ASTM E879-93

Standard Specification for Thermistor Sensors for Clinical Laboratory Temperature Measurements

SCOPE
1.1 This specification covers the general requirements for negative temperature coefficient thermistor-type sensors intended to be used for clinical laboratory temperature measurements or control, or both, within the range from -10 to 105oC.
1.2 This specification also covers the detailed requirements for ASTM designated sensors.
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: 09-May-2001
• ICS: 17.200.20 - Temperature-measuring instruments
• Technical Committee: E20 - Temperature Measurement
• Drafting Committee: E20.03 - Resistance Thermometers

Relations

• Replaced By: ASTM E879-01 - Standard Specification for Thermistor Sensors for Clinical Laboratory Temperature Measurements
• Effective Date: 10-May-2001
• Referred By: ASTM D70/D70M-21 - Standard Test Method for Specific Gravity and Density of Semi-Solid Asphalt Binder (Pycnometer Method)
• Effective Date: 10-May-2001
• Referred By: ASTM E2877-12(2019) - Standard Guide for Digital Contact Thermometers
• Effective Date: 10-May-2001
• Referred By: ASTM E344-20 - Terminology Relating to Thermometry and Hydrometry
• Effective Date: 10-May-2001
• Referred By: ASTM D2170/D2170M-22 - Standard Test Method for Kinematic Viscosity of Asphalts
• Effective Date: 10-May-2001
• Referred By: ASTM D1525-17e1 - Standard Test Method for Vicat Softening Temperature of Plastics
• Effective Date: 10-May-2001
• Referred By: ASTM D2171/D2171M-22 - Standard Test Method for Viscosity of Asphalts by Vacuum Capillary Viscometer
• Effective Date: 10-May-2001

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: E 879 – 93
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 Specification for
Thermistor Sensors for Clinical Laboratory Temperature
Measurements
This standard is issued under the fixed designation E 879; 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 under the specification.
3.2.4 response time, n—the time required for a sensor to
1.1 This specification covers the general requirements for
change a specified percentage of the total difference between
negative temperature coefficient thermistor-type sensors in-
its initial and final temperatures as determined from zero-
tended to be used for clinical laboratory temperature measure-
power resistances when the sensor is subjected to a step
ments or control, or both, within the range from −10 to 105°C.
function change in temperature.
1.2 This specification also covers the detailed requirements
3.2.5 time constant, n—the 63.2 % response time of a
for ASTM designated sensers.
sensor that exhibits a single-exponential response.
2. Referenced Documents
3.2.6 zero-power resistance, n—the dc resistance of a de-
vice, at a specified temperature, calculated for zero-power.
2.1 ASTM Standards:
3.2.6.1 Discussion—Accurate zero-power resistance is ob-
E 344 Terminology Relating to Thermometry and Hydrom-
tained by extrapolating to zero-power the resistance values
etry
obtained from measurements at three or more levels of power
E 563 Practice for Preparation and Use of Freezing Point
with the sensor immersed in a constant temperature medium.
Reference Baths
For the purpose of this specification, this is obtained from
3. Terminology
measurements at a single power level adjusted such that the
power is not greater than one-fifth the product of the dissipa-
3.1 Definitions—The definitions given in Terminology
tion constant specified in Table 1 (see 3.2.1 and 7.3) and the
E 344 shall apply to this specification.
appropriate tolerance requirement of Table 2. When making
3.2 Definitions of Terms Specific to This Standard:
stability measurements, the power shall be kept constant.
3.2.1 dissipation constant, d, n—the ratio of the change in
˙
energy dissipated per unit time (power) in a thermistor, DQ
4. Classification
˙ ˙
5 Q − Q , to the resultant temperature change of the ther-
2 1
4.1 Thermistor sensors covered by this specification shall be
mistor, Dt 5 t − t .
2 1
classified with a type designation code that includes the ASTM
˙
DQ
detailed specification number followed by a descriptive code.
d5 (1)
Dt
See Fig. 1.
The dimensions of the dissipation constant are W/°C.
4.2 ASTM Specification Number—The ASTM specification
For this specification, t is in the range from 20 to 38°C and
number specifies uniquely the design and construction of the
Dt 5 10°C.
sensor including the type designation if more than one type
3.2.2 insulation resistance, dc, n—the resistance at a speci-
appears in the same specification.
fied direct-current voltage between the insulated leads of a
4.3 Operating Temperature Range—The operating tempera-
thermistor sensor and the metallic enclosure of the sensor, if
ture range shall be designated by a letter symbol (see Table 3).
such an enclosure is present, or else between the sensor leads
4.4 Accuracy Class—The accuracy class shall be designated
and a conductive medium in which the sensor is immersed.
by a single-digit number (see Table 2).
3.2.3 qualification test, n—a series of tests conducted by the
4.5 Calibration Type—The calibration type shall be desig-
procuring agency or an agent thereof to determine conform-
nated by a letter symbol. The letter I shall be used to denote
ance of thermistor sensors to the requirements of a specifica-
units that are interchangeable with respect to a single
tion, normally for the development of a qualified products list
resistance-temperature relationship. The letter N shall be used
to denote noninterchangeable units for which resistance-
temperature information must be furnished for each unit. For
This specification is under the jurisdiction of ASTM Committee E-20 on
Temperature Measurement and is the direct responsibility of Subcommittee E20.08 N-type sensors, serial number identification must be provided.
on Medical Thermometry.
Current edition approved Feb. 15, 1993. Published April 1993. Originally
5. Requirements
published as E 879 – 82. Last previous edition E 879 – 92.
5.1 Specifications—Sensors shall comply with the general
Annual Book of ASTM Standards, Vol 14.03.
E 879
TABLE 1 Specification for ASTM Clinical Laboratory Thermistor Sensors
ASTM No. B1N B1N B2N B2N
Description Silicone Rubber Coated Glass Epoxy Coated Glass Probe Silicone Rubber Coated Glass Epoxy Coated Glass Probe
Probe Probe
Major Application General Purpose Clinical General Purpose Clinical General Purpose Clinical General Purpose Clinical
Laboratory Temperature Laboratory Temperature Laboratory Temperature Laboratory Temperature
Measurement Measurement Measurement Measurement
Operating Temperature Range −10 to 60°C −10 to 60°C −10 to 60°C −10 to 60°C
Accuracy Class 1 (60.01°C) 1 (60.01°C) 2 (60.02°C) 2 (60.02°C)
Temperatures for Accuracy Class −10 to 60°C −10 to 60°C −10 to 60°C −10 to 60°C
Accuracies for other Temperatures
Within Specified Temperature
Range
Calibration Type Non-interchangeable Non-interchangeable Non-interchangeable Non-interchangeable
Nominal R-T Characteristic
R 5 exp[A + A /T + A /T +
0 1 2
A /T ] (T in kelvins)
T(°C) 5 [a +a LnR +a (LnR) +
0 1 2
3 −1
a (LnR) ] − 273.15
A −4.4495078 −4.4495078 −4.4495078 −4.4495078
A 3614.7764 3614.7764 3614.7764 3614.7764
A 88190.906 88190.906 88190.906 88190.906
A −22328247 −22328247 −22328247 −22328247
−2 −2 −2 −2
a 0.11766716 3 10 0.11766716 3 10 0.11766716 3 10 0.11766716 3 10
−3 −3 −3 −3
a 0.28173082 3 10 0.28173082 3 10 0.28173082 3 10 0.28173082 3 10
−5 −5 −5 −5
a −0.23285292 3 10 −0.23285292 3 10 −0.23285292 3 10 −0.23285292 3 10
−6 −6 −6 −6
a 0.24131652 3 10 0.24131652 3 10 0.24131652 3 10 0.24131652 3 10
Type of Immersion Fluid water, air water, oil, air water, air water, oil, air
Nominal R at 25°C 2.5 kV 2.5 kV 2.5kV 2.5 kV
Dissipation Constant 3.5 6 0.9 mW/°C 5.0 6 1.2 mW/°C 3.56 0.9 mW/°C 5.0 6 1.2 mW/°C
63.2 % Response Time 0.55 6 0.16 s 0.45 6 0.11 s 0.55 6 0.16 s 0.45 6 0.11 s
Ratio of 95 % to 63.2 % Response 2.5 6 0.6 2.1 6 0.5 2.5 6 0.6 2.1 6 0.5
Times
Design and Construction Fig. 2 Fig. 3 Fig. 2 Fig. 3
ASTM No. A2N A2N B1N B1N
Description Silicone Rubber Coated Glass 5kV -4-Wire 5kV -2-Wire
Probe Non-interchangeable Sensor Non-interchangeable
Epoxy Coated Glass Probe
in S.S. Housing Sensor
in S.S. Housing
Major Application General Purpose Clinical General Purpose Clinical General Purpose Clinical General Purpose Clinical
Laboratory Temperature Laboratory Temperature Laboratory Temperature Laboratory Temperature
Measurement Measurement Measurement Measurement
Operating Temperature Range −10 to 105°C −10 to 105°C −10 to 60°C −10 to 60°C
Accuracy Class 2 (60.02°C) 2 (60.02°C) 1 (60.01°C) 1 (60.01°C)
Temperatures for Accuracy Class −10 to 105°C −10 to 105°C −10 to 60°C −10 to 60°C
Accuracies for other Temperatures
Within Specified Temperature
Range
Calibration Type Non-interchangeable Non-interchangeable Non-interchangeable Non-interchangeable
Nominal R-T Characteristic
R 5 exp[A + A /T + A /T +
0 1 2
A /T ]
T(°C) 5 [a +a LnR +a (LnR) +
0 1 2
3 −1
a (LnR) ] − 273.15
A −4.3332974 −4.3332947 −3.7563605 −3.7563605
A 4440.1603 4440.1603 3614.7764 3614.7764
A −104525.78 −104525.78 88190.906 88190.906
A −4581329.78 −4581329.78 −22328247 −22328247
−3 −3 −3 −3
a 0.98667965 3 10 0.98667965 3 10 0.98019160 3 10 0.98019160 3 10
−3 −3 −3 −3
a 0.24329879 3 10 0.24329879 3 10 0.28530667 3 10 0.28530667 3 10
−6 −6 −5 −5
a −0.59584872 3 10 −0.59584872 3 10 −0.28303328 3 10 −0.28303328 3 10
−7 −7 −6 −6
a 0.97166167 3 10 0.97166167 3 10 0.24131652 3 10 0.24131652 3 10
Type of Immersion Fluid water, air water, air all fluids compatible with Type all fluids compatible with
304 S.S. Type 304 S.S.
R at 25°C 10kV 10 kV 5 kV 5 kV
Dissipation Constant 3.5 6 0.9 mW/°C 5.0 6 1.2 mW/°C 4.86 1.2 mW/°C 4.8 6 1.2 mW/°C
63.2 % Response Time 0.55 6 0.16 s 0.45 6 0.11 s 4.5 6 1.1 s 4.5 6 1.1 s
Ratio of 95 % to 63.2 % Response 2.5 6 0.6 2.1 6 0.5 2.6 6 0.3 2.6 6 0.3
Times
Design and Construction Fig. 2 Fig. 3 Fig. 4 Fig. 5
requirements specified herein as well as with the applicable 5.2 Zero-Power Resistance versus Temperature
detailed specifications of Table 1. In the event of conflict Relationship—The zero-power resistance versus temperature
between this requirement paragraph and the detailed specifi- relationship shall be presented in a form such that any
cation of Table 1, Figs. 2-7 the latter shall govern. temperature within the specified operating temperature range
E 879
TABLE 1 (continued)
ASTM No. B1N B1N A2N A2N
Description 10 kV 4-Wire Non- 10 kV 2-Wire Non- 10 kV 4-Wire Non- 10 kV 2-Wire Non-
interchangeable Sensor in interchangeable Sensor in interchangeable Sensor in interchangeable Sensor in
S.S. Housing S.S. Housing S.S. Housing S.S. Housing
Major Application General Purpose Clinical General Purpose Clinical General Purpose Clinical General Purpose Clinical
Laboratory Temperature Laboratory Temperature Laboratory Temperature Laboratory Temperature
Measurement Measurement Measurement Measurement
Operating Temperature Range −10 to 60°C −10 to 60°C −10 to 105°C −10 to 105°C
Accuracy Class 1 (60.01°C) 1 (60.01°C) 2 (60.02°C) 2 (60.02°C)
Temperatures for Accuracy −10 to 60°C −10 to 60°C −10 to 105°C −10 to 105°C
Class
Accuracies for other
Temperatures
Within Specified Temperature
Range
Calibration Type Non-interchangeable Non-interchangeable Non-interchangeable Non-interchangeable
Nominal R-T Characteristic
R 5 exp[A + A /T + A /T +
0 1 2
A /T ]
T(°C) 5 [a +a LnR +a (LnR) +
0 1 2
3 −1
a (LnR) ] − 273.15
A −3.5684919 −3.5684919 −3.7191520 −3.7191520
A 3907.7065 3907.7065 4045.1666 4045.1666
A 33480.382 33480.382 −8181.7100 -8181.7100
A −18666997 −18666997 −14472122 −14472122
−3 −3 −3 −3
a 0.86972495 3 10 0.86972495 3 10 0.89898144 3 10 0.89898144 3 10
−3 −3 −3 −3
a 0.27135335 3 10 0.27135335 3 10 0.26152805 3 10 0.26152805 3 10
−5 −5 −6 −6
a −0.20689100 3 10 −0.20689100 3 10 −0.97537969 3 10 −0.97537969 3 10
−6 −6 −6 −6
a 0.20547429 3 10 0.20547429 3 10 0.16613292 3 10 0.16613292 3 10
Type of Immersion Fluid all fluids compatible with Type all fluids compatible with Type all fluids compatible with Type all fluids compatible with Type
304 S.S. 304 S.S. 304 S.S. 304 S.S.
Nominal R at 25°C 10 kV 10kV 10 kV 10 kV
Dissipation Constant 4.8 6 1.2 mW/°C 4.8 6 1.2 mW/°C 4.86 1.2 mW/°C 4.8 6 1.2 mW/°C
63.2 % Response Time 4.5 6 1.1 s 4.5 6 1.1 s 4.56 1.1 s 4.5 6 1.1 s
Ratio of 95 % to 63.2 % 2.6 6 0.3 2.6 6 0.3 2.6 6 0.3 2.6 6 0.3
Response
Times
Design and Construction Fig. 4 Fig. 5 Fig. 4 Fig. 5
ASTM No. B3I B3N
Description Interchangeable Sensor Non-interchangeable Sensor
Enclosed in 1.17 mm Plastic Enclosed in 0.92 mm Plastic
Tube Tube
Major Application Cuvette Thermometry Cuvette Thermometry
Operating Temperature Range −10 to 60°C −10 to 60°C
Accuracy Class 3 (60.05°C) 3 (60.05°C)
Temperatures for Accuracy 24 to 45°C −10 to 60°C
Class
Accuracies for other −10 to 24°C: 60.1°C
Temperatures 45 to 60°C: 60.1°C
Within Specified Temperature
Range
Calibration Type Interchangeable Non-interchangeable
Nominal R-T Characteristic
R 5 exp[A + A /T + A /T +
0 1 2
A /T ]
T(°C) 5 [a +a LnR +a (LnR) +
0 1 2
3 −1
a (LnR) ] − 273.15
A −3.1645305 −3.0612396
A 3763.4399 3613.0051
A 47816.278 88718.122
A −18332303 −22380305
−3 −3
a 0.78686094 3 10 0.78069589 3 10
−3 −3
a 0.28128740 3 10 0.28967541 3 10
−5 −5
a −0.25226292 3 10 −0.38427027 3 10
−6 −6
a 0.20852922 3 10 0.24169639 3 10
Type of Immersion Fluid water water
Nominal R at 25°C 11 kV 10 kV
Dissipation Constant 1.1 6 0.3 mW/°C 0.8 6 0.2 mW/°C
63.2 % Response Time 0.5 6 0.12 s 0.26 6 0.06 s
Ratio of 95 % to 63.2 % 3.0 6 0.3 3 6 0.3
Response
Times
Design and Construction Fig. 6 Fig. 7
E 879
TABLE 2 Equivalent Temperature Tolerances for Different Class
with 7.8.1, there shall be no evidence of mechanical damage
Sensors (See 4.1 and 4.4)
and the insulation resistance shall be sufficiently high that its
Accuracy Temperature
shunting effect will not prevent the unit from complying with
Class Tolerance, °C
the accuracy requirement of Table 2. In no case shall the
1 60.02
insulation resistance be less than 10 ohms.
2 60.03
3 60.05 5.8.2 Wet Test—This requirement shall apply to sensors that
4 60.1
are designed for use in conductive solutions. When tested in
accordance with 7.8.2, there shall be no evidence of mechani-
cal damage and the insulation resistance shall be sufficiently
can be obtained from that relationship and have an uncertainty
high that its shunting effect will not prevent the unit from
no greater than one-tenth the specified tolerance in Table 2.
complying with the accuracy requirement of Table 2. In no case
When tested in accordance with 7.2, the zero-power resistance 8
shall the insulation resistance be less than 10 ohms.
versus temperature relationship for interchangeable parts shall
comply to within the tolerance specified in Table 2. The
6. Quality Assurance Provisions
manufacturer of the sensor shall, for noninterchangeable parts,
6.1 General—The methods of examination and tests con-
supply this relationship with each part shipped.
tained in Section 7 are to be used to determine the conformance
5.2.1 Accuracy—The resistance-temperature relationship,
of sensors to the requirements of this specification. Each
provided in Table 1, or with the sensor, or both, shall not differ
manufacturer or distributor who represents his products as
from that obtained from measurements made in accordance
conforming to this specification may, as agreed upon between
with 7.2 by more than the tolerances specified in Table 2 for the
the purchaser and seller, use statistically based sampling plans
applicable intervals specified in Table 1.
that are appropriate for each inspection lot. Records shall be
5.3 Thermal Requirements:
kept as necessary to document the claim that all of the
5.3.1 Dissipation Constant—When tested in accordance
requirements of this specification are met. The tests
...