SeanMoran
Elsevier
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Notices
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Preface
Theauthorofanynonfictionworkshouldinmyviewhaveacleardefinitionof theintendedscopeofthatwork,andtheirtitleshouldmatchthatscope,otherwisetheyarejustsettingthereaderupfordisappointment.So,thisis Moran’s DictionaryofChemicalEngineeringPractice,alexiconofmyprofession,Chemical Engineering,inwhichIdefinethemeaningofthetermsusedprofessionallyby myfellowpractitionersofthedesignandoperationofprocessplants.
However,itisnotreallyjust“Moran’sDictionary.”Thatwouldnotbemuch use,asIalreadyknowwhat I mean!Thepurposeofthebookistohelpchemicalengineerstocommunicateunambiguouslywitheachother,andwithmembersoftheotherprofessionsandtradeswithwhomweinteractinprofessional life.Bothmyfellowchemicalengineersandthoseothersusethesamewordsto meandifferentthingsanddifferentwordstomeanthesamethings.So,when writingthisbook,IhavefollowedtheapproachIhavedevelopedinwritingmy previousbooks,seekingandconsideringthecontributionsofhundredsof chemicalengineersworldwideonthecontent,toensurethatitrepresentsa complete,currentconsensusview.
Evenwithinengineering,therearetermswhicharecommonlyusedinerror,or easilyconfused.Thiscanhappenforanumberofreasons,includingthepresence ofsub-sub-languages,usagedifferencesbetweenindustrysectors,anddifferences betweenthejargonofchemicalengineeringandthatoftheotherprofessionsand tradeswhichweworkwith.Thereforethis dictionaryalsocontainssometerms frommoregeneralengineering,management,quality,etc.Practicedoesnotexist inavacuum:engineeringisamultidisciplinaryeffort.
Let’salsobeclearonwhatthisdictionaryis not.
Firstly,thisisnotanencyclopedia(asetofshortarticlesonawiderangeofsubjects,summarizingfactualknowledge).Therearenoarticles,historiesorbiographiesinthisdictionary,thoughthereareafewshortdiscussionsofselected termswhichmeritedamorediscursiveapproach.
Thisisatechnicaldictionary,ratherthanageneraldictionarysuchastheOED. Asatechnicaldictionary,thisbookdoesnotdefine“words”assuch.Theelementsoftechnicalvocabularyare‘terms’,ortoputitanotherway,theelements ofasub-languageorjargon—theshorthandusedwithinagroup.Technical termsmay,confusingly,meandifferentthingsfromtheeverydaywordsthey resemble.
Thisisnotadictionaryofscience.Itisadictionaryofengineering,andengineeringisnotappliedscience.Howcanitbewhenengineeringpredatesit? Theengineeringscienceswhichprofessionalengineersutilize,suchasthermodynamics,weredevisedposthoctoexplainwhatengineeringhadalready achieved,andthenaturalsciencesareverylittletodowithengineeringpractice.Wherescientifictermsdoappearinthisdictionary,itisbecausetheyare relevanttopractice.
Bythesametoken,thisisnotadictionarywrittentoaccompanytheacademic studyofchemicalengineering,thoughIbelievemanyacademicswouldbenefit fromusingit.Inmyview(havingpracticedinbothareas),academiaand ChemicalEngineeringareentirelydifferentprofessions.Ihavethereforeleftout ofthisbookallthatistaught—orhelddear—inacademia,butwhichisofno practicalutility,aswellasthemajorityofthosetermswhichshouldbewell understoodbyanygraduateofchemicalengineering.Ihavehowevermadean exceptionforthoseelementsoftheoreticalknowledgewhichweallpassed examsin,butexperiencesuggestsmanyofusdonotremember,orperhaps didnotreallyunderstandinthefirstplace.
Ihopethatmyfellowpractitionerswillfindthisdictionaryusefulintheirprofessionaljourney,whetherpreparingforprofessionalexaminations,enteringa newsector,progressingintheirown,workinginanewterritory,orcollaboratingwithotherdisciplines.
Introduction
1Commonplace,Generic,and SpecificDefinitions
Atechnicaldictionarysuchasthisshouldbydefinitioncontainonly“words” withspecificmeaningswithinafieldofexpertise—properlycalledindustry terms.Thecommonplacemeaningsofthewordsareexcluded.Thisispotentiallyproblematic,asmisunderstandingsmayarisewhensomeoneusesaword initscommonplacesense,butisunderstoodtobeusingatechnicalterm,or viceversa.
Severaltermsaremarkedinthisbookashavingboth“generic”and“specific” meanings.“Generic”meaningsarethoseusedprofessionallyinthesameway acrossallindustries,ratherthanbeingcommonplacemeanings.Ihaveusually developedagenericmeaningfromaconsensusofmyunderstanding,thatof mycorrespondents,andpossiblyanumberofcodesandstandards.Ageneric meaningisintendedtoconveyasuccinctviewofwhatIunderstandtobethe coremeaninggenericallygiventotheterminourprofession.“Specific”meaningsarenotofferedasanillustrationofthegenericmeaning;indeed,theymay actuallyclashwiththegenericmeaning.Ifinyourpractice,youcomeacrossa termbeingusedinthecontext(usuallyindustrysector)Ireference,thenitsuse couldeasilybeinthespecificsenseratherthanthegenericorcommonplace ones.
2Sector-specificTerminology
Oneofthekeywaysinwhichterminologydifferswithinourprofessionisacross sectors.Ihavethereforedividedourprofessioninto10nominalsectorsforthe purposeofcategorizingterms:Hygienic,BiochemicalEngineering,OilandGas, BulkChemicals,FineChemicals,Environmental,Products,GeneralEngineering, NuclearandSafety.
Thesesectorclassificationsare,tosomeextent,subjective,andIamawarethat engineersindifferentdisciplines(especiallyoilandgas!)mightwelldisagree withmyclassifications.However,theseareintendedsimplytoalignapproximatelywithmyunderstandingofboththeprofessionalandlinguisticdistinctions.Someoneinoilrefiningorpetrochemicalsmightobjecttoatermbeing lumpedinwiththoseinvolvedinprimaryproduction,buttheyunderstand
mostofthejargonofthatrelatedfieldinawaythatsomeoneinvolvedinpharmaceuticalswillnot.(Imentionoilandgasbecauseadisproportionateamount ofthejargoninthisdictionary,someofitquitecoarse,emanatesfromthis sector!)
Wemightaddan11thcategory,engineeringscience,aheadingunderwhich thosefewtermsfromacademiawhichhavemadetheirwayintothisdictionary wouldtendtofall.Whereithasprovennecessarytodifferentiatesuchacademicterminologyfromprofessionalterminology,Ihaveflaggedthisup.
InsomecasesImaynotrefertoanindustrysectordirectly,butIsignpostaformaldefinitioninanindustry-specificstandard,suchasforexampleanAPIstandard.APIstandardsareusedinmanysectorsotherthanoilandgas,especially thoseinfluencedbytheUnitedStates.However,aswithmyindustryclassifications,theboundariesofmysectorsarelinguisticratherthanabsolute.
Itisreasonablyfrequentthatdifferentsectorsuseatermindifferentways. WhereIamawareofthis,Ihaveflaggedthisinthedefinition.Forexample, chemicallycombinedwater meansdifferentthingstochemists,cementandceramic-specialists.
3Swearing,Jokes,andInsults
Ihaveincludedsomecoarselanguage,asisnormalpracticeinlexicography. Dictionaries(otherthanthoseintendedforyoungchildren)routinelycontain termsconsideredvulgaroroffensiveso,wherethesetermsarepartofengineeringpractice,Ihaveincludedthem,markingthemaseither potentiallyoffensive, or offensive.
ItisarguablyeasiertocauseoffensenowadaysthanwhenIfirststartedintheprofession,somyapproachwillprobablynotsatisfyallreaders,someofwhomare boundtoconsidertheinclusionofanycoarselanguageatall“unprofessional.” Iwouldsuggesthoweverthatswearingandslangcanbeprofessional,even whenitisobscene.Engineersoftenuseswearingforwhatresearchshowsitis goodfor,inthesamewayasdoctors:forstressrelief(aneffectcalledlalochezia), tobuildgroupsolidarity,andforaddingemphasis.Likedoctors,wemayuse in-jokeacronymstohelpusdisguisefromoutsidersthatweareswearing;someof theseacronymsappearinthisdictionary.
Thesetermshoweverconstituteatinyfractionofonepercentofthecontent. Onlypeoplelookingfortheminthemannerofan11-year-oldboylookingfor thenaughtywordsinhisfirstrealdictionaryarelikelytofindthem,unlessthey havealreadyheardthetermandarewonderingwhatitmeans.
Ihavealsoincludedsomedefinitionswhichare“engineerjokes”:acertainflavorofwrycommentarywhichdefineswordscommonlyusedinengineeringin awaywhichreflectssomeofthecultureoftheprofession,andsomeofthe nuanceofthecommonunderstandingofthesetermsinthemindsofprofessionalengineers.Ihavehowevermarkedtheseas jocular,foravoidanceof doubt.
4Formaldefinitions
Throughoutthedictionary,Ireferencethe“formaldefinitions”oftermsas foundincodesandstandards,thoughinalmostallcasesIhavebeenunableto reproducethemforcopyrightreasons.Thiswasinitiallyadisappointment,until itbecameclearthatmany“formaldefinitions”bearthehallmarksofdesignby committee.Manyofthemlacksuccinctness.Someappeartocontainerrors. Fewofthemarewellwritten.Inmanycasesthereferencestoastandardand itsformaldefinitionareincludedbecausethestandardisthesourceofthe term,inothersitisbecausethereisadifferentmeaningfortheterminthat context.Termsarenotcopyright,onlydefinitions.
Thepointofincludingreferencetotheformaldefinitionsisnotthattheyare “correct,”evenintheirlimitedsphereofapplication.Thepointisthatthey haveagoodchanceofbeingtheconsensusterminthatsphere,oratleast representingacommonly-heldview.Thismaywellprovecrucialintheeventof adispute,andbeingunfamiliarwiththedefinitiongiveninrelevantcodesand standardsisthereforesomethingtobeavoided.
WhereIhavefoundtermsformallydefinedindifferentapplications,Iquote multiplestandards.WhereIamaware—throughmyexperienceorthatofmy collaborators—ofwiderapplicationsofaterm,Icitethose.
Forsometerms,myreferencesmaynotalwaysbetothemostcurrentedition ofacodeorstandard.Mostoftenthisisbecausethecodeorstandardwas updatedduringthewritingprocess.Ireferencemorethan200codesandstandardsinthisbook,andittookthreeandahalfyearstowriteit.Sometimes,the morerecentversionnolongerdefinestheterm.Occasionally,theversionIhad onhandwasnotthemostcurrentevenonthedayIstartedwriting.Inafew cases,theoriginalstandardwaswithdrawnsometimeagoandnotreplaced, butneverthelesscontinuestobecommonlyused.
Therearealsoseveralcasesinthedictionaryofclashesbetweentheformaldefinitionsofterms.Thevariationbetweenthemrangesfromsubtledifferencesin terminologytocompletedifferencesinmeaning(see risk foranextremecase). Ihaveflaggedwherethisisthecase.
5Erroneous,Deprecated,and ContestedTerms
Ihaveincludedtermswhicharecommonlyusedinerror,markedassuch,as wellasalargernumberoftermswhicharebestnotusedatall,inorderto avoidconfusion;thesearemarkedas deprecated
However,whilecompilingthisdictionary,Ialsofoundseveralterms,orclusters ofinterrelatedterms,whichweresoambiguousthatasuccinctdefinitionsimplycouldnotbewritten.Thiswasnosurprise—infactIwasratherexpecting thisbasedonmyexperienceofwritingpreviousbooks.
Myapproachhasbeentoavoidrelyingonthedefinitionsincodes,standards andotherdictionaries,especiallynon-technicaldictionariesasbeing“correct.”I havealsoresistedfallingbackonwhattheword/termusedtomeanwhenit wasfirstcoined,oronwhattherootversionofthewordmeantintheclassical languageitwasderivedfrom.
Instead,Ihavetakenadescriptivist,ratherthanprescriptivist,approachreflectingwhatis,ratherthanwhatshouldbe.Itdoesnotmatterwhataterm “should”mean.The raisond’eˆtre ofthisdictionary,afterall,isthatdifferent groupsofengineersusetermstomeandifferentthings.Ihavetherefore includedmoredetaileddiscussiononsuchterms—thoughtheseareinsome casesverymuchmyownviewonthematter,insomecasesexpressedinmy characteristicoccasionallysomewhatprovocativetone.Ididsayitwas Moran’s dictionary!
Youareofcoursefreetodifferonwhatyouthinkthecorrectmeaningtobe andwhethermyviewiscorrect,orwideofthemark.Mypointisthatthereare arangeofopinions—notthatmineistheonlycorrectonebutthatthereisno correctone.
6Disclaimersandapologies
IamalltooawarethatthisbookfallsshortofperfectioninwayswhichIwill notbeabletoaddressbeforepublication.Codesandstandardsareupdated, popularcultureandprofessionalsubculturescreatenewterms,andworld eventsshapeourpriorities.
Thecontenthasbeencheckedthoroughlybymyselfforcompletenessand reviewedbyhundredsofotherengineerstohelpensurecorrectnessandaconsensusposition.Ithasbeenrecheckedrepeatedlyduringthecourseofcopyeditingandtypesetting.However,Iknowthattheremustbeasmallresidueof errors,andindeedomissions,inadictionarywithover10,000entries.
Ifyoufindone,pleasedoletmeknow.IcanbecontactedthroughElsevier, socialmediaordirectlyat sean.moran@expertise-limited.co.uk.
A&E
1.Architectandengineer
2.Accidentandemergency
A/G see aboveground
A/Gtank see abovegroundtank
A/Oprocess see anoxic/oxicprocess
A0
A1
A2
A2flask
A3
A4
AnISOpapersizesimilartoANSI‘E’
AnISOpapersizesimilartoANSI‘D’
AnISOpapersizesimilartoANSI‘C’
TheshippingcontainerusedintheUKtotransportspentnuclearfuel frompowerstationstoreprocessing/storageatSellafield
AnISOpapersizesimilartoUS’Tabloid’/’Ledger’andANSI’B’
AnISOpapersizesimilarToUS’Letter’andANSI‘A’
AACE AssociationfortheAdvancementofCostEngineering
AAPM Artificialadvancedprojectmanagement
AB (drawingnotation) Anchorbolt
abandonment
1.Inthecontextofpipelines,permanentlyshuttingdowntheoperation ofapipelineorfacilitywhereregulatoryapprovalhasbeenreceivedto doso;alternatively,itmayrefertotheactionstogainsuchapproval
2.Inthecontextofoilwells,theactivitiesperformedtoplugawellto preventfluidsfrommigratingup-holefromareservoirandcontaminatingotherformationsand/orfreshwateraquifers abatement
Reducinganuisancesuchaspollutionornoise ABEfermentation aka theWeizmannprocess.ABE(acetonebutanolethanol)fermentation isusedtoproduceacetone,n-butanol,andethanolfromcarbohydrates bybacterialfermentationwitha Clostridium species,mostcommonly C.acetobutylicum
abioticresources
Thenon-livingpartsofanecosystem ablation
Inanengineeringcontext,theremovalofmaterialbyerosion,which findspracticalapplicationincoatingswhichprotectagainstbiological foulingandthermaleffects ablimation
Theoppositeof sublimation (qv)i.e.directtransitionfromvaporto solidphase abortdamper see abortgate
abortgate aka abortdamper.Asafetydevicewhichautomaticallyventsfire, harmfulgasesandburningmaterialtoatmosphere;definedformally in NFPA654:StandardforthePreventionofFireandDustExplosions fromtheManufacturing,Processing,andHandlingofCombustible ParticulateSolids,2017Edition .Maythereforebedescribedas ‘NFPAcompliant’
aboveground aka A/G.Acommondesignationona P&ID (qv)orpipinglayoutdrawingtoindicateifacomponentisaboveorbelowthesurfaceofthe Earth;cf underground(U/G) abovegroundpiping
abovegroundstorage tank
Pipingwhichislocatedabovepiperacksorsupportsaccordingtostandards(e.g. ASMEStandardB.31.3)
Astationary(oftencylindrical)fluidcontainingvessel,withmorethan 90%ofworkingvolumeabovelocalgrade
abovegroundtank aka A/Gtank.Astationary(oftencylindrical)fluidcontainingvessel installed(ratherconfusingly)above,at,orbelowgrade(withoutbackfill),accordingto NFPA30:FlammableandCombustibleLiquidsCode, 2018Edition
absolutealcohol aka absoluteethanol.Ahighpuritygradeofethanol
absolutedensity 1.Inthecontextofionexchange,theweightingramsofwetresinthatdisplacesagivenunitvolume;cf relativedensity and specificgravity 2.(Otherthaninthecontextofionexchange)theratioofmasstounit volume
absoluteerror
Thedifferencebetweenameasuredorinferredquantityanditstrue value;see BoxA1
absoluteethanol see absolutealcohol absolutefilter
Afilterwhichremoves100%ofhardsphericalparticlesgreaterthanits ratedporesizeunderconstantlowpressureinalaboratory;thismeasureshouldnothoweverbeassumedtopredictrealworldbehavior;cf nominalfilter
absolutehumidity
absolutepressure
Thewatercontentofairwithoutallowancefortemperature,calculated asthemassofwaterpresentdividedbythetotalvolume(sometimes mass)ofairandwater
Fluidpressurerelativetoabsolutevacuum;cf gaugepressure absoluteroughness (symbol ε)Ameasureofthedeviationofasurfacefromabsolutely planar.Commonlyusedmeasuresofabsoluteroughnessinclude RMS and Ra; N.B.notthesameas hydraulicroughness (qv);cf relative roughness, roughness
absolutetemperature see Kelvin or Rankine absoluteviscosity aka dynamicviscosity;see viscosity
absorbance see opticaldensity absorbent aka absorbentmaterial.Aliquidorsolidinwhichanothermaterialis dissolved/dispersed absorbentmaterial see absorbent absorber
1.Innuclearreactors,slightlycontested,butmaybeamaterialwhich absorbsalphaparticles,neutronsandionisingradiation,orsolelya neutronabsorber (qv),themoregeneral’absorber’beingreferredto as shielding (qv)
2.Aunitoperationdependentuponabsorption,alsosometimesused tomean absorbent (qv) absorption
Amasstransferprocessinwhichonefluidcomponentistakenintothe bulkofanabsorbentmaterial;cf adsorption absorptiontower aka column.Generically,averticalvesselwithahighaspectratioin whichabsorptionisusedtoseparateafluidmixture.Innaturalgas treatmentitcommonlyrefersonlytoacidgasscrubbingtowers
ABV Alcoholbyvolume;cf proof
AC see alternatingcurrent
ACC AmericanChemistryCouncil
accelerant
Generally,asubstancewhichaltersasecondsubstancetoincreasethe speedofachemicalprocess,suchase.g.,acatalyst.Themostcommon useofthewordishoweverinthecontextoffiresafety,inwhichan accelerantacceleratesfiredevelopment
accelerationdueto gravity (symbol g)thenominalgravitationalaccelerationofanobjectinavacuumnearthesurfaceoftheEarth.DefinedinISO/IEC80000as 9.80665m/s2
accelerationphase
Inthecontextofbiologicalgrowth,thephaseofincreasinggrowthin numbersoforganismsprecedingthe logphase (qv) acceleration transducer see accelerometer accelerator see accelerant accelerometer
Atransducerwhichconvertsaninputaccelerationtoaproportional electricalorelectronicoutput;definedformallyin BSISO2041:2018 Mechanicalvibration,shockandconditionmonitoring.Vocabulary acceptancecertificate
Acertificateformallyconfirmingonbehalfofapurchaserthatasupplier hassuccessfullymetallcontractualacceptancecriteria acceptancenumber
Themaximumallowablenumberofdefectsinabatchofproductforit topassacceptancecriteria
acceptancesampling Theprocessoftestingasamplefromabatchforqualityassessment purposes
accessdoors
accessgauge
Doorsallowingaccessformaintenance
Thespacearoundanitemofequipmentwhichmustremainunobstructedtoenablesafeaccess;definedformallyin BSENISO14122 Safetyofmachinery.Permanentmeansofaccesstomachinery.Working platformsandwalkways
accessplatform
Aplatformusedforapersontoaccessmachinery;definedformallyin BSENISO14122Safetyofmachinery.Permanentmeansofaccessto machinery.Workingplatformsandwalkways accessible see easilyorreadilyaccessible accessibledesign product
Adesignproductintendedtomaximizethenumberofpotentialusers; definedformallyin BSEN82079-1:2012Preparationofinstructionsfor use.Structuring,contentandpresentation.Generalprinciplesanddetailed requirements
accessways
Routesforaccess accident
Anunexpectedoccurrencethateitherleadstodeathorinjury,orhasa highprobabilityofcausingthese;cf incident.Somesafetyspecialists thinkthattherearenotrueaccidents/incidents,asthereshouldbeno unexpectedoccurrences
AccountablePipeline SafetyandPartnership Actof1996
accumulation
accumulator
A(USA)lawintendedtoreducetherisktopublicsafetyandtheenvironmentassociatedwithpipelinetransportationofnaturalgasandhazardousliquids
1.Theallowedpressureincreaseoverthe maximumallowable workingpressure (qv)ofavesselduringoperationofa pressure reliefdevice (qv);definedformally(andveryslightlydifferently)in API RP520P17thEdition,January2000Sizing,Selection,andInstallationof Pressure-RelievingDevicesinRefineries;PartI-SizingandSelection,API Standard521.Pressure-relievingandDepressuringSystems.SixthEdition| January2014 and APIRP576-InspectionofPressureRelievingDevices; 2.Buildupofamaterialinsideamassbalanceenvelope
1. aka pulsationdamper.Adevicewhichequalizesflowandpressure variationintheoutputofareciprocatingfluidtransferdevice 2.Atankinpulpandpapermanufacturingusedforenergyrecovery fromcondensedsteam
3.Equipmentthatstoresmaterialinrelativelyminorquantitiestoeliminatefluctuationinacontinuousprocess,suchasa refluxdrum (qv) accuracy Theclosenessofameasuredorinferredvaluetoitstruevalue; cf absoluteerror, precision;see BoxA1
BoxA1AccuracyorPrecision?
ISOstandard5725-1 1 providesdefinitionsoftrueness,accuracyandprecisionwhichare foundedinstatistics,butasmydiscussionof‘ risk’ ( BoxR2 .)shows,thatisnottheendof thestory.ThisdiscussionishoweverinformedbytheISOstandard,aswellasprofessional usageatvaryingdegreesofformality.Its houldbenotedthatengineersmightuse thesetermsinanyofthefollowingsenses,orinthecommonplaceway,soifindoubt, check!
Idefine accuracy inthisbookas“theclosenessofameasuredorinferredvaluetoitstruevalue”, absoluteerror as“thedifferencebetweenameasuredorinferredquantityanditstruevalue”, and precision as“whetheraninstrumentwillgivethesamereadingagainstthesametruevalue thenexttimeitistested”.However,Ihavewrittenelsewhere2 abouthowprecisionisoften defined(bymathematicians)tomeanwhatengineerscallresolution,whilstprecisionisusedby engineerstomeanallkindsofthings,includingaccuracy.
Inengineering,weareusingthelanguageofmathematics3 whenwetalkabout‘impliedprecision’:forexample,ifweneedcontrolofpHtowithin0.1pHunits,thisisnotthesameassaying thatweneedcontroltowithin0.10pHunits,whichimplies10timesthe(mathematician’s)precision.Whensomeonegivesusallofthefiguresontheircalculatordisplaywithoutconsidering howmanyaresignificant,theimpliedprecisionisspurious,hencewecallit‘spurious precision’.Thenumberofsignificantdigitsissometimescalledresolution,andisalwaysrelated toit,butthistermismorecommonlyusedforthesmallestchangeinthemeasuredvaluewhich aninstrumentcandetect.
Accuracy (alsoknownas,orcloselyrelatedtotrueness)isaboutthegapbetweenthetrue valueandthevalueindicatedbytheinstrument.Intheexampleabove,IneedpHtobecontrolledwithintherangearoundthesetpoint 6 0.05pHunits,thereforemymeasurement accuracyneedstobereliablyatleastthisgood.
Precision inengineering,ontheotherhand,isnotus uallythemathematician’sprecision, nortodowithanengineer’sdefinitionofaccuracyorresolution.Engineeringprecision reliesuponreproducibilityandrepeatability ,thefirstencompassingvariabilityovertime, andthesecondbeingprecisionundertight lycontrolledconditionsoverashorttime period.
Relatedterms
impliedprecision,limitofdetection,limitofquantification,resolution
1BSISO5725 1:1994Accuracy(truenessandprecision)ofmeasurementmethodsandresults.Generalprinciplesand definitions
2Moran,S.(2019) AnAppliedGuidetoProcessandPlantDesign,2nd Ed.Oxford:Elsevier
3By‘thelanguageofmathematics’,Iamexcludingstatistics.Statisticiansdefineprecisionasthereciprocalofvariance
acentricfactor A fudgefactor (qv)usedinthermodynamicstoaccountforthe degreetowhichmoleculesarenotspherical,andthereforedonot behaveaspredictedbytheprincipleofcorrespondingstates(whichis basedonanassumptionofsphericalmolecules)
acetylene
acetylenes
ACFM
Thesimplest alkyne (qv),agasusedalongwithoxygenforwelding andcutting.Explosivelyunstableasacompressedgas,sonormallysuppliedinanacetonesolutionunderpressure
Ageneric(non-IUPAC)namefor alkynes(qv)stillincommonusein industry
1.Alternatingcurrentmagneticfluxleakagetesting,aplantinspection testmethod;definedformallyin APIRP571-DamageMechanism AffectingFixedRefineryEquipment
2.Actualcubicfeetperminute
ACGIH see AmericanConferenceofGovernmentalIndustrial Hygienists
ACI AmericanConcreteInstitute
acicularcoke see needlecoke
acid
Asubstancewhichcanactasaprotondonor,orlesscommonlycan formacovalentbondwithanelectronpair acidegg
Anovoidceramicvesselusedtotransportsmallquantitiesofacids acidgas Oilandgasterminologyforanypetroleumderivedgas,suchas producedgas (qv),containingsignificantquantitiesofgaseswhich arethemselvesacidinaqueoussolutionsuchasCO2 andH2S. Sometimesextended(incorrectlyinmostpeople’sview)togaseswith acidiccombustionproductssuchH2S,moreproperlyknownassour gases;cf sourgas, sweetgas
acidgasrespirator aka organicvaporrespirator.PPEwhichprovidesprotectionagainst acidicvapors,chlorineandcertainorganicsaswell.Oftenalimited-life, highlyportableitemusedonrefineriesandchemicalsiteshandling chlorine
acidnumber aka acidvalue,AV,neutralizationnumber,acidity,totalacidnumber.A measureoftheamountofcarboxylicacidicgroupsinasubstance,measuredasthemassofpotassiumhydroxide(KOH)inmilligramsrequired toneutralizeonegramofthesubstance,especiallyanoil.Inthecaseof edibleoils,itisanindicatorofrancidity.Inthecaseofmineraloil,a measureofcorrosiveness
acidvalue see acidnumber
acidified
acidity
Treatedwithacid,commonlytoneutralisealkalipresent,ortooccupy bindingsitesinionexchangemediaoracidifiedzeolitecatalyst
1.see acidnumber
2.Abilitytodonateaproton,theoppositeof basicity (qv)
acidogenesis
ACM
Generically,aprocessofacidformation.Inenvironmentalengineering, thestageof anaerobicdigestion inwhichfattyacidsareproduced frommorecomplexsubstances
Asbestos-containingmaterial
ACOchannel Agenericizedtrademarkforasunkencoveredfloordrain;therearea largenumberofmanufacturersandstyles;see Fig.A1
acousticemission testing aka AET.Amethodfordetectingcracksinmetalliccomponents,discussedin APIRP571-DamageMechanismAffectingFixedRefinery Equipment
ACS Automationcontrolsystems
ACT see automaticcustodytransfer actinides Elements90 103(thoriumtolawrencium),namedafter actinium actinium Element89
activatedcarbon
Anadsorbentmaterialproducedfromvarioushigh-carbonmaterials suchascoal,coconutshellsorvegetablematter
activatedsludge see activatedsludgeprocess activatedsludge process Along-establishedprocessusedtotreatwastewaterbyrecirculating sludgerecoveredbysettlementafterbiologicaltreatmenttomixwith incomingfeed
activationenergy (symbol Ea)Theenergyrequiredtoinitiateachemicalreaction. Catalysts (qv)workbyreducingthis activehotstandby Havingparallel standby (qv)unit(s)inservice,ratherthanidling activeoptoelectronic protectivedevice Machinesafetydevicebasedonlightsensing;definedformallyin BSEN ISO12100:2010Safetyofmachinery.Generalprinciplesfordesign.Risk assessmentandriskreduction
activepharmaceutical ingredient aka API.Themedicinalcontentinapharmaceuticalproduct;cf active pharmaceuticalintermediate activepharmaceutical intermediate aka API.Acompoundformingastepinthechainofsyntheseswhich produce activepharmaceuticalingredients(qv) activesite Thepartofacatalystwhichbindstoasubstratetofacilitateareaction. Almostexclusivelyusedinthecontextofenzymes
FigureA1 ACOchannels.
activity
1.Inprojectmanagement,thesmallestincrementofwork;defined moreformallyin BSENISO9000Qualitymanagementsystems Fundamentalsandvocabulary
2.Theratioofthechangeintworelatedconditions,suchase.g. water activity (qv)
3.Inthecontextoftechnicaldocumentation,aprocess,procedureor partsofthem;definedformallyin ISO10209:2012Technicalproduct documentation—Vocabulary—Termsrelatingtotechnicaldrawings,productdefinitionandrelateddocumentation
activitycoefficient aka fugacitycoefficient.Afiddlefactor(UK)orfudgefactor(USA)used inthermodynamicstoaccountfordeviationsfromidealbehaviorina mixtureofchemicals
activitycoefficient model see Margules’activitymodel
activitymatrix
Adocumentsimilartoaprojectprogram,placingactivitiesinphasesof aproductlifecycle;definedformallyin ISO10209:2012Technicalproductdocumentation-Vocabulary-Termsrelatingtotechnicaldrawings, productdefinitionandrelateddocumentation
ACTR see actuatingelement
ACTS see AsbestosContractorTrackingSystem actualcubicfeetper minute aka ACFM.AUSAcustomarymeasureofgasflowdefinedinanumber ofways;cf standardcubicfeetperminute actualdischargearea aka actualorificearea.Theminimumareathatdeterminestheflow throughapressurereliefdevice;definedformallyin APIRP520P17th Edition,January2000Sizing,Selection,andInstallationofPressureRelievingDevicesinRefineries;PartI-SizingandSelection actualflowrate Theflowrateunderrealworking/flowingconditions;definedformally in BSENISO13705:2012/ISO13705:2012(E)Petroleum,petrochemical andnaturalgasindustries.Firedheatersforgeneralrefineryservice actualinside diameter Theinsidediameterofanewheatexchangertube,definedformallyin APISTD530-CalculationofTubeHeaterThickness actualorificearea see actualdischargearea actuatedliquid withdrawalexcess flowvalve
AnadapteroperatedvalveusedtowithdrawliquidfromanLPGcontainer,withintegratedexcess-flowvalve;definedformallyin NFPA58: LiquefiedPetroleumGasCode,2017Edition actuatedvalve aka AV,CV,motoroperatedvalve.Avalvecontrolledbyan actuating element (qv);cf manualvalve actuatingelement aka ACTR,actuator.Anitemofinstrumentationequipmentwhichreceivesa signal(pneumatic,hydraulic,orelectrical)andadjustsacontrolelement (e.g.valve,motorcontroller)accordingtothatsignal;definedformallyin BS1646-1SymbolicRepresentationforProcessMeasurementControlFunctions andInstrumentationPart1:BasicRequirements,ISO3511/1(W/D) and BS 1646 3:1984Symbolicrepresentationforprocessmeasurementcontrolfunctionsandinstrumentation.Specificationfordetailedsymbolsforinstrument interconnectiondiagrams
actuator see actuatingelement
actuatorvalve see actuatedvalve
AD see anaerobicdigestion
ADC see analoguetodigitalconverter additive
1.Generally,asmallamountofsomethingaddedtoenhance performance
2.Specifically,inthecaseoffireprotection,foamconcentrates,emulsifiers,andsoonaddedtowatertoenhancefirefightingperformance; definedformallyin NFPA20:StandardfortheInstallationofStationary PumpsforFireProtection,2019Edition additivepump
1.Generally,apumpusedtointroduceadditives,inwhichcasesynonymouswith dosingpump
2.Inafirefightingcontext,definedformallyin NFPA20:Standardfor theInstallationofStationaryPumpsforFireProtection,2019Edition adequaterisk reduction Riskreductionmeetinglegalrequirementsattheveryminimum; definedformallyin BSENISO12100:2010Safetyofmachinery.General principlesfordesign.Riskassessmentandriskreduction
adequateventilation
adiabatic
adiabaticefficiency
adiabaticflame temperature
1.Sufficientventilationtopreventtheaccumulationofsignificantquantitiesoffuelairmixturesat . 20%oftheir LEL (qv)/LFL (qv);defined formallyin APIRP5052ndEdition,August2018RecommendedPractice forClassificationofLocationsforElectricalInstallationsatPetroleum FacilitiesClassifiedasClassI,Zone0,Zone1,andZone2
2.Mayalsosometimesbeusedinabroadersense,ofventilationsufficienttomaintainaworkareaasasafeplace;cf inadequate ventilation
Strictly,aconditioninwhichheatdoesnotenterorleavethesystem concerned;definedformallyin APIRP2510A-FireProtection ConsiderationsfortheDesignandOperationofLiquefiedPetroleumGas (LPG)StorageFacilities
Inthecontextofcompressorsandfans,thepowertheoreticallynecessarytocompressanddeliveragasadiabaticallydividedbythepower suppliedatthedriveshaft
Thetheoreticalflametemperatureunderadiabaticconditionsdefined formallyin APIRP535-BurnersforFiredHeatersatRefineries
adiabaticflash see flashevaporation
adiabaticsaturation temperature
adjustableguard
adjustedsetpressure
Thetheoreticaltemperatureofavolumeofairifcooledadiabaticallyto saturationbytheevaporationofwater.Itisapproximatelyequaltothe wetbulbtemperature (qv)
Amachinesafetydevicewhichcanbeadjusted;definedformallyin BS ENISO12100:2010Safetyofmachinery.Generalprinciplesfordesign. Riskassessmentandriskreduction
Thestaticinletpressureatwhichapressurereliefvalveisadjustedto openontheteststand;definedformallyin API2000,Venting AtmosphericandLowPressureStorageTank,7thEd adjuster (jocular)Hammer
