Designation: D6910/D6910M – 09

Standard Test Method for

Marsh Funnel Viscosity of Clay Construction Slurries1
This standard is issued under the fixed designation D6910/D6910M; 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.

1. Scope API Recommended Practice, Standard Procedure for Test-

1.1 This test method provides an indirect measurement of ing Drilling Fluids, Sixth Edition3
the viscosity of clay slurries using a funnel (Marsh Funnel) and 3. Terminology
a graduated cup of specific dimensions. This test method
provides a practical indicator of the viscosity on a routine 3.1 Definitions: For common definitions of technical terms
basis. This test method has been modified from the API in this standard, refer to Terminology D653.
Recommended Practice 13B-2. 3.2 Definitions of Terms Specific to This Standard:
1.2 The result determined using the method is referred to as 3.2.1 marsh funnel viscosity (MFV)—also known as funnel
the Marsh Funnel Viscosity. viscosity. The time required (in seconds) for 946 mL [1 qt] of
1.3 This test can be performed in the laboratory, or used in a slurry to flow into a graduated cup from a funnel (known as
the field to assess the apparent viscosity of a clay slurry for a Marsh Funnel) with specific dimensions. The Marsh Funnel
quality control purposes. The most commonly used slurry is a Viscosity is not a true viscosity, it is only an apparent value and
bentonite clay slurry. good in a relative sense. High MFV values are obtained for
1.4 The values stated in either SI units or inch-pound units slurries with high viscosity and low MFV values are obtained
[given in brackets] are to be regarded separately as standard. for slurries with low viscosity.
The values stated in each system may not be exact equivalents; 4. Summary of Test Method
therefore, each system shall be used independently of the other.
Combining values from the two systems may result in non- 4.1 In this method, a slurry is poured into a funnel with
conformance with the standard. specific dimensions (Marsh Funnel). The slurry is then allowed
1.5 This standard does not purport to address all of the to flow into a graduated cup. The time for the slurry to fill a
safety concerns, if any, associated with its use. It is the volume of 946 mL [1 qt] is measured and reported as the Marsh
responsibility of the user of this standard to establish appro- Funnel Viscosity. The test temperature is also reported for
priate safety and health practices and determine the applica- comparison purposes.
bility of regulatory limitations prior to use. 5. Significance and Use
2. Referenced Documents 5.1 This test method allows for the assessment of an
2.1 ASTM Standards:2 apparent viscosity of clay slurries in the laboratory and in the
D653 Terminology Relating to Soil, Rock, and Contained field. Viscosity is a fundamental characteristic for slurries in
Fluids construction applications. The Marsh Funnel Viscosity test can
D3740 Practice for Minimum Requirements for Agencies be used for field quality control of slurries. Relative changes in
Engaged in Testing and/or Inspection of Soil and Rock as slurry viscosity can be identified using Marsh Funnel measure-
Used in Engineering Design and Construction ments and modifications can be made to mixing and handling
2.2 API Document: procedures.
5.2 In this test, it is assumed that the apparent viscosity of a
slurry is directly related to the flow duration through a specially
1
This test method is under the jurisdiction of ASTM Committee D18 on Soil and shaped funnel (the Marsh Funnel).
Rock and is the direct responsibility of Subcommittee D18.04 on Hydrologic
Properties and Hydraulic Barriers. NOTE 1—The development of the Marsh Funnel is credited to Hallan N.
Current edition approved Oct. 1, 2009. Published October 2009. Originally Marsh of Los Angeles who published the design and use of his funnel
approved in 2004. Last previous edition approved in 2004 as D6910 – 04. DOI: viscometer in 1931.
10.1520/D6910_D6910M-09.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
3
Standards volume information, refer to the standard’s Document Summary page on Available from American Petroleum Institute (API), 1220 L. St., NW, Wash-
the ASTM website. ington, DC 20005-4070, http://www.api.org.

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 D6910/D6910M – 09
5.3 In slurry wall construction and other applications, the comply with the following:
viscosity of a slurry must be maintained at a level high enough 6.1.1 Funnel Cone—A cone with a length of 305-mm
to assist in stabilizing the trench walls. Slurry viscosity is also [12-in.] and a diameter of 152-mm [6-in.] equipped with a
directly related to filter cake permeability. screen at the top and an orifice tube at the bottom. The capacity
5.4 The Marsh Funnel Viscosity has been widely used in of the cone from the orifice opening to the bottom of the screen
drilling soil and rock for water wells, oil, gas, soil stabilization, shall be 1500 mL [1.6 qt]. It may be manufactured from plastic,
and the application of hydraulic barriers. metal, or other rigid and durable material, and may be provided
5.5 Inert suspended solids such as fine sands and additives with handles or stands.
affect the viscosity of slurries. This test may be used to 6.1.2 Funnel Orifice—An orifice tube of 51-mm [2-in.] in
determine the relative effects of this and other such materials length, with an inside diameter of 4.75-mm [3⁄16-in.]. The
on the viscosity of a slurry. diameter of this outlet directly affects the Marsh Funnel test
NOTE 2—The quality of the result produced by this standard is
results and has been standard with the test since the inception
dependent on the competence of the personnel performing it, and the of this method.
suitability of the equipment and facilities used. Agencies that meet the 6.1.3 Screen—A screen with openings of approximately 3.2
criteria of Practice D3740 are generally considered capable of competent mm [0.125 in.]. The screen is normally placed at the 1500 mL
and objective testing, sampling/inspection/etc. Users of this standard are [1.6 qt] level of the funnel; approximately 19 mm [0.75 in.]
cautioned that compliance with Practice D3740 does not in itself assure below the top of the funnel. The screen is used to separate
reliable results. Reliable results depend on many factors; Practice D3740 larger particles that could plug the orifice during the test.
provides a means of evaluating some of those factors.
6.2 Graduated Cup—A metal or plastic graduated cup with
6. Apparatus a 946-mL [1-qt] marking.
6.1 Marsh Funnel (see Fig. 1)—The Marsh Funnel will 6.3 Timer—A stopwatch or equivalent timer with a resolu-
tion of 0.5 s or better.
6.4 Thermometer—A thermometer with a range of 0 to
105°C [32 to 220°F] with a resolution of 1°C [2°F].
6.5 Sampling and Cleaning Equipment.
7. Hazards
7.1 Appropriate eye and hand protection is recommended
for direct work with the slurries.
8. Sampling
8.1 Obtain a 7.5 L [2 gal] representative sample of the slurry
to be tested using dippers, buckets, mud or slurry samplers, or
equivalent equipment from a field construction operation (for
example, from a hydrated mix pond) or from a laboratory
slurry mix. A specimen 1500 mL [1.6 qt] in volume is required
for a test.

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9. Calibration Checks
9.1 Periodically check the Marsh Funnel and the graduated
cup for damage or wear. For the Marsh Funnel pay special
attention to the orifice tube. Verify that the graduation marks
are present and readable in the funnel and the cup. In particular,
make sure that the 946 mL mark is readable in the cup.
9.2 Fill the Marsh funnel with 1500-mL [1.6-qt] of water
while holding a finger over the orifice. If the water surface is at
the screen, no further marking is required. If the surface is
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above or below the screen, a mark should be placed inside the

funnel for reference when running the test.
9.3 Verify that the flow duration for 946 mL [1 qt] of water
is 26 6 0.5 s at a temperature of 21 6 3°C [70 6 5°F]. If the
Funnel does not meet these criteria for fresh water, clean the
Dimensional Equivalents orifice tube and inspect to verify that the tube has not been
mm in. bent, flattened or otherwise distorted. If the funnel continues to
3.2 0.125 provide inaccurate readings, it may have been damaged and the
4.75 0.1825
51.0 2.0
funnel should be replaced.
152.0 6.0
305.0 12.0 10. Procedure
FIG. 1 Marsh Funnel 10.1 Verify that the funnel and cup are both clean and dry.

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 D6910/D6910M – 09
10.2 Cover the Marsh Funnel orifice with a finger and pour 11.1.4 The temperature of the slurry.
the freshly sampled slurry through the screen into the upright
funnel. 12. Precision and Bias
10.3 Holding the funnel over the graduated cup, remove the
12.1 Precision—Test data on precision is not presented due
finger and start the timer.
10.4 Measure the time for the slurry to fill the graduated cup to the nature of this test method. It has not been feasible at this
to the 946 mL [1 qt] line. time to have ten or more agencies participate in an in situ
10.5 Determine the temperature of the slurry. testing program at a given site.
12.1.1 The Subcommittee D18.20 is seeking any data from
NOTE 3—Repeating the test several times and averaging the results may
reduce the chance for error and provide more reproducible results. the users of this test method that might be used to make a
limited statement on precision.
11. Report 12.2 Bias—There is no accepted reference value for this test
11.1 Test data forms or test reports will include the follow- method, therefore bias cannot be determined.
ing:
11.1.1 The source of the sample. 13. Keywords
11.1.2 The date and time of the test.
11.1.3 The elapsed time to the nearest second for 946-mL 13.1 bentonite slurry; clay slurry; funnel viscosity; hydrau-
[1-qt] of the slurry to flow into the graduated cup. This value lic barriers; marsh funnel; slurry; viscosity
to be recorded as the Marsh Funnel Viscosity.

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