b'employerinterviews,alsoexistsintheabsenceofarecognizedunion. 11 Thus,thetwodissentersbel ievetheCourthassustainedtherightof employeesofnon-unionemployerstohaveaco-employeeatt heinterview. TheanswertothisquestionandthefullimpactoftheWeingartendecision remain"upforgrabs"infurtherlitigation. NBSBUILDINGSCIENCESERIES55 Ahighlightoflastyear\'sconventionwasthebusinessprogramin whichBillCullenoftheNationalBureauofStandardsreportedonthe developmentofaperformanceapproachtobuilt-uproofmembranes.Enclosed isacopyofNBSBuildingScienceSeries55entitled\'\'PreliminaryPerformance CriteriaforBituminousMembraneRoofing\'\'.Thisisthebookletsetting forthdetailedinformationconcerningtheperformanceapproacht owhichM . rCullenreferredduringhisprogram. Weurgeyoutoreadthebooklet.Admittedly,portionsofthebooklet, particularlythesectiondescribingthelaboratoryresearchprogram,are technical.However,mostofthebookletisveryreadable. Whatdoestheperformanceapproachmean?Upuntilnow,therehas beennomethodbywhichamembranecouldbeeffectivelyt estedorevaluatedpriortofielduse.Theconsequencehasbeenprematurefailureof newtypesofroofmembraneswhichwerebutshouldnothavebeenm d arketeandappliedinthefield.Attheriskofoversimplification,thereal benefitoftheperformanceapproachasdescribedintheenclosedbooklet isthatmodificationstoprovenconventionalmembranesystemsandnew. systemscanbeeffectivelyevaluatedastotheirabilitytoperf ormunder\'-serviceconditionspriortomarketingandi nstallation. Twentyseparateperformancecriteriaorattributesareidentifiedin thebookletashavingsignificantimpactonroofsystemperformanceunder in-serviceconditions,andteststomeasureperformanceofroofmembranes for9ofthe20criteriaaredescribed. Duringhispresentation,Mr.Cullenmadeseveralpointsconcerning theperformanceapproachwhichareworthrepeatinghere: (1)Performancel evelscanvarybaseduponc l imateand theneedsoftheowner. (2)Theperformanceapproachcanbeusedasabaseto selectproducts,thepurposebeingtoprotectagainsta repeatofproblemsencounteredbytheindustrythroughmarketingandapplicationofnew,untestedsystems,suchasthetwoplycoatedsheetsystem. (3)Theperformanceapproachcanbeusedindocuments toevaluatemarketedinnovations. (4)Theperformanceapproachcanserveasacommonbasis uponwhichtocomparevariousmembraneproducts. (5)Theperformanceapproachcanbeusedtoevaluate substituteproducts.'