ASTM F479-06(2011)
(Specification)Standard Specification for In-Service Care of Insulating Blankets
Standard Specification for In-Service Care of Insulating Blankets
SIGNIFICANCE AND USE
Compliance with this specification should continue to provide personnel with insulating blankets of known and acceptable quality after initial acceptance in accordance with Specification D1048. The standards herein are to be considered as minimum requirements.
SCOPE
1.1 This specification covers the in-service care, inspection, testing, and use voltage of insulating blankets for protection of workers from accidental contact with live electrical conductors, apparatus, or circuits. The product requirements and acceptance testing are as shown in Specification D1048.
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.3 This standard does not purport to address all of the safety problems, 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. See Section 6 and 8.2 for specific precautionary statements.
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Designation:F479 −06 (Reapproved 2011)
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 3.1.1 breakdown—the electrical discharge or arc occurring
betweentheelectrodesandthroughtheequipmentbeingtested.
1.1 This specification covers the in-service care, inspection,
3.1.2 compatible—not injurious to or changing the physical
testing, and use voltage of insulating blankets for protection of
workers from accidental contact with live electrical or electrical characteristics of the blankets or affecting their
application, use, or acceptability.
conductors, apparatus, or circuits. The product requirements
and acceptance testing are as shown in Specification D1048.
3.1.3 designated person—an individual who is qualified by
experience or training to perform an assigned task.
1.2 The values stated in inch-pound units are to be regarded
as standard. The values given in parentheses are mathematical
3.1.4 electrical testing facility—a location with qualified
conversions to SI units that are provided for information only
personnel,testingequipment,andproceduresfortheinspection
and are not considered standard.
and electrical testing of electrical insulating protective equip-
ment.
1.3 This standard does not purport to address all of the
safety problems, if any, associated with its use. It is the
3.1.5 electrode—the energized or grounded conductor por-
responsibility of the user of this standard to establish appro-
tion of electrical test equipment which is placed near or in
priate safety and health practices and determine the applica-
contact with the material or equipment being tested.
bility of regulatory limitations prior to use. See Section 6 and
3.1.6 flashover—the electrical discharge or arc occurring
8.2 for specific precautionary statements.
between electrodes and over or around, but not through, the
equipment being tested.
2. Referenced Documents
3.1.7 insulated—separated from other conducting surfaces
2.1 ASTM Standards:
by a dielectric substance (including air space) offering a high
D1048 Specification for Rubber Insulating Blankets
resistance to the passage of current.
D2865 Practice for Calibration of Standards and Equipment
3.1.7.1 Discussion—Whenanyobjectissaidtobeinsulated,
for Electrical Insulating Materials Testing
it is understood to be insulated in a suitable manner for the
F819 Terminology Relating to Electrical Protective Equip-
conditions to which it is subjected. Otherwise, it is, within the
ment for Workers
purposes of this definitions, uninsulated. Insulating covering of
2.2 ANSI Standard:
conductors is one means of making the conductor insulated.
C39.5 Safety Requirements for Electrical and Electronic
Measuring and Controlling Instrumentation 3.1.8 ozone—a very active form of oxygen that may be
C84.1 Voltage Ratings for Electric Power Systems and produced by corona, arcing, or ultraviolet rays.
Equipment (60 Hz)
3.1.9 ozone cutting and checking—the cracks produced by
ozone in a material under mechanical stress.
3. Terminology
3.1.10 retest—the tests given after the initial acceptance test
3.1 Definitions:
usually performed at regular periodic intervals or as required
because of physical inspection.
This specification is under the jurisdiction of ASTM Committee F18 on
3.1.11 unassigned blankets—blankets that are in storage
Electrical Protective Equipment for Workers and is the direct responsibility of
prior to being issued for use.
Subcommittee F18.25 on Insulating Cover-Up Equipment.
Current edition approved Dec. 1, 2011. Published January 2012. Originally
3.1.12 voltage, maximum use—the ac voltage (rms), classi-
approved in 1976. Last previous edition approved in 2006 as F479–06. DOI:
fication of the protective equipment that designates the maxi-
10.1520/F0479-06R11.
mum nominal design voltage of the energized system that may
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
be safely worked. The nominal design voltage is equal to the
Standards volume information, refer to the standard’s Document Summary page on
phase-to-phase voltage on multiphase circuits.
the ASTM website.
3.1.12.1 Discussion—If there is no multiphase exposure in a
Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036, http://www.ansi.org. system area, and the voltage exposure is limited to the phase
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F479−06 (2011)
TABLE 1 Voltage Requirements for Blankets
(polarityondcsystems)togroundpotential,thephase(polarity
ondcsystems)togroundpotentialshallbeconsideredtobethe Class AC Use AC Retest DC Retest
Designation of Voltage, Voltage, Voltage,
nominal design voltage.
A
Blankets rms, max max max
3.1.12.2 Discussion—If electrical equipment and devices
0 1000 5000 20 000
are insulated or isolated, or both, such that the multiphase 1 7500 10 000 40 000
2 17 000 20 000 50 000
exposure on a grounded wye circuit is removed, then the
3 26 500 30 000 60 000
nominal design voltage may be considered as the phase-to-
4 36 000 40 000 70 000
ground voltage on that circuit.
A
The maximum use voltage is based on the following equations:
3.1.12.3 Discussion—The work practices and methods as-
Maximum ac use voltage = 0.95 ac maximum retest voltage − 2 000
v
Classes 1, 2, 3, and 4.
sociated with removing multiphase exposures at any given
Maximum ac use voltage = 0.95 dc maximum retest voltage − 30 500
v
work site are not addressed in the ASTM standards. The users
Classes 1, 2, 3, and 4.
of ASTM standards should reference appropriate industry Maximum ac use voltage = 0.95 dc maximum retest voltage − 18 000
v
Class 0.
consensus standards for proper work practices.
3.1.13 voltage, maximum retest—the voltage, either ac rms
or dc avg, that is equal to the proof test voltage for new
6.2 The user of this type of protective equipment shall be
protective equipment.
knowledgeable of and instructed in the correct and safe visual
3.1.14 voltage, nominal design—a nominal value consistent
inspection and use of this equipment.
with ANSI C84.1-2001, assigned to the circuit or system for
the purpose of conveniently designating its voltage class.
7. Inspection and Testing at an Electrical Testing Facility
3.1.15 voltage, retest—the voltage, either ac rms or dc avg,
7.1 The recommended sequence for inspection and testing
that used protective equipment must be capable of withstand-
of insulating blankets at the electrical testing facility is as
ing for a specified test period without breakdown.
follows:
7.1.1 Check in, washing, and preliminary inspection,
3.2 For definitions of other terms, refer to Terminology
7.1.2 Electrical test,
F819.
7.1.3 Final inspection,
4. Significance and Use
7.1.4 Recordkeeping and marking, and
7.1.5 Packing for storage and shipping.
4.1 Compliance with this specification should continue to
provide personnel with insulating blankets of known and
7.2 Dirty blankets should be cleaned. They may be washed
acceptable quality after initial acceptance in accordance with
with a mild soap or mild detergent and water. Mild household-
Specification D1048.The standards herein are to be considered
type chlorine bleach may be used for disinfectant purposes.
as minimum requirements.
Soaps, detergents, and bleaches shall not be used at strengths
that would attack or harm the rubber surface. They shall be
5. Classification
rinsed thoroughly with water to remove all of the soap or
5.1 Blankets covered under this specification shall be des-
detergent. Severe dirt and grime may be wiped off using a
ignated as Type I or Type II; Class 0, Class 1, Class 2, Class 3,
compatible solvent.
or Class 4; Style A or Style B.
7.2.1 The cleaning agent shall not degrade the insulating or
physical qualities of the blankets.
5.2 Type I, not resistant to ozone, made from a high-grade
7.2.2 A commercial tumble type washing machine may be
cis-1,4-polyisoprene rubber compound of natural or synthetic
used. Caution must be observed to eliminate any interior
origin, properly vulcanized.
surfaces or edges that may damage the blankets.
5.3 Type II, ozone-resistant, made of any elastomer or
7.3 Ifwashed,blanketsshouldbeair-dried.Theairtempera-
combination of elastomeric compounds.
ture should not be over 150°F (65.5°C).
5.4 The class designation shall be based on the electrical
7.4 Prior to the electrical test, the blankets shall be given a
properties as shown in Specification D1048.
preliminary inspection for punctures, cuts, corona cutting, or
5.5 Style A, constructed of the elastomers indicated under
any obvious condition which would adversely affect the
Type I or Type II, shall be free of any reinforcement.
performance. If any of these conditions are found, blankets
5.6 Style B, constructed of the elastomers indicated under
shall be rejected or repaired.
Type I or Type II, shall incorporate a reinforcement. This
7.5 The blankets shall be tested in accordance with Section
reinforcement shall not affect adversely the dielectric charac-
8.
teristics of the blankets.
7.6 After the test, the blankets shall be given an inspection
6. Safety Precautions
for corona and ozone damage.
6.1 A margin of safety shall be provided between the
8. Electrical Tests
maximum use voltage on which the blankets are used and the
voltage at which they are retested. The relationship between 8.1 All blankets issued for service shall be retested and shall
retest voltage and maximum use voltage at which the blankets withstand the 60-Hz ac test voltage (rms value) or the dc
shall be used is shown in Table 1. voltage (average value) specified in Table 1.The retest shall be
F479−06 (2011)
performedinaccordancewithSection8andshallbeconducted 8.5.1.3 An ac meter connected in series with appropriate
continuously for not less than 1 min, and not more than 3 min. high-voltage type resistors directly across the high voltage
circuit.
8.1.1 The interval between date of issue and retests shall be
8.5.1.4 Thecrestfactormaybecheckedbytheuseofapeak
based on work practices and test experience, but shall not
reading voltmeter connected directly across the high-voltage
exceed 1 year. Blankets that have been tested electrically, but
circuit.
not issued for service, shall not be placed into service unless
8.5.2 AC Retest:
they have been tested electrically within the previous 12
8.5.2.1 Each blanket shall be given an electrical retest in
months.
accordance with 8.1. The test period shall start at the instant
8.1.2 Where a visual inspection indicates that there may be
that the prescribed testing voltage is reached.
reason to suspect the electrical integrity of a blanket, an
electrical test shall be performed before reissuing the blanket
NOTE 2—It is recommended that the retest voltage be applied initially
for service.
at a low value and increased at a constant rate-of-rise of approximately
1000 V/s until the prescribed test voltage level is reached. Unless an
8.2 The test apparatus shall be designed to afford the
electrical puncture has already occurred, the applied voltage should be
operator full protection in the performance of his duties. reduced to at least half value at the end of the test period before opening
the test circuit.
Reliable means of de-energizing and grounding the high
voltage circuit shall be provided. It is particularly important to
8.5.2.2 Electrodes shall be of such design so as to apply the
incorporate positive means of grounding the high voltage
electricalstressuniformlyoverthetestareatominimizecorona
section of dc test apparatus due to the likely presence of
and mechanical strain in the material. The electrodes used in
high-voltage capacitance charges at the conclusion of the test.
the proof test shall be designed to comply with the flashover
See ANSI C39.5.
clearances specified in Table 2.
8.2.1 To eliminate damaging ozone and possible flashover
NOTE 3—Recommended Electrodes for Classes 0, 1, and
along the blanket, there should be a sufficient flow of air into
2—Rectangular metal sheets approximately ⁄16 in. (2 mm) thick having
and around the blanket and an exhaust system to adequately
edges and corners rounded smoothly and wet pads approximately ⁄4 in. (6
mm) thick, placed between the metal sheets and the blanket.
remove ozone from the test machine. Consistent ozone cutting
Recommended Electrodes for Classes 3 and 4—Maximum area can be
and checking during the test procedure should be cause to
tested when both electrodes are the same size. When an insulated table is
ascertain the adequacy of the exhaust system.
not convenient, the following mask method may be used. A 0.12 to 0.18
8.2.2 The equipment shall be inspected at least annually to
in. (3 to 5 mm) thick sheet of insulating material which is a minimum of
2 2
50 in. (1270 mm ) and has a 30 by 30 in. (762 by 762 mm) opening in
ensurethatthegeneralconditionoftheequipmentisacceptable
the center, is placed on a grounded metal plate. This mask which has a
and to verify the characteristics and accuracy of the test
“pictureframe”appearanceshallhavetheopeningfilledwithaconductive
voltages. To ensure the continued accuracy of the test voltage,
material of such thickness as to bring the ground electrode to approxi-
asindicatedbythetestequipmentvoltmeter,thetestequipment
mately the same level as the mask in order to maintain direct contact with
shall be calibrated at least annually, in accordance with the
the blanket to be tested. The blanket is placed over the ground electrode,
and a wet pad approximately the same size as the ground electrode, is
latest revision of Practice D2865.
placed on top of the blanket. The wet pad is energized with the test
8.3 Both ac and dc voltage retest methods are included and
voltage. This method will test a 30 by 30 in. (762 by 762 mm) area of a
36 by 36 in. (914 by 914 mm) blanket at 40 kV ac as the mask prevents
either method may be selected for electrical testing.
flashover.
8.4 All electrical tests shall be performed on clean blankets Other electrode designs may be used to achieve the same result.
at normal room temperatures.
8.6 DC Test:
8.6.1 Voltage Supply and Regulation—The dc test voltage
NOTE 1—All blankets should be in an unstressed physical condition
prior to testing. Failure to achieve this may result in excessive breakdown may be obtained
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