ASTM D5423-93(1999)

Standard Specification for Forced-Convection Laboratory Ovens for Evaluation of Electrical Insulation

SCOPE
1.1 This specification covers forced-convection ventilated electrically-heated ovens, operating over all or part of the temperature range from 20°C above the ambient temperature to 500°C, and used for thermal endurance evaluation of electrical insulating materials.
1.2 The specification requirements for Type I ovens are based on IEC Publication 216-4-1, and are technically identical to it. The requirements for Type II ovens are essentially identical to the requirements of Specification D2436. This specification and an associated test method, D5374, will eventually replace Specification D2436.
1.3 While the ovens covered by this specification are intended primarily for thermal endurance evaluation, they can also be used wherever their characteristics make them suitable for other applications.
1.4 This specification does not address safety aspects. If it is anticipated that oven contents or the location in which the oven is to be installed may create a hazard, the purchaser should determine and specify what additional requirements are needed.

General Information

• Status: Historical
• Publication Date: 09-Mar-1999
• ICS: 71.040.10 - Chemical laboratories. Laboratory equipment
• Technical Committee: D09 - Electrical and Electronic Insulating Materials
• Drafting Committee: D09.17 - Fire and Thermal Properties

Relations

• Replaced By: ASTM D5423-93(2005) - Standard Specification for Forced-Convection Laboratory Ovens for Evaluation of Electrical Insulation (Withdrawn 2014)
• Effective Date: 01-Sep-2005
• Referred By: ASTM D7894/D7894M-19 - Standard Test Method for Thermal Endurance of Coating Powders Used for Integral Bus Bar Insulation Systems
• Effective Date: 10-Mar-1999
• Referred By: ASTM B987/B987M-20 - Standard Specification for Carbon Fiber Thermoset Polymer Matrix Composite Core (CFC) for use in Overhead Electrical Conductors
• Effective Date: 10-Mar-1999
• Referred By: ASTM D1932-19 - Standard Test Method for Thermal Endurance of Flexible Electrical Insulating Varnishes
• Effective Date: 10-Mar-1999
• Referred By: ASTM D3045-18 - Standard Practice for Heat Aging of Plastics Without Load
• Effective Date: 10-Mar-1999
• Referred By: ASTM D2633-21 - Standard Test Methods for Thermoplastic Insulations and Jackets for Wire and Cable
• Effective Date: 10-Mar-1999
• Referred By: ASTM D3032-21a - Standard Test Methods for Hookup Wire Insulation
• Effective Date: 10-Mar-1999
• Referred By: ASTM D3145-20 - Standard Test Method for Thermal Endurance of Electrical Insulating Varnishes by Helical Coil Method
• Effective Date: 10-Mar-1999
• Referred By: ASTM D7895/D7895M-19 - Standard Test Method for Thermal Endurance of Coating Powders Used for Powder Coating Insulation Systems
• Effective Date: 10-Mar-1999
• Referred By: ASTM D2304-23 - Standard Test Method for Thermal Endurance of Rigid Electrical Insulating Materials
• Effective Date: 10-Mar-1999
• Referred By: ASTM D1830-17 - Standard Test Method for Thermal Endurance of Flexible Sheet Materials Used for Electrical Insulation by the Curved Electrode Method
• Effective Date: 10-Mar-1999
• Referred By: ASTM D69-19 - Standard Test Methods for Friction Tapes
• Effective Date: 10-Mar-1999
• Referred By: ASTM D4568-13(2020) - Standard Test Methods for Evaluating Compatibility Between Cable Filling and Flooding Compounds and Polyolefin Wire and Cable Materials
• Effective Date: 10-Mar-1999
• Referred By: ASTM D3312-18 - Standard Test Method for Percent Reactive Monomer in Solventless Varnishes
• Effective Date: 10-Mar-1999
• Referred By: ASTM D3288/D3288M-20 - Standard Test Methods for Magnet-Wire Enamels
• Effective Date: 10-Mar-1999

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
An American National Standard
Designation: D 5423 – 93 (Reapproved 1999)
Standard Specification for
Forced-Convection Laboratory Ovens for Evaluation of
Electrical Insulation
This standard is issued under the fixed designation D 5423; 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 Thermal Endurance Properties of Electrical Insulating
Materials, Part 4—Aging Ovens, Section 1—Single-
1.1 This specification covers forced-convection ventilated
Chamber Ovens
electrically-heated ovens, operating over all or part of the
temperaturerangefrom20°Cabovetheambienttemperatureto
3. Terminology
500°C, and used for thermal endurance evaluation of electrical
3.1 Definitions of Terms Specific to This Standard:
insulating materials.
3.1.1 rate of ventilation, n—the number of air changes per
1.2 The specification requirements for Type I ovens are
hour in the oven chamber.
basedonIECPublication216-4-1,andaretechnicallyidentical
3.1.2 set temperature, n—the average of all of the measured
to it. The requirements for Type II ovens are essentially
temperatures within the oven, averaged over the period of any
identical to the requirements of Specification D 2436. This
cyclic temperature variation that may occur.
specification and an associated test method, D5374, have
3.1.2.1 Discussion—This is the actual operating tempera-
replaced Specification D 2436.
ture of the oven.
1.3 While the ovens covered by this specification are
3.1.3 temperature fluctuation, n—temperature differences at
intended primarily for thermal endurance evaluation, they can
one point in the oven over a period of time.
also be used wherever their characteristics make them suitable
3.1.3.1 Discussion—This property depends upon the sensi-
for other applications.
tivity and type (on/off or proportional) of control used and the
1.4 This specification does not address safety aspects. If it is
heater mass in relation to surface area.
anticipated that oven contents or the location in which the oven
3.1.4 temperature gradient, n—the maximum temperature
is to be installed may create a hazard, the purchaser should
difference at one time between different points in the oven
determine and specify what additional requirements are
chamber.
needed.
3.1.4.1 Discussion—This property depends on such factors
2. Referenced Documents as uniformity of heater temperature, heater distribution about
the oven, and air flow patterns within the oven.
2.1 ASTM Standards:
3.1.5 temperature variation, n—temperature differences
D 2436 Specification for Forced-Convection Laboratory
2 with time and location due to the combination of temperature
Ovens for Electrical Insulation
gradient and temperature fluctuation.
D 5374 Test Methods for Forced-Convection Laboratory
3 3.1.6 thermal lag time, n—the time required for a defined
Ovens for Evaluation of Electrical Insulation
specimen to reach a specified temperature (or range of tem-
2.2 Other Document:
perature).
IEC Publication 216-4-1 Guide for the Determination of
3.1.6.1 Discussion—This property is largely dependent
upontherateofaircirculationwithintheoven.InIEC216-4-1,
this term is called“ time constant.”
This specification is under the jurisdiction of ASTM Committee D-9 on
Electrical and Electronic Insulating Materials and is the direct responsibility of 3.1.7 time constant, n—See thermal lag time.
Subcommittee D09.17 on Thermal Characteristics.
Current edition approved Sept. 15, 1993. Published November 1993.
2 4
Discontinued; see 1993 Annual Book of ASTM Standards, Vol 10.01. Available from American National Standards Institute, 11 West 42nd St., 13th
Annual Book of ASTM Standards, Vol 10.02. Floor, New York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 5423
4. Classification 7.2 The interior of the oven shall be constructed of suitable
corrosion-resistant, non-absorbent material, so fabricated that
4.1 Type I—Ovens with rate of ventilation of 5 to 20 air
any joints are leak-proof and not subject to corrosion, and so
changes per hour.
that the interior surfaces shall be easy to clean.
4.2 Type II—Ovens with rate of ventilation of 100 to 200 air
7.3 The door(s) shall be fitted with hinges and latches which
changes per hour.
will provide sufficient pressure for an effective seal between
5. Test Methods
the interior of the oven and the external atmosphere, using a
5.1 Determine the properties specified in Section 6 using
gasket, if necessary.
Test Methods D 5374.
7.4 The oven shall have provisions for automatically
switching off the heaters when the actual oven temperature
6. Performance Requirements
substantially exceeds the set temperature.
6.1 Rate of Ventilation—The rate of ventilation at 100°C
7.5 Ports for admitting and exhausting air shall be provided,
and at the maximum temperature at which the oven may be
with fittings for attaching conduits for exhaust air. When
used shall be:
specified, provisions shall be made for supplying inlet air or
6.1.1 For Type I ovens, 5 to 20 air changes per hour,
other gases from a controlled source.
6.1.2 For Type II ovens, 100 to 200 air changes per hour.
7.6 Dampers for adjusting the rate of ventilation and the air
NOTE 1—Past experience in the United States has been to specify 100
circulation shall be provided to enable compliance with other
to 200 air changes per hour, as required for Type II ovens. However,
requirements of this specification.
international practice, as defined in IEC Publication 216-4-1, has been to
use the lower rate of ventilation, which is specified for Type I ovens.
8. Certification
6.2 Set Temperature—The set temperature, measured over a
8.
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