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Improving ASTM D445, the Manual Viscosity Test, by Video Recording
Article in Journal of Testing and Evaluation · January 2019
DOI: 10.1520/JTE20170341
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Journal of Testing and Evaluation
doi:10.1520/JTE20170341
/
Vol. 47
/
No. 1
/
2019
/
available online at www.astm.org
Hung Khuu,1 Nay Yee,1 Albert Butterfield,1 Mark Meiser,1 Tao Wei,1 Alexander Gutsol,2
and Michael Moir1
Improving ASTM D445, the Manual
Viscosity Test, by Video Recording
Reference
Khuu, H., Yee, N., Butterfield, A., Meiser, M., Wei, T., Gutsol, A., and Moir, M., “Improving ASTM
D445, the Manual Viscosity Test, by Video Recording,” Journal of Testing and Evaluation, Vol. 47,
No. 1, 2019, pp. 310–323, https://doi.org/10.1520/JTE20170341. ISSN 0090-3973
ABSTRACT
Manuscript received June 14, 2017;
accepted for publication
November 20, 2017; published
online June 21, 2018.
1
2
Chevron Energy Technology
Company, 100 Chevron Way,
Richmond, CA 94801, USA
Chevron Energy Technology
Company, 100 Chevron Way,
Richmond, CA 94801, USA
Corresponding author, e-mail:
alexander.gutsol@gmail.com,
https://orcid.org/0000-00020458-4774
Video recording of the manual version of the ASTM D445, Standard Test Method
for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of
Dynamic Viscosity), effectively automated this method, resolved ergonomic
concerns, reduced chemical exposure of an operator, drastically reduced probability
of errors of the operator, significantly improved productivity, and simplified the
analyst training process and work turnover. The accuracy of results is acceptable
from the standpoint of the ASTM D445 method.
Keywords
video registration, manual viscosity test, ASTM D445, automation
Introduction
ASTM D445, Standard Test Method for Kinematic Viscosity of Transparent and Opaque
Liquids (and Calculation of Dynamic Viscosity) [1], was approved for the first time in 1937
and is still one of the most frequently used methods for liquid petroleum products and
crude oil. There are many methods and standards for viscosity measurements (see the list
of the methods in an appendix of the book in Ref. [2]). Under the jurisdiction of ASTM
Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and in the direct
responsibility of Subcommittee D02.07 on Flow Properties, there are two other methods,
ASTM D7042, Standard Test Method for Dynamic Viscosity and Density of Liquids by
Stabinger Viscometer (and the Calculation of Kinematic Viscosity) [3], and ASTM
D7945, Standard Test Method for Determination of Dynamic Viscosity and Derived
Copyright © 2018 by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959
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KHUU ET AL. ON IMPROVING D445 BY VIDEO RECORDING
Kinematic Viscosity of Liquids by Constant Pressure Viscometer [4], that have about the
same accuracy and are applicable to the same petroleum products with Newtonian viscosity. Nevertheless, so far, these methods have not reached as wide a penetration in the oil
industry as ASTM D445. This might be related to the industry inertia as well as to some
range limitations in viscosity (≈30,000 mm2/s for ASTM D7042 [5] and 1,000 mm2/s for
ASTM D7945 [4] versus 100,000 mm2/s for ASTM D445) and temperature (135°C for
ASTM D7042 [5] and 120°C for ASTM D7945 [4] versus 200°C for ASTM D445).
Another important limitation of ASTM D7042 and ASTM D7945 is that the equipment
they use measures dynamic viscosity together with density for the calculation of kinematic
viscosity. Measurement of density is realized using a very precise method based on the
oscillation of a U-shaped tube filled with a specimen. This equipment is rather complex
and needs to be serviced by specially trained technicians in contrast with rather simple and
robust equipment for the manual version of ASTM D445. Equipment complexity becomes
especially important when specimens are very viscous or difficult to wash out using conventional solvents, so-called difficult-to-run specimens. For example, our experience with
ASTM D7042 revealed significant disadvantages of this method in comparison with
ASTM D445 when working with viscous specimens. Thus, when putting the viscous specimen into a syringe, it is necessary to heat the specimen before transferring it into the
preheated syringe without any bubbles, and the injection of the specimen into a cell with
such a small opening caused pain in the operators’ hands after the injections. Also, cleaning parts after a test takes much effort and time.
Under the jurisdiction of Subcommittee D02.07, there are two other active standard
methods, D7483, Standard Test Method for Determination of Dynamic Viscosity and
Derived Kinematic Viscosity of Liquids by Oscillating Piston Viscometer [6], and
D7279, Standard Test Method for Kinematic Viscosity of Transparent and Opaque
Liquids by Automated Houillon Viscometer [7]; however, they have significantly lower
accuracy and applicability ranges.
Different automatic and automated viscometers were developed for ASTM D445 that
provide higher productivity and have better determinability: 0.15 % at 40°C and 0.20 %
at 100°C [8] versus 0.37 % at 40°C and 0.36 % at 100°C for the manual version of the
method [9]. Per ASTM D445, determinability is “the difference between successive determined values obtained by the same operator in the same laboratory using the same apparatus for a series of operations leading to a single result, would in the long run, in the
normal and correct operation of this test method, exceed the values indicated only in one
case in twenty” [1]. Despite the availability of automated viscometers, there is still a need
for a manual version of this method. Examples that prove a reason for such a necessity can
be found in paragraph 10.2.3 of ASTM D445: “Viscometers used for silicone fluids, fluorocarbons, and other liquids which are difficult to remove by the use of a cleaning agent,
shall be reserved for the exclusive use of those fluids except during their calibration.”
Another reason for limited applicability of the automated method is related to the nature
of the automation. Most of the available automated viscometers have sensors (e.g., thermistors) for flow time determination that are embedded in the volume marks of the viscosity
tubes. Therefore, the viscosity tubes are permanently fixed in the temperature bath. This
normally causes the automated instrument to have a limited viscosity measurement range,
and thus it is not appropriate to measure difficult-to-run specimens since the viscosity tube
cannot be removed easily from the bath for cleaning.
In different laboratories, this necessity can be caused by other reasons; for example, a
small number of tests of a particular type don’t justify the purchase of an automated
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viscometer. For example, in our kinematic viscosity lab, in addition to four automated viscometers, we use seven baths for manual viscometers. These baths cover a temperature range
from −40°C to 190°C. Note that, according to the “Precision and Bias” section of ASTM
D445, “Results from Manual and Automated Instruments in Test Method D445 may be
considered to be practically equivalent” [1]. The only substantial requirement that is stricter
for the manual version of the test is that the flow time for manual viscometers shall not be
less than 200 s, while flow times of less than 200 s are permitted for automated viscometers.
The absence of the significant accuracy advantage of automatic and automated viscometers
in comparison with the manual ones can be explained by the following two factors: (1) The
tolerance bands of the certified viscosity reference standards are rather large (from ±0.30 to
±0.73 %, see Table 1 in ASTM D445 [1]). These bands combine both the uncertainties of the
certified viscosity reference standards as well as the uncertainties of the laboratories using the
certified viscosity reference standards [1]. (2) An extremely important factor in repeatability
and reproducibility of the method is temperature control [10], which is based on the same
liquid bath technology in both versions of the method. Other factors that have an influence
on accuracy that is mostly reflected in the uncertainties just mentioned are specimen handling, viscometer cleanliness, loading procedure, and mounting alignment.
Thus, the manual version of ASTM D445 is still widely used and will continue to be
used in the foreseeable future.
The manual version of ASTM D445 is a well-established method that should not
cause any significant problems. However, this is not the case. Results of the D445 Grand
Design Inter-Laboratory Study (ILS) that took place in 2005–2009 forced subcommittee
D02.07A to form a special Task Group TG7A.27 “Investigation of Manual Viscometer
Imprecision in D445.” The precision estimate for manual viscometers that was calculated
from the ILS [9] was found to be worse than the previously published precision and
much worse than many of the premier ISO 17025–accredited laboratories claim is possible. For example, in the last version of ASTM D445 published in 2014 [11] that used the
old precision data, the repeatability (r) and reproducibility (R) were given as
r = 0.11 % and R = 0.65 % for base oils at 40°C and 100°C, respectively. Later, starting
in 2015 when the Grand Design ILS data were incorporated into a new ASTM D445
standard, for base oils at 40°C, r = 1.01 % and R = 1.36 %; and for base oils at
100°C, r = 0.85 % and R = 1.90 %. The Task Group identified many factors that contributed to the imprecision, and one key factor was formulated as follows: “Loss of experience by technicians due to most labs now using automation version of D445
primarily and manual one only for backup. Also, older technicians who were really
skilled running manual viscometers have retired, and the younger ones haven’t been
properly trained” (Personal communication, P. Maggi) in addition to precision concerns
that are important to customers, a manual version of ASTM D445 raises other issues and
TABLE 1
Approximate tolerance bands.
Viscosity of Reference Material, mm2/s
Tolerance Band
<10
±0.30 %
10 to 100
±0.32 %
100 to 1,000
±0.36 %
1,000 to 10,000
±0.42 %
10,000 to 100,000
±0.54 %
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FIG. 1
Typical position of an operator
during the manual ASTM D445
test run.
challenges that are important to laboratories and operators. Thus, Fig. 1 demonstrates
some of these issues. It is rather difficult to make working spaces free of ergonomic problems. Timing marks on the capillary tube should be at eye level (black line in Fig. 1, consider the lines to be in the plane of the tubes) while the total height of the system (white
line) should be convenient for specimen loading. In our case, the loading level is at a height
of 147 cm, which is too high for some operators. To have an easily accessible stopwatch
(usually a system of stopwatches for multiple simultaneous tests, as in Fig. 1), an additional
level is necessary. Eyestrain will be an issue in any case because it is necessary to catch a
precise moment in the motion of a small object. It is also very difficult to keep a neutral,
unstrained posture during this operation. As the operator’s eyes (and, thus, head) should
be in the ultimate vicinity to the test tube, it is almost impossible to eliminate exposure to
chemical vapors (level of loading, white line in Fig. 1), or ventilation wind (ventilation
snorkel is marked by white arrow in Fig. 1), or both.
In addition to ergonomic issues, an operator faces other challenges, for example,
filling a precise volume of the specimen into a viscometer tube (e.g., Zeitfuchs
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cross-arm viscometer, CANNON Instrument Company, State College, PA [12]) may
require several additions and removals of tested liquid. To increase productivity, an
operator very often works with several test tubes simultaneously, or even performs other
tests in parallel. This multitasking significantly increases the probability of a mistake, and if
a mistake is made, the reason is not always obvious. The traditional manual version of
ASTM D445 does not create any records for data incident review, and this makes the
process of new operator training rather difficult.
We use the manual version of the method in our laboratory for specimens that
cannot be tested by the available automated viscometers because of their very high viscosity or required odd temperature measurements. Because of the high viscosity of some
specimens that we test manually, the test time together with the time for preparation and
test tube cleaning can be rather long and can easily reach one hour. In such conditions,
the cost of any potential operator mistake becomes very high as the whole hour of work
can be lost. Also, there is one potential mistake that is difficult to avoid completely:
precise timing. According to ASTM D445, the operator should “measure, in seconds
to within 0.1 s, the time required for the meniscus to pass from the first to the second
timing mark” [1]. There is also a second measurement requirement in ASTM D445, and
the difference between the two measurements should be within the stated determinability for reporting the result. It is necessary to understand that 0.1 s is probably the best
repeatability that can be reached by any human who is using a stopwatch for an event
that is very well determined in time. The exact position of the meniscus in motion is not
an easily determined event, especially if the liquid is transparent (Fig. 2). Two consecutive measurements can have random errors of the same sign, thus the difference between
the two measurements will be within the stated determinability, and the result will be
reported even if it is rather far from the correct value.
To avoid potential systematic mistakes that are caused by invisible capillar contamination, we always use two viscometer tubes for the manual procedure as is allowed in
ASTM D445: “Two determinations of the kinematic viscosity of the test material are
required. For those viscometers that require a complete cleaning after each flow time
measurement, two viscometers may be used” [1]. However, this precaution does not
remove the possibility of having two random timing errors of the same sign.
Another very costly and common mistake is to hit the wrong button on the stopwatch
system array (see Fig. 1). Such a mistake ruins two tests simultaneously.
In this article, we present a technical approach that can be used to partially automate
the test and thus resolve almost all ergonomic issues, reduce the number of mistakes, and
improve the productivity of an analyst. For automation, we used a rather obvious approach
that has been applied at sporting events for many years—a “photo finish.” In our version,
we recorded the whole test. This approach allows high-precision measurement of the test
time (e.g., 1/30 s for 30 frames per second (fps) video), and sometimes also allowed us to
determine the reason why two consecutive measurements give significantly different results. For example, sometimes the video recording allows us to find that there are particles
or bubbles in a liquid that prevent correct measurements.
Technical Solutions in Automation
Though the photo finish approach sounds like a rather simple one, there were several
technical issues to resolve, which are reported in this section.
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KHUU ET AL. ON IMPROVING D445 BY VIDEO RECORDING
FIG. 2
Images showing the meniscus
of transparent liquid before and
after the first mark.
CAMERA
At first glance, it would seem that any reliable camera with video-recording capabilities
or a camcorder could serve our purpose. This is not completely true. In recent years,
there has been very rapid progression in the development of digital video recording devices, so the choice of acceptable and relatively inexpensive cameras is much better than
it was several years ago when we performed this automation project. First, a camera or
camcorder? We considered several requirements: (a) high sensitivity because lighting for
the test tubes cannot be very strong so as to preserve temperature stability and avoid
temperature gradients; (b) high-quality optics are required to ensure high resolution,
which is necessary to fix precisely the event when the meniscus passes a timing mark
while recording several tests simultaneously; (c) per ASTM D445 requirements, a test
time should be between 200 and 1,000 s, and several tests with long times can be started
at different times, so a recording time limit that is longer than 1,000 s is preferable; (d)
limited application, i.e., the same focus during the whole recording and an absence of
ergonomic issues for the cameraman because of the stationary position of the recording
device, which removes the need for a large zoom; and (e) reasonable cost: good Digital
Single-Lens Reflex (DSLR) cameras were (and still are) significantly cheaper than camcorders with comparable quality optics and sensors. Considering all these factors, we
selected a Nikon D8000 camera, which was one of the best compact DSLRs at the time.
It provided Full HD (High Density, 1,920 × 1,080 pixels) capabilities with a potential
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FIG. 3
Camera fixed on clamp support
in use for the ASTM D445 test
video registration.
recording time of up to 20 minutes (4 GB). Per National Television System Committee
(NTFC) standard, the recording rate is 29.97 fps, which should provide time registration
accuracy of about 0.03 s. A special, easily removed clamp support was designed and
manufactured to fix the camera to a test bench in a stationary and safe position
(Fig. 3) and to save floor space in comparison with standard tripods. The clamp also
allowed for the removal of the camera when it is not in use.
LIGHT
As it was mentioned earlier, intense lighting can disturb temperature stability and create
temperature gradients. As a reminder, per ASTM D445, the temperature should be maintained within ±0.02°C, which is a requirement that is very difficult to obey for bath manufacturers [10]. Fortunately, LED lights were available when we performed this
automation. Use of LED is illustrated in Fig. 3. We used a Humanscale Element 790 lamp
(Humanscale Ergonomics, Cary, NC) that has the following important features: 360° of
adjustability; the same light equivalency as that from a 90 W incandescent bulb all while
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using less than 7 W of power; a seven-level dimmer; neutral light with a color temperature
of 3,500 K.
PC HARDWARE AND SOFTWARE
First, video records require significant PC memory for storage (hard drive) and operational
memory (RAM) for processing. We used the practice of keeping video records of an ASTM
D445 test for 6 months in case customers come back to us with questions. For video handling, we selected an Adobe Premiere software package (Adobe Systems, San Jose, CA) to
edit our recordings. However, our experience shows that editing is not necessary. Without
editing, we can still use some of the convenient features of the software; for example,
zooming in on important frames, looking through the whole video frame by frame,
etc. Very important is the ability to replay a part or the whole video as many times as
necessary because it prevents unnecessary retesting of a specimen or, vice versa, it shows
the necessity for retesting (e.g., when we review the video and see a bubble in the tested
liquid).
Together with the ASTM D445 method automation, we also automated data input to
a system that reports results to customers. Using the same computer where the video is
processed (Fig. 4), the data input software (Fig. 5) helps gather all necessary information
about the tests. Fig. 5 presents part of an Excel spreadsheet (Microsoft Corporation,
Albuquerque, NM) where “green fields” contain information about the required test conditions and “white fields” require operator input before and after the test.
When the tests are done, an operator uploads the video to the PC and opens it in the
video processing software (Fig. 6). Then, the operator can easily find frames (start and
end, Fig. 7) where the events of meniscus passing the first and the second timing marks are
recorded. The operator inputs these frame numbers into the table (Fig. 5). The frame
number is displayed in orange in Fig. 6. The software calculates time and viscosity (using
the tube constant), the report results are delivered to the customer, and all relevant test
data (e.g., tube ID) is sent to storage. The total time required for an operator to transfer the
video recordings from the camera to the PC, then to find all start and end frames and put
the data into a software table is about 10 minutes.
Different operators, if they were not trained in the same way, may have different
methods for determining the frame when a meniscus passes the timing mark, yet the important advantage of this automation approach becomes obvious: it is very easy to train a
new operator using multiple video records. Also, it is possible to discuss any trainee
questions after the test because a record of the whole test is available.
FIG. 4 Example of video registration of eight tests simultaneously.
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FIG. 5 Data input software table.
FIG. 6 Analysis of the test record using video processing software. The frame number is displayed in orange in the lower left part of
the right window.
FIG. 7
The frames selected as the start
and end frame of a test.
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TIME VERIFICATION
Per the NTSC standard, the video recording rate is 29.97 fps that corresponds to a time
interval of 0.033374 s per frame. Per ASTM D445, a timing device should be capable of
taking readings with a discrimination of 0.1 s or better and has an accuracy within ±0.07 %.
To verify that a camera video recording satisfies these requirements, we did five tests using
a site with official U.S. time [13]. Fig. 8 demonstrates an example of a record for such a
test. Note that we select the frames where the new second digit appeared clearly for the first
time. This allowed time verification with high accuracy. Average time per frame calculated
using these tests is 0.033365 ± 0.000019 s. Thus the accuracy is within ±0.06 %.
VISCOSITY MEASUREMENTS VERIFICATION
As a final test of the automated system, we measured viscosities of the available Certified
Viscosity Reference Standards during several months using different standards and
different batches of the same standards. In parallel to video recording, we used conventional manual (“click”) time registration for a fair comparison. Results are presented in
Fig. 9 as differences in percentage between the measured viscosity and that from the
sample certificate of analysis.
FIG. 8
An example of the time
accuracy verification test that
shows time interval between
frames #2 and #10012.
FIG. 9 Differences between the data for viscosity standards and our measurements.
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Per ASTM D445 recommendations, we used Table 1 to determine the approximate
tolerance bands for the reference materials we used.
ASTM D445 requires that when the determined kinematic viscosity did not agree
with the acceptable tolerance band of the certified value (e.g., an experimental point
for the standard with a certified viscosity of 33.47 mm2/s that has a difference of
+0.33 %), it was necessary to recheck each step in the procedure to locate the source
of error. However, it was not possible to recheck timing in the case of the manual measurement. Thus, when all other potential sources of errors were eliminated, we simply
repeated the test.
Note that, for some standards, all experimental points are on one side of the X-axis,
e.g., for the standard with a certified viscosity of 310.4 mm2. We did not investigate the
reason for such “oriented” differences because this kind of investigation is not required by
the ASTM D445 method. As we understand, the reason why it is not required lies in wellbalanced requirements and uncertainties in viscosity measurements and characterization
of viscosity standards. Standards are characterized and certified using the same methods all
laboratories use. Therefore, for example, in ASTM Cooperative Kinematic Viscosity
Measuring Program tests, a corrected value of a sample is accepted as the average value
derived from all measurements. As described in the Introduction, the tolerance bands of
the certified viscosity reference standards are rather large for multiple reasons, most of
which are listed in the Introduction. Only improving the time measurement cannot significantly improve the method accuracy, and the goal of our automation project was not
accuracy improvement.
It is possible to see that the differences between the video-recorded results and the
viscosity standard’s data are within the tolerance bands in all cases. Thus, the accuracy of
measurements using video recording is acceptable from the standpoint of the ASTM D445
method.
Method Benefits and Limitations
Video recording of the manual version of ASTM D445 allowed us to resolve ergonomic
concerns for our operators. It is reasonable to estimate an average time per test itself of
10 minutes (600 s) and average simultaneous load per bath of four tubes. Also, it takes
about 2 minutes per load before the last of the four specimens reaches the first timing
mark. Thus, an operator spends about 3 minutes per test in a rather awkward pose
(see Fig. 1). The time for loading and tube cleaning is about 10 minutes per test. This
means that the operator who runs a manual ASTM D445 test is spending about one quarter of the total working time in a strained position. Keep in mind, however, that some tests
can be as long as 1,000 s, so the operator can be in this position continuously for almost
20 minutes. Video recording resolved this issue completely.
From the numbers above, we estimate that exposure to chemical vapors was reduced
by about 25 % when video recording is used.
With the conventional manual method, we estimated that about 10 % of the tests
needed to be rerun because the difference between the two measurements was larger than
the specified determinability that was due to timing errors. With video recording, this
percentage is virtually zero. Just this factor alone provides a 10 % time savings. More significant time savings arise from the substitution of observing time with video analysis. As
we mentioned earlier, the analysis requires about 10 minutes per load. As estimated earlier,
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observation time was about 12 minutes plus time for uploading the results. All together it
takes at least 15 minutes. Thus, automation provides at least a 30 % time savings. Also,
from a time management perspective, it is not necessary to perform a record analysis just
after the test. This yields much more flexibility for the operator, who can then run other
tests simultaneously or take a break. It also enables work turnover: one operator can start a
test while another operator can finish it.
We have a rather long history of participation in ASTM Cooperative Kinematic
Viscosity Measuring Program, and, starting from 2014, we use video registration for
manual tests. Fig. 10 provides information on the difference between our results and
the mean value for all participating laboratories. The number of participating laboratories
varied with time, and in 2017, this number was 24. Not all laboratories participated in
testing of all materials at all requested temperatures. In recent years, we tried to participate
in all possible tests.
The presented results are not differentiated by substance, only by method (manual or
automated) and temperature. It is possible to see that with an automated method, the
relative differences between our results and the mean values are always within a rather
narrow range. The situation with the manual method is worse, and it is significantly worse
than with measurements of viscosity standards (Fig. 9). One of the reasons for this difference can be larger uncertainty for uncertified samples in comparison with certified viscosity standards. In general, the situation agrees with the conclusion of the Task Group
TG7A.27 (personal communication, P. Maggi), which is that there are systemic problems
with the manual version of ASTM D445. On the other hand, we can compare our results
and the mean values before and after we started to used video registration. It is possible to
see that during the last four years we had only one rather big difference of −1.00 % that is
FIG. 10 Results of our participation in ASTM Cooperative Kinematic Viscosity Measuring Program.
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still considered acceptable now when acceptable reproducibility R = 1.36 %. During the
previous four years, in 2010–2013, we had three big differences of about 1 % in absolute
value, and one difference of −1.75 %, which is outside the acceptable reproducibility. We
cannot conclude that we have statistical evidence of higher accuracy using the manual
method with video registration because much more data need to be produced by different
labs; however, we obviously have encouraging progress.
Though we are happy with the automation we did, and we have used it for several
years already, this automation has some limitations. The first one being the inability to
record tests in several baths simultaneously using a single camera. Secondly, the recording
time is limited for the camera we use (20 minutes = 1,200 s), which is comparable to the
longest possible time of a test (1,000 s); therefore, we need to be efficient when we are
setting several long tests for simultaneous recording.
Note that in many other ASTM standard tests developed long ago, it was necessary to
“catch” an event (which was not always obvious). Such standard tests can benefit from the
addition of affordable video recording, at least from the standpoint of new operator training and odd result investigations. For example, the flash point for some liquids is difficult
to distinguish from the appearance of a blue halo or an enlarged flame [14]. Smoke point
determination [15] by manual testing requires a significantly experienced operator, and it
would be much easier done with the test video record.
Conclusion
We developed a video recording process for the manual version of ASTM D445 and
started to use it in 2013. This approach effectively automated the test, resolved ergonomic
concerns, reduced chemical exposure of operators, significantly improved productivity,
and simplified analyst training and work turnover. The accuracy of the results is acceptable
from the standpoint of the ASTM D445 method. With good cameras that have videorecording capabilities (though not necessarily a DSLR) becoming much more affordable,
along with bright LED light sources, this approach can be attractive to many labs that use
the manual version of ASTM D445. Since the probability of an uncorrectable operator
mistake becomes negligible with this simple automation, the method improvement is especially beneficial for the labs that use two similar viscometer tubes to produce duplicate
results. In addition to obtaining the viscosity measurement, the method allows for verification of the condition of both tubes.
References
[1] ASTM D445-17a, Standard Test Method for Kinematic Viscosity of Transparent and
Opaque Liquids (and Calculation of Dynamic Viscosity), ASTM International, West
Conshohocken, PA, 2017, www.astm.org
[2] Gupta, S. V., Viscometry for Liquids, Springer International Publishing, New York,
2014, 256p.
[3] ASTM D7042-16, Standard Test Method for Dynamic Viscosity and Density of Liquids
by Stabinger Viscometer (and the Calculation of Kinematic Viscosity) (Superseded),
ASTM International, West Conshohocken, PA, 2016, www.astm.org
[4] ASTM D7945-16, Standard Test Method for Determination of Dynamic Viscosity and
Derived Kinematic Viscosity of Liquids by Constant Pressure Viscometer, ASTM
International, West Conshohocken, PA, 2016, www.astm.org
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KHUU ET AL. ON IMPROVING D445 BY VIDEO RECORDING
[5] “Stabinger Viscometer,” Anton Paar, 2018, https://web.archive.org/web/2017
1027044000/https://www.viscopedia.com/methods/instrument-categories/stabingerviscometertm/ (accessed 27 Oct. 2017).
[6] ASTM D7483-13a, Standard Test Method for Determination of Dynamic Viscosity
and Derived Kinematic Viscosity of Liquids by Oscillating Piston Viscometer,
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[7] ASTM D7279-16, Standard Test Method for Kinematic Viscosity of Transparent and
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Conshohocken, PA, 2016, www.astm.org
[8] Interlaboratory Study to Determine Suitability of ASTM D445 for Automated and
Automatic Instruments Used to Measure Viscosity of Base Oils and Formulated
Oils, Research Report D02-1787, ASTM International, West Conshohocken, PA,
2014, 162p.
[9] Interlaboratory Study to Determine Precision of ASTM D445-11a Manual Method
when Used to Measure Viscosity of Base Oils and Formulated Oils, Research
Report D02-1788, ASTM International, West Conshohocken, PA, 2014, 40p.
[10] Lane, J. L. and Henderson, K. O., “Viscosity Measurement: So Easy, Yet So Difficult,”
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International, West Conshohocken, PA, 2014, www.astm.org
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Capillary Kinematic Viscometers, ASTM International, West Conshohocken, PA,
2017, www.astm.org
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time.gov/widget/widget.html (accessed 31 Oct. 2017).
[14] ASTM D92-16b, Standard Test Method for Flash and Fire Points by Cleveland Open
Cup Tester, ASTM International, West Conshohocken, PA, 2016, www.astm.org
[15] ASTM D1322-15e1, Standard Test Method for Smoke Point of Kerosine and Aviation
Turbine Fuel (Superseded), ASTM International, West Conshohocken, PA, 2015,
www.astm.org
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