1、Designation: F3272 17F3272 18Standard Guide forSelection, Care, and Use of Arc Protective Blankets1This standard is issued under the fixed designation F3272; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision
2、. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide provides information for the selection, care, and use of arc protective blankets for personnel protection.1.2 This guide
3、 covers positioning,positioning and securing,securing arc protective blankets (tested to Test Method F2676) andchanneling the thermal, ballistic, and concussive forces generated by an arc flash event using arc protective blankets.1.3 This guide definesdescribes the use of the arc protective blanket
4、to maximize its protective effectiveness to workers exposedto energized electrical equipment where complete de-energizing of the work zone cannot be achieved or for low-risk exposureswith sufficient arc flash incident energy to warrant secondary protective means in the event of an arc flash.1.4 The
5、values stated in SI units are to be regarded as the standard. See IEEE/ASTM SI-10.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety, health, and environmental
6、 practices and determine the applicability ofregulatory limitations prior to use.1.6 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides a
7、nd Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D4391 Terminology Relating to The Burning Behavior of TextilesF819 Terminology Relating to Electrical Protective Equipment for WorkersF2676 Test Method for
8、Determining the Protective Performance of an Arc Protective Blanket for Electric Arc Hazards2.2 IEEE/ASTM Standard:2IEEE/ASTM SI-10 American National Standard for Metric Practice2.3 NFPA Standard:3NFPA 70E70E-2018 Standard for Electrical Safety in the Workplace2.4 CSA Standard:4CSA Z462Z462-2018 Wor
9、kplace electrical safety2.5 OSHA Standards:529 CFR 1910.269 Occupational Safety and Health Standards: Special Industries29 CFR 1926.950-969 Safety and Health Regulations for Construction3. Terminology3.1 Definitions:3.1.1 For definitions relating to the burning behavior of textiles, see Terminology
10、D4391 and for definitions relating to electricalprotective equipment for workers, see Terminology F819.1 This guide is under the jurisdiction of ASTM Committee F18 on Electrical Protective Equipment for Workers and is the direct responsibility of Subcommittee F18.65on Wearing Apparel.Current edition
11、 approved Nov. 15, 2017March 1, 2018. Published December 2017May 2018. DOI: 10.1520/F3272-17.Originally approved in 2017. Last previous editionapproved in 2017 as F3272-17. DOI: 10.1520/F3272-18.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at s
12、erviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from National Fire Protection Association (NFPA), 1 Batterymarch Park, Quincy, MA 02169-7471, http:/www.nfpa.org.4 Available from Canadian Standards Assoc
13、iation (CSA), 178 Rexdale Blvd., Toronto, ON M9W 1R3, Canada, http:/www.csagroup.org.5 Available from Occupational Safety and Health Administration (OSHA), 200 Constitution Ave., NW, Washington, DC 20210, http:/www.osha.gov.This document is not an ASTM standard and is intended only to provide the us
14、er of an ASTM standard an indication of what changes have been made to the previous version. Becauseit 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 versionof the standard a
15、s published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.2 abnormal condition, nabnormalities such as but not limited to, oil or compound leaking from cable or joints, brokencab
16、le sheaths or joint sleeves, hot localized surface temperatures of cables or joints, or joints that are swollen beyond normaltolerance are presumed to lead to or be an indication of an impending fault. Note: this term does not appear in the standard.3.1.3 anchoring, vnmethod of physical attachment f
17、or securing the blanket and all attached components (straps, stanchions,other hardware, etc.) in place for the duration of the protection level for which the blanket is rated.3.1.4 arc protective blanket, na flat assembly of fabric(s) with locations for attachments used to protect workers from theef
18、fects of arc flash and arc blast.3.1.5 arc protective blanket maximum arc current lmax, nmaximum value of RMS arc current that blanket can withstandwithout breakopen for no less than ten cycles of 60 Hz.3.1.5.1 DiscussionStandard values of the maximum arc current for this test method are 16 kA, 25 k
19、A, or 40 kA.3.1.6 arc protective blanket breakopen threshold performance (BTP), nthe product of the arc current l, kA and arc durationin cycles required for breakopen to occur at this same arc current level.3.1.7 blistered insulation, na condition in which electrical insulation exhibits visible sign
20、s of thermal deformation usuallyexhibited as a bubble on the insulation.3.1.8 conduit channel type construction, nthis is a common choice by many utilities because it is already widely used in theirsystems and they are typically stock and coded items that can be easily issued from company stores.a s
21、tandardized formedstructural system used in the construction and electrical industries for light structural support, often for supporting wiring,plumbing, or mechanical components such as air conditioning or ventilation systems. The strut is typically formed from sheetmetal, folded over into an open
22、 channel shape with inwards-curving lips to provide additional stiffness and as a location to mountinterconnecting components.3.1.8.1 DiscussionThe sizing and types of strut vary, but typically it is 14-gauge with half-inch hardware construction or equivalent for concreteconstruction. Rated blanket
23、attachment straps with rated carabineerscarabiners are used to hold the blankets in place. Thisconstruction method is also widely used when the integrity of the vault wall is questionable and the need to spread the load isnecessary. So, Using this method, longer pieces of strut are used and more anc
24、hor bolts are used to attach it, thus spreading theload.3.1.9 fixed mechanical concrete anchor, nthis type of anchor is produced in a variety of styles that includes standard fasteninghardware and rated hardware and may come with torque indicators (shear bolts) notifying the user the anchor has been
25、 installedproperly.3.1.10 inverse square distance formula, nheat and concussive energy/force decreases generally as the square of the distance.3.1.11 removable concrete anchor, nthis type of anchor is produced in a variety of styles that include, but are not limited to,D-ring anchors with and withou
26、t friction sleeve bolt attachments and are typically rated at 5000- and 10 000-lbs. (2268- and4536-kg) maximum capacity.a removable securing device for securely attaching an arc protective blanket to walls made ofconcrete.3.1.11.1 DiscussionThis type of anchor is quick and easy to install and can be
27、 reused, thus holding down hardware costs. This type of anchor isproduced in a variety of styles that include, but are not limited to, D-ring anchors with and without friction sleeve bolt attachmentsand are typically rated at 5000- and 10 000-lb (2268- and 4536-kg) maximum capacity.4. Summary of Gui
28、de4.1 This guide provides background understanding for selection, care and use of arc protective blankets as tested byTest MethodF2676. The guide is not a work practice and does not require blankets be used in the conditions described.4.2 The guide provides guidance for users can use to inform work
29、practices, for development of blanket use schemes,schemesand ideas for testing efficacy of blanket configurations and practices.4.3 The guide is based on the collective knowledge of the committee, published practices of committee members, testing, andOSHA testimony in 29 CFR 1910.269.F3272 1825. Sig
30、nificance and Use5.1 This guide provides positioning, installation, and anchoring techniques that may be used to arrange arc protective blanketsto confine or divert the energies found from a fault that may include plasma arcing, pressure wave, and projectiles.5.2 Arc protective blankets may be used
31、in anyan electrical application to confine or divert energy away from a work zone forelectrical or other workers who may be exposed to an electric arc in the event of an equipment or conductor failure.5.3 Cables, This guide provides information for working around cables, splices, and any equipment c
32、omponents whichthat havehistorical failures deemed to require additional protection or engineering controls, which could benefit from added protectionprovided by an arc protective blanket.5.4 This guide is designed for electrical engineers and qualified installers of arc protective blankets.5.5 The
33、practice is limited by the blanket protective value, the sturdiness of the installation, and the engineering assumptionsof the hazard assessment.5.6 These blankets do not typically provide dielectric protection.5.7 TheyThese blankets do not eliminate the need for arc-rated PPE but may reduce the lev
34、el of the hazard in some installations.6. How Blankets Work to Help Protect from Arc Flash6.1 An arc protective blanket is designed to direct heat, gases,gasses, and projectiles away from the worker. While the arcprotective blanket is tested to confine or divert an ejected arc up to the arc protecti
35、ve blanket breakopen threshold performance(BTP) level in the rating. Itrating, it is always safer to channel energy away from the workers rather than challenge the energy.For example, putting slack in the center at the top of the blanket to allow the energy to be directed above the blanket may be mo
36、reprotective in some scenarios.6.2 Tension in testing ensures full, worst case exposure to arc (The(the blanket is installed like a trampoline). This installationmethod is typically used only when installing the blanket like a wall. Installing blankets with other methods typically will allowbetter p
37、erformance of the blanket but may compromise the area protected by the blanket by diverting the energy. Energy diversionaway from workers is a key method to use in blanket installation. Some allowance for blanket movement away from arc can allowfor greater protection.6.3 Some blankets have a sidedne
38、ss and the marked side should always be installed as recommended by the manufacturer.7. Installation Practices7.1 General:7.1.1 Choose a blanket with a maximum rating greater than the predicted fault current at the location. Exceeding the blanketrating or failure to secure the blanket by the method
39、as tested may result in failure to completely protect or provide limited or noprotection.7.1.2 Use the largest blanket that will fit into the available space.7.1.3 Use the attachments provided by or required by the manufacturer, which are typically flame resistant. If the manufacturersconnecting mea
40、ns do not use manufacturers connecting means, are not used, any alternate connecting means should have tensilestrength equal to or greater than the manufacturers supplied means and not be affected by the thermal energy from the arc to ensurethe efficacy of the connecting means. This is typically don
41、e through testing.7.1.4 Install the top of blankets at a height ideally above the workers head in a work situation to allow energy to be divertedabove the workers head. Secure the blanket at the top to prevent energy diverting into the area of the face.NOTE 1Typically, a workers head may not be as w
42、ell protected as the torso. This is not typically true In the case of an arc flash suit which suit, thetorso typically has more protection on the torso than the legs.than the head or the legs due to the overlap of the bib from the overalls and the hood bibthat covers the top of the torso.NOTE 2When
43、wrapping or installing in a horizontal, planar installation, tools, equipment, or parts placed on a blanket could be ejected in the eventof a failure.7.1.5 Match the blanket to the worst case Ensure the blankets rating is adequate for the anticipated fault current and predictedclearing time for the
44、work location using the BTP of the blanket and but not above the maximum rated current of the blanket. Useof a blanket beyond its maximum fault current or its maximum BTP may have unintended effects such as complete blanket failureor extensive after flame of the blanket. In an enclosed area, this ef
45、fect can be dangerous. Some blankets may havedeleteriousharmful effects at higher levels but this is typically not discernable by standard test results. Contact the manufacturerfor guidance on blanket use in unusual conditions (oil-filled (such as oil-filled cables or breakers, higher fault currents
46、, enclosedspaces, etc.)spaces), or in abnormal conditions.7.1.6 Disturbing energized electrical equipment, especially cables and cable splices, can cause an arc flash. Exercise bestpractices when installing blankets for worker protection.7.1.7 Engineering a blanket installation by using distance fro
47、m the exposure, electrode geometry, the clearing time, and otherapplicable factors would be acceptable.F3272 1837.1.8 The complexity and arrangement of cable, cable splices, and other energized equipment; the variety of vault space,purpose, and configuration; the composition of each spaces infrastru
48、cture; the wide variety of hardware used to hold and secureelectrical components and devices found therein; and the deterioration exerted, as a result of both electrical and environmentalstress, may require the use of more than one anchoring and shielding method outlined in this guide.7.1.9 Stations
49、, straps and buckles, carabiners, lugs, and other items which blankets are installed onto used to install blankets canbecome a hazard if they cannot withstand the pressure from the arc fault.7.2 Shielding Methods:7.2.1 “J” Type ShieldingThe “J” Type installation (Fig. 1) is so named because, upon placement of the blanket in front of theracks and splices, the bottom of the blanket is tucked back toward the vault wall and the top is arrayed in a “D” shape with themiddle of the blanket bowed out so that the completed arrangement looks much like a sail. The
