bsi. ...making excellence a habit Inspiring trust foramore resilient world 需要更多标准请联系 wechat: wpwyq310 BSENIS011691:2020 BSlStandardsPublication AcousticsMeasurementofinsertionlossofducted silencerswithoutflowLaboratorysurveymethod bsi. BSENIS011691:2020 BRITISHSTANDARD Nationalforeword ThisBritishStandardistheUKimplementationofENIS011691:2020 ItisidenticaltoISO11691:2020.ItsupersedesBSENIS011691:2009, whichiswithdrawn. TheUKparticipation in its preparationwas entrustedtoTechnical CommitteeEH/1/4,Machinerynoise. A listoforganizations represented onthis committeecanbeobtained on request to its committeemanager. This publication does not purportto includeall the necessaryprovisions ofacontract.Usersareresponsibleforitscorrectapplication. TheBritishStandardsInstitution2020 PublishedbyBSIStandardsLimited2020 ISBN9780539020953 ICS91.140.30;91.120.20;17.140.20 CompliancewithaBritishStandardcannotconferimmunityfrom legal obligations. This British Standard waspublished underthe authority of the Amendments/corrigendaissuedsincepublication Date Textaffected 3