ASTM_F_2676_-_09.pdf

Designation:F267609Standard Test Method forDetermining the Protective Performance of an ArcProtective Blanket for Electric Arc Hazards1This standard is issued under the fixed designation F2676;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.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 test method is used to evaluate the ability of the arcprotective blankets to withstand the effects of arc flash and arcblast in a configuration in which the blanket is hung oranchored near energized equipment.Specifically,this testmethod is used to determine the arc protective blankets(1)resistance to breakopen,(2)mechanical strength,and(3)ability to self-extinguish flames following a controlled arcexposure.1.2This method is used to determine the performance ofarc protective blankets in terms of:maximum arc current levelexpressed in kAand BTP(BTP)expressed as the product of arccurrent in kA and arc duration in number of cycles to causebreakopen(kA*cycles).Cycles are on the basis of 60 Hz.1.3 Blanket test specimens used in this test method are testsize blankets of 152 6 5 cm(60 6 2 in.)by 122 6 5 cm(486 2 in.).The test specimen size is for testing purposes only.Commercially available arc protective blankets either larger orsmaller than the test specimen size are covered by thisstandard.1.4 The arc protective blankets described in this test methodare made of flame-resistant materials and are available invarying sizes and configurations based on the application.1.5 This test method shall be used to measure and describethe properties of materials,products,or assemblies in responseto incident thermal(convective and radiant)and pressureenergies generated by an electric arc under controlled labora-tory conditions.1.6 The values stated in SI units shall be regarded asstandard.The values given in parentheses are mathematicalconversion to inch-pound or other units commonly used for arctesting.1.7 This standard shall not be used to describe or appraisethe fire hazard or fire risk of materials,products,or assembliesunder actual fire conditions.However,results of this test maybe used as elements of a fire assessment,which takes intoaccount all of the factors,which are pertinent to an assessmentof the fire hazard of a particular end use.1.8 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 and health practices and determine the applica-bility of regulatory limitations prior to use.For specificprecautions,see Section 7.2.Referenced Documents2.1 ASTM Standards:2D4391 Terminology Relating to The Burning Behavior ofTextilesF819 Terminology Relating to Electrical Protective Equip-ment for Workers3.Terminology3.1 Definitions:3.1.1 arc,nconductive path in air for the electric currentcaused by ionization of air between two electrodes.3.1.2 arc induced fragmentation,nmolten metal frag-ments or other fragments emitted from an electric arc.3.1.3 arc protective blanket,na flat assembly of fabric(s)with locations for attachment used to protect workers from theeffects of arc flash and arc blast.3.1.4 arc protective blanket maximum arc current Imax,nmaximum value of RMS arc current that blanket canwithstand without breakopen for no less than ten cycles of 60Hz.3.1.4.1 DiscussionStandard values of the maximum arccurrent for this test method are 15 kA,25 kA,or 40 kA.3.1.5 arc protective blanket breakopen threshold perfor-mance(BTP),nthe product of the arc current I,kA and arcduration in cycles required for breakopen to occur at this samearc current level.1This test method is under the jurisdiction of ASTM Committee F18 onElectrical Protective Equipment for Workers and is the direct responsibility ofSubcommittee F18.65 on Wearing Apparel.Current edition approved May 1,2009.Published June 2009.DOI:10.1520/F2676-09.2For referenced ASTM standards,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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.1.6 breakopen,nin electrical arc testing,a materialresponse evidenced by the formation of one or more holes inthe material which may allow thermal energy to pass throughthe material.3.1.6.1 DiscussionThe instant of breakopen will only bevisible with a high-speed(HS)camera.The size of thebreakopen will quickly expand as the arc blows through theblanket and burns back the edges of the materials.The finalsize of the breakopen hole is not significant,as it will dependto a great extent on the duration of the arc once the breakopenpoint is reached.The important measure us