ASTM F479-06(2022)

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: F479 −06 (Reapproved 2022)
Standard Specification for
In-Service Care of Insulating Blankets
ThisstandardisissuedunderthefixeddesignationF479;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope C84.1 Voltage Ratings for Electric Power Systems and
Equipment (60 Hz)
1.1 This specification covers the in-service care, inspection,
testing, and use voltage of insulating blankets for protection of
3. Terminology
workers from accidental contact with live electrical
3.1 Definitions:
conductors, apparatus, or circuits. The product requirements
3.1.1 breakdown—the electrical discharge or arc occurring
and acceptance testing are as shown in Specification D1048.
betweentheelectrodesandthroughtheequipmentbeingtested.
1.2 The values stated in inch-pound units are to be regarded
3.1.2 compatible—not injurious to or changing the physical
as standard. The values given in parentheses are mathematical
or electrical characteristics of the blankets or affecting their
conversions to SI units that are provided for information only
application, use, or acceptability.
and are not considered standard.
3.1.3 designated person—an individual who is qualified by
1.3 This standard does not purport to address all of the
experience or training to perform an assigned task.
safety concerns, if any, associated with its use. It is the
3.1.4 electrical testing facility—a location with qualified
responsibility of the user of this standard to establish appro-
personnel,testingequipment,andproceduresfortheinspection
priate safety, health, and environmental practices and deter-
and electrical testing of electrical insulating protective equip-
mine the applicability of regulatory limitations prior to use.See
ment.
Section 6 and 8.2 for specific precautionary statements.
3.1.5 electrode—the energized or grounded conductor por-
1.4 This international standard was developed in accor-
tion of electrical test equipment which is placed near or in
dance with internationally recognized principles on standard-
contact with the material or equipment being tested.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
3.1.6 flashover—the electrical discharge or arc occurring
mendations issued by the World Trade Organization Technical
between electrodes and over or around, but not through, the
Barriers to Trade (TBT) Committee.
equipment being tested.
3.1.7 insulated—separated from other conducting surfaces
2. Referenced Documents
by a dielectric substance (including air space) offering a high
2.1 ASTM Standards:
resistance to the passage of current.
D1048 Specification for Rubber Insulating Blankets
3.1.7.1 Discussion—Whenanyobjectissaidtobeinsulated,
D2865 Practice for Calibration of Standards and Equipment
it is understood to be insulated in a suitable manner for the
for Electrical Insulating Materials Testing
conditions to which it is subjected. Otherwise, it is, within the
F819 Terminology Relating to Electrical Protective Equip-
purposes of this definitions, uninsulated. Insulating covering of
ment for Workers
conductors is one means of making the conductor insulated.
2.2 ANSI Standard:
3.1.8 ozone—a very active form of oxygen that may be
C39.5 Safety Requirements for Electrical and Electronic
produced by corona, arcing, or ultraviolet rays.
Measuring and Controlling Instrumentation
3.1.9 ozone cutting and checking—the cracks produced by
ozone in a material under mechanical stress.
This specification is under the jurisdiction of ASTM Committee F18 on
Electrical Protective Equipment for Workers and is the direct responsibility of
3.1.10 retest—the tests given after the initial acceptance test
Subcommittee F18.25 on Insulating Cover-Up Equipment.
usually performed at regular periodic intervals or as required
Current edition approved Feb. 1, 2022. Published March 2022. Originally
approvedin1976.Lastpreviouseditionapprovedin2017asF479–06(2017).DOI:
because of physical inspection.
10.1520/F0479-06R22.
3.1.11 unassigned blankets—blankets that are in storage
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
prior to being issued for use.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
3.1.12 voltage, maximum use—the ac voltage (rms), classi-
the ASTM website.
3 fication of the protective equipment that designates the maxi-
Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036, http://www.ansi.org. mum nominal design voltage of the energized system that may
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F479 − 06 (2022)
be safely worked. The nominal design voltage is equal to the 6. Safety Precautions
phase-to-phase voltage on multiphase circuits.
6.1 A margin of safety shall be provided between the
3.1.12.1 Discussion—If there is no multiphase exposure in a
maximum use voltage on which the blankets are used and the
system area, and the voltage exposure is limited to the phase
voltage at which they are retested. The relationship between
(polarityondcsystems)togroundpotential,thephase(polarity
retest voltage and maximum use voltage at which the blankets
ondcsystems)togroundpotentialshallbeconsideredtobethe
shall be used is shown in Table 1.
nominal design voltage.
6.2 The user of this type of protective equipment shall be
3.1.12.2 Discussion—If electrical equipment and devices
knowledgeable of and instructed in the correct and safe visual
are insulated or isolated, or both, such that the multiphase
inspection and use of this equipment.
exposure on a grounded wye circuit is removed, then the
nominal design voltage may be considered as the phase-to-
7. Inspection and Testing at an Electrical Testing Facility
ground voltage on that circuit.
7.1 The recommended sequence for inspection and testing
3.1.12.3 Discussion—The work practices and methods as-
of insulating blankets at the electrical testing facility is as
sociated with removing multiphase exposures at any given
follows:
work site are not addressed in the ASTM standards. The users
7.1.1 Check in, washing, and preliminary inspection,
of ASTM standards should reference appropriate industry
7.1.2 Electrical test,
consensus standards for proper work practices.
7.1.3 Final inspection,
3.1.13 voltage, maximum retest—the voltage, either ac rms 7.1.4 Recordkeeping and marking, and
or dc avg, that is equal to the proof test voltage for new 7.1.5 Packing for storage and shipping.
protective equipment.
7.2 Dirty blankets should be cleaned. They may be washed
with a mild soap or mild detergent and water. Mild household-
3.1.14 voltage, nominal design—a nominal value consistent
type chlorine bleach may be used for disinfectant purposes.
with ANSI C84.1-2001, assigned to the circuit or system for
Soaps, detergents, and bleaches shall not be used at strengths
the purpose of conveniently designating its voltage class.
that would attack or harm the rubber surface. They shall be
3.1.15 voltage, retest—the voltage, either ac rms or dc avg,
rinsed thoroughly with water to remove all of the soap or
that used protective equipment must be capable of withstand-
detergent. Severe dirt and grime may be wiped off using a
ing for a specified test period without breakdown.
compatible solvent.
3.2 For definitions of other terms, refer to Terminology 7.2.1 The cleaning agent shall not degrade the insulating or
F819. physical qualities of the blankets.
7.2.2 A commercial tumble type washing machine may be
4. Significance and Use used. Caution must be observed to eliminate any interior
surfaces or edges that may damage the blankets.
4.1 Compliance with this specification should continue to
7.3 Ifwashed,blanketsshouldbeair-dried.Theairtempera-
provide personnel with insulating blankets of known and
ture should not be over 150°F (65.5°C).
acceptable quality after initial acceptance in accordance with
Specification D1048.The standards herein are to be considered
7.4 Prior to the electrical test, the blankets shall be given a
as minimum requirements.
preliminary inspection for punctures, cuts, corona cutting, or
any obvious condition which would adversely affect the
5. Classification
performance. If any of these conditions are found, blankets
shall be rejected or repaired.
5.1 Blankets covered under this specification shall be des-
ignated as Type I or Type II; Class 0, Class 1, Class 2, Class 3, 7.5 The blankets shall be tested in accordance with Section
8.
or Class 4; Style A or Style B.
5.2 Type I, not resistant to ozone, made from a high-grade
cis-1,4-polyisoprene rubber compound of natural or synthetic
TABLE 1 Voltage Requirements for Blankets
origin, properly vulcanized.
Class AC Use AC Retest DC Retest
Designation of Voltage, Voltage, Voltage,
5.3 Type II, ozone-resistant, made of any elastomer or
A
Blankets rms, max max max
combination of elastomeric compounds.
0 1000 5000 20 000
1 7500 10 000 40 000
5.4 The class designation shall be based on the electrical
2 17 000 20 000 50 000
properties as shown in Specification D1048. 3 26 500 30 000 60 000
4 36 000 40 000 70 000
5.5 Style A, constructed of the elastomers indicated under
A
The maximum use voltage is based on the following equations:
Type I or Type II, shall be free of any reinforcement.
Maximum ac use voltage = 0.95 ac maximum retest voltage − 2 000
v
Classes 1, 2, 3, and 4.
5.6 Style B, constructed of the elastomers indicated under Maximum ac use voltage = 0.95 dc maximum retest voltage − 30 500
v
Classes 1, 2, 3, and 4.
Type I or Type II, shall incorporate a reinforcement. This
Maximum ac use voltage = 0.95 dc maximum retest voltage − 18 000
v
reinforcement shall not affect adversely the dielectric charac-
Class 0.
teristics of the blankets.
F479 − 06 (2022)
7.6 After the test, the blankets shall be given an inspection 8.5.1.1 A voltmeter used in conjunction with a calibrated
for corona and ozone damage. instrument transformer connected directly across the high
voltage circuit,
8. Electrical Tests
8.5.1.2 A calibrated electrostatic voltmeter connected di-
8.1 Allblanketsissuedforserviceshallberetestedandshall
rectly across the high voltage circuit, or
withstand the 60-Hz ac test voltage (rms value) or the dc
8.5.1.3 An ac meter connected in series with appropriate
voltage (average value) specified in Table 1.The retest shall be
high-voltage type resistors directly across the high voltage
performedinaccordancewithSection8andshallbeconducted
circuit.
continuously for not less than 1 min, and not more than 3 min.
8.5.1.4 Thecrestfactormaybecheckedbytheuseofapeak
8.1.1 The interval between date of issue and retests shall be
reading voltmeter connected directly across the high-voltage
based on work practices and test experience, but shall not
circuit.
exceed 1 year. Blankets that have been tested electrically, but
8.5.2 AC Retest:
not issued for service, shall not be placed into service unless
8.5.2.1 Each blanket shall be given an electrical retest in
they have been tested electrically within the previous 12
accordance with 8.1. The test period shall start at the instant
months.
that the prescribed testing voltage is reached.
8.1.2 Where a visual inspection indicates that there may be
NOTE 2—It is recommended that the retest voltage be applied initially
reason to suspect the electrical integrity of a blanket, an
at a low value and increased at a constant rate-of-rise of approximately
electrical test shall be performed before reissuing the blanket
1000 V/s until the prescribed test voltage level is reached. Unless an
for service.
electr
...