ASTM D7962-15
(Practice)Standard Practice for Determination of Minimum Immersion Depth and Assessment of Temperature Sensor Measurement Drift
Standard Practice for Determination of Minimum Immersion Depth and Assessment of Temperature Sensor Measurement Drift
SIGNIFICANCE AND USE
5.1 This practice provides a means for the users of ASTM Committee D02 standards to monitor the drift in sensed temperature of liquid-in-glass thermometer (LiG), and digital contact thermometers (DCT). Digital contact thermometers are sometimes referred to as portable electronic thermometers (PET) or simply digital thermometers.
5.2 This practice is not suitable for determining the accuracy or calibration of a temperature measuring device as the error in the ice bath temperature can be greater than 0.02 °C. For greater accuracy, the user should use Practice E563 to prepare the ice bath.
5.3 The ice point is a common practical industrial reference point of thermometry. The ice point is relatively simple to realize and provides a readily available natural fixed-point reference temperature.
5.4 This practice only checks the measurement drift at a single temperature. It will not detect a change in measurement response with change in temperature. Temperature measuring devices should be recalibrated at set intervals. See device supplier for recommendations.
5.5 This practice provides a technique to determine minimum immersion depth of the sensing probe of the thermometer using an ice bath. The minimum immersion depth determined by this practice may change when the differential temperature differs significantly from the conditions described. A greater differential will likely increase the minimum immersion depth.
SCOPE
1.1 This practice describes a two procedures for use with temperature measurement devices. Methodology is described for determining minimum immersion depth for thermal sensors, in particular RTDs or similar temperature sensors. Included is a procedure for consistently preparing a reference bath for the purpose of monitoring measurement drift of thermal sensors such as liquid-in-glass or digital contact thermometers.
1.2 This practice focuses on temperature measurement drift in a laboratory. If the user requires greater measurement accuracy, then they should follow the instructions in Practice E563.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: D7962 − 15
StandardPractice for
Determination of Minimum Immersion Depth and
1
Assessment of Temperature Sensor Measurement Drift
This standard is issued under the fixed designation D7962; 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 3.1.2 minimum immersion length, n—depth that a thermom-
eter should be immersed, in a uniform temperature
1.1 This practice describes a two procedures for use with
environment, such that further immersion does not produce a
temperature measurement devices. Methodology is described
change in indicated temperature greater than the specified
for determining minimum immersion depth for thermal
tolerance.
sensors, in particular RTDs or similar temperature sensors.
Included is a procedure for consistently preparing a reference
4. Summary of Practice
bath for the purpose of monitoring measurement drift of
thermal sensors such as liquid-in-glass or digital contact
4.1 This practice describes a procedure for consistently
thermometers. preparing an ice bath that is an intimate mixture of crushed ice
or ice particles and water in a thermally insulating vessel open
1.2 This practice focuses on temperature measurement drift
to the atmosphere.
in a laboratory. If the user requires greater measurement
4.1.1 Caution—when the ice bath is not made from distilled
accuracy, then they should follow the instructions in Practice
water, its temperature will differ from the natural fixed-point
E563.
temperature by a consistent amount, typically less than
1.3 The values stated in SI units are to be regarded as
0.02 °C. If the user needs a more accurate ice point, then they
standard. No other units of measurement are included in this
should use Practice E563 to prepare the ice bath.
standard.
4.2 This practice includes a procedure for determining the
1.4 This standard does not purport to address all of the
minimum immersion depth of the temperature sensor using an
safety concerns, if any, associated with its use. It is the
ice bath.
responsibility of the user of this standard to establish appro-
4.2.1 This procedure determines minimum immersion depth
priate safety and health practices and determine the applica-
with a 25 °C differential between sensed temperature and
bility of regulatory limitations prior to use.
ambient temperature. If the probe is subjected to a greater
differential temperature, a larger immersion depth may be
2. Referenced Documents
required to correctly measure the temperature.
2
2.1 ASTM Standards:
E563 Practice for Preparation and Use of an Ice-Point Bath
5. Significance and Use
as a Reference Temperature
5.1 This practice provides a means for the users of ASTM
Committee D02 standards to monitor the drift in sensed
3. Terminology
temperature of liquid-in-glass thermometer (LiG), and digital
3.1 Definitions:
contact thermometers (DCT). Digital contact thermometers are
3.1.1 ice-point bath, n—physical system containing ice and
sometimes referred to as portable electronic thermometers
water assembled to realize the ice point as a reference
(PET) or simply digital thermometers.
temperature, or to establish a constant temperature near 0 °C.
5.2 This practice is not suitable for determining the accu-
racy or calibration of a temperature measuring device as the
1
error in the ice bath temperature can be greater than 0.02 °C.
This practice is under the jurisdiction of ASTM Committee D02 on Petroleum
Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcom-
For greater accuracy, the user should use Practice E563 to
mittee D02.91 on Coordinating Subcommittee on Thermometry.
prepare the ice bath.
Current edition approved April 1, 2015. Published April 2015. DOI: 10.1520/
D7962-15.
5.3 The ice point is a common practical industrial reference
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
point of thermometry. The ice point is relatively simple to
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
realize and provides a readily available natural fixed-point
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. reference temperature.
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D7962 − 15
5.4 This practice only checks the measurement drift at a 7.1.6 Cover the ice-point bath leaving just enough open
single temperature. It will not detect a change in measurement space to access the thermometer probe and agitate the mix.
re
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