TransmissionSystemsAPIRECOMMENDEDPRACTICE552FIRSTEDITION,OCTOBER1994REAFFIRMED,AUGUST2015TransmissionSystemsManufacturing,DistributionandMarketingDepartmentAPIRECOMMENDEDPRACTICE552FIRSTEDITION,OCTOBER1994REAFFIRMED,FEBRUARY2007SPECIALNOTES1.APIPUBLICATIONSNECESSARILYADDRESSPROBLEMSOFAGENERALNATURE.WITHRESPECTTOPARTICULARCIRCUMSTANCES,LOCAL,STATE,ANDFEDERALLAWSANDREGULATIONSSHOULDBEREVIEWED.2.APIISNOTUNDERTAKINGTOMEETTHEDUTIESOFEMPLOYERS,MANU-FACTURERS,ORSUPPLIERSTOWARNANDPROPERLYTRAINANDEQUIPTHEIREMPLOYEESANDOTHERSEXPOSEDCONCERNINGHEALTHANDSAFETYRISKSANDPRECAUTIONS,NORUNDERTAKINGTHEIROBLIGATIONSUNDERLOCAL,STATE,ORFEDERALLAWS.3.INFORMATIONCONCERNINGSAFETYANDHEALTHRISKSANDPROPERPRECAUTIONSWITHRESPECTTOPARTICULARMATERIALSANDCONDI-TIONSSHOULDBEOBTAINEDFROMTHEEMPLOYER,THEMANUFACTURER,ORSUPPLIEROFTHATMATERIAL,ORTHEMATERIALSAFETYDATASHEET.4.NOTHINGCONTAINEDINANYAPIPUBLICATIONISTOBECONSTRUEDASGRANTINGANYRIGHT,BYIMPLICATIONOROTHERWISE,FORTHEMANU-FACTURE,SALE,ORUSEOFANYMETHOD,APPARATUS,ORPRODUCTCOVEREDBYLETTERSPATENT.NEITHERSHOULDANYTHINGCONTAINEDINTHEPUBLICATIONBECONSTRUEDASINSURINGANYONEAGAINSTLIABILITYFORINFRINGEMENTOFLETTERSPATENT.5.GENERALLY,APISTANDARDSAREREVIEWEDANDREVISED,REAF-FIRMED,ORWITHDRAWNATLEASTEVERYFIVEYEARS.SOMETIMESAONE-TIMEEXTENSIONOFUPTOTWOYEARSWILLBEADDEDTOTHISREVIEWCYCLE.THISPUBLICATIONWILLNOLONGERBEINEFFECTFIVEYEARSAFTERITSPUBLICATIONDATEASANOPERATIVEAPISTANDARDOR,WHEREANEXTENSIONHASBEENGRANTED,UPONREPUBLICATION.STATUSOFTHEPUBLICATIONCANBEASCERTAINEDFROMTHEAPIAUTHORINGDEPARTMENT[TELEPHONE[(202)682-8000].ACATALOGOFAPIPUBLICATIONSANDMATERIALSISPUBLISHEDANNUALLYANDUPDATEDQUARTERLYBYAPI,1220LSTREET,N.W.,WASHINGTON,D.C.20005.Copyright©1994AmericanPetroleumInstituteiiiFOREWORDThispublicationreflectsthecurrentpracticesinthetransmissionofinstrumentmeasure-mentandcontrolsignalsinarefinery.Throughoutthispublication,soft-conversion(calculated)unitsareprovidedinparen-thesesfollowingactualunits.Soft-conversionunitsareprovidedfortheuserÕsreferenceonly.APIpublic...
