ASTM D2878-95

NOTICE: This standard has either been superseded and replaced by a new version or
withdrawn.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.
Designation: D 2878 – 95 An American National Standard
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Estimating Apparent Vapor Pressures and Molecular
1
Weights of Lubricating Oils
This standard is issued under the fixed designation D 2878; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope D 2595 Test Method for Evaporation Loss of Lubricating
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Greases over Wide Temperature Range
1.1 This test method provides a calculation procedure for
D 2883 Test Method for Reaction Threshold Temperature of
converting data obtained by Test Method D 972 to apparent
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Liquid and Solid Materials
vapor pressures and molecular weights. It has been demon-
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E 1 Specification for ASTM Thermometers
strated to be applicable to petroleum-based and synthetic ester
2
E 659 Test Method for Autoignition Temperature of Liquid
lubricating oils, at temperatures of 395 to 535K (250 to
7
Chemicals
500°F). However, its applicability to lubricating greases has
not been established.
3. Terminology
NOTE 1—Most lubricants boil over a fairly wide temperature range, a
3.1 Definitions of Terms Specific to This Standard:
fact recognized in discussion of their vapor pressures. For example, the
3.1.1 apparent vapor pressure (p), n—the time-averaged
apparent vapor pressure over the range 0 to 0.1 % evaporated may be as
3 value of the vapor pressure from the start to the end of the
much as 100 times that over the range 4.9 to 5.0 % evaporated.
evaporation test.
1.2 The values stated in SI units are to be regarded as the
3.1.1.1 Discussion—While this may include some effects of
standard. In cases in which materials, products, or equipment
differences in nonideality of the vapor, heat of vaporization,
are available in inch-pound units only, SI units are omitted.
surface tension, and viscosity between the m-terphenyl and the
1.3 This standard does not purport to address all of the
lubricating oil, these factors have been demonstrated to be
safety concerns, if any, associated with its use. It is the
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negligible. Unless stated, this average shall cover the range 0
responsibility of the user of this standard to establish appro-
to 5 6 1%.
priate safety and health practices and determine the applica-
3.1.2 cell constant (k), n—the ratio of the amount of
bility or regulatory limitations prior to use. For specific hazard
m-terphenyl or lubricating oil carried off per unit volume of gas
statements, see Note 3, Note 4, and Note 6.
to that predicted by Dalton’s law.
k 5 22.41 PW /VpM (1)
2. Referenced Documents
2.1 ASTM Standards:
where:
A 240 Specification for Heat-Resisting Chromium and
k 5 call constant
Chromium-Nickel Stainless Steel Plate, Sheet, and Strip
P 5 ambient atmospheric pressure, torr
3
for Pressure Vessels
W 5 mass of lubricant evaporated, g
D 92 Test Method for Flash and Fire Points by Cleveland
V 5 volume of gas passed through all litres at 273K and
4
Open Cup 101.3 kPa (760 torr)
D 972 Test Method for Evaporation Loss of Lubricating p 5 apparent vapor pressure, torr
4
M 5 mole average molecular weight of lubricant vapor,
Greases and Oils
g/mole
D 2503 Test Method for Molecular Weight (Relative Mo-
T 5 test temperature, K
lecular Mass) of Hydrocarbons by Thermoelectric Mea-
4
It has been empirically determined that for m-terphenyl in air
surement of Vapor Pressure
k 5 0.1266 2 12.60/ T 2 273! (2)
~
and that the cell constant is independent of the composition
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This test method is under the jurisdiction of Committee D-2 on Petroleum
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of the lubricant.
Products and Lubricants and is the direct responsibility of Subcommittee D02.11 on
Engineering Sciences of High Performance Fluids and Solids. —Test Method D 972 is normally run with air, which may
Current edition approved Jan. 15, 1995. Published March 1995. Originally
cause changes in easily oxidized fluids. In such cases, use of
published as D 2878 – 70. Last previous edition D 2878 – 93.
2
Coburn, J. F., “Lubricant Vapor Pressure Derived from Evaporation Loss,”
Transactions, American Society of Lubricating Engineers, ASLTA, Vol 12, 1969, pp.
5
129–134. Annual Book of ASTM Standards, Vol 05.02.
3 6
Annual Book of ASTM Standards, Vol 01.03. Annual Book of ASTM Standards, Vol 14.03.
4 7
Annual Book of ASTM Standards, Vol 05.01. Annual Book of ASTM Standards, Vol 14.02.
1

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D 2878
common reactive gas nitrogen and recalibration to obtain a
Temperature Evaporation to Conform
K °F Time, h to Eq 2, g
s
...