ASTM E41-92(1998)
(Terminology)Terminology Relating to Conditioning
Terminology Relating to Conditioning
SCOPE
1.1 These definitions pertain to the conditioning of materials for test purposes. Unless otherwise specified, they are intended to apply to all cases where combinations of atmospheric influences are an essential part of the testing of materials.
1.2 It is the intent of this standard to include those conditioning terms in wide use in ASTM for which standard definitions appear desirable.
General Information
Relations
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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
Designation: E 41 – 92 (Reapproved 1998)
Standard Terminology Relating To
Conditioning
This standard is issued under the fixed designation E 41; 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 atmosphere, standard—air maintained at a specified tempera-
ture, relative humidity, and standard atmospheric pressure.
1.1 These definitions pertain to the conditioning of materials
E 171
for test purposes. Unless otherwise specified, they are intended
condition, standard—the condition reached by a specimen
to apply to all cases where combinations of atmospheric
when it is in temperature and moisture equilibrium with a
influences are an essential part of the testing of materials.
standard atmosphere.
1.2 It is the intent of this standard to include those condi-
conditioning—the exposure of a material to the influence of a
tioning terms in wide use in ASTM for which standard
prescribed atmosphere for a stipulated period of time or until
definitions appear desirable.
a stipulated relation is reached between material and atmo-
2. Referenced Documents sphere.
dehumidify—to reduce, by any process, the quantity of water
2.1 ASTM Standards:
vapor within a given space.
E 171 Specification for Standard Atmospheres for Condi-
dew point—the temperature to which water vapor must be
tioning and Testing Materials
reduced to obtain saturation vapor pressure, that is, 100 %
E 337 Test Method for Measuring Humidity with a Psy-
relative humidity.
chrometer (the Measurement of Wet- and Dry-Bulb Tem-
peratures)
NOTE 1—As air is cooled, the amount of water vapor that it can hold
decreases. If air is cooled sufficiently, the actual water vapor pressure
3. Terminology
becomes equal to the saturation water-vapor pressure, and any further
cooling beyond this point will normally result in the condensation of
3.1 Definitions:
moisture.
air conditioning—the simultaneous control of all, or at least
humidify—to increase, by any process, the quantity of water
the first three, of those factors affecting both the physical and
vapor within a given space.
chemical conditions of the atmosphere within any structure.
humidistat—a regulatory device, activated by changes in
These factors include temperature, humidity, motion, distri-
humidity, used for the automatic control of relative humidity.
bution, dust, bacteria, odor, and toxic gases.
humidity—the condition of the atmosphere in respect to water
air, dry—air containing no water vapor.
vapor. (See also humidity, absolute; humidity, relative.)
air, saturated—a mixture of dry air and water vapor in which
humidity, absolute—the weight of water vapor present in a
the latter is at its maximum concentration for the prevailing
unit volume of air, for example, grains per cubic foot, or
temperature and pressure.
grams per cubic metre.
atmospheric pressure—the pressure due to the weight of the
atmosphere. It is the pressure indicated by a barometer that
NOTE 2—The amount of water vapor is also reported in terms of weight
registers actual atmospheric pressure which is not corrected per unit weight of dry air, for example, grains per pound of dry air. This
value differs from values calculated on a volume basis and should not be
to sea level equivalence. Standard atmospheric pressure is a
referred to as absolute humidity. It is designated as humidity ratio,
pressure of 76 cm Hg (101325 Pa) having a density of
3 2 specific humidity, or moisture content, which also see.
13.5951 g/cm , under standard gravity of 980.665 cm/s .
humidity ratio—in a mixture of water vapor and air, the mass
of water vapor per unit mass of dry air.
humidity, relative—the ratio of the actual pressure of existing
These definitions are under the jurisdiction of ASTM Committee G-3 on
water vapor to the maximum possible (saturation) pressure
Durability of Nonmetallic Materials and are the direct responsibility of Subcom-
mittee G03.92 on Terminology.
of water vapor in the atmosphere at the same temperature,
Current edition approved May 15, 1992. Published September 1992. Originally
expressed as a percentage.
published as E 41 – 42 T. Last previous edition E 41 – 86.
humidity, specific—in a mixture of water vapor and air, the
Annual Book of ASTM Standards Vol 15.09.
Annual Book of ASTM Standards Vol 11.03. mass of water vapor per unit mass of mois
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.