ASTM D3948-22

Standard Test Method for Determining Water Separation Characteristics of Aviation Turbine Fuels by Portable Separometer

SIGNIFICANCE AND USE
5.1 This test method provides a measure of the presence of surfactants in aviation turbine fuels. Like previous obsolete Test Methods D2550 and D3602, and current Test Methods D7224 and D8073, this test method can detect carryover traces of refinery treating residues in fuel as produced. They can also detect surface active substances added to or picked up by the fuel during handling from point of production to point of use. Certain additives can also have an adverse effect on the rating. Some of these substances affect the ability of filter separators to separate free water from the fuel.  
5.2 The Micro-Separometer has a measurement range from 50 to 100. Values obtained outside of those limits are undefined and invalid. In the event a value greater than 100 is obtained, there is a good probability that light transmittance was reduced by material contained in the fuel used to set the 100 reference level. The material was subsequently removed during the coalescing portion of the test, thus, the processed fuel had a higher light transmittance than the fuel sample used to obtain the 100 reference level resulting in the final rating measuring in excess of 100.  
5.3 Test Mode A function of the separometer will give approximately the same rating for Jet A, Jet A-1, MIL JP-5, MIL JP-7, and MIL JP-8 fuels as Test Methods D2550 and D3602. Using Mode A water separation characteristic ratings of Jet B and MIL JP-4 fuels will not necessarily be equivalent to Test Method D2550 but will give approximately the same rating as Test Method D3602. All Micro-Separometers have Test Mode A capability.  
5.4 The Test Mode B option is used to determine water separation ratings for MIL JP-4 fuels containing fuel system corrosion and icing inhibitors. These ratings are approximately the same as those obtained using Test Method D2550.  
5.5 Selection of Mode A or Mode B depends on the specific fuel and specification requirement. Table 1 identifies the recommended test method for various ...
SCOPE
1.1 This test method covers a rapid portable means for field and laboratory use to rate the ability of aviation turbine fuels to release entrained or emulsified water when passed through fiberglass coalescing material.  
1.2 The procedure section of this test method contains two different modes of test equipment operation. The primary difference between the modes of operation is the rate of fuel flow through the fiberglass coalescing material. Test method selection is dependent on the particular fuel to be tested.  
1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Sep-2022
• ICS: 75.160.20 - Liquid fuels
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.J0.05 - Fuel Cleanliness

Relations

• Refers: ASTM D1655-24 - Standard Specification for Aviation Turbine Fuels
• Effective Date: 15-Mar-2024
• Refers: ASTM D4175-23a - Standard Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 15-Dec-2023
• Refers: ASTM D1655-23a - Standard Specification for Aviation Turbine Fuels
• Effective Date: 01-Oct-2023
• Refers: ASTM D4175-23e1 - Standard Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 01-Jul-2023
• Refers: ASTM D1655-18 - Standard Specification for Aviation Turbine Fuels
• Effective Date: 01-Jan-2018
• Refers: ASTM D1655-17a - Standard Specification for Aviation Turbine Fuels
• Effective Date: 01-Dec-2017
• Refers: ASTM D1655-16c - Standard Specification for Aviation Turbine Fuels
• Effective Date: 01-Dec-2016
• Refers: ASTM D1655-16b - Standard Specification for Aviation Turbine Fuels
• Effective Date: 01-Sep-2016
• Refers: ASTM D1655-16 - Standard Specification for Aviation Turbine Fuels
• Effective Date: 01-Jun-2016
• Refers: ASTM D1655-15d - Standard Specification for Aviation Turbine Fuels
• Effective Date: 01-Oct-2015
• Refers: ASTM D4306-15 - Standard Practice for Aviation Fuel Sample Containers for Tests Affected by Trace Contamination
• Effective Date: 01-Oct-2015
• Refers: ASTM D6615-15a - Standard Specification for Jet B Wide-Cut Aviation Turbine Fuel
• Effective Date: 01-Sep-2015
• Refers: ASTM D1655-15b - Standard Specification for Aviation Turbine Fuels
• Effective Date: 15-Jul-2015
• Refers: ASTM D6615-15 - Standard Specification for Jet B Wide-Cut Aviation Turbine Fuel
• Effective Date: 01-Jul-2015
• Refers: ASTM D1655-15 - Standard Specification for Aviation Turbine Fuels
• Effective Date: 01-Jan-2015

Overview

ASTM D3948-22 is the Standard Test Method for Determining Water Separation Characteristics of Aviation Turbine Fuels by Portable Separometer. Developed by ASTM International, this standard outlines a rapid, reliable method for measuring the ability of aviation turbine fuel to shed entrained or emulsified water using a field-portable separometer device. This test is crucial for ensuring aviation fuel cleanliness and safety, directly impacting filter-separator performance and aircraft system reliability. The method serves both laboratory and field settings for routine quality assurance and supports compliance with fuel specifications for commercial and military aviation.

Key Topics

• Water Separation Testing: Evaluates the fuel’s ability to separate from water, an essential property for minimizing the risk of water carryover in aircraft fuel systems.
• Detection of Surfactants: Assesses the presence of surface active agents (surfactants), refinery residues, or additives that can impair the performance of filter-separators.
• Portable Separometer: Utilizes a standardized, portable instrument that delivers a quick, numerical rating (Micro-Separometer or MSEP rating) on a standardized 0-100 scale.
• Test Modes (A and B): Offers two modes to accommodate different aviation fuel types and additive packages; Mode A for most common jet fuels (e.g., Jet A, Jet A-1), and Mode B primarily for JP-4 fuels containing icing inhibitors.
• Field and Laboratory Use: Designed for rapid application in both laboratory quality control and on-site field testing, aiding fuel management and operational decision-making.

Applications

The practical value of ASTM D3948-22 is wide-ranging in the aviation industry:

• Fuel Quality Assurance: Ensures that aviation turbine fuels meet water separability requirements at each stage from production to point-of-use, preventing operational delays or safety hazards.
• Filter Separator Protection: Identifies fuel contamination that could deactivate filter separators, thereby minimizing operational risks and maintenance issues in aircraft fueling systems.
• Surfactant and Additive Monitoring: Detects surface active materials from both refinery processes and fuel handling operations, helping fuel managers comply with specification limits.
• Military and Commercial Aviation: Applies to a variety of jet fuels, including Jet A, Jet A-1, Jet B, MIL JP-4, JP-5, JP-7, and JP-8, ensuring both commercial fleets and defense operations use high quality, safe fuel.
• Compliance and Troubleshooting: Helps fuel suppliers, airports, and operators comply with international standards and investigate fuel system contamination problems efficiently.

Related Standards

ASTM D3948-22 is part of a family of ASTM standards and specifications related to aviation fuel quality:

• ASTM D1655 – Specification for Aviation Turbine Fuels
• ASTM D7224 – Test Method for Determining Water Separation Characteristics of Kerosine-Type Aviation Turbine Fuels Containing Additives
• ASTM D8073 – Test Method for Water Separation Characteristics by Small Scale Water Separation Instrument
• ASTM D4306 – Practice for Aviation Fuel Sample Containers for Tests Affected by Trace Contamination
• ASTM D6615 – Specification for Jet B Wide-Cut Aviation Turbine Fuel
• ASTM D7261 – Test Method for Water Separation Characteristics of Diesel Fuels by Portable Separometer
• Withdrawn Predecessors: Test Methods D2550 and D3602

Additionally, military specifications such as MIL-DTL-5624 (JP-4, JP-5), MIL-DTL-38219 (JP-7), and MIL-DTL-83133 (JP-8) reference or rely on water separation performance testing as defined by ASTM D3948.

Summary

Adopting ASTM D3948-22 helps stakeholders in the aviation fuel supply chain uphold rigorous safety and reliability standards. Its field-portable, quantitative assessment of water separation properties supports both regulatory compliance and operational excellence in aviation fuel management. Integrating this standard into quality control protocols enables early detection of contaminants, protects critical filter-separator systems, and ensures aircraft receive fuel that meets or exceeds industry and military standards. For comprehensive fuel quality assurance, ASTM D3948-22 is an essential tool in aviation fueling operations worldwide.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D3948 − 22
Standard Test Method for
Determining Water Separation Characteristics of Aviation
Turbine Fuels by Portable Separometer
This standard is issued under the fixed designation D3948; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* of Aviation Turbine Fuels (Withdrawn 1989)
D3602 Test Method for Water Separation Characteristics of
1.1 This test method covers a rapid portable means for field
Aviation Turbine Fuels (Withdrawn 1994)
and laboratory use to rate the ability of aviation turbine fuels to
D4175 Terminology Relating to Petroleum Products, Liquid
release entrained or emulsified water when passed through
Fuels, and Lubricants
fiberglass coalescing material.
D4306 Practice for Aviation Fuel Sample Containers for
1.2 The procedure section of this test method contains two
Tests Affected by Trace Contamination
different modes of test equipment operation. The primary
D6615 Specification for Jet B Wide-Cut Aviation Turbine
difference between the modes of operation is the rate of fuel
Fuel
flow through the fiberglass coalescing material. Test method
D7224 TestMethodforDeterminingWaterSeparationChar-
selection is dependent on the particular fuel to be tested.
acteristics of Kerosine-Type Aviation Turbine Fuels Con-
taining Additives by Portable Separometer
1.3 The values stated in SI units are to be regarded as
D7261 TestMethodforDeterminingWaterSeparationChar-
standard. The values given in parentheses after SI units are
acteristics of Diesel Fuels by Portable Separometer
provided for information only and are not considered standard.
D8073 Test Method for Determination of Water Separation
1.4 This standard does not purport to address all of the
Characteristics of Aviation Turbine Fuel by Small Scale
safety concerns, if any, associated with its use. It is the
Water Separation Instrument
responsibility of the user of this standard to establish appro- 4
2.2 Military Standards:
priate safety, health, and environmental practices and deter-
MIL-DTL-5624 Turbine Fuel, Aviation Grades JP-4 and
mine the applicability of regulatory limitations prior to use.
JP-5
1.5 This international standard was developed in accor-
MIL-DTL-38219 Turbine Fuel, Low Volatility, JP-7
dance with internationally recognized principles on standard-
MIL-DTL-83133 Turbine Fuel, Aviation, Kerosene Types,
ization established in the Decision on Principles for the
JP-8 NATO F-34, NATO F-35, and JP-8+100 NATO F-37
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical 3. Terminology
Barriers to Trade (TBT) Committee.
3.1 Definitions:
3.1.1 For definitions of terms used in this test method that
2. Referenced Documents
arenotshownbelow,refertoTestMethodsD7224,D7261,and
Terminology D4175.
2.1 ASTM Standards:
5 5
3.1.2 Micro-Separometer rating (MSEP rating), n—in the
D1655 Specification for Aviation Turbine Fuels
aviation fuel industry, a numerical value indicating the ease of
D2550 Method of Test for Water Separation Characteristics
separating emulsified water from aviation (jet) fuel by coales-
cence as affected by the presence of surface active materials
(also known as surface active agents or surfactants).
This test method is under the jurisdiction of ASTM Committee D02 on
3.1.2.1 Discussion—MSEP ratings obtained using Test A
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
and Test B are termed MSEP-A and MSEP-B, respectively.
Subcommittee D02.J0.05 on Fuel Cleanliness.
Current edition approved Oct. 1, 2022. Published November 2022. Originally
approved in 1980. Last previous edition approved in 2020 as D3948 – 20. DOI:
10.1520/D3948-22. The last approved version of this historical standard is referenced on
For referenced ASTM standards, visit the ASTM website, www.astm.org, or www.astm.org.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Available online at ASSIST Quick Search, http:/quicksearch.dla.mil.
Standards volume information, refer to the standard’s Document Summary page on ‘MSEP’, ‘DSEP’, and ‘Micro-Separometer’ are trademarks of EMCEE
theASTM website. Electronics, Inc., 520 Cypress Ave., Venice, FL 34285.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3948 − 22
TABLE 1 Applicable Test Mode for Various Fuels
3.1.2.2 Discussion—MSEPratings are only valid within the
range of 50 to 100, with ratings at the upper end of the range Available Test Mode(s)
indicating a clean fuel with little or no contamination by Fuel Applicable Test Mode
surfactants, which is expected to show good water-separating Jet A A
Jet A-1 A
properties when passed through a filter-separator (coalescing-
Jet B A
type filter) in actual service.
MIL JP-5 A
5 MIL JP-7 A
3.1.3 reference fluid, n—in MSEP and DSEP [diesel sepa-
MIL JP-8 A
rability] water separability tests, a reference fluid base to
MIL JP-4 B
which a prescribed quantity of a known surface active agent
has been added.
5.3 Test Mode A function of the separometer will give
3.1.3.1 Discussion—The known surface active agent is typi-
cally bis-2-ethylhexyl sodium sulfosuccinate, commonly re- approximately the same rating for Jet A, Jet A-1, MIL JP-5,
MIL JP-7, and MIL JP-8 fuels as Test Methods D2550 and
ferred to as AOT, dissolved in toluene.
D3602. Using Mode A water separation characteristic ratings
3.1.4 reference fluid base, n—in aviation MSEP water
of Jet B and MIL JP-4 fuels will not necessarily be equivalent
separability tests, jet fuel that has been cleaned in a prescribed
to Test Method D2550 but will give approximately the same
manner to remove all surface-active contaminants (agents).
rating as Test Method D3602. All Micro-Separometers have
3.1.5 surfactant, n—in petroleum fuels, surface active ma-
Test Mode A capability.
terial (or surface active agent) that could disarm (deactivate)
5.4 The Test Mode B option is used to determine water
filter separator (coalescing) elements so that free water is not
separation ratings for MIL JP-4 fuels containing fuel system
removed from the fuel in actual service.
corrosion and icing inhibitors.These ratings are approximately
3.1.5.1 Discussion—Technically, surfactants affect the inter-
the same as those obtained using Test Method D2550.
facial tension between water and fuel which affects the
5.5 Selection of ModeAor Mode B depends on the specific
tendency of water to coalesce into droplets.
fuel and specification requirement. Table 1 identifies the
recommended test method for various fuels.
4. Summary of Test Method
5.6 The basic difference between ModesAand B is the flow
4.1 A water/fuel sample emulsion is created in a syringe
rate at which the water/fuel emulsion is forced through the
using a high-speed mixer. The emulsion is then expelled from
standard fiberglass coalescer cell. The lapsed time required to
the syringe at a programmed rate through a standard fiberglass
force the emulsion through the coalescer cell in ModeAis 45 s
coalescer and the effluent is analyzed for uncoalesced water by
6 2 s, whereas, Mode B requires 25 s 61s.
a light transmission measurement. The results are reported on
a 0-to-100 scale to the nearest whole number. High ratings
6. Apparatus
indicate the water is easily coalesced, implying that the fuel is
6,7
6.1 AMicro-Separometer is used to perform the test. The
relatively free of surfactant materials. A test can be performed
unit is completely portable and self-contained, capable of
in 5 min to 10 min.
operating on an internal rechargeable battery pack or being
connected to an ac power source using power cords which are
5. Significance and Use
available for various voltages. Connection to an ac power
5.1 This test method provides a measure of the presence of
source will provide power to the unit and affect battery
surfactants in aviation turbine fuels. Like previous obsolete
recharge. The accessories as well as the expendable materials
Test Methods D2550 and D3602, and current Test Methods
for six tests can be packed in the cover of the lockable case.
D7224 and D8073, this test method can detect carryover traces
NOTE 1—An extensive study was performed to verify that the Mark X
of refinery treating residues in fuel as produced. They can also
Micro-Separometer gives equivalent results to the Mark V Deluxe
detect surface active substances added to or picked up by the
Micro-Separometer. See Research Report RR:D02-1647.
fuel during handling from point of production to point of use. NOTE 2—The Mark X has a universal power supply and requires only
onepowercordascomparedtotheMarkVDeluxethatrequiresindividual
Certain additives can also have an adverse effect on the rating.
power cords for different voltages.
Some of these substances affect the ability of filter separators
to separate free water from the fuel.
The sole source of supply of the apparatus, the Model 1140 Micro-Separometer
5.2 The Micro-Separometer has a measurement range from
Mark V Deluxe and Mark X, known to the committee at this time is Emcee
50to100.Valuesobtainedoutsideofthoselimitsareundefined
Electronics, Inc., 520 Cypress Ave., Venice, FL 34285, www.emcee-
electronics.com. If you are aware of alternative suppliers, please provide this
and invalid. In the event a value greater than 100 is obtained,
information to ASTM International Headquarters. Your comments will receive
there is a good probability that light transmittance was reduced
careful consideration at a meeting of the responsible technical committee, which
by material contained in the fuel used to set the 100 reference
you may attend.
level. The material was subsequently removed during the
The Model 1140 Micro-Separometers Mark III and Mark V Standard versions
may also be used, but they are no longer supported by the manufacturer. For
coalescing portion of the test, thus, the processed fuel had a
operating procedures using these instruments, the user is referred to D3948–87.
higher light transmittance than the fuel sample used to obtain
Supporting data have been filed at ASTM International Headquarters and may
the100referencelevelresultinginthefinalratingmeasuringin
beobtainedbyrequestingResearchReportRR:D02-1647.ContactASTMCustomer
excess of 100. Service at [e-mail].
D3948 − 22
FIG. 1 Micro-Separometer Mark V Deluxe and Associated Control Panel
6.2 The Micro-Separometer Mark V Deluxe and Mark X nism to travel to the UP position and the emulsifier motor to
and associated control panel are shown in Fig. 1 and Fig. 2, operate for the cleaning operation.
respectively. The emulsifier is on the right side of the raised
6.2.6.3 The START pushbutton, when depressed after the
panel and the syringe drive mechanism is on the left side. The
CLEAN cycle, initiates the automatic program sequence caus-
control panel containing the operating controls is mounted on
ing the read indicator and the twoARROWED pushbuttons to
the fixed panel in the left side of the case. Table 2 lists the
illuminate, indicating that a full-scale adjustment period is in
manual and audio operating characteristics of the instruments.
effect. A numerical value also appears on the meter.
6.2.1 Allofthecontrolsarelocatedinapushbuttonarrayon
6.2.6.4 By depressing the appropriate ARROWED
the control panel. The pushbuttons illuminate when depressed
pushbutton, the displayed value on the meter can be increased
thus indicating operational status. A circuit breaker located on
or decreased, as required, to attain the 100 reference level for
the control panel provides protection for the ac power circuit.
the vial of fuel sample in the turbidimeter.
6.2.2 The Mark X has an LCD display on the control panel
6.2.7 Mark X Operation:
that provides information to the operator during the test. The
6.2.7.1 SelectionofTestModeAorTestModeBprogramis
information includes test status and an error code that defines
accomplished by depressing either the Jet A or Jet B lettered
a malfunction in the Micro-Separometer.
pushbutton. The depressed pushbutton illuminates and the
6.2.3 The turbidimeter is located under the main control
panel and consists of a well in which the sample vial is placed, sequential illumination of the other lettered pushbuttons
ceases. The CLEAN 1 pushbutton also illuminates.
a light source, and a photocell.
6.2.4 By depressing the ON pushbutton, the electronic
6.2.7.2 The first and second clean cycles are initiated by
circuits are energized. The ON pushbutton pulses on and off
depressing the CLEAN 1 and CLEAN 2 pushbuttons. The
when the instruments are being operated by an ac source and
RUN pushbutton will illuminate at the end of the second clean
constantly remains on when the battery (dc) pack is used. The
cycle.
lettered pushbuttons will sequentially illuminate on and off
6.2.7.3 The automatic portion of the test sequence is initi-
indicating READY operational status.
ated by depressing the RUN pushbutton.
NOTE 3—Of the lettered (A-G) pushbuttons on the control panel of the
6.2.7.4 The 100 reference level for the vial of fuel in the
Mark V Deluxe, only the A and B pushbuttons are applicable to this test
turbidimeter is set automatically and does not require any
method. Of the lettered (Jet A – Diesel) pushbuttons on the control panel
adjustment.Iftheturbidimetercouldnotautoadjustto100,the
of the Mark X, only the JetAand Jet B pushbuttons are applicable to this
error alert indicator illuminates and an ERR-04 is displayed.
test method.
6.2.5 The RESET pushbutton can be depressed at any time
6.3 Accessory equipment and expendable materials needed
to cancel the test in progress and restore the program to the
to perform the test are shown in Fig. 3 and consist of the
initial start mode. The lettered pushbuttons commence to
following:
sequentially illuminate, thus indicating a READY operational
6.3.1 Syringe Plug, (A)—A plastic plug used to stopper the
status enabling test mode selection.
syringe during the CLEAN and EMULSION cycles.
6.2.6 Mark V Operation:
6.3.2 Syringe, (Barrel (B) and Plunger (C))—A disposable
6.2.6.1 Selection of Test ModeAor Test Mode B programs
plastic syringe.
is accomplished by depressing either the A or B lettered
6.3.2.1 Use of syringes other than those demonstrated to be
pushbutton. The depressed pushbutton illuminates and the
free of surfactant contamination in a precision program such as
sequential illumination of the other lettered pushbuttons
described in Section 12 will render test results invalid.
ceases. The START pushbutton also illuminates.
6.3.3 Vials, (D), 25 mm outside diameter vial premarked for
6.2.6.2 The START pushbutton, when depressed initially,
initiates the CLEAN cycle causing the syringe drive mecha- proper alignment in the turbidimeter well.
D3948 − 22
FIG. 2 Micro-Separometer Mark X and Associated Control Panel
TABLE 2 Manual and Audio Operating Characteristics of the Various Model 1140 Micro-Separometer Instruments
Available Test Mode(s) Deluxe A and B Mark X
Function
Test Mode Select Pushbutton Pushbutton
Mode A Depress A Depress Jet A
Mode B Depress B Depress Jet B
Syringe Drive Not required Not required
Speed Selection
Clean Cycle START Depress Clean 1
Depress Depress Clean 2
Pushbutton
Automatic Sequence
Initiate START Depress Run
Cancel RESET
1st Meter Read
1st Meter Depress No Action Required
Adjust ARROWED
Pushbuttons
2nd Meter Read
2nd Meter Depress No Action Required
Adjust ARROWED
Pushbuttons
Collect Sample Short Tone and C/S Short Tone and C/S
Annunciator Lamp Annunciator Lamp
Illuminates Illuminates
3rd Meter Read
Record Pulsed Tone Sounds 5 s Steady Tone
Measurement into 3rd Meter Read
6.3.4 Alumicel, Coalescer (E), is an expendable, precali-
brated aluminum coalescer cell with a tapered end to fit the
syringe. The coalescer has three labels as follows:Alumicel—
D3948—JET FUEL.
6.3.5 Pipet, (G) with Plastic Tip (F)—An automatic hand
pipetwithadisposableplastictip.Apipetissuppliedwitheach
Micro-Separometer.
6.3.6 Water Container (H)—A clean container of distilled
water (supplied with each six pack).
6.3.7 Beaker, Catch Pan, or Plastic Container—Supplied
witheachMicro-Separometermaybeusedtoreceivethewaste
fuel during the coalescence period of the test (not shown).
FIG. 3 Test Supplies and Small Parts
A registered trademark of Emcee Electronics, Inc.
D3948 − 22
TABLE 3 Expected Performance with Jet A, Jet A-1, MIL JP-5, TABLE 4 Expected Performance with Jet B Reference Fluid
MIL JP-7, or MIL JP-8 Reference Fluid Containing a Dispersing Containing a Dispersing Agent Using Mode A
Agent Using Mode A Operation
Limits for
Concentration
Acceptable
Limits for Standard
of Dispersing A
Concentration
Performance
Acceptable
Rating
Standard
Agent, mL/L
of Dispersing A
Performance
Rating
min max
Agent, mL/L
min max
0 99 96 100
0.3 92 86 97
0 99 97 100
0.6 88 81 95
0.2 89 82 94
0.9 86 78 94
0.4 80 69 88
1.2 79 69 90
0.6 72 59 83
0.8 65 51 77
A
Expected range of values obtained by using increasing amounts of dispersing
A
agent used to verify instrument calibration. Ranges developed by performing a
Expected range of values obtained by using increasing amounts of dispersing
linear regression (two sigma limits) on MSS data from RR:D02-1050.
agent used to verify instrument calibration.
TABLE 5 Expected Performance with MIL JP-4 Reference Fluid
Containing a Dispersing Agent Using Mode B
6.4 Anew syringe, pipet tip, test sample vials, syringe plug,
Alumicel coalescer, and distilled water are used in each test.
NOTE 1—Standard ratings are based on actual averages and the limits
are based on ± ⁄2 calculated reproducibility value from the average. A
7. Reagents
standard rating of 99 was used for the base reference fuel instead of the
actual average since this value is preferred.
7.1 Aerosol OT, solid (100 % dry) bis-2-ethylhexyl sodium
Limits for
sulfosuccinate.
Concentration
Acceptable
Standard
of Dispersing A
Performance
7.2 Toluene, ACS reagent grade. (Warning—Flammable.
Rating
Agent, mL/L
min max
Vapor harmful.).
0 99 93 100
7.3 Dispersing Agent—Toluene solution (Warning—
0.2 88 83 93
Flammable. Vapor harmful.) containing 1 mg of Aerosol OT
0.4 81 76 86
0.6 74 69 79
per millilitre of toluene.
0.8 69 64 74
7.4 Reference Fluid Base—A surfactant-free clean hydro- 1.0 64 59 69
1.2 60 55 65
carbon material which is used to verify proper operation and is
A
Expected range of values obtained using increasing amounts of dispersing agent
prepared in the manner described in Appendix X1.
used to verify instrument calibration. Developed using the data from eight of the
(Warning—Flammable. Vapor harmful.)
ten laboratories of the 1983 test program. Refer to RR:D02-1274. See Note 4.
7.5 Reference Fluids—(Warning—Flammable. Vapor
harmful.) (for checking the operational performance of the
Micro-Separometer instrumentation) consist of increasing con-
adispersingagentblendshouldbeheldforaminimumof24 h,
centrations (0 mL⁄Lto 1.2 mL/L) of dispersing agent added to
discarded, and replaced with a fresh blend.
the reference fluid base. The MSEP-Aratings for this range of
7.5.1.2 For field use, instrument calibration can be verified
concentration appear in Table 3 for Jet A, Jet A-1, MIL JP-5,
by performing MSEP tests using a dilution of the dispersing
MIL JP-7, and MIL JP-8 fuels, and in Table 4 for Jet B fuels
agent (as prepared in 7.3), a reference fluid base (as prepared
using Mode A. The MSEP-B ratings for MIL JP-4 fuels using
in Appendix X1), and distilled water. A 10:1 dilution is
Mode B are shown in Table 5. The reference fluids are tested
prepared by diluting 10 mL of dispersing agent with 90 mL of
as described in Section 10 using the applicable mode of
toluene (7.2). Since 1 mL of dilution is equal to 0.1 mL of
operation. If the results do not fall within the range of limits
dispersing agent, 50 µL of dilution is equal to 0.1 mL⁄L when
shown in Tables 3-5, the reference fluid shall be discarded, a
added to 50 mL of reference fluid base. The 0.1 mL⁄L of
fresh quantity of reference fluid prepared, and the check
dispersing agent corresponds to even multiples of the concen-
repeated. Repeated out-of-tolerance test results are cause for
tration levels listed in Tables 3-5. This facilitates using the
returning the instrument to the factory for adjustment and
50 µLpipet(6.3.5)toaddincrementsof0.1 mL⁄Lofdispersing
calibration. See Note 4.
agent, as well as the distilled water required for the MSEPtest.
Depending on the type of reference fluid base, the MSEP
NOTE 4—A Micro-Separometer Operation Manual is furnished with
each instrument.
ratings are compared to the values listed in the applicable table
NOTE 5—The reference fluid base should have standard MSEPrating of
for the particular concentration of dispersing agent used.
+ 97 to 100 without any dispersing agent; otherwise, the results may not
7.6 Water, clean, distilled, and surfactant free.
be indicative of the accuracy of the instrument. Values obtained outside
the measurement range from 50 to 100 are undefined and invalid.
7.6.1 Use of water other than distilled water (such as tap
water) will render test results invalid.
7.5.1 Reference fluid shall be prepared by adding dispersing
agentasdescribedin7.3toasuitablequantityofreferencefuel
8. Preparation of Apparatus
basecontainedinaproperlyequilibratedcontainerorgraduate.
7.5.1.1 If a new or nonequilibrated container is used, the 8.1 Locate the instrument on a clean workbench in an area
dispersingagentmayadsorbonthewallsandtheMSEPratings where the temperature is between 18 °C and 29 °C (65 °F and
mayimprovesignificantly.Toequilibratethecontainersurface, 85 °F) and does not vary more than 63 °C (5 °F).
D3948 − 22
8.2 Open the case and raise the right panel until completely pouring the test sample from the container, wipe the container
vertical and locked in place. If ac power is available, connect outlet thoroughly with a clean, lintless wiper; pour the test
the power cord and turn the instrument on. If the internal sample into a clean beaker or directly into the barrel of the test
battery power is used, ensure that the batteries are charged syringe.
sufficientlytoperformthedesirednumberoftests.Lowbattery
NOTE 8—Test method results are known to be sensitive to trace
power is indicated when the power lamp does not illuminate.
contamination from sampling containers. For recommended sampling
Connect the instrument to an ac power source for at least 16 h
containers, refer to Practice D4306.
(full charge) prior to use. Approximately 25 tests can then be
9.3 If the sample for test is not within the test temperature
performed.
limits, 18 °C to 29 °C (65 °F to 85 °F), allow the sample to
stand until an in-tolerance temperature is attained.
NOTE 6—If the battery in the Mark X is not charged sufficiently to run
a test, an ERR-06 will be displayed indicating that the battery must be
recharged.
10. Procedure
8.2.1 MarkVDeluxe and Mark X instruments are turned on
10.1 Select either ModeAor B operation. (Refer to Table 1
by depressing the switch (pushbutton) marked ON. The ON
for applicable Mode for a specific fuel.)
power indicator light will alternately pulse on and off when the
NOTE 9—Only JP-4 requires Mode B operation.
instrument is connected to an ac power source and will stay on
continuously when operated by the battery pack. Flickering of
10.1.1 Depress either pushbuttonAor B (Mark V), JetAor
the power indicator light, during any portion of a test sequence
Jet B (Mark X) for Mode A or B operation, respectively.
being performed using battery power, indicates that recharging
Sequential illumination of the pushbuttons will cease and the
is necessary.
depressed pushbutton will stay lit. The correct syringe drive
speed is set automatically.
8.3 Have ready a supply of syringes, vials, Alumicel
coalescers, syringe plugs, and pipet tips, as well as a clean
10.2 Remove the plunger from a new 50 mL syringe and
container with distilled water. In addition, have the pipet
wipe the tip using a clean, lintless wipe to remove any sheen
readily available.
caused by excess lubricant. Insert a plug into the exit hole of
the syringe barrel, add 50 mL 6 1 mL of fuel, and place the
8.4 Syringe drive travel times during the coalescing test
syringebarrelontheemulsifiermount,turningtolockinplace.
period were initially calibrated at the factory for each mode of
Ensurethatthesyringebarrelisproperlyalignedconcentrically
operationandhaveasignificantbearingonthefinaltestresults.
with the mixer shaft and is not touching the propeller.
Both the Mark V Deluxe and Mark X instruments have
10.2.1 To mitigate the buildup of static charge, only nitrile
self-check circuitry to detect out-of-tolerance syringe drive
gloves are recommended for use while handling the syringe
travel times.
barrel.
NOTE 7—Syringe drive travel times exceeding the upper limit will
10.2.2 Ensure that the syringe barrel is properly aligned
cause the final results to measure high; conversely, travel times below the
concentrically with the mixer shaft. Proper alignment can be
lower limit will cause the final results to measure low.
verified by grasping the syringe barrel and moving the same
8.4.1 Mark V Deluxe—The alert indicator lamp (marked
until the propeller on the end of the mixer shaft is free and not
SYR) illuminates and depending on the degree (more than 3 s)
touching. Misalignment can cause plastic shavings to form and
of the out-of-tolerance condition, three short (1 s) tones will
collect on the coalescer filter material resulting in erroneous
also sound. An occasional out-of-tolerance alert may be expe-
test results. This applies to all instruments manufactured and
rienced due to some intermittent condition, which probably
those which have not been serviced by Emcee Electronics, Inc.
will not be indicative of instrument failure. However, repeated
since July of 1988. Since that date, all new instruments and
alerts are cause for returning the instrument to the factory for
those returned for service have had a standoff installed on the
adjustment.
mixer shaft to prevent the syringe barrel from coming into
8.4.2 Mark X—During a test, the error alert indicator will
contact with the mixer blades.
illuminate and ERR-03 will be displayed indicating an out of
10.3 Initiate the first CLEAN cycle by depressing the
tolerance syringe travel time. Error alerts ERR-01 and ERR-02
START (Mark V) or CLEAN 1 (Mark X) pushbutton as
will be displayed if the syringe stalls while traveling up or
designated by the annunciator light. (Warning—Do not oper-
down, respectively.
ate the mixer without having a syringe with fuel in place. The
9. Sample Preparation
mixer bearings depend on the fuel for lubrication.)
9.1 Under no circumstances shall test fuel be prefiltered as
NOTE 10—The Mark X will illuminate ERRORALERT and display an
filter media can remove the very materials, surfactants, that the
ERR-05 when the emulsifier speed is outside of acceptable limits.
test method is designed to detect. If the test fuel is contami-
10.4 At the end of the first clean cycle, when the mixer
nated with particulate matter, allow such materials to settle out
motor stops, remove the syringe barrel from the emulsifier,
of the fuel befor
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D3948 − 20 D3948 − 22
Standard Test Method for
Determining Water Separation Characteristics of Aviation
Turbine Fuels by Portable Separometer
This standard is issued under the fixed designation D3948; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope*
1.1 This test method covers a rapid portable means for field and laboratory use to rate the ability of aviation turbine fuels to release
entrained or emulsified water when passed through fiberglass coalescing material.
1.2 The procedure section of this test method contains two different modes of test equipment operation. The primary difference
between the modes of operation is the rate of fuel flow through the fiberglass coalescing material. Test method selection is
dependent on the particular fuel to be tested.
1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for
information only and are not considered standard.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D1655 Specification for Aviation Turbine Fuels
D2550 Method of Test for Water Separation Characteristics of Aviation Turbine Fuels (Withdrawn 1989)
D3602 Test Method for Water Separation Characteristics of Aviation Turbine Fuels (Withdrawn 1994)
D4175 Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
D4306 Practice for Aviation Fuel Sample Containers for Tests Affected by Trace Contamination
D6615 Specification for Jet B Wide-Cut Aviation Turbine Fuel
D7224 Test Method for Determining Water Separation Characteristics of Kerosine-Type Aviation Turbine Fuels Containing
Additives by Portable Separometer
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.J0.05 on Fuel Cleanliness.
Current edition approved May 1, 2020Oct. 1, 2022. Published May 2020November 2022. Originally approved in 1980. Last previous edition approved in 20182020 as
D3948 – 14 (2018).D3948 – 20. DOI: 10.1520/D3948-20.10.1520/D3948-22.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3948 − 22
D7261 Test Method for Determining Water Separation Characteristics of Diesel Fuels by Portable Separometer
D8073 Test Method for Determination of Water Separation Characteristics of Aviation Turbine Fuel by Small Scale Water
Separation Instrument
2.2 Military Standards:
MIL-DTL-5624 Turbine Fuel, Aviation Grades JP-4 and JP-5
MIL-DTL-38219 Turbine Fuel, Low Volatility, JP-7
MIL-DTL-83133 Turbine Fuel, Aviation, Kerosene Types, JP-8 NATO F-34, NATO F-35, and JP-8+100 NATO F-37
3. Terminology
3.1 For definitions of terms used in this test method that are not shown below, refer to Test Methods D7224 and D7261.
3.1 Definitions:
3.1.1 For definitions of terms used in this test method that are not shown below, refer to Test Methods D7224, D7261, and
Terminology D4175.
5 5
3.1.2 Micro-Separometer rating (MSEP rating), n—in the aviation fuel industry, a numerical value indicating the ease of
separating emulsified water from aviation (jet) fuel by coalescence as affected by the presence of surface active materials (also
known as surface active agents or surfactants).
3.1.2.1 Discussion—
MSEP ratings obtained using Test A and Test B are termed MSEP-A and MSEP-B, respectively.
3.1.2.2 Discussion—
MSEP ratings are only valid within the range of 50 to 100, with ratings at the upper end of the range indicating a clean fuel with
little or no contamination by surfactants, which is expected to show good water-separating properties when passed through a
filter-separator (coalescing-type filter) in actual service.
3.1.3 reference fluid, n—in MSEP and DSEP [diesel separability] water separability tests, a reference fluid base to which a
prescribed quantity of a known surface active agent has been added.
3.1.3.1 Discussion—
The known surface active agent is typically bis-2-ethylhexyl sodium sulfosuccinate, commonly referred to as AOT, dissolved in
toluene.
3.1.4 reference fluid base, n—in aviation MSEP water separability tests, jet fuel that has been cleaned in a prescribed manner to
remove all surface-active contaminants (agents).
3.1.5 surfactant, n—in petroleum fuels, surface active material (or surface active agent) that could disarm (deactivate) filter
separator (coalescing) elements so that free water is not removed from the fuel in actual service.
3.1.5.1 Discussion—
Technically, surfactants affect the interfacial tension between water and fuel which affects the tendency of water to coalesce into
droplets.
3.3 Definitions of Terms Specific to This Standard:
3.3.1 reference fluid base, n—in aviation MSEP water separability tests, jet fuel that has been cleaned in a prescribed manner to
remove all surface-active contaminants (agents), and having a minimum MSEP rating of 97.
4. Summary of Test Method
4.1 A water/fuel sample emulsion is created in a syringe using a high-speed mixer. The emulsion is then expelled from the syringe
at a programmed rate through a standard fiberglass coalescer and the effluent is analyzed for uncoalesced water by a light
transmission measurement. The results are reported on a 0-to-100 scale to the nearest whole number. High ratings indicate the
water is easily coalesced, implying that the fuel is relatively free of surfactant materials. A test can be performed in 5 min to 10
min.
Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700 Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.online at ASSIST Quick
Search, http:/quicksearch.dla.mil.
‘MSEP’, ‘DSEP’, and ‘Micro-Separometer’ are trademarks of EMCEE Electronics, Inc., 520 Cypress Ave., Venice, FL 34285.
D3948 − 22
TABLE 1 Applicable Test Mode for Various Fuels
Available Test Mode(s)
Fuel Applicable Test Mode
Jet A A
Jet A-1 A
Jet B A
MIL JP-5 A
MIL JP-7 A
MIL JP-8 A
MIL JP-4 B
5. Significance and Use
5.1 This test method provides a measure of the presence of surfactants in aviation turbine fuels. Like previous obsolete Test
Methods D2550 and D3602, and current Test Methods D7224 and D8073, this test method can detect carryover traces of refinery
treating residues in fuel as produced. They can also detect surface active substances added to or picked up by the fuel during
handling from point of production to point of use. Certain additives can also have an adverse effect on the rating. Some of these
substances affect the ability of filter separators to separate free water from the fuel.
5.2 The Micro-Separometer has a measurement range from 50 to 100. Values obtained outside of those limits are undefined and
invalid. In the event a value greater than 100 is obtained, there is a good probability that light transmittance was reduced by
material contained in the fuel used to set the 100 reference level. The material was subsequently removed during the coalescing
portion of the test, thus, the processed fuel had a higher light transmittance than the fuel sample used to obtain the 100 reference
level resulting in the final rating measuring in excess of 100.
5.3 Test Mode A function of the separometer will give approximately the same rating for Jet A, Jet A-1, MIL JP-5, MIL JP-7, and
MIL JP-8 fuels as Test Methods D2550 and D3602. Using Mode A water separation characteristic ratings of Jet B and MIL JP-4
fuels will not necessarily be equivalent to Test Method D2550 but will give approximately the same rating as Test Method D3602.
All Micro-Separometers have Test Mode A capability.
5.4 The Test Mode B option is used to determine water separation ratings for MIL JP-4 fuels containing fuel system corrosion and
icing inhibitors. These ratings are approximately the same as those obtained using Test Method D2550.
5.5 Selection of Mode A or Mode B depends on the specific fuel and specification requirement. Table 1 identifies the
recommended test method for various fuels.
5.6 The basic difference between Modes A and B is the flow rate at which the water/fuel emulsion is forced through the standard
fiberglass coalescer cell. The lapsed time required to force the emulsion through the coalescer cell in Mode A is 45 s 6 2 s,
whereas, Mode B requires 25 s 6 1 s.
6. Apparatus
6,7
6.1 A Micro-Separometer is used to perform the test. The unit is completely portable and self-contained, capable of operating
on an internal rechargeable battery pack or being connected to an ac power source using power cords which are available for
various voltages. Connection to an ac power source will provide power to the unit and affect battery recharge. The accessories as
well as the expendable materials for six tests can be packed in the cover of the lockable case.
NOTE 1—An extensive study was performed to verify that the Mark X Micro-Separometer gives equivalent results to the Mark V Deluxe
Micro-Separometer. See Research Report RR:D02-1647.
The sole source of supply of the apparatus, the Model 1140 Micro-Separometer Mark V Deluxe and Mark X, known to the committee at this time is Emcee Electronics,
Inc., 520 Cypress Ave., Venice, FL 34285, www.emcee-electronics.com. If you are aware of alternative suppliers, please provide this information to ASTM International
Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend.
The Model 1140 Micro-Separometers Mark III and Mark V Standard versions may also be used, but they are no longer supported by the manufacturer. For operating
procedures using these instruments, the user is referred to D3948–87.
Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D02-1647. Contact ASTM Customer
Service at [e-mail].
D3948 − 22
FIG. 1 Micro-Separometer Mark V Deluxe and Associated Control Panel
NOTE 2—The Mark X has a universal power supply and requires only one power cord as compared to the Mark V Deluxe that requires individual power
cords for different voltages.
6.2 The Micro-Separometer Mark V Deluxe and Mark X and associated control panel are shown in Fig. 1 and Fig. 2, respectively.
The emulsifier is on the right side of the raised panel and the syringe drive mechanism is on the left side. The control panel
containing the operating controls is mounted on the fixed panel in the left side of the case. Table 2 lists the manual and audio
operating characteristics of the instruments.
6.2.1 All of the controls are located in a pushbutton array on the control panel. The pushbuttons illuminate when depressed thus
indicating operational status. A circuit breaker located on the control panel provides protection for the ac power circuit.
6.2.2 The Mark X has an LCD display on the control panel that provides information to the operator during the test. The
information includes test status and an error code that defines a malfunction in the Micro-Separometer.
6.2.3 The turbidimeter is located under the main control panel and consists of a well in which the sample vial is placed, a light
source, and a photocell.
6.2.4 By depressing the ON pushbutton, the electronic circuits are energized. The ON pushbutton pulses on and off when the
instruments are being operated by an ac source and constantly remains on when the battery (dc) pack is used. The lettered
pushbuttons will sequentially illuminate on and off indicating READY operational status.
NOTE 3—Of the lettered (A-G) pushbuttons on the control panel of the Mark V Deluxe, only the A and B pushbuttons are applicable to this test method.
Of the lettered (Jet A – Diesel) pushbuttons on the control panel of the Mark X, only the Jet A and Jet B pushbuttons are applicable to this test method.
6.2.5 The RESET pushbutton can be depressed at any time to cancel the test in progress and restore the program to the initial start
mode. The lettered pushbuttons commence to sequentially illuminate, thus indicating a READY operational status enabling test
mode selection.
6.2.6 Mark V Operation:
6.2.6.1 Selection of Test Mode A or Test Mode B programs is accomplished by depressing either the A or B lettered pushbutton.
The depressed pushbutton illuminates and the sequential illumination of the other lettered pushbuttons ceases. The START
pushbutton also illuminates.
6.2.6.2 The START pushbutton, when depressed initially, initiates the CLEAN cycle causing the syringe drive mechanism to travel
to the UP position and the emulsifier motor to operate for the cleaning operation.
6.2.6.3 The START pushbutton, when depressed after the CLEAN cycle, initiates the automatic program sequence causing the
read indicator and the two ARROWED pushbuttons to illuminate, indicating that a full-scale adjustment period is in effect. A
numerical value also appears on the meter.
6.2.6.4 By depressing the appropriate ARROWED pushbutton, the displayed value on the meter can be increased or decreased,
as required, to attain the 100 reference level for the vial of fuel sample in the turbidimeter.
D3948 − 22
FIG. 2 Micro-Separometer Mark X and Associated Control Panel
TABLE 2 Manual and Audio Operating Characteristics of the Various Model 1140 Micro-Separometer Instruments
Available Test Mode(s) Deluxe A and B Mark X
Function
Test Mode Select Pushbutton Pushbutton
Mode A Depress A Depress Jet A
Mode B Depress B Depress Jet B
Syringe Drive Not required Not required
Speed Selection
Clean Cycle START Depress Clean 1
Depress Depress Clean 2
Pushbutton
Automatic Sequence
Initiate START Depress Run
Cancel RESET
1st Meter Read
1st Meter Depress No Action Required
Adjust ARROWED
Pushbuttons
2nd Meter Read
2nd Meter Depress No Action Required
Adjust ARROWED
Pushbuttons
Collect Sample Short Tone and C/S Short Tone and C/S
Annunciator Lamp Annunciator Lamp
Illuminates Illuminates
3rd Meter Read
Record Pulsed Tone Sounds 5 s Steady Tone
Measurement into 3rd Meter Read
6.2.7 Mark X Operation:
6.2.7.1 Selection of Test Mode A or Test Mode B program is accomplished by depressing either the Jet A or Jet B lettered
pushbutton. The depressed pushbutton illuminates and the sequential illumination of the other lettered pushbuttons ceases. The
CLEAN 1 pushbutton also illuminates.
6.2.7.2 The first and second clean cycles are initiated by depressing the CLEAN 1 and CLEAN 2 pushbuttons. The RUN
pushbutton will illuminate at the end of the second clean cycle.
6.2.7.3 The automatic portion of the test sequence is initiated by depressing the RUN pushbutton.
6.2.7.4 The 100 reference level for the vial of fuel in the turbidimeter is set automatically and does not require any adjustment.
If the turbidimeter could not auto adjust to 100, the error alert indicator illuminates and an ERR-04 is displayed.
D3948 − 22
FIG. 3 Test Supplies and Small Parts
6.3 Accessory equipment and expendable materials needed to perform the test are shown in Fig. 3 and consist of the following:
6.3.1 Syringe Plug, (A)—A plastic plug used to stopper the syringe during the CLEAN and EMULSION cycles.
6.3.2 Syringe, (Barrel (B) and Plunger (C))—A disposable plastic syringe.
6.3.2.1 Use of syringes other than those demonstrated to be free of surfactant contamination in a precision program such as
described in Section 12 will render test results invalid.
6.3.3 Vials, (D), 25 mm outside diameter vial premarked for proper alignment in the turbidimeter well.
6.3.4 Alumicel, Coalescer (E), is an expendable, precalibrated aluminum coalescer cell with a tapered end to fit the syringe. The
coalescer has three labels as follows: Alumicel—D3948—JET FUEL.
6.3.5 Pipet, (G) with Plastic Tip (F)—An automatic hand pipet with a disposable plastic tip. A pipet is supplied with each
Micro-Separometer.
6.3.6 Water Container (H)—A clean container of distilled water (supplied with each six pack).
6.3.7 Beaker, Catch Pan, or Plastic Container—Supplied with each Micro-Separometer may be used to receive the waste fuel
during the coalescence period of the test (not shown).
6.4 A new syringe, pipet tip, test sample vials, syringe plug, Alumicel coalescer, and distilled water are used in each test.
7. Reagents
7.1 Aerosol OT, solid (100 % dry) bis-2-ethylhexyl sodium sulfosuccinate.
7.2 Toluene, ACS reagent grade. (Warning—Flammable. Vapor harmful.).
7.3 Dispersing Agent—Toluene solution (Warning—Flammable. Vapor harmful.) containing 1 mg of Aerosol OT per millilitre of
toluene.
7.4 Reference Fluid Base—A surfactant-free clean hydrocarbon material which is used to verify proper operation and is prepared
in the manner described in Appendix X1. (Warning—Flammable. Vapor harmful.)
A registered trademark of Emcee Electronics, Inc.
D3948 − 22
TABLE 3 Expected Performance with Jet A, Jet A-1, MIL JP-5,
MIL JP-7, or MIL JP-8 Reference Fluid Containing a Dispersing
Agent Using Mode A Operation
Limits for
Concentration
Acceptable
Standard
of Dispersing A
Performance
Rating
Agent, mL/L
min max
0 99 97 100
0.2 89 82 94
0.4 80 69 88
0.6 72 59 83
0.8 65 51 77
A
Expected range of values obtained by using increasing amounts of dispersing
agent used to verify instrument calibration.
7.5 Reference Fluids—(Warning—Flammable. Vapor harmful.) (for checking the operational performance of the Micro-
Separometer instrumentation) consist of increasing concentrations (0 mL ⁄L to 1.2 mL/L) of dispersing agent added to the reference
fluid base. The MSEP-A ratings for this range of concentration appear in Table 3 for Jet A, Jet A-1, MIL JP-5, MIL JP-7, and MIL
JP-8 fuels, and in Table 4 for Jet B fuels using Mode A. The MSEP-B ratings for MIL JP-4 fuels using Mode B are shown in Table
5. The reference fluids are tested as described in Section 10 using the applicable mode of operation. If the results do not fall within
the range of limits shown in Tables 3-5, the reference fluid shall be discarded, a fresh quantity of reference fluid prepared, and the
check repeated. Repeated out-of-tolerance test results are cause for returning the instrument to the factory for adjustment and
calibration. See Note 4.
NOTE 4—A Micro-Separometer Operation Manual is furnished with each instrument.
NOTE 5—The reference fluid base should have standard MSEP rating of 99+ without + 97 to 100 without any dispersing agent; otherwise, the results may
not be indicative of the accuracy of the instrument. Values obtained outside the measurement range from 50 to 100 are undefined and invalid.
7.5.1 Reference fluid shall be prepared by adding dispersing agent as described in 7.3 to a suitable quantity of reference fuel base
contained in a properly equilibrated container or graduate.
7.5.1.1 If a new or nonequilibrated container is used, the additive dispersing agent may adsorb on the walls and the MSEP ratings
may improve significantly. To equilibrate the container surface, an additive a dispersing agent blend should be held for a minimum
of 24 h, 24 h, discarded, and replaced with a fresh blend.
7.5.1.2 For field use, instrument calibration can be verified by performing MSEP tests using a dilution of the dispersing agent (as
prepared in 7.3), a reference fluid base (as prepared in Appendix X1), and distilled water. A 10:1 dilution is prepared by diluting
10 mL of dispersing agent with 90 mL of toluene (7.2). Since 1 mL of dilution is equal to 0.1 mL of dispersing agent, 50 μL of
dilution is equal to 0.1 mL ⁄L when added to 50 mL of reference fluid base. The 0.1 mL ⁄L of dispersing agent corresponds to even
multiples of the concentration levels listed in Tables 3-5. This facilitates using the 50 μL pipet (6.3.5) to add increments of
0.1 mL ⁄L of dispersing agent, as well as the distilled water required for the MSEP test. Depending on the type of reference fluid
base, the MSEP ratings are compared to the values listed in the applicable table for the particular concentration of dispersing agent
used.
7.6 Water, clean, distilled, and surfactant free.
7.6.1 Use of water other than distilled water (such as tap water) will render test results invalid.
8. Preparation of Apparatus
8.1 Locate the instrument on a clean workbench in an area where the temperature is between 18 °C and 29 °C (65 °F and 85 °F)
and does not vary more than 63 °C (5 °F).
8.2 Open the case and raise the right panel until completely vertical and locked in place. If ac power is available, connect the
power cord and turn the instrument on. If the internal battery power is used, ensure that the batteries are charged sufficiently to
D3948 − 22
TABLE 4 Expected Performance with Jet B Reference Fluid
Containing a Dispersing Agent Using Mode A
Limits for
Concentration
Acceptable
Standard
of Dispersing A
Performance
Rating
Agent, mL/L
min max
0 99 96 100
0.3 92 86 97
0.6 88 81 95
0.9 86 78 94
1.2 79 69 90
A
Expected range of values obtained by using increasing amounts of dispersing
agent used to verify instrument calibration. Ranges developed by performing a
linear regression (two sigma limits) on MSS data from RR:D02-1050.
TABLE 5 Expected Performance with MIL JP-4 Reference Fluid
Containing a Dispersing Agent Using Mode B
NOTE 1—Standard ratings are based on actual averages and the limits
are based on ± ⁄2 calculated reproducibility value from the average. A
standard rating of 99 was used for the base reference fuel instead of the
actual average since this value is preferred.
Limits for
Concentration
Acceptable
Standard
of Dispersing A
Performance
Rating
Agent, mL/L
min max
0 99 93 100
0.2 88 83 93
0.4 81 76 86
0.6 74 69 79
0.8 69 64 74
1.0 64 59 69
1.2 60 55 65
A
Expected range of values obtained using increasing amounts of dispersing agent
used to verify instrument calibration. Developed using the data from eight of the
ten laboratories of the 1983 test program. Refer to RR:D02-1274. See Note 4.
perform the desired number of tests. Low battery power is indicated when the power lamp does not illuminate. Connect the
instrument to an ac power source for at least 16 h (full charge) prior to use. Approximately 25 tests can then be performed.
NOTE 6—If the battery in the Mark X is not charged sufficiently to run a test, an ERR-06 will be displayed indicating that the battery must be recharged.
8.2.1 Mark V Deluxe and Mark X instruments are turned on by depressing the switch (pushbutton) marked ON. The ON power
indicator light will alternately pulse on and off when the instrument is connected to an ac power source and will stay on
continuously when operated by the battery pack. Flickering of the power indicator light, during any portion of a test sequence being
performed using battery power, indicates that recharging is necessary.
8.3 Have ready a supply of syringes, vials, Alumicel coalescers, syringe plugs, and pipet tips, as well as a clean container with
distilled water. All of the items are furnished in the six pack provided with the instrument. In addition, have the pipet readily
available.
8.4 Syringe drive travel times during the coalescing test period were initially calibrated at the factory for each mode of operation
and have a significant bearing on the final test results. Both the Mark V Deluxe and Mark X instruments have self-check circuitry
to detect out-of-tolerance syringe drive travel times.
NOTE 7—Syringe drive travel times exceeding the upper limit will cause the final results to measure high; conversely, travel times below the lower limit
will cause the final results to measure low.
8.4.1 Mark V Deluxe—The alert indicator lamp (marked SYR) illuminates and depending on the degree (more than 3 s) of the
out-of-tolerance condition, three short (1 s) tones will also sound. An occasional out-of-tolerance alert may be experienced due to
D3948 − 22
some intermittent condition, which probably will not be indicative of instrument failure. However, repeated alerts are cause for
returning the instrument to the factory for adjustment.
8.4.2 Mark X—During a test, the error alert indicator will illuminate and ERR-03 will be displayed indicating an out of tolerance
syringe travel time. Error alerts ERR-01 and ERR-02 will be displayed if the syringe stalls while traveling up or down, respectively.
9. Sample Preparation
9.1 Under no circumstances shall test fuel be prefiltered as filter media can remove the very materials, surfactants, that the test
method is designed to detect. If the test fuel is contaminated with particulate matter, allow such materials to settle out of the fuel
before testing.
9.2 Special precautions concerning sample containers and sampling technique are discussed in Appendix X2. Extreme care and
cleanliness are required in taking samples either directly into the test syringe or into a sample container. Before pouring the test
sample from the container, wipe the container outlet thoroughly with a clean, lintless wiper; pour the test sample into a clean beaker
or directly into the barrel of the test syringe.
NOTE 8—Test method results are known to be sensitive to trace contamination from sampling containers. For recommended sampling containers, refer
to Practice D4306.
9.3 If the sample for test is not within the test temperature limits, 18 °C to 29 °C (65 °F to 85 °F), allow the sample to stand until
an in-tolerance temperature is attained.
10. Procedure
10.1 Select either Mode A or B operation. (Refer to Table 1 for applicable Mode for a specific fuel.)
NOTE 9—Only JP-4 requires Mode B operation.
10.1.1 Depress either pushbutton A or B (Mark V), Jet A or Jet B (Mark X) for Mode A or B operation, respectively. Sequential
illumination of the pushbuttons will cease and the depressed pushbutton will stay lit. The correct syringe drive speed is set
automatically.
10.2 Remove the plunger from a new 50 mL syringe and wipe the tip using a clean, lintless wipe to remove any sheen caused by
excess lubricant. Insert a plug into the exit hole of the syringe barrel, add 50 mL 6 1 mL of fuel, and place the syringe barrel on
the emulsifier mount, turning to lock in place. Ensure that the syringe barrel is properly aligned concentrically with the mixer shaft
and is not touching the propeller.
10.2.1 To mitigate the buildup of static charge, only nitrile gloves are recommended for use while handling the syringe barrel.
10.2.2 Ensure that the syringe barrel is properly aligned concentrically with the mixer shaft. Proper alignment can be verified by
grasping the syringe barrel and moving the same until the propeller on the end of the mixer shaft is free and not touching.
Misalignment can cause plastic shavings to form and collect on the coalescer filter material resulting in erroneous test results. This
applies to all instruments manufactured and those which have not been serviced by Emcee Electronics, Inc. since July of 1988.
Since that date, all new instruments and those returned for service have had a standoff installed on the mixer shaft to prevent the
syringe barrel from coming into contact with the mixer blades.
10.3 Initiate the first CLEAN cycle by depressi
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