ASTM E145-19
(Specification)Standard Specification for Gravity-Convection and Forced-Ventilation Ovens
Standard Specification for Gravity-Convection and Forced-Ventilation Ovens
ABSTRACT
This specification covers the performance requirements for four types (Types IA, IB, IIA, and IIB) of general-purpose air ovens of the gravity-convection and forced-ventilation types ordinarily used in testing operations. The temperature within the testing chamber shall be controllable by an automatic device and, when examined with appropriate test methods provided herein, shall be uniform within the tolerances for temperature uniformity, time constant, and rate of ventilation requirements for the particular type of oven.
SCOPE
1.1 This specification covers the performance requirements for general-purpose air ovens ordinarily used in testing operations, which have a testing chamber up to 0.6 m3 (25 ft3) in volume. It is applicable to gravity-convection ovens designed to operate over all or part of the temperature range from 20 °C above ambient temperature to 200 °C and to forced-ventilation ovens designed to operate over all or part of the temperature range from 20 °C above ambient temperature to 500 °C.
Note 1: Ovens are designed for maximum operating temperatures of about 200 °C, 300 °C, and 500 °C, the thermal insulation and cost of the oven being dependent on the maximum temperature required.
1.2 This specification does not include safety requirements that are essential for ovens used in the presence of combustible vapors or gases.
1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.5 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.
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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:E145 −19
Standard Specification for
1
Gravity-Convection and Forced-Ventilation Ovens
This standard is issued under the fixed designation E145; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope 2.1.1 Type IA—an oven ventilated by gravity convection
having a uniformity of temperature within 62 % of the
1.1 This specification covers the performance requirements
differential between oven and ambient temperatures.
for general-purpose air ovens ordinarily used in testing
3 3 2.1.2 Type IB—an oven ventilated by gravity convection
operations, which have a testing chamber up to 0.6 m (25 ft )
having a uniformity of temperature within 65 % of the
in volume. It is applicable to gravity-convection ovens de-
differential between oven and ambient temperatures.
signed to operate over all or part of the temperature range from
2.1.3 Type IIA—an oven having forced ventilation and a
20 °C above ambient temperature to 200 °C and to forced-
uniformity of temperature within 61 % of the differential
ventilation ovens designed to operate over all or part of the
between oven and ambient temperatures.
temperature range from 20 °C above ambient temperature to
2.1.4 Type IIB—an oven having forced ventilation and a
500 °C.
uniformity of temperature within 62.5 % of the differential
NOTE 1—Ovens are designed for maximum operating temperatures of
between oven and ambient temperatures.
about 200 °C, 300 °C, and 500 °C, the thermal insulation and cost of the
oven being dependent on the maximum temperature required.
3. Performance Requirements
1.2 This specification does not include safety requirements
3.1 The temperature within the testing chamber shall be
that are essential for ovens used in the presence of combustible
controllable by an automatic device, and shall be uniform
vapors or gases.
within the tolerances given in Table 1 for the particular type of
1.3 The values stated in SI units are to be regarded as
oven when tested in accordance with Section 4.
standard. The values given in parentheses after SI units are
3.2 The“timeconstant”isanarbitrarymeasureoftherateat
provided for information only and are not considered standard.
which a standard specimen is heated following the procedure
1.4 This standard does not purport to address all of the
prescribedinSection5.Thevalueofthetimeconstantshallnot
safety concerns, if any, associated with its use. It is the
exceed the maximum value given in Table 1 for the particular
responsibility of the user of this standard to establish appro-
type of oven.
priate safety, health, and environmental practices and deter-
3.3 The rate of ventilation of the testing chamber shall
mine the applicability of regulatory limitations prior to use.
conform to the requirements specified in Table 1 for the
1.5 This international standard was developed in accor-
particular type of oven when measured in accordance with the
dance with internationally recognized principles on standard-
procedure given in Section 6.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
TEST METHODS
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
4. Temperature Uniformity
4.1 Placeninecalibratedthermocouples(Note2)madefrom
2. Types
iron or copper-constantan wire, approximately 0.5 mm in
2.1 This specification covers the following four types of air
diameter (No. 24 gauge) and having a junction size of not more
ovens:
than 2 mm (0.08 in.), in the empty testing chamber with
shelves in place and vents open. Locate one thermocouple in
eachoftheeightcornersoftheovenapproximately5cm(2in.)
1
from each wall and place the ninth thermocouple within 2.5 cm
This specification is under the jurisdiction of ASTM Committee E41 on
Laboratory Apparatus and is the direct responsibility of Subcommittee E41.06 on
(1 in.) of the geometric center of the chamber. A minimum
Laboratory Instruments and Equipment.
length of 30 cm (12 in.) of lead wire for each thermocouple
Current edition approved March 1, 2019. Published March 2019. Originally
shall be inside the oven to minimize the conduction of heat
approved in 1959. Last previous edition approved in 2011 as E145 – 94(2011). DOI:
10.1520/E0145-19. from the thermocouple.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West C
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E145 − 94 (Reapproved 2011) E145 − 19
Standard Specification for
1
Gravity-Convection and Forced-Ventilation Ovens
This standard is issued under the fixed designation E145; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope
1.1 This specification covers the performance requirements for general-purpose air ovens ordinarily used in testing operations,
3 3
which have a testing chamber up to 0.6 m (25 ft ) in volume. It is applicable to gravity-convection ovens designed to operate over
all or part of the temperature range from 20°C20 °C above ambient temperature to 200°C200 °C and to forced-ventilation ovens
designed to operate over all or part of the temperature range from 20°C20 °C above ambient temperature to 500°C.500 °C.
NOTE 1—Ovens are designed for maximum operating temperatures of about 200°C, 300°C,200 °C, 300 °C, and 500°C,500 °C, the thermal insulation
and cost of the oven being dependent on the maximum temperature required.
1.2 This specification does not include safety requirements that are essential for ovens used in the presence of combustible
vapors or gases.
1.3 The values stated in inch-poundSI units are to be regarded as the standard. The metric equivalents of inch-pound units may
be approximate.values given in parentheses after SI units are provided for information only and are not considered 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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.5 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.
2. Types
2.1 This specification covers the following four types of air ovens:
2.1.1 Type IA—Anan oven ventilated by gravity convection having a uniformity of temperature within 62 % of the differential
between oven and ambient temperatures.
2.1.2 Type IB—Anan oven ventilated by gravity convection having a uniformity of temperature within 65 % of the differential
between oven and ambient temperatures.
2.1.3 Type IIA—Anan oven having forced ventilation and a uniformity of temperature within 61 % of the differential between
oven and ambient temperatures.
2.1.4 Type IIB—Anan oven having forced ventilation and a uniformity of temperature within 62.5 % of the differential between
oven and ambient temperatures.
3. Performance Requirements
3.1 The temperature within the testing chamber shall be controllable by an automatic device, and shall be uniform within the
tolerances given in Table 1 for the particular type of oven when tested in accordance with Section 4.
3.2 The “time constant” is an arbitrary measure of the rate at which a standard specimen is heated following the procedure
prescribed in Section 5. The value of the time constant shall not exceed the maximum value given in Table 1 for the particular type
of oven.
3.3 The rate of ventilation of the testing chamber shall conform to the requirements specified in Table 1 for the particular type
of oven when measured in accordance with the procedure given in Section 6.
1
This specification is under the jurisdiction of ASTM Committee E41 on Laboratory Apparatus and is the direct responsibility of Subcommittee E41.06 on Weighing
DevicesLaboratory Instruments and Equipment.
Current edition approved Dec. 1, 2011March 1, 2019. Published December 2011March 2019. Originally approved in 1959. Last previous edition approved in 20062011
as E145 – 94 (2006).(2011). DOI: 10.1520/E0145-94R11.10.1520/E0145-19.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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E145 − 19
TABLE 1 Performance Requirements for Ovens
Characteristic Type IA Type IB Type IIA Type IIB
Deviation from specified temperature of test throughout testing chamber during
24-h peri
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