ASTM F479-06(2017) Standard Specification for In-Service Care of Insulating Blankets.pdf

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1、Designation: F479 06 (Reapproved 2017)Standard Specification forIn-Service Care of Insulating Blankets1This standard is issued under the fixed designation F479; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last revis

2、ion. A number in parentheses indicates the year of last reapproval. A superscriptepsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers the in-service care, inspection,testing, and use voltage of insulating blankets for protection ofworke

3、rs from accidental contact with live electricalconductors, apparatus, or circuits. The product requirementsand acceptance testing are as shown in Specification D1048.1.2 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions t

4、o SI units that are provided for information onlyand are not considered standard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental

5、practices and deter-mine the applicability of regulatory limitations prior to use.SeeSection 6 and 8.2 for specific precautionary statements.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Prin

6、ciples for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1048 Specification for Rubber Insulating BlanketsD2865 Practice for Calibration of Standards

7、 and Equipmentfor Electrical Insulating Materials TestingF819 Terminology Relating to Electrical Protective Equip-ment for Workers2.2 ANSI Standard:3C39.5 Safety Requirements for Electrical and ElectronicMeasuring and Controlling InstrumentationC84.1 Voltage Ratings for Electric Power Systems andEqu

8、ipment (60 Hz)3. Terminology3.1 Definitions:3.1.1 breakdownthe electrical discharge or arc occurringbetween the electrodes and through the equipment being tested.3.1.2 compatiblenot injurious to or changing the physicalor electrical characteristics of the blankets or affecting theirapplication, use,

9、 or acceptability.3.1.3 designated personan individual who is qualified byexperience or training to perform an assigned task.3.1.4 electrical testing facilitya location with qualifiedpersonnel, testing equipment, and procedures for the inspectionand electrical testing of electrical insulating protec

10、tive equip-ment.3.1.5 electrodethe energized or grounded conductor por-tion of electrical test equipment which is placed near or incontact with the material or equipment being tested.3.1.6 flashoverthe electrical discharge or arc occurringbetween electrodes and over or around, but not through, theeq

11、uipment being tested.3.1.7 insulatedseparated from other conducting surfacesby a dielectric substance (including air space) offering a highresistance to the passage of current.3.1.7.1 DiscussionWhen any object is said to be insulated,it is understood to be insulated in a suitable manner for thecondi

12、tions to which it is subjected. Otherwise, it is, within thepurposes of this definitions, uninsulated. Insulating covering ofconductors is one means of making the conductor insulated.3.1.8 ozonea very active form of oxygen that may beproduced by corona, arcing, or ultraviolet rays.3.1.9 ozone cuttin

13、g and checkingthe cracks produced byozone in a material under mechanical stress.3.1.10 retestthe tests given after the initial acceptance testusually performed at regular periodic intervals or as requiredbecause of physical inspection.3.1.11 unassigned blanketsblankets that are in storageprior to be

14、ing issued for use.3.1.12 voltage, maximum usethe ac voltage (rms), classi-fication of the protective equipment that designates the maxi-mum nominal design voltage of the energized system that may1This specification is under the jurisdiction of ASTM Committee F18 onElectrical Protective Equipment fo

15、r Workers and is the direct responsibility ofSubcommittee F18.25 on Insulating Cover-Up Equipment.Current edition approved Dec. 15, 2017. Published January 2018. Originallyapproved in 1976. Last previous edition approved in 2011 as F47906(2011). DOI:10.1520/F0479-06R17.2For referenced ASTM standards

16、, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New

17、 York, NY 10036, http:/www.ansi.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Pr

18、inciples for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1be safely worked. The nominal design voltage is equal to thephase-to-phase voltage on multiphase circuits.3.1.12.1 DiscussionIf there

19、 is no multiphase exposure in asystem area, and the voltage exposure is limited to the phase(polarity on dc systems) to ground potential, the phase (polarityon dc systems) to ground potential shall be considered to be thenominal design voltage.3.1.12.2 DiscussionIf electrical equipment and devicesar

20、e insulated or isolated, or both, such that the multiphaseexposure on a grounded wye circuit is removed, then thenominal design voltage may be considered as the phase-to-ground voltage on that circuit.3.1.12.3 DiscussionThe work practices and methods as-sociated with removing multiphase exposures at

21、 any givenwork site are not addressed in the ASTM standards. The usersof ASTM standards should reference appropriate industryconsensus standards for proper work practices.3.1.13 voltage, maximum retestthe voltage, either ac rmsor dc avg, that is equal to the proof test voltage for newprotective equi

22、pment.3.1.14 voltage, nominal designa nominal value consistentwith ANSI C84.1-2001, assigned to the circuit or system forthe purpose of conveniently designating its voltage class.3.1.15 voltage, retestthe voltage, either ac rms or dc avg,that used protective equipment must be capable of withstand-in

23、g for a specified test period without breakdown.3.2 For definitions of other terms, refer to TerminologyF819.4. Significance and Use4.1 Compliance with this specification should continue toprovide personnel with insulating blankets of known andacceptable quality after initial acceptance in accordanc

24、e withSpecification D1048. The standards herein are to be consideredas minimum requirements.5. Classification5.1 Blankets covered under this specification shall be des-ignated as Type I or Type II; Class 0, Class 1, Class 2, Class 3,or Class 4; Style A or Style B.5.2 Type I, not resistant to ozone,

25、made from a high-gradecis-1,4-polyisoprene rubber compound of natural or syntheticorigin, properly vulcanized.5.3 Type II, ozone-resistant, made of any elastomer orcombination of elastomeric compounds.5.4 The class designation shall be based on the electricalproperties as shown in Specification D104

26、8.5.5 Style A, constructed of the elastomers indicated underType I or Type II, shall be free of any reinforcement.5.6 Style B, constructed of the elastomers indicated underType I or Type II, shall incorporate a reinforcement. Thisreinforcement shall not affect adversely the dielectric charac-teristi

27、cs of the blankets.6. Safety Precautions6.1 A margin of safety shall be provided between themaximum use voltage on which the blankets are used and thevoltage at which they are retested. The relationship betweenretest voltage and maximum use voltage at which the blanketsshall be used is shown in Tabl

28、e 1.6.2 The user of this type of protective equipment shall beknowledgeable of and instructed in the correct and safe visualinspection and use of this equipment.7. Inspection and Testing at an Electrical Testing Facility7.1 The recommended sequence for inspection and testingof insulating blankets at

29、 the electrical testing facility is asfollows:7.1.1 Check in, washing, and preliminary inspection,7.1.2 Electrical test,7.1.3 Final inspection,7.1.4 Recordkeeping and marking, and7.1.5 Packing for storage and shipping.7.2 Dirty blankets should be cleaned. They may be washedwith a mild soap or mild d

30、etergent and water. Mild household-type chlorine bleach may be used for disinfectant purposes.Soaps, detergents, and bleaches shall not be used at strengthsthat would attack or harm the rubber surface. They shall berinsed thoroughly with water to remove all of the soap ordetergent. Severe dirt and g

31、rime may be wiped off using acompatible solvent.7.2.1 The cleaning agent shall not degrade the insulating orphysical qualities of the blankets.7.2.2 A commercial tumble type washing machine may beused. Caution must be observed to eliminate any interiorsurfaces or edges that may damage the blankets.7

32、.3 If washed, blankets should be air-dried. The air tempera-ture should not be over 150F (65.5C).7.4 Prior to the electrical test, the blankets shall be given apreliminary inspection for punctures, cuts, corona cutting, orany obvious condition which would adversely affect theperformance. If any of t

33、hese conditions are found, blanketsshall be rejected or repaired.7.5 The blankets shall be tested in accordance with Section8.TABLE 1 Voltage Requirements for BlanketsClassDesignation ofBlanketsAC UseVoltage,rms, maxAAC RetestVoltage,maxDC RetestVoltage,max0 1000 5000 20 0001 7500 10 000 40 0002 17

34、000 20 000 50 0003 26 500 30 000 60 0004 36 000 40 000 70 000AThe maximum use voltage is based on the following equations:Maximum ac use voltage = 0.95 ac maximum retest voltage 2 000vClasses 1, 2, 3, and 4.Maximum ac use voltage = 0.95 dc maximum retest voltage 30 500vClasses 1, 2, 3, and 4.Maximum

35、 ac use voltage = 0.95 dc maximum retest voltage 18 000vClass 0.F479 06 (2017)27.6 After the test, the blankets shall be given an inspectionfor corona and ozone damage.8. Electrical Tests8.1 All blankets issued for service shall be retested and shallwithstand the 60-Hz ac test voltage (rms value) or

36、 the dcvoltage (average value) specified in Table 1. The retest shall beperformed in accordance with Section 8 and shall be conductedcontinuously for not less than 1 min, and not more than 3 min.8.1.1 The interval between date of issue and retests shall bebased on work practices and test experience,

37、 but shall notexceed 1 year. Blankets that have been tested electrically, butnot issued for service, shall not be placed into service unlessthey have been tested electrically within the previous 12months.8.1.2 Where a visual inspection indicates that there may bereason to suspect the electrical inte

38、grity of a blanket, anelectrical test shall be performed before reissuing the blanketfor service.8.2 The test apparatus shall be designed to afford theoperator full protection in the performance of his duties.Reliable means of de-energizing and grounding the highvoltage circuit shall be provided. It

39、 is particularly important toincorporate positive means of grounding the high voltagesection of dc test apparatus due to the likely presence ofhigh-voltage capacitance charges at the conclusion of the test.See ANSI C39.5.8.2.1 To eliminate damaging ozone and possible flashoveralong the blanket, ther

40、e should be a sufficient flow of air intoand around the blanket and an exhaust system to adequatelyremove ozone from the test machine. Consistent ozone cuttingand checking during the test procedure should be cause toascertain the adequacy of the exhaust system.8.2.2 The equipment shall be inspected

41、at least annually toensure that the general condition of the equipment is acceptableand to verify the characteristics and accuracy of the testvoltages. To ensure the continued accuracy of the test voltage,as indicated by the test equipment voltmeter, the test equipmentshall be calibrated at least an

42、nually, in accordance with thelatest revision of Practice D2865.8.3 Both ac and dc voltage retest methods are included andeither method may be selected for electrical testing.8.4 All electrical tests shall be performed on clean blanketsat normal room temperatures.NOTE 1All blankets should be in an u

43、nstressed physical conditionprior to testing. Failure to achieve this may result in excessive breakdownor damage.8.5 AC Test:8.5.1 Voltage Supply and RegulationThe voltage supplyand its control equipment shall be of such size and design that,with the test specimens in the circuit, the crest factor (

44、ratio ofpeak to mean effective) of the test voltage shall differ by notmore than 5 % from that of a sinusoidal wave over the upperhalf of the range of the test voltage. The accuracy of the voltagemeasuring circuit shall be within 62 % of full scale. Thecorrect rms value of the sinusoidal voltage wav

45、e form appliedto the blanket may be measured by one of the followingmethods:8.5.1.1 A voltmeter used in conjunction with a calibratedinstrument transformer connected directly across the highvoltage circuit,8.5.1.2 A calibrated electrostatic voltmeter connected di-rectly across the high voltage circu

46、it, or8.5.1.3 An ac meter connected in series with appropriatehigh-voltage type resistors directly across the high voltagecircuit.8.5.1.4 The crest factor may be checked by the use of a peakreading voltmeter connected directly across the high-voltagecircuit.8.5.2 AC Retest:8.5.2.1 Each blanket shall

47、 be given an electrical retest inaccordance with 8.1. The test period shall start at the instantthat the prescribed testing voltage is reached.NOTE 2It is recommended that the retest voltage be applied initiallyat a low value and increased at a constant rate-of-rise of approximately1000 V/s until th

48、e prescribed test voltage level is reached. Unless anelectrical puncture has already occurred, the applied voltage should bereduced to at least half value at the end of the test period before openingthe test circuit.8.5.2.2 Electrodes shall be of such design so as to apply theelectrical stress unifo

49、rmly over the test area to minimize coronaand mechanical strain in the material. The electrodes used inthe proof test shall be designed to comply with the flashoverclearances specified in Table 2.NOTE 3Recommended Electrodes for Classes 0, 1, and2Rectangular metal sheets approximately116 in. (2 mm) thick havingedges and corners rounded smoothly and wet pads approximately14 in. (6mm) thick, placed between the metal sheets and the blanket.Recommended Electrodes for Classes 3 and 4Maximum area can betested when both electrodes are the same s