changed in increments of 0.001, with each change corresponding to a directly related change of 0.3 % evaporation loss. The orifice chosen should be of the smallest size giving accurate results. Rerun the test on the reference fluid after making any changes.

NOTE 17 - If using new glassware, or approximate orifice size is unknown, begin with an 0.084 orifice and increase until good results are achieved.

28.33 If problems persist, contact the instrument manufacturer.

29. Sample Procedure
29.1 Perform steps 28.4-28.28 substituting a test sample for the reference fluid.

29.2 Calculate the percent evaporation loss of the test sample to the nearest 0.1 %.

29.3 Collect the volatilized oil (if desired for further analysis) from the coalescing filter by placing a small container under the filter petcock and opening it to release the oil.

NOTE 18 - It is recommended that a reference fluid be tested to confirm calibration at the beginning of each series of sample tests and at the beginning of every other day of continuous testing. If testing is not conducted on a daily basis, test the reference fluid at the beginning of each test day. If the percent evaporation loss of the reference fluid is not within limits, check the instrument for operating precision or re-calibrate before samples are tested, or both.

30. Cleaning
30.1 Clean all of the glassware and hardware, with the exception of the reaction flask bottom, with a suitable hydrocarbon solvent (for example, hexane, heptane, cyclo-hexane).

30.2 If the coalescing filter is to be used for collecting volatilized oil, it can be cleaned while disassembled. Unscrew the collection cup, remove the filter cartridge, and clean with a suitable hydrocarbon solvent (for example, hexane, heptane, cyclo-hexane). Upon reassembly, the filter cartridge can be replaced with a new, clean cartridge. The filter can also be removed from the bracket, if necessary, for cleaning.

30.3 In order to prevent oil from coming into contact with the outside of the reaction flask bottom, wrap the outside lip of the reaction flask bottom with clean toweling and quickly pour out the contents into a beaker in order to catch the stirrer bar. While still holding the flask upside down remove the towel, wipe the lip dry, and then carefully rinse the inside of the flask with a hydrocarbon solvent. When the unit is clean, wipe it dry with another towel.

NOTE 19 - If the insulating covering of the reaction flask bottom becomes contaminated, follow the directions in Note 14.

30.4 If oil is spilled on the outside insulation of the reaction flask bottom, immediately rinse the oil off with a suitable hydrocarbon solvent. Exercise care not to spread the oil to other areas of the insulation. When all oil has been removed, dry the reaction flask bottom with an air source. The flask should be allowed to completely; dry at room temperature before continuing with the test procedure.

30.5 Place 10 mL of a varnish removing solvent into the reaction flask bottom. Insert clean paper towel into the solvent and wipe inside of flask thoroughly, removing any varnish that may be present on the wall. Rinse carefully with hot water and dry.

30.6 If other glass parts develop a varnish film, clean these with the same procedure as indicated in 30.5 or put the parts into a half/half water or full-strength solution of varnish remover overnight.

30.7 With a towel dampened with varnish removing solvent, clean the end of the thermocouple. Wipe with towel dampened with hot water and dry to remove any remaining cleaning solvent.

31. Calculation
31.1 Percent volatility is determined by mass loss found by subtracting the combined weight of the flask bottom and oil after testing (see 28.27) from their combined weight before the test (see 28.4 and 28.5).

NOTE 20 - The percent volatility is obtained by taking the mass loss of the reaction flask and dividing that by the exact mass of the test oil sample recorded earlier: that is if weight of the oil sample is 65.1 g and weight of the oil lost is 10.2 g, then (10.2 g/65.1 g) x 100 = 15.67 %.

31.2 The mass of volatiles collected is obtained by subtracting the coalescing filter assembly weight before the test (see 28.10) from its weight at the end of the test (see 28.26).

NOTE 21 - The percent of volatiles collected is obtained by dividing the mass of volatiles collected by the mass loss: that is, If the weight of the empty coalescing filter assembly is 163.2 g and the weight of the filter assembly after volatilization gained 9.8 g, and if the weight loss shown by 31.1 is 10.2 g, then (9.8 g/10.2 g) x 100 = 96.08 % of the volatiles were collected.

32. Report
32.1 Report the evaporation loss to the nearest 0.1 %.

32.2 Limited amount of data available shows that Procedures A and C give similar results for formulated engine oils. However, no comparative data is available for the basestocks. Further work is necessary to quantitate the relationship.

33. Precision
NOTE 22 - The equipment listed in the research report, was used to develop this precision statement. This is not an endorsement or certification by ASTM International.

33.1 The interlaboratory study included six test oils tested on eight apparatus with eight different operators. The samples measured in the study were engine oils covering the range of 11.84 % loss to 20.18 % loss.

33.2 Repeatability - The difference between successive results obtained by the same operator with the same apparatus under constant operating conditions on identical test materials would, in the long run, in the normal and correct operation of the test method, exceed the following value in only one case in twenty:
Repeatability, % evaporation loss = 0.81

33.3 Reproducibility - The difference between two single and independent results obtained by different operators working in different laboratories on identical test materials would, in the long run, in the normal and correct operation of the test method, exceed the following value in only one case in twenty:
Reproducibility, % evaporation loss = 1.62