Designation:E1121−15StandardPracticeforMeasuringPaybackforInvestmentsinBuildingsandBuildingSystems1ThisstandardisissuedunderthefixeddesignationE1121;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thispracticeprovidesarecommendedprocedureforcalculatingandapplyingthepaybackmethodinevaluatingbuildingdesignsandbuildingsystems.2.ReferencedDocuments2.1ASTMStandards:2E631TerminologyofBuildingConstructionsE833TerminologyofBuildingEconomicsE917PracticeforMeasuringLife-CycleCostsofBuildingsandBuildingSystemsE964PracticeforMeasuringBenefit-to-CostandSavings-to-InvestmentRatiosforBuildingsandBuildingSystemsE1057PracticeforMeasuringInternalRateofReturnandAdjustedInternalRateofReturnforInvestmentsinBuildingsandBuildingSystemsE1074PracticeforMeasuringNetBenefitsandNetSavingsforInvestmentsinBuildingsandBuildingSystemsE1185GuideforSelectingEconomicMethodsforEvaluat-ingInvestmentsinBuildingsandBuildingSystemsE1369GuideforSelectingTechniquesforTreatingUncer-taintyandRiskintheEconomicEvaluationofBuildingsandBuildingSystems2.2Adjuncts:DiscountFactorTablesAdjuncttoPracticesE917,E964,E1057,E1074,andE112133.Terminology3.1Definitions—Fordefinitionsofgeneraltermsrelatedtobuildingconstructionusedinthispractice,refertoTerminol-ogyE631;andforgeneraltermsrelatedtobuildingeconomics,refertoTerminologyE833.4.SummaryofPractice4.1Thispracticeisorganizedasfollows:4.1.1Section2,ReferencedDocuments—ListsASTMstan-dardsandadjunctsreferencedinthispractice.4.1.2Section3,Definitions—Addressesdefinitionsoftermsusedinthispractice.4.1.3Section4,SummaryofPractice—Outlinesthecon-tentsofthepractice.4.1.4Section5,SignificanceandUse—Explainsthesignifi-canceanduseofthispractice.4.1.5Section6,Procedures—Describesstep-by-steptheproceduresformakingeconomicevaluationsofbuildings.4.1.6Section7,Ob...
