ASTM D91-02(2012)e1

Standard Test Method for Precipitation Number of Lubricating Oils

SIGNIFICANCE AND USE
4.1 Fully refined petroleum oils normally contain no naphtha insoluble material. Semirefined or black oils frequently contain some naphtha insoluble material (sometimes referred to as asphaltenes ). This test measures the amount of naphtha insoluble material in the oil. This quantity is reported as the precipitation number.
SCOPE
1.1 This test method covers the determination of the precipitation number of steam cylinder stocks and black oils, and can be used for other lubricating oils.  
1.2 The values stated in acceptable SI units are to be regarded as the standard.  
1.3 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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 31-Oct-2012
• ICS: 75.100 - Lubricants, industrial oils and related products
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.06 - Analysis of Liquid Fuels and Lubricants

Relations

• Replaces: ASTM D91-02(2012) - Standard Test Method for Precipitation Number of Lubricating Oils
• Effective Date: 01-Nov-2012
• Replaced By: ASTM D91-02(2017) - Standard Test Method for Precipitation Number of Lubricating Oils
• Effective Date: 01-Jul-2017
• Referred By: ASTM D4636-17 - Standard Test Method for Corrosiveness and Oxidation Stability of Hydraulic Oils, Aircraft Turbine Engine Lubricants, and Other Highly Refined Oils
• Effective Date: 01-Nov-2012
• Referred By: ASTM D4871-11(2022) - Standard Guide for Universal Oxidation/Thermal Stability Test Apparatus
• Effective Date: 01-Nov-2012
• Referred By: ASTM D5534-94(2018) - Standard Test Method for Vapor-Phase Rust-Preventing Characteristics of Hydraulic Fluids
• Effective Date: 01-Nov-2012
• Referred By: ASTM D2893-19 - Standard Test Methods for Oxidation Characteristics of Extreme-Pressure Lubrication Oils
• Effective Date: 01-Nov-2012
• Referred By: ASTM D1611-12(2019) - Standard Test Method for Corrosion Produced by Leather in Contact with Metal
• Effective Date: 01-Nov-2012
• Referred By: ASTM D6074-15(2022) - Standard Guide for Characterizing Hydrocarbon Lubricant Base Oils
• Effective Date: 01-Nov-2012
• Referred By: ASTM D187-18 - Standard Test Method for Burning Quality of Kerosene
• Effective Date: 01-Nov-2012
• Referred By: ASTM D6710-21 - Standard Guide for Evaluation of Hydrocarbon-Based Quench Oil
• Effective Date: 01-Nov-2012
• Referred By: ASTM D5372-20 - Standard Guide for Evaluation of Hydrocarbon Heat Transfer Fluids
• Effective Date: 01-Nov-2012
• Referred By: ASTM D1093-23 - Standard Test Method for Acidity of Hydrocarbon Liquids and Their Distillation Residues
• Effective Date: 01-Nov-2012
• Referred By: ASTM D665-19 - Standard Test Method for Rust-Preventing Characteristics of Inhibited Mineral Oil in the Presence of Water
• Effective Date: 01-Nov-2012
• Referred By: ASTM D3705-14(2019) - Standard Test Method for Misting Properties of Lubricating Fluids
• Effective Date: 01-Nov-2012
• Referred By: ASTM D3603-20 - Standard Test Method for Rust-Preventing Characteristics of Steam Turbine Oil in the Presence of Water (Horizontal Disk Method)
• Effective Date: 01-Nov-2012

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
´1
Designation: D91 − 02 (Reapproved 2012)
Standard Test Method for
1,2
Precipitation Number of Lubricating Oils
This standard is issued under the fixed designation D91; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscript
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.
ε NOTE—Subsection 5.2 was corrected editorially in July 2016.
1. Scope contain some naphtha insoluble material (sometimes referred
to as asphaltenes ). This test measures the amount of naphtha
1.1 This test method covers the determination of the pre-
insoluble material in the oil. This quantity is reported as the
cipitation number of steam cylinder stocks and black oils, and
precipitation number.
can be used for other lubricating oils.
1.2 The values stated in acceptable SI units are to be
5. Apparatus
regarded as the standard.
5.1 Centrifuge Tube, cone-shaped, conforming to the di-
1.3 This standard does not purport to address all of the
mensions given in Fig. 1, and made of thoroughly annealed
safety concerns, if any, associated with its use. It is the
glass. The graduations, numbered as shown in Fig. 1, shall be
responsibility of the user of this standard to establish appro-
clearanddistinct,andthemouthshallbeconstructedinashape
priate safety and health practices and determine the applica-
suitable for closure with a cork. Scale-error tolerances and
bility of regulatory limitations prior to use.
smallest graduations between various calibration marks are
given in Table 1 and apply to calibrations made with air-free
2. Referenced Documents
water at 20 °C.
2.1 ASTM Standards:
D4057 Practice for Manual Sampling of Petroleum and
5.2 Centrifuge, meeting all the safety requirements for
Petroleum Products normal use and capable of whirling two or more filled
D4177 Practice for Automatic Sampling of Petroleum and
centrifuge tubes at a speed which can be controlled to give a
Petroleum Products relative centrifugal force (rcf) between 600 and 700 at the tips
of the tubes. The revolving head, trunnion rings, and trunnion
3. Terminology
cups, including the rubber cushion, shall be soundly con-
3.1 Definitions of Terms Specific to This Standard: structed to withstand the maximum centrifugal force capable of
being delivered by the power source. The trunnion cups and
3.1.1 ASTM precipitation number, of lubricating oils, n—the
number of millilitres of precipitate formed when 10 mL of cushions shall firmly support the tubes when the centrifuge is
in motion.The centrifuge shall be enclosed by a metal shield or
lubricating oil are mixed with 90 mL of ASTM precipitation
naphtha, and centrifuged under the conditions of the test. case strong enough to eliminate danger if any breakage occurs.
Calculate the speed of the rotating head by means of the
4. Significance and Use
following equation:
4.1 Fully refined petroleum oils normally contain no naph-
speed, r/min 5 1337 =rcf/d (1)
tha insoluble material. Semirefined or black oils frequently
where:
rcf = relative centrifugal force, and
This test method is under the jurisdiction of ASTM Committee D02 on
d = diameter of swing, in mm, measured between tips of
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.06 on Analysis of Liquid Fuels and Lubricants.
opposite tubes when in rotating position.
Current edition approved Nov. 1, 2012. Published November 2012. Originally
Table 2 shows the relationship between diameter swing, rcf,
approved in 1921. Last previous edition approved in 2007 as D91 – 02 (2007). DOI:
10.1520/D0091-02R12E01.
and revolutions per minute.
This test method has been adopted for use by government agencies to replace
Method 3101 of Federal Test Method Standard No. 791b.
3 6. Reagent
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
6.1 Hexanes, Reagent Grade. (Warning—Extremely
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. flammable, harmful if inhaled.)
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
D91 − 02 (2012)
least 20 times, allowing the liquid to drain thoroughly from the
taperedtipofthetubeeachtime.Placethetubesinawaterbath
at 32 °C to 35 °C for 5 min 6 1 min. Momentarily remove the
corkstorelieveanypressure,andinverteachtubeagainatleast
20 t
...

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.
´1
Designation: D91 − 02 (Reapproved 2012) D91 − 02 (Reapproved 2012)
Standard Test Method for
1,2
Precipitation Number of Lubricating Oils
This standard is issued under the fixed designation D91; 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.
ε NOTE—Subsection 5.2 was corrected editorially in July 2016.
1. Scope
1.1 This test method covers the determination of the precipitation number of steam cylinder stocks and black oils, and can be
used for other lubricating oils.
1.2 The values stated in acceptable SI units are to be regarded as the standard.
1.3 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 and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 ASTM precipitation number, of lubricating oils, n—the number of millilitres of precipitate formed when 10 mL 10 mL of
lubricating oil are mixed with 90 mL 90 mL of ASTM precipitation naphtha, and centrifuged under the conditions of the test.
4. Significance and Use
4.1 Fully refined petroleum oils normally contain no naphtha insoluble material. Semirefined or black oils frequently contain
some naphtha insoluble material (sometimes referred to as asphaltenes ). This test measures the amount of naphtha insoluble
material in the oil. This quantity is reported as the precipitation number.
5. Apparatus
5.1 Centrifuge Tube, cone-shaped, conforming to the dimensions given in Fig. 1, and made of thoroughly annealed glass. The
graduations, numbered as shown in Fig. 1, shall be clear and distinct, and the mouth shall be constructed in a shape suitable for
closure with a cork. Scale-error tolerances and smallest graduations between various calibration marks are given in Table 1 and
apply to calibrations made with air-free water at 20°C.20 °C.
5.2 Centrifuge, meeting all the safety requirements for normal use and capable of whirling two or more filled centrifuge tubes
at a speed which can be controlled to give a relative centrifugal force (rcf) between 600 and 700 at the tiptips of the tubes. The
revolving head, trunnion rings, and trunnion cups, including the rubber cushion, shall be soundly constructed to withstand the
maximum centrifugal force capable of being delivered by the power source. The trunnion cups and cushions shall firmly support
the tubes when the centrifuge is in motion. The centrifuge shall be enclosed by a metal shield or case strong enough to eliminate
danger if any breakage occurs. Calculate the speed of the rotating head by means of the following equation:
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.06 on Analysis of Liquid Fuels and Lubricants.
Current edition approved Nov. 1, 2012. Published November 2012. Originally approved in 1921. Last previous edition approved in 2007 as D91 – 02 (2007). DOI:
10.1520/D0091-02R12.10.1520/D0091-02R12E01.
This test method has been adopted for use by government agencies to replace Method 3101 of Federal Test Method Standard No. 791b.
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.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
D91 − 02 (2012)
NOTE 1—For volumetric tolerances see Table 1.
FIG. 1 ASTM Cone-Shaped Centrifuge Tube
TABLE 1 Calibration Tolerances for 200 mm Centrifuge Tube
Range, mL Subdivision, mL Volume Tolerance, mL
0 to 0.1 0.05 ±0.02
Above 0.1 to 0.3 0.05 ±0.03
Above 0.3 to 0.5 0.05 ±0.05
Above 0.5 to 1.0 0.10 ±0.05
Above 1.0 to 2.0 0.10 ±0.10
Above 2.0 to 3.0 0.20 ±0.10
Above 3.0 to 5.0 0.5 ±0.20
Above 5.0 to 10 1.0 ±0.50
Above 10 to 25 5.0 ±1.00
Above 25 to 100 25 ±1.00
rpm 5 1337 =rcf
...