ASTM E1965-98(2023)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E1965 − 98 (Reapproved 2023)
Standard Specification for
Infrared Thermometers for Intermittent Determination of
Patient Temperature
This standard is issued under the fixed designation E1965; 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 1.7 This international standard was developed in accor-
dance with internationally recognized principles on standard-
1.1 This specification covers electronic instruments in-
ization established in the Decision on Principles for the
tended for intermittent measuring and monitoring of patient
Development of International Standards, Guides and Recom-
temperatures by means of detecting the intensity of thermal
mendations issued by the World Trade Organization Technical
radiation between the subject of measurement and the sensor.
Barriers to Trade (TBT) Committee.
1.2 The specification addresses assessing subject’s body
internal temperature through measurement of thermal emission
2. Referenced Documents
from the ear canal. Performance requirements for noncontact
2.1 ASTM Standards:
temperature measurement of skin are also provided.
E177 Practice for Use of the Terms Precision and Bias in
1.3 The specification sets limits for laboratory accuracy and
ASTM Test Methods
requires determination and disclosure of clinical accuracy of
E344 Terminology Relating to Thermometry and Hydrom-
the covered instruments.
etry
E667 Specification for Mercury-in-Glass, Maximum Self-
1.4 Performance and storage limits under various environ-
Registering Clinical Thermometers (Withdrawn 2022)
mental conditions, requirements for labeling, and test proce-
E1112 Specification for Electronic Thermometer for Inter-
dures are established.
mittent Determination of Patient Temperature
NOTE 1—For electrical safety, consult Underwriters Laboratory Stan-
dards.
2.2 International Electrotechnical Commission Standards:
NOTE 2—For electromagnetic emission requirements and tests, refer to
IEC 601-1-2:1993 Medical Electrical Equipment, Part 1;
CISPR 11: 1990 Lists of Methods of Measurement of Electromagnetic
General Requirements for Safety. Collateral Standard:
Disturbance Characteristics of Industrial, Scientific, and Medical (ISM)
Electromagnetic Compatibility—Requirements and Tests
Radiofrequency Equipment.
IEC 1000-4-2:1995 Electromagnetic Compatibility
1.5 The values of quantities stated in SI units are to be
(EMC)—Part 4: Testing and Measurement Techniques;
regarded as the standard. The values of quantities in parenthe-
Section 2: Electrostatic Discharge Immunity Test: Basic
ses are not in SI and are optional.
EMC Publication (Rev. of IEC 801-2)
1.6 The following precautionary caveat pertains only to the
IEC 1000-4-3:1995 Electromagnetic Compatibility
test method portion, Section 6, of this specification: This
2.3 Other Standards:
standard does not purport to address all of the safety concerns,
International Vocabulary of Basic and General Terms in
if any, associated with its use. It is the responsibility of the user
Metrology (VIM)
of this standard to establish appropriate safety, health, and
environmental practices and determine the applicability of
3. Terminology
regulatory limitations prior to use.
3.1 Definitions—The definitions given in Terminology E344
apply.
1 3.2 Definitions of Terms Specific to This Standard:
This specification is under the jurisdiction of ASTM Committee F04 on
Medical and Surgical Materials and Devices and is the direct responsibility of
Subcommittee F04.33 on Medical/Surgical Instruments.
Current edition approved Feb. 1, 2023. Published February 2023. Originally
approved in 1998. Last previous edition approved in 2016 as E1965 – 98 (2016). For referenced ASTM standards, visit the ASTM website, www.astm.org, or
DOI: 10.1520/E1965-98R23. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Available from Underwriters Laboratories (UL), 2600 N.W. Lake Rd., Camas, Standards volume information, refer to the standard’s Document Summary page on
WA 98607-8542, http://www.ul.com. the ASTM website.
3 5
Available from Global Engineering Documents, 15 Inverness Way East, The last approved version of this historical standard is referenced on www.ast-
Englewood, CO 80112. m.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1965 − 98 (2023)
3.2.1 The terms defined below are for the purposes of this 3.2.16 displayed temperature range, n—temperature range
specification only. Manufacturers should use this terminology in degrees Celsius or Fahrenheit that can be shown by an IR
in labeling instruments and in technical and sales literature. thermometer.
3.2.2 accuracy, n—ability of an infrared thermometer to
3.2.17 IR thermometer type, n—an optoelectronic instru-
give a reading close to the true temperature.
ment that is capable of noncontact infrared temperature mea-
3.2.3 adjusted mode, n—output of an IR thermometer that surement when placed into the auditory canal of a subject (ear
gives the temperature measured and calculated from a subject canal type) or from the subject’s body surface (skin type).
or object, by correcting such temperature for variations in
3.2.18 ear canal temperature [t ], n—displayed unadjusted
ec
ambient temperature, the subject’s temperature, emissivity,
temperature measured from the field of view of an IR thermom-
body site (that is, oral, or rectal), etc.
eter whose probe is placed into the auditory canal of a subject
3.2.4 axillary temperature [t ], n—temperature at the apex according to the manufacturer’s recommendations.
ba
of either axilla (armpit) as measured by a contact thermometer.
3.2.19 field of view, n—area of a subject’s surface that
3.2.5 blackbody, n—a reference source of infrared radiation exchanges thermal radiation with the sensor.
made in the shape of a cavity and characterized by precisely
3.2.20 infrared (IR), adj—of the electromagnetic radiation
known temperature of the cavity walls and having effective
within the mid- and far infrared spectral ranges (approximately
emissivity at the cavity opening arbitrarily considered equal to
from 3 to 30 μm wavelength).
unity.
3.2.21 infrared (IR) thermometer, n—optoelectronic instru-
3.2.6 blackbody temperature [t ], n—temperature of
BB
ment adapted for noncontact measurement of the temperature
blackbody cavity walls as measured by an imbedded or
of a subject by utilizing infrared radiation exchange between
immersed contact thermometer.
the subject and the sensor.
3.2.7 bladder temperature, n—temperature of the interior of
3.2.22 instrumentational offset [μ ], n—calculated differ-
d
the urinary bladder as measured by a contact thermometer.
ence in degrees of measured temperature between core tem-
3.2.8 body temperature, n—temperature measured from the perature and ear canal temperature, derived from the popula-
interior of a human body cavity, such as pulmonary artery, tion of representative study samples.
distal esophagus, urinary bladder, ear canal, oral, or rectal.
3.2.23 internal, adj—of the interior of subject’s body or
3.2.9 clinical accuracy, n—ability of an infrared ear canal body cavity, such as pulmonary artery, urinary bladder, oral,
thermometer to give a reading close to true temperature of the
rectal, etc.
site that it purports to represent.
3.2.24 laboratory error [δ], n—difference between unad-
3.2.10 clinical bias [x¯¯ ], n—mean difference between IR justed temperature as measured by an IR thermometer and
d
thermometer output and an internal body site temperature from
temperature of a blackbody, over specified operating condi-
subjects at specified conditions of ambient temperature and tions of ambient temperature and humidity and blackbody
humidity and averaged over a selected group of subjects.
temperature ranges.
3.2.11 clinical repeatability [s ], n—pooled standard devia-
3.2.25 operating temperature, n—ambient temperature that
r
tion of changes in multiple ear canal temperature readings as allows operation of an IR thermometer within specified labo-
taken from the same subject from the same ear with the same
ratory error range.
infrared thermometer by the same operator within a relatively
3.2.26 operating humidity, n—relative humidity of ambient
short time.
air which allows operation of an IR thermometer within a
3.2.12 combined site offset [μ ], n—calculated difference in specified laboratory error range.
s
degrees of measured temperature between a selected reference
3.2.27 oral temperature [t ], n—posterior sublingual tem-
bm
body site and ear canal temperature and averaged over the
perature as measured by a contact thermometer.
population of representative study samples.
3.2.28 physiological site offset, [μ ], n—difference in de-
p
3.2.13 contact thermometer, n—an instrument that is
grees of measured temperature between two body sites derived
adapted for measuring temperature by means of thermal
from the representative study samples.
conductivity by determining temperature at the moment when
3.2.29 probe, n—part of an IR thermometer that channels
negligible thermal energy flows between the thermometer and
net infrared radiation between the subject and the sensor and is
the object of measurement.
intended to be positioned near or inside the subject.
3.2.14 core temperature [t ], n—temperature at a subject’s
c
3.2.30 probe cover, n—disposable or reusable sanitary bar-
body site, such as the pulmonary artery, distal esophagus,
rier enveloping that part of the probe which otherwise would
urinary bladder, or tympanic membrane, recognized as indica-
come in contact with a subject.
tive of internal body temperature and obtained with a contact
thermometer. 3.2.31 professional use, n—intended or implied use of an
instrument by individuals that are licensed or certified for
3.2.15 mode, n—an output of an IR thermometer that gives
collecting information for medical diagnosing purposes.
a representation of a temperature using a disclosed calculation
technique with respect to selected reference (for example, 3.2.32 rectal temperature [t ], n—temperature in the anal
br
blackbody, oral, rectal, etc.). canal as measured by a contact thermometer.
E1965 − 98 (2023)
3.2.33 resolution, n—minimum temperature increment dis- 5.4.1 Within the manufacturer’s specified operating ambient
played by an IR thermometer in degrees Celsius or Fahrenheit. conditions (see 5.6) over the display temperature range as
specified in 5.2.2, laboratory error δ as measured according to
3.2.34 scale, n—graduation of temperature display in de-
6.1.5 shall be no greater than 0.3 °C (0.5 °F).
grees Celsius or Fahrenheit.
5.5 Special Requirements:
3.2.35 sensor, n—device designed to respond to net IR
5.5.1 Clinical Accuracy:
radiation and convert that response into electrical signals.
5.5.1.1 The clinical accuracy requirement is applicable only
3.2.36 skin temperature, n—average temperature of a flat
to an ear canal IR thermometer system and the corresponding
skin surface as measured from the field of view of an IR skin
age groups of subjects for which such a thermometer is labeled
type thermometer, with an appropriate adjustment for skin
or implied to be used.
emissivity.
5.5.1.2 Clinical accuracy shall be determined separately for
3.2.37 system, n—combination of an IR thermometer and an
each of the following conditions: for each device model, for
installed probe cover.
each adjusted display mode, and for every age group of febrile
3.2.38 subject, n—a human whose temperature is measured.
and afebrile subjects on which the IR thermometer is intended
to be used.
3.2.39 true temperature, n—temperature attributed to a
5.5.1.3 Any disclosure of clinical accuracy claims shall be
particular site of a subject or object of measurement and
accompanied by disclosure of methodology and procedures.
accepted as having a specified uncertainty.
Such information shall be made available on request.
3.2.40 tympanic temperature [t ], n—temperature of either
ty
5.5.1.4 Clinical accuracy should be determined in the form
tympanic membrane as measured by a contact thermometer.
of two characteristics—clinical bias with stated uncertainty and
3.2.41 unadjusted mode, n—an output of IR thermometer
clinical repeatability, as defined in 3.2.9.
that displays temperature measured and calculated from a
5.6 Ambient Conditions:
subject or object, without any corrections for variations in
5.6.1 Operating Temperature Range:
operating temperature, subject temperature, emissivity, etc.
5.6.1.1 The system shall meet laboratory error requirements
as specified in 5.3 or 5.4, or both, when operating in an
4. Classification
environment from 16 to 40 °C (60.8 to 104.0 °F).
4.1 IR thermometers may be classified into two types: “ear
5.6.1.2 If the operating temperature range is narrower than
canal IR thermometers” and “skin IR thermometers.”
specified in 5.6.1.1, the device shall be clearly labeled with a
4.1.1 The ear canal IR thermometer is intended for assessing
cautionary statement of the maximum or minimum operating
the internal temperature of a subject.
temperatures, or both.
4.1.2 The skin IR thermometer is intended for assessing the
5.6.1.3 Under no circumstances may the upper limit of
outer surface temperature of a subject.
operating temperature range be less than 35 °C (95 °F).
5.6.2 Operating Humidity Range—The relative humidity
5. Requirements
range for the operating temperature range as specified in 5.6.1
5.1 The following requirements shall apply to any IR
is up to 95 %, noncondensing.
thermometer that is labeled to meet these specifications.
5.6.3 Shock:
5.6.3.1 The instrument with batteries installed (if appli-
5.2 Displayed Temperature Range:
cable) without a carrying (storage) casing shall withstand drops
5.2.1 In any display mode, an ear canal IR thermometer
with controlled orientation of the device without degradation of
shall display a subject’s temperature over a minimum range of
accuracy as specified in 5.3 or 5.4, or both, for a blackbody
34.4 to 42.2 °C (94.0 to 108.0 °F).
temperature of or near 37 °C (98.6 °F), when tested according
5.2.2 A skin IR thermometer shall display a subject’s
to 6.3.
temperature over a minimum range of 22 to 40.0 °C (71.6 to
5.6.3.2 If an IR thermometer does not meet the requirement
104.0 °F).
of 5.6.3.1, a means of detecting and informing the user of its
5.3 Maximum Permissible Laboratory Error (for an Ear
inoperable state, after being subjected to shock, shall be
Canal IR Thermometer):
provided.
5.3.1 Within the manufacturer’s specified operating ambient
5.6.4 Storage Conditions—The instrument shall meet the
conditions (see 5.6), laboratory error δ as measured according
accuracy requirements of 5.3 or 5.4, or both, after having been
to 6.1.4 shall be no greater than values specified below:
stored or transported, or both, at any point in an environment
5.3.1.1 For blackbody temperature range from 36 to 39 °C
of –20 to +50 °C (–4 to +122 °F) and relative humidity up to
(96.8 to 102.2 °F):
95 %, noncondensing, for a period of one month. The test
0.2 °C (0.4 °F).
procedure is specified in 6.1.6.
5.3.1.2 For blackbody temperatures less than 36 °C (96.8
5.6.5 Cleaning and Disinfection—Instrument performance
°F) or greater than 39 °C (102.2 °F):
shall not be degraded by using the manufacturer’s recom-
0.3 °C (0.5 ° F).
mended procedures for cleaning and disinfection provided in
5.4 Maximum Permissible Laboratory Error (for a Skin IR the instruction manual. Such procedures are part of the
Thermometer): required documentation in 7.2.2.
E1965 − 98 (2023)
5.6.6 Electromagnetic Immunity—An IR thermometer that display only one mode and are intended for non-professional
is intended for professional use shall meet the accuracy use. However, as required in 7.2.1.3, the instruction manual for
requirements of 5.3 or 5.4, or both, for temperature ranges of both professional and non-professional use IR thermometers
6.3.2, during and after exposure to electromagnetic interfer- shall specify the body site(s) (that is, oral, rectal, core) used to
ence. reference the adjusted temperature value(s) displayed.
5.6.7 Electrostatic Discharge—An IR thermometer shall
NOTE 3—All markings shall not deteriorate after prolonged use or
meet the accuracy requirements of 5.3 and 5.4, or both, for
cleaning.
temperature ranges of 6.3.2, after 5 s after being subjected to
5.10.2 Probe Covers Package:
electrostatic discharge.
5.10.2.1 The package shall state the name and type of the
5.7 Low Power Supply Operation—The instrument shall
enclosed products, name of the manufacturer or distributor, lot
operate at power supply voltage lower by no less than 0.1 V
number or serial number, and expiration date (if the probe
than that required for indication of low power supply sign as
covers have limited shelf life).
specified by 5.8.3. The test of operation is defined in 6.3.2 and
5.10.2.2 The thermometer model(s) for which the covers are
6.3.3.
intended for use shall be specified on the probe cover package.
5.10.2.3 The package shall state whether the probe cover is
5.8 Display and Human Interface:
intended for single use or multiple use.
5.8.1 Resolution—The resolution of a display shall be
5.10.2.4 Any probe cover handling, application, storage, or
0.1 °C (0.1 °F).
cleaning procedures which impact the ability of an IR ther-
5.8.2 Modes:
mometer to meet the requirements for maximum permissible
5.8.2.1 An IR thermometer shall indicate in what mode the
laboratory error specified in 5.3 shall be stated.
instrument is set.
5.8.2.2 Unadjusted Mode—The unadjusted mode shall be
6. Test Methods
accessible by the user either by setting the instrument into that
mode directly or by a conversion technique from adjusted 6.1 The tests are not required for every produced instru-
mode. ment. However, each producer or distributor who represents its
5.8.2.3 The adjusted mode sets an IR thermometer to instruments as conforming to this specification shall utilize
represent a reference body site, such as core, oral, rectal, etc. statistically based sampling plans that are appropriate for each
particular manufacturing process, in the design qualification of
5.8.3 Warning Signs—The instrument shall have means to
inform the operator when the following are outside the the device, and shall keep such essential records as are
operating ranges specified by the manufacturer: power supply, necessary to document with a high degree of assurance its
subject temperature, and ambient temperature. claims that all of the requirements of this specification are met.
6.1.1 The manufacturer shall make the sampling plans
5.9 Construction:
available upon request.
5.9.1 Housing Materials—All materials that may come in
6.1.1.1 Laboratory Accuracy Tests:
contact with the operator or a subject shall be nontoxic.
6.1.1.2 General—Laboratory accuracy tests are intended for
5.9.2 Probe Covers:
verifying compliance of the design and construction of a
5.9.2.1 To provide a sanitary barrier between a subject and
particular type or model of IR thermometer with the error
the probe, a probe cover that comes in contact with a subject,
limitations specified in 5.3 or 5.4, or both.
if such a probe cover is required by the manufacturer, shall
6.1.2 Laboratory accuracy of an IR thermometer shall be
maintain its physical integrity while being placed on the probe
tested in all available display modes.
and during temperature measurement.
6.1.3 Blackbody:
5.9.2.2 A probe and a probe cover of the system shall have
6.1.3.1 Under laboratory conditions, an IR thermometer
shape and dimensions that prevent injury to a subject of any
shall be tested against a blackbody standard. A recommended
age.
blackbody design is provided in Annex A1. The temperature of
5.9.2.3 A probe cover shall not increase laboratory errors
a blackbody shall be measured by the IR thermometer being
whose limits are set in 5.3.1.
tested in accordance with a procedure recommended by the
5.10 Labeling and Marking (Instruments and Accessories):
manufacturer for the particular IR thermometer.
5.10.1 Thermometer and Accessories:
6.1.3.2 The true temperature of the blackbody shall be
5.10.1.1 A thermometer shall clearly indicate the units of its monitored by a contact imbedded or immersed thermometer
temperature scale.
with uncertainty no greater than 60.03 °C (60.05 °F).
5.10.1.2 An IR thermometer housing shall be clearly 6.1.3.3 A manufacturer may require that an IR thermometer
marked with the trade name or type of the device, or both,
is tested only with a manufacturer-specified blackbody, rather
model designation, name of the manufacturer or distributor, than that described in Annex A1.
and lot number or serial number.
6.1.4 Ear Canal Type IR Thermometer:
5.10.1.3 An IR thermometer intended for professional use 6.1.4.1 Tests shall be repeated for three blackbody
shall be conspicuously labelled with an indication of the temperatures, t , set within 60.5 °C (61 °F) of the following
BB
unadjusted or adjusted mode(s), or both, that correspond to the temperatures: 35, 37, and 41 °C, (95, 98.6, and 105.8 °F). At
temperature value(s) capable of being displayed by the instru- each blackbody temperature, the tests shall be repeated under
ment. Such labeling is optional for IR thermometers that the ambient conditions stated in Table 1.
E1965 − 98 (2023)
TABLE 1 Conditions of Ambient Temperature and Humidity for
humidity below 50 %, for a period of 30 days and at 50 °C
Testing an IR Thermometer with a Blackbody for Each of Three
(122 °F), relative humidity no less than 75 % noncondensing,
Blackbody Settings
for a period of 30 days. After each exposure the IR thermom-
Operating Temperature Relative Humidity (%)
eter shall be tested according to 6.3.2 and 6.3.3.
*
16 to 18 °C (60 to 65 °F) less than 50
*
16 to 18 °C (60 to 65 °F) 90 to 95
6.2 Clinical Accuracy Tests—This specification does not
24 to 26 °C (75 to 80 °F) 40 to 60
* prescribe an actual method for determining clinical accuracy or
38 to 40 °C (100 to 104 °F) less than 25
establish specifications for values which characterize clinical
38 to 40 °C (100 to 104 °F) 75 to 85
accuracy. Manufacturers shall perform clinical accuracy testing
in accordance with methods acceptable to the U.S. Food and
Drug Administration. An example of a method which may be
NOTE 4—For an IR thermometer that is specified for a different
used for this purpose is provided in X2.3.
operating temperature range than that required in 5.6.1.1, temperatures in
6.2.1 Purpose of Tests—Clinical accuracy tests are intended
Table 1 marked with an asterisk shall be changed for the respective limits
for evaluation of accuracy of built-in instrumentational or
of such specified operating temperature range.
combined site offsets, or both, and performance of an IR
6.1.4.2 Prior to the measurements, the IR thermometer shall
thermometer in assessing internal body temperatures from
be stabilized at given conditions of ambient temperature and
actual subjects. While this specification does not set limits for
humidity for a minimum of 30 min or longer if so specified by
clinical accuracy, it is the responsibility of a manufacturer to
the manufacturer.
determine values characterizing clinical accuracy and disclose
6.1.4.3 At each combination of operating temperature and
them upon request.
humidity in Table 1, at least six measurements shall be taken
6.2.2 Reference Sites—The tests shall be performed on
for each blackbody temperature, t . The number of readings
BB
groups of subjects by using an internal body site (for example,
shall be the same for all combinations. A new disposable probe
pulmonary artery or sublingual cavity) for the reference
cover (if applicable) must be used for each test reading. The
measurements. During clinical tests, the IR thermometer under
rate and method of temperature taking shall be in compliance
test shall be set in the corresponding mode.
with the manufacturer’s recommendations.
6.1.4.4 The requirements of 5.3 demand that no individual 6.3 Shock Test:
error δ exceeds the specified limits for laboratory error. The 6.3.1 To test the ability of an IR thermometer to comply
j
individual measurement error is: with 5.6.3, it shall be subjected to a fall from a height of 1 m
(39 in.) onto a 50 mm (2 in.) thick hardwood board (hardwood
δ 5 t 2 t (1)
j ? j BB?
of density higher than 700 kg/m ) that lies flat on a rigid base
where:
(concrete block). The test shall be performed with a controlled
t = displayed or calculated value of unadjusted
orientation of the device once for each of two axes (see Fig. 1)
j
temperature, where the IR thermometer probe faces down. Axis A is defined
t = true temperature of the blackbody,
BB
j = sequential number of a reading, and
i = signifies taking an absolute value.
6.1.4.5 In each mode, three data sets shall be formed. Each
data set is comprised of values δ obtained at the same
j
blackbody temperature setting by pooling together values for
all combinations of operating temperature and humidities
obtained at that blackbody temperature. The largest δ is a
j
measure of the laboratory error of a system.
6.1.4.6 The correction method to arrive at unadjusted tem-
perature t from readings in adjusted mode(s) shall be used
j
according to the manufacturer’s recommendation. Such recom-
mendations shall be available from the manufacturer on request
and provided in the service and repair manual, if any (see 7.3).
6.1.4.7 To comply with this standard, the greatest calculated
error δ from all data sets measured and calculated for all
j
display modes shall conform with requirements set forth in 5.3.
6.1.5 Skin Type IR Thermometer:
6.1.5.1 Testing is as specified in 6.1.4 except that blackbody
temperatures shall be set within 61 °C (62 °F) from the
following temperatures: 23, 30, and 38 °C (73, 86, and 100 °F).
6.1.5.2 The greatest calculated error δ from all data sets
j
shall conform with requirements set forth in 5.4.
6.1.6 Storage Test—To test compliance with storage
NOTE 1—IR thermometer is shown in the fall position along Axis B.
conditions, an IR thermometer shall be maintained in an
FIG. 1 Axes of IR Thermometer Defined for the Purpose of Shock
environmental chamber at temperature –20 °C (–4 °F), relative Test
E1965 − 98 (2023)
NOTE 6—Modification of the circuit should not affect dimensions of the
as an optical axis of the probe. Axis B passes through the IR
circuit board or significantly alter position of components and conductors.
thermometer center of gravity and the point where the window
of the probe crosses axis A. 6.4.2.6 Nonconductive and dielectric connections (for
example, fiber-optic) shall be used between the IR thermom-
NOTE 5—If axes as in Fig. 1 cannot be identified for a particular
eter and all test equipment so as to minimize perturbations of
thermometer, the drop direction shall be that which may cause the greatest
the electromagnetic field.
damage.
6.4.2.7 Calculated temperature excursions shall deviate
6.3.2 The IR thermometer’s operation shall be tested by
from one another by value no greater than required by 5.6.6.
measuring the temperature of a blackbody that is set within
60.5 ° C (61 °F) from 37 °C (98.6 °F), at ambient temperature 6.5 Electrostatic Discharge Tests:
in the range from 20 to 26 °C (68 to 79 °F) and relative 6.5.1 The effects of electrostatic discharge on accuracy of an
humidity in the range from 40 to 70 %. A total of at least five IR thermometer shall be tested in compliance with provisions
measurements shall be performed by using a new disposable of standard IEC 1000-4-2:1995. Specific conditions for testing
probe cover (if applicable) for every measurement. The IR are as follows:
thermometer shall be set in an unadjusted mode as specified in 6.5.1.1 The IR thermometer shall be in a “power on” state
5.8.2.2. when subjected to electrostatic discharge.
6.5.1.2 Ten air and ten contact discharges shall be applied.
6.3.3 The unadjusted temperature value shall be subtracted
from the blackbody setting. The absolute value of the largest 6.5.1.3 If IR thermometer under test has no exposed elec-
trically conductive parts, only air discharge shall be applied.
error shall be no greater than the error limit set forth in 5.3 (or
5.4, whichever is applicable) for the blackbody temperature 6.5.2 Air Discharge:
6.5.2.1 The discharge shall be aimed at an electrically
range from 36 to 39 °C (96.8 to 102.2 °F).
nonconductive part of the IR thermometer probe with no probe
6.4 Electromagnetic Susceptibility Test:
cover attached.
6.4.1 The instrument under test shall be exposed to a
6.5.2.2 The level of discharge shall be 2, 4, and 8 kV.
modulated electromagnetic radiofrequency field with the fol-
6.5.3 Contact Discharge:
lowing characteristics and in accordance with standards
6.5.3.1 The probe of the electrostatic discharge device shall
IEC601-1-2 and IEC 1000-4-3.
touch one of the electrically conductive parts on the outside of
6.4.1.1 Field Strength—3 V/m;
the IR thermometer housing.
6.4.1.2 Carrier Frequency Range—26 MHz to 1 GHz;
6.5.3.2 The level of discharge shall be 2, 4, and 6 kV.
6.4.1.3 Frequency Sweep Interval—1 MHz/s, minimum;
6.5.4 After electrostatic discharge, the IR thermometer shall
6.4.1.4 Frequency Interval Dwell Time—The greater of
be tested according to the procedures of 6.3.2 and 6.3.3.
either 1 s. or the measurement response time of the instrument
under test;
7. Documentation
6.4.1.5 AM modulation, 80 % index with a sine wave or
7.1 Identification:
100 % with a square wave having a 50 % duty cycle. A
7.1.1 In order that purchasers may identify products con-
modulation frequency that is within each significant signal-
forming to requirements of this specification, producers and
processing passband of the instrument under test shall be used.
distributors may include a statement of compliance in conjunc-
For devices not having a defined passband, modulation shall be
tion with their name and address on product labels or associ-
1 Hz, 10 Hz, and 1 kHz.
ated printed materials, or both, such as invoices, sales
6.4.2 Specific conditions for testing are as follows:
literature, and the like. The following statement is suggested:
6.4.2.1 No change of the probe covers is required while
“This infrared thermometer meets requirements established in
performing the electromagnetic compatibility test.
ASTM Standard (E1965-98). Full responsibility for the confor-
6.4.2.2 The IR thermometer probe shall be aimed at a target
mance of this product to the standard is assumed by (name and
whose surface temperature is within the display range of the IR
address of producer or distributor).” In the event one or more
thermometer. The target does not have to be a blackbody.
provisions of this standard are not met, a cautionary statement
6.4.2.3 IR thermometers capable of producing continuous
shall be included.
temperature readings shall have their readings taken succes-
7.1.2 The IR thermometer shall be identified as intended for
sively and compared to one another during the frequency
professional or consumer use, or both, as applicable.
sweep interval.
6.4.2.4 IR thermometers not capable of producing continu- 7.2 Instruction Manual:
ous temperature readings shall have their circuitry modified to 7.2.1 Specifications—An instruction manual shall be pro-
allow for continuous monitoring of the IR and reference vided and contain the system specifications including, but not
temperature signals. The peak excursions of the monitored IR limited to, the following:
and reference temperature signals measured during frequency 7.2.1.1 Displayed temperature range.
sweep interval shall be recalculated to represent the corre-
7.2.1.2 Maximum laboratory error.
sponding temperature excursions. On request, the manufacturer 7.2.1.3 Body site(s) used as a reference for adjusting the
shall make available the method of the circuit modification.
displayed temperature value.
6.4.2.5 IR thermometers having digital output shall have 7.2.1.4 Applicable subject categories for each display mode.
their signal monitored at the output of the analog-to-digital 7.2.1.5 Required period of recalibration or reverification, if
converter. applicable.
E1965 − 98 (2023)
7.2.1.6 Environmental characteristics (operating and storage in-glass and electronic thermometers). Such differences shall
ranges for temperature and humidity). include, whenever applicable, a description of the anticipated
7.2.1.7 Statement informing that clinical accuracy charac- error sources associated with disposable or reusable probe
teristics and procedures are available from the manufacturer on covers and sleeves, operator’s technique, anatomical
request.
variations, earwax buildups, subject cooperation, etc. In
7.2.2 Detailed Instructions—The instruction manual shall addition, this section of the instruction manual that explains
contain adequate instructions for use with sufficient detail for
differences in the accuracy of measurements obtained with IR
training in the operation, application, care, and biological and thermometers versus contact thermometers shall conspicuously
physical cleaning of the instrument and accessories. The
include the following statement: “ASTM laboratory accuracy
instruction manual shall include warnings if performance of the requirements in the display range of 37 to 39 °C (98 to 102 °F)
instrument may be adversely affected should one or more of the
for IR thermometers is 60.2 °C (60.4 °F), whereas for
following occur: mercury-in-glass and electronic thermometers, the requirement
7.2.2.1 Operation outside of the manufacturer-specified sub-
per ASTM Standards E667–86 and E1112–86 is 60.1 °C
ject temperature range. (60.2 °F).”
7.2.2.2 Operation outside of the manufacturer-specified op-
7.3 Service and Repair Manual:
erating temperature and humidity ranges.
7.3.1 A detailed service manual shall be made available if
7.2.2.3 Storage outside of the manufacturer-specified ambi-
user service or repair is permitted by the manufacturer.
ent temperature and humidity ranges.
7.3.2 A service manual shall disclose values of instrumen-
7.2.2.4 Mechanical shock.
tation or combined site offsets, or both.
7.2.2.5 Manufacturer-defined soiled or damaged infrared
optical components.
7.3.3 A service manual shall provide a method of arriving at
7.2.2.6 Absent, defective, or soiled probe cover (if appli-
unadjusted readings from temperatures displayed in an ad-
cable).
justed mode.
7.2.2.7 Use of unspecified probe covers.
7.4 Accuracy Determination—A manufacturer shall make
7.2.3 Blackbody—The instruction manual shall indicate the
available upon request specific instructions for tests to deter-
type and availability of a blackbody recommended for verify-
mine the laboratory error, clinical bias, and clinical repeatabil-
ing laboratory or clinical accuracy, or both, if only such type is
ity of an IR thermometer. When describing how clinical tests
required by the manufacturer as addressed in 6.1.3.3.
are performed, the manufacturer shall disclose the profile of
7.2.4 The instruction manual shall specify whether the
subject groups tested, including age and febrile status. A
probe cover is intended for single use or multiple use. If
detailed procedure for taking reference temperatures also shall
multiple use is allowed, cleaning instructions and criteria for
be disclosed.
determining when a probe cover should be discarded shall be
specified. Cleaning instructions shall be adequate to prevent
8. Keywords
cross-contamination between patients.
7.2.5 The instruction manual shall inform the user of 8.1 auditory canal; body temperature; ear; fever; infrared;
differences in the accuracy of measurements obtained with IR medical instrument; temperature; thermometer; tympanic
thermometers versus contact thermometers (that is, mercury- membrane
ANNEX
(Mandatory Information)
A1. STANDARD BLACKBODY DESCRIPTION
A1.1 A blackbody that is intended for use in the laboratory (at the rim X of the opening in the upper portion of the cavity)
tests shall have effective emissivity approaching unity. The should be considered equal to unity.
most efficient way of designing a blackbody is to form it in a
A1.1.1 The blackbody cavity is fabricated of metal having
shape of a cavity whose wall temperature is precisely known
high thermal conductivity, preferably oxygen-free copper. The
and from which infrared radiation is allowed to escape through
outer surface of the cavity may be plated with a thin layer of
a small opening (1, 2). A recommended design is based on the
gold over nickel to retard oxidation of the copper surface. The
blackbody source developed in The National Institute of
interior surface of the copper cavity is painted with organic
Standards and Technology (3) and is shown in Fig. A1.1. For
enamel paint with thickness after drying of between 20 and
the purpose of this specification, emissivity of this blackbody
50 μm. The color of the paint is not critical. The cavity is
immersed into a stirred water bath (liquids other than water
may be used). The metal cavity is connected to a surface box
The boldface numbers given in parentheses refer to a list of references at the
end of the text. fabricated of a material having low thermal conductivity, such
E1965 − 98 (2023)
the surface of the water. Alternatively, the cavity may be
secured horizontally with the opening in a water bath wall as in
(3).
A1.2 The cavity opening for the insertion of the probe end
must have a diameter sufficiently small for the snug fitting of
the probe with a probe cover attached (if applicable). The probe
end preferably should be aligned with the rim of the opening
and should not protrude into the cavity by more than 2 m
(0.08 in.). No metal portion of the cavity should be positioned
above the water level. The shape and dimensions of the
opening into the blackbody shall correspond to those specified
by the manufacturer of the instrument being tested. The
opening shall ensure that the probe is properly positioned in the
blackbody when manually inserted.
A1.3 The water bath shall have a volume of 2 L (2 qt) or
greater and temperature stability within 6 0.02 °C (0.04 °F).
True temperature of the water shall be monitored with an
uncertainty no greater than 60.03 °C (0.05 °F) by an immersed
contact thermometer for which the calibration is traceable to a
national physical standard of temperature. The contact ther-
mometer should be positioned in the water in close proximity
to the blackbody cavity.
FIG. A1.1 Water-Immersed Blackbody A1.4 It is possible for the test purposes to use a blackbody
of a different design. However, emissivity of such a blackbody
as Delrin or ABS plastic. The box shall be reliably secured to shall be known in comparison to the one described above, and
the water bath to prevent the blackbody from free floating on used for correction in measured temperatures.
APPENDIXES
(Nonmandatory Information)
X1. BACKGROUND
X1.1 The materials of this section contain statements which magnitude and the spectral distribution of the radiation are
do not represent any standard or requirement and should be
functions of the subject’s and sensor’s temperatures and their
used only for reference purposes.
respective emissivities. The spectral density of the radiation is
governed by Planck’s law and theoretically occupies an infi-
X1.2 The intensity of infrared (IR) radiation represents the
nitely wide spectrum. However, due to the shape of the density
temperature of the surface from which it is emitted. A medical
curve and a filtering effect in the optical components, the
IR noncontact thermometer covered by this specification is an
bandwidth of a medical IR thermometer is generally limited to
electronic device having an optical probe. IR radiation is
the range from 3 to 30 μm, that is well beyond the visible
collected from the field of view of the probe and is converted
region and is situated in the near and far infrared spectral
into an electrical signal for calculation of the surface tempera-
ranges.
ture of the subject. Assessing temperatures measured by IR
thermometers has both technical and medical aspects. The
X1.3.2 Wien’s displacement law for absolute blackbody
former depend on the design of a particular thermometer, while
radiation of 37 °C (98.6 °F) gives a peak wavelength at
the latter relate to properties of the subject of measurement.
9.34 μm, while the net IR flux spectral density for blackbody
radiation of 37 °C and the IR sensor at normal room tempera-
X1.3 Technical Background:
ture has a maximum spectral density near 8 μm of wavelength
X1.3.1 While contact thermometers, of either equilibrium or
(see Fig. X1.1). The net infrared flux over a broad spectral
predictive type, rely on conductive heat transfer, IR thermom-
range may be determined from the Stefan-Boltzmann equation:
eters use naturally emitted electromagnetic radiation. The
E1965 − 98 (2023)
FIG. X1.2 General Structure of a Medical IR Thermometer for
Measuring Temperature from an Ear Canal
X1.3.5.1 In practice, the essential elements of the measure-
ment system may have many configurations and additions to
enhance accuracy and add features required for use of the
device. These may include the IR flux choppers or shutters,
protective probe covers, reference targets, etc. Regardless of
any practical implementation, the ultimate technical goal of the
instrument is an accurate assessment of the subject’s surface
temperature T .
b
FIG. X1.1 Normalized with Respect to t =37 °C Spectral Net Flux
b
X1.3.6 Emissivity:
Density for Three Blackbody Temperatures and IR Sensor at
X1.3.6.1 Emissivity is an indicator of how well an object
20 °C (68 °F)
emits electromagnetic radiation from its surface. It is expressed
using a dimensionless scale which ranges from 0 to 1.0. An
ideal “blackbody” has an emissivity of 1.0 and, by definition,
4 4
is a perfect emitter. In reality, objects are never this efficient.
Φ 5 Aσε ε ~T 2 T ! (X1.1)
b b s b s
Therefore, ideal blackbodies are modeled with practical black-
where:
bodies which have emissivities approaching unity as closely as
A = the optical coefficient,
possible.
σ = Stefan-Boltzmann constant,
X1.3.6.2 A cavity-type blackbody is commonly used to
ε = emissivity of the subject,
b
calibrate and verify the accuracy of IR thermometers. Due to
ε = emissivity of the sensor,
s
multiple internal reflections of infrared photons inside the
T = surface temperature (in degrees Kelvin) of the subject,
b
cavity, those which emerge through the cavity opening have IR
and
flux characteristics very near that which would emanate from
T = surface temperature (in degrees Kelvin) of the sensor.
s
an ideal blackbody surface (1). Thus, the opening in the cavity
X1.3.3 Eq X1.1 is a fundamental formula for calculating the
is considered a blackbody surface, though such a surface does
surface temperature T of the subject. For that purpose, the
not exist in reality.
b
formula is rearranged as:
X1.3.6.3 Some practical “blackbodies” may have lower
emissivities than that of the recommended blackbody of Annex
Φ
b
T 5ŒT 1 (X1.2) A1 (often, they are called “graybodies”). In such cases,
b s
Aσε ε
b s
laboratory error measured according to 6.1 will appear too
where: T represents the calculated temperature.
high.
b
X1.3.6.4 Therefore, in reality all “blackbodies” do not have
X1.3.4 The calculation requires an accurate detection of two
the same emissivity. When an IR thermometer’s laboratory
independent variables, the surface temperature T of the sensor
s
accuracy is verified according to 6.1 using a blackbody whose
(or reference target) and the net infrared flux Φ between the
b
emissivity (ε ) is different than that of the blackbody originally
b
sensor and subject.
used to calibrate the device (ε ), an emissivity error (δ ) is
o ε
X1.3.5 It follows from the above that, in general terms, any
introduced. The error in temperature measurement by an IR
noncontact IR thermometer must contain at least four essential
thermometer as function of ambient and subject’s temperatures
components: an IR sensor to measure that net t
...