Probatio pars integralis est conservationis integritatis salutis systematum instrumentalium salutis (SIS) nostrorum et systematum ad salutem pertinentium (e.g., alarmis criticis, systematibus ignis et gasis, systematibus interclusionis instrumentatis, etc.). Probatio est probatio periodica ad defectus periculosos detegendos, functiones ad salutem pertinentes probandas (e.g., reset, bypasses, alarmis, diagnostica, clausura manualis, etc.), et ad confirmandum systema normas societatis et externas implere. Resultata probationis etiam mensura sunt efficaciae programmatis integritatis mechanicae SIS et fidelitatis in agro systematis.
Rationes probationum gradus probationum comprehendunt, ab acquirendis permissionibus, notificationibus factis, et systemate ex usu ad probandum removendo, usque ad probationes completas curandas, probationem eiusque eventus documentandas, systema in usum restituendum, et eventus probationum praesentium et priorum aestimandos.
ANSI/ISA/IEC 61511-1, Articulus 16, probationes SIS tractat. Relatio technica ISA TR84.00.03 – “Integritas Mechanica Systematum Instrumentatorum Salutis (SIS),” probationes tractat et nunc revidetur, cum nova versio mox exspectatur. Relatio technica ISA TR96.05.02 – “Probationes In situ Valvarum Automatarum” nunc elaboratur.
Relatio CRR 428/2002 de HSE Britannia – “Principia ad probationes systematum instrumentatorum securitatis in industria chemica” informationem de probationibus et de iis quae societates in Britannia agunt praebet.
Ratio probationis fundatur in analysi modorum defectus periculosorum notorum pro singulis componentibus in via itineris functionis instrumentatae securitatis (SIF), functione SIF ut systemate, et quomodo (et si) modum defectus periculosum probandum sit. Elaboratio rationum in phase designationis SIF incipere debet cum designatione systematis, selectione componentum, et determinatione quando et quomodo probandum sit. Instrumenta SIS varios gradus difficultatis probationis habent, qui considerandi sunt in designatione, operatione et sustentatione SIF. Exempli gratia, metra orificii et transmissores pressionis facilius probantur quam metra fluxus massae Coriolis, metra magnetophonica vel sensoria livelli radar per aera. Applicatio et designatio valvae etiam comprehensivitatem probationis valvae afficere possunt ut defectus periculosi et incipientes propter degradationem, obstructionem vel defectus tempore pendentes non ad defectum criticum intra intervallum probationis selectum ducant.
Quamquam rationes probationum typice per tempus machinationis SIF excogitantur, etiam ab Auctoritate Technica SIS situs, Operationibus et technicis instrumentorum qui probationes agent, recognosci debent. Analysis securitatis operis (JSA) etiam peragenda est. Interest consensum officinae de quibus probationibus et quando peragendis, et de earum possibilitate physica et securitatis obtinere. Exempli gratia, nihil prodest probationes partialis cursus specificare cum grex Operationum eas facere non consentiet. Etiam commendatur ut rationes probationum a perito in materia independente (SME) recognoscantur. Probationes typicae requisitae ad probationem functionis plenae in Figura 1 illustrantur.
Requisita probationis functionis plenae Figura 1: Specificatio probationis functionis plenae pro functione instrumentata securitatis (SIF) et eius systemate instrumentato securitatis (SIS) gradus in ordine a praeparationibus probationis et rationibus probationis ad notificationes et documentationem explicare vel ad eos referre debet.
Figura 1: Specificatio plena probationis functionis pro functione instrumentata securitatis (SIF) et eius systemate instrumentato securitatis (SIS) gradus ordine explicare vel ad eos referre debet, a praeparationibus probationis et rationibus probationis ad notificationes et documentationem.
Probatio est actio sustentationis designata quae a peritis personis, in probatione SIS, ratione probationis, et circuitibus SIS quos probabunt, eruditis, perfici debet. Antequam probatio initialis peragatur, percursus processus fieri debet, et postea responsa ad Auctoritatem Technicam SIS situs pro emendationibus vel correctionibus dari debent.
Duo modi defectus primarii sunt (tutus vel periculosus), qui in quattuor modos subdividuntur—periculosus non detectus, periculosus detectus (per diagnostica), tutus non detectus et tutus detectus. Termini defectus periculosi et periculosi non detecti in hoc articulo permutatim adhibentur.
In probatione SIF, imprimis modis defectuum periculosis non detectis studemus, sed si diagnostica usoris adsunt quae defectus periculosos detegunt, haec diagnostica probari debent. Nota bene, dissimiliter diagnostica usoris, diagnostica interna machinae typice ab usore ut functionalia validari non posse, et hoc philosophiam probationis afficere potest. Cum laus diagnosticae in computationibus SIL sumitur, alarmae diagnosticae (e.g., alarmae extra limites) tamquam pars probationis probari debent.
Modi defectus porro dividi possunt in eos qui in probatione probationis probantur, eos qui non probantur, et defectus incipientes vel defectus tempore pendentes. Quidam modi defectus periculosi directe non probantur ob varias causas (e.g., difficultatem, decisionem machinalem vel operationalem, ignorantiam, incompetentiam, errores systematicos omissionis vel commissionis, probabilitatem eventus humilem, etc.). Si modi defectus noti sunt qui non probabuntur, compensatio fieri debet in consilio instrumenti, ratione probationis, substitutione vel reconstructione periodica instrumenti, et/vel probatio inferentialis fieri debet ad effectum in integritatem SIF non probationis minuendum.
Defectus incipiens est status vel condicio degradans talis ut defectus criticus et periculosus rationabiliter exspectari possit nisi actiones correctivae tempestive suscipiantur. Typice deteguntur per comparationem effectuum cum probationibus recentioribus vel initialibus (e.g., signaturis valvulae vel temporibus responsorum valvulae) vel per inspectionem (e.g., portus processus obstructus). Defectus incipientes plerumque tempore dependent — quo diutius instrumentum vel congeries in usu est, eo magis degradatur; condiciones quae defectum fortuitum facilitant probabiliores fiunt, obstructio portus processus vel accumulatio sensoris per tempus, vita utilis exhausta est, etc. Ergo, quo longius intervallum probationum, eo probabilius defectus incipiens vel tempore dependens. Quaevis protectiones contra defectus incipientes etiam probationi subiici debent (purgatio portus, vestigatio caloris, etc.).
Rationes scribendae sunt ad probandas defectus periculosos (non detectos). Methodi analysis modi et effectus defectus (FMEA) vel analysis modi, effectus et diagnosticae defectus (FMEDA) adiuvare possunt ad defectus periculosos non detectos identificandos, et ubi probationum cobertura emendanda sit.
Multae rationes probationis scriptae sunt, fundatae in experientia et exemplaribus ex rationibus iam exstantibus. Novae rationes et SIFs magis implicatae postulant modum magis artificiosum utens FMEA/FMEDA ad defectus periculosos investigandos, ad determinandum quomodo ratio probationis defectus illos examinabit vel non examinabit, et ad ambitum probationum. Diagramma obstructum analysis modorum defectus macro-gradus pro sensore in Figura 2 ostenditur. FMEA typice semel tantum perfici debet pro certo genere instrumenti et iterum adhiberi pro instrumentis similibus, consideratis eorum facultatibus servitii processus, institutionis et probationis in situ.
Analysis defectuum macro-gradus Figura 2: Hoc diagramma obstructum analysis modi defectus macro-gradus pro sensore et transmissore pressionis (PT) functiones maiores ostendit quae typice in multiplices analyses micro-defectuum dividuntur ut defectus potentiales in probationibus functionum tractandi plene definiantur.
Figura 2: Hoc diagramma obstructum analysis modorum defectus macro-gradus pro sensore et transmissore pressionis (PT) functiones maiores ostendit quae typice in multiplices analyses micro-defectus dividuntur ut defectus potentiales in probationibus functionum tractandi plene definiantur.
Percentatio errorum notorum, periculosorum, et non detectorum, qui probatione subiecti sunt, "proof test coverage" (PTC) appellatur. PTC vulgo in computationibus SIL adhibetur ad "compensandum" pro defectu in SIF plenius probando. Homines erroneam opinionem habent, quia defectum probationis in computatione SIL consideraverunt, SIF fidum designavisse. Res simplex est, si probationis coverage 75% est, et si hunc numerum in computatione SIL in rationem duxeris et res quas iam saepius probas probaveris, 25% errorum periculosorum adhuc statistice occurrere possunt. Certe in illis 25% esse nolo.
Relationes approbationis FMEDA et manuales salutis pro instrumentis typice minimum modum probationis probationis et operimentum probationis probationis praebent. Haec tantummodo ducem praebent, non omnes gradus probationis requisiti ad modum probationis probationis comprehensivum. Alia genera analysis defectuum, ut analysis arboris defectuum et sustentatio centrata in fide, etiam adhibentur ad defectus periculosos investigandos.
Probationes functionales in probationes plenas functionales (ab initio ad finem) vel partiales dividi possunt (Figura 3). Probationes functionales partiales vulgo fiunt cum partes SIF intervalla probationum diversa in computationibus SIL habent quae cum clausuris vel conversionibus designatis non congruunt. Interest ut rationes probationum functionalium partialium inter se congruant, ita ut simul omnes functiones salutis SIF probent. Cum probationibus functionalibus partialibus, adhuc commendatur ut SIF probationem initialem ab initio ad finem habeat, et subsequentes durante conversionibus.
Probationes partiales summam adipisci debent. Figura 3: Probationes partiales coniunctae (infra) omnes functiones probationis plenae functionalis (summa) tegere debent.
Figura 3: Probationes partiales coniunctae (infra) omnes functiones probationis functionalis plenae (summa) tegere debent.
Examen probationis partialis tantum partem modorum defectus instrumenti examinat. Exemplum commune est probatio valvulae ictus partialis, ubi valvula paulum (10-20%) movetur ut verificetur eam non haerere. Hoc probationis minorem extensionem habet quam probatio in intervallo probationis primario.
Rationes probationis variari possunt secundum complexitatem SIF et philosophiam rationum probationis societatis. Quaedam societates rationes probationis gradatim et accuratas scribunt, aliae autem rationes satis breves habent. Aliquando ad alias rationes, ut calibrationem normatam, adhibentur ad magnitudinem rationum probationis minuendam et ad constantiam in probatione curandam. Bona ratio probationis satis singularium praebere debet ut omnes probationes rite perficiantur et documententur, sed non tot singulares ut technici gradus omittere velint. Technicus, qui gradum probationis peragendi curat, gradum probationis perfectum initialiter apponere potest ut probatio recte perficiatur. Approbatio probationis perfectae a Supervisore Instrumentorum et repraesentantibus Operationum etiam momentum demonstrabit et probationem rite perfectam confirmabit.
Sententiae technicorum semper petendae sunt ad processum emendandum. Successus processus probationis magna ex parte in manibus technicorum positum est, ergo conatus communis vehementer commendatur.
Pleraque probationes typice extra lineam fiunt tempore clausurae vel conversionis. Interdum, probationes in linea fieri possunt dum currit ut calculationibus SIL vel aliis requisitis satisfaciant. Probationes in linea consilium et coordinationem cum Operationibus requirunt ut probatio tuto perfici possit, sine perturbatione processus, et sine causando errore spurio. Uno tantum errore spurio sufficit ad omnes tuas potentias consumendas. Per hoc genus probationis, cum SIF non plene praesto est ad munus suum securitatis exsequendum, 61511-1, clausula 11.8.5, statuit "Mensuras compensatorias quae operationem tutam continuam curant praeberi debere secundum 11.3 cum SIS in bypass est (reparatione vel probatione)." Ratio administrationis situationis abnormalis cum ratione probationis coniungi debet ut adiuvet ad curandum hoc recte perfici.
SIF typice in tres partes principales dividitur: sensoria, solutores logicos et elementa finalia. Sunt etiam typice instrumenta auxiliaria quae intra singulas has tres partes associari possunt (e.g., repagula IS, amplificatores detonatoris, interponentes relees, solenoides, etc.) quae etiam probari debent. Aspectus critici probationis cuiusque harum technologiarum in parte laterali, "Probatio sensoriorum, solutorum logicorum et elementorum finalium" (infra), inveniri possunt.
Quaedam res facilius probantur quam aliae. Multae technologiae fluxus et livelli modernae et paucae vetustiores in categoria difficiliore sunt. Hae includunt fluxometra Coriolis, vorticometra, magnetometra, radar per aera, gradus ultrasonici, et commutatores processus in situ, ut pauca nominem. Feliciter, multae ex his nunc diagnostica meliora habent quae probationes meliores permittunt.
Difficultas probationis talis instrumenti in campo consideranda est in consilio SIF. Facile est ingeniariis instrumenta SIF eligere sine seria consideratione eorum quae ad probationem instrumenti requirantur, cum non erunt homines qui ea probant. Hoc etiam verum est de probatione partialis ictus, quae via communis est ad meliorem probabilitatem mediam defectus SIF in postulatione (PFDavg), sed postea Operationes fabricae id facere nolunt, et saepe non possunt. Semper supervisionem fabricae praebe machinationis SIF quod ad probationem attinet.
Probatio inspectionem institutionis et reparationis SIF, prout opus est ad 61511-1, clausula 16.3.2 implendam, includere debet. Inspectio finalis fieri debet ut omnia recte sint confirmata, et bis verificatio ut SIF rite in usum processuale restitutum sit.
Scribere et adhibere bonam rationem probationis est gradus magni momenti ad integritatem SIF per totam vitam suam confirmandam. Ratio probationis satis detalia praebere debet ut probationes requisitae constanter et tuto peragantur et documententur. Defectus periculosi qui probationibus non probantur compensandi sunt ut integritas securitatis SIF per totam vitam suam rite conservetur.
Scribere bonam rationem probationis requirit accessum logicum ad analysin machinalem defectuum periculosorum potentialium, ad delectum mediorum, et ad scribendum gradus probationis qui intra facultates probationis fabricae sunt. Interea, consensum fabricae ab omnibus gradibus pro probatione obtine, et technicos erudi ut probationem perficiant et documentent, necnon momentum probationis intellegant. Instructiones scribe quasi tu esses technicus instrumentorum qui opus facere debebit, et quasi vitas a probatione recte perficienda pendeant, quia recte faciunt.
Testing sensors, logic solvers and final elements A SIF is typically divided up into three main parts, sensors, logic solvers and final elements. There also typically are auxiliary devices that can be associated within each of these three parts (e.g. I.S. barriers, trip amps, interposing relays, solenoids, etc.) that must also be tested.Sensor proof tests: The sensor proof test must ensure that the sensor can sense the process variable over its full range and transmit the proper signal to the SIS logic solver for evaluation. While not inclusive, some of the things to consider in creating the sensor portion of the proof test procedure are given in Table 1. Table 1: Sensor proof test considerations Process ports clean/process interface check, significant buildup noted Internal diagnostics check, run extended diagnostics if available Sensor calibration (5 point) with simulated process input to sensor, verified through to the DCS, drift check Trip point check High/High-High/Low/Low-Low alarms Redundancy, voting degradation Out of range, deviation, diagnostic alarms Bypass and alarms, restrike User diagnostics Transmitter Fail Safe configuration verified Test associated systems (e.g. purge, heat tracing, etc.) and auxiliary components Physical inspection Complete as-found and as-left documentation Logic solver proof test: When full-function proof testing is done, the logic solver’s part in accomplishing the SIF’s safety action and related actions (e.g. alarms, reset, bypasses, user diagnostics, redundancies, HMI, etc.) are tested. Partial or piecemeal function proof tests must accomplish all these tests as part of the individual overlapping proof tests. The logic solver manufacturer should have a recommended proof test procedure in the device safety manual. If not and as a minimum, the logic solver power should be cycled, and the logic solver diagnostic registers, status lights, power supply voltages, communication links and redundancy should be checked. These checks should be done prior to the full-function proof test.Don’t make the assumption that the software is good forever and the logic need not be tested after the initial proof test as undocumented, unauthorized and untested software and hardware changes and software updates can creep into systems over time and must be factored into your overall proof test philosophy. The management of change, maintenance, and revision logs should be reviewed to ensure they are up to date and properly maintained, and if capable, the application program should be compared to the latest backup.Care should also be taken to test all the user logic solver auxiliary and diagnostic functions (e.g. watchdogs, communication links, cybersecurity appliances, etc.).Final element proof test: Most final elements are valves, however, rotating equipment motor starters, variable-speed drives and other electrical components such as contactors and circuit breakers are also used as final elements and their failure modes must be analyzed and proof tested.The primary failure modes for valves are being stuck, response time too slow or too fast, and leakage, all of which are affected by the valve’s operating process interface at trip time. While testing the valve at operating conditions is the most desirable case, Operations would generally be opposed to tripping the SIF while the plant is operating. Most SIS valves are typically tested while the plant is down at zero differential pressure, which is the least demanding of operating conditions. The user should be aware of the worst-case operational differential pressure and the valve and process degradation effects, which should be factored into the valve and actuator design and sizing.Commonly, to compensate for not testing at process operating conditions, additional safety pressure/thrust/torque margin is added to the valve actuator and inferential performance testing is done utilizing baseline testing. Examples of these inferential tests are where the valve response time is timed, a smart positioner or digital valve controller is used to record a valve pressure/position curve or signature, or advance diagnostics are done during the proof test and compared with previous test results or baselines to detect valve performance degradation, indicating a potential incipient failure. Also, if tight shut off (TSO) is a requirement, simply stroking the valve will not test for leakage and a periodic valve leak test will have to be performed. ISA TR96.05.02 is intended to provide guidance on four different levels of testing of SIS valves and their typical proof test coverage, based on how the test is instrumented. People (particularly users) are encouraged to participate in the development of this technical report (contact crobinson@isa.org).Ambient temperatures can also affect valve friction loads, so that testing valves in warm weather will generally be the least demanding friction load when compared to cold weather operation. As a result, proof testing of valves at a consistent temperature should be considered to provide consistent data for inferential testing for the determination of valve performance degradation.Valves with smart positioners or a digital valve controller generally have capability to create a valve signature that can be used to monitor degradation in valve performance. A baseline valve signature can be requested as part of your purchase order or you can create one during the initial proof test to serve as a baseline. The valve signature should be done for both opening and closing of the valve. Advanced valve diagnostic should also be used if available. This can help tell you if your valve performance is deteriorating by comparing subsequent proof test valve signatures and diagnostics with your baseline. This type of test can help compensate for not testing the valve at worst case operating pressures.The valve signature during a proof test may also be able to record the response time with time stamps, removing the need for a stopwatch. Increased response time is a sign of valve deterioration and increased friction load to move the valve. While there are no standards regarding changes in valve response time, a negative pattern of changes from proof test to proof test is indicative of the potential loss of the valve’s safety margin and performance. Modern SIS valve proof testing should include a valve signature as a matter of good engineering practice.The valve instrument air supply pressure should be measured during a proof test. While the valve spring for a spring-return valve is what closes the valve, the force or torque involved is determined by how much the valve spring is compressed by the valve supply pressure (per Hooke’s Law, F = kX). If your supply pressure is low, the spring will not compress as much, hence less force will be available to move the valve when needed. While not inclusive, some of the things to consider in creating the valve portion of the proof test procedure are given in Table 2. Table 2: Final element valve assembly considerations Test valve safety action at process operating pressure (best but typically not done), and time the valve’s response time. Verify redundancy Test valve safety action at zero differential pressure and time valve’s response time. Verify redundancy Run valve signature and diagnostics as part of proof test and compare to baseline and previous test Visually observe valve action (proper action without unusual vibration or noise, etc.). Verify the valve field and position indication on the DCS Fully stroke the valve a minimum of five times during the proof test to help ensure valve reliability. (This is not intended to fix significant degradation effects or incipient failures). Review valve maintenance records to ensure any changes meet the required valve SRS specifications Test diagnostics for energize-to-trip systems Leak test if Tight Shut Off (TSO) is required Verify the command disagree alarm functionality Inspect valve assembly and internals Remove, test and rebuild as necessary Complete as-found and as-left documentation Solenoids Evaluate venting to provide required response time Evaluate solenoid performance by a digital valve controller or smart positioner Verify redundant solenoid performance (e.g. 1oo2, 2oo3) Interposing Relays Verify correct operation, redundancy Device inspection
SIF typice in tres partes principales dividitur: sensoria, solutores logicos, et elementa finalia. Sunt etiam typice instrumenta auxiliaria quae intra singulas has tres partes associari possunt (exempli gratia, repagula IS, amplificatores disruptionis, relea interponentes, solenoides, etc.) quae etiam probanda sunt.
Probationes sensoriales: Probatio sensorialis curare debet ut sensor variabilem processus per totum ambitum suum sentire et signum aptum ad solutorem logicum SIS ad aestimationem transmittere possit. Quamquam non inclusiva, quaedam ex rebus considerandis in creando parte sensoriali processus probationis in Tabula 1 dantur.
Probatio solvendi logici: Cum probatio functionis plenae perficitur, pars solvendi logici in perficienda actione securitatis SIF et actiones conexae (e.g., alarmae, reinitializatio, praetergressio, diagnostica usoris, redundantiae, HMI, etc.) probantur. Probationes functionis partiales vel partiales omnes has probationes perficere debent ut partem probationum singularum superpositionum. Fabricator solvendi logici modum probationis commendatum in manuali securitatis instrumenti habere debet. Si non et saltem, potentia solvendi logici iterum exstinguenda est, et registra diagnostica solvendi logici, lumina status, tensiones potentiae, nexus communicationis et redundantia inspiciendae sunt. Hae probationes ante probationem functionis plenae fieri debent.
Noli assumere programmata in perpetuum bona esse et logicam non debere post probationem initialem probari, cum mutationes programmatum et apparatuum sine documentis, non auctorizatae et non probatae necnon renovationes programmatum in systemata irrepere possint tempore procedente et in philosophia tua probationis generalis considerandae sint. Administratio diariorum mutationum, conservationis, et revisionum revidenda est ut recentissima et rite conservata sint, et si capax est, programma applicativum cum recentissima copia subsidiaria comparandum est.
Cura etiam adhibenda est ut omnes functiones auxiliares et diagnosticae solveris logicae usoris (exempli gratia, custodes, nexus communicationis, apparatus securitatis cyberneticae, etc.) probentur.
Examen elementi finalis: Pleraque elementa finalia sunt valvae, attamen, initiatores motorum apparatuum rotantium, impulsores celeritatis variabilis et alia elementa electrica, ut contactores et interruptores automatici, etiam ut elementa finalia adhibentur et modi eorum defectus analysandi et probandi sunt.
Primarii modi defectus valvarum sunt haesio, tempus responsionis nimis tardum vel nimis celer, et effusio, quae omnia afficiuntur ab interfacie processus operandi valvae tempore disruptionis. Cum probatio valvae sub condicionibus operandi sit casus optatissimus, Operationes plerumque adversarentur disruptioni SIF dum fabrica operatur. Pleraeque valvae SIS typice probantur dum fabrica est sub pressione differentiali nulla, quae est condicio operandi minime exigens. Usor conscius esse debet pessimum casum pressionis differentialis operationalis et effectus degradationis valvae et processus, qui in designio et dimensione valvae et actuatoris considerandi sunt.
Commonly, to compensate for not testing at process operating conditions, additional safety pressure/thrust/torque margin is added to the valve actuator and inferential performance testing is done utilizing baseline testing. Examples of these inferential tests are where the valve response time is timed, a smart positioner or digital valve controller is used to record a valve pressure/position curve or signature, or advance diagnostics are done during the proof test and compared with previous test results or baselines to detect valve performance degradation, indicating a potential incipient failure. Also, if tight shut off (TSO) is a requirement, simply stroking the valve will not test for leakage and a periodic valve leak test will have to be performed. ISA TR96.05.02 is intended to provide guidance on four different levels of testing of SIS valves and their typical proof test coverage, based on how the test is instrumented. People (particularly users) are encouraged to participate in the development of this technical report (contact crobinson@isa.org).
Temperaturae ambientis etiam onera frictionis valvularum afficere possunt, ita ut probatio valvularum tempore calido plerumque minimum onus frictionis erit cum operatione tempore frigido comparatur. Quapropter, probatio valvularum temperatura constanti consideranda est ut data constantia pro probatione inferentiali ad determinandam degradationem functionis valvulae praebeantur.
Valvae cum positionatoribus intelligentibus vel moderatore valvae digitali plerumque facultatem habent signaturam valvae creandi quae ad degradationem in functione valvae monitorandam adhiberi potest. Signatura valvae fundamentalis peti potest ut pars mandati tui emptionis, vel unam creare potes durante probatione initiali ut linea fundamentalis serviat. Signatura valvae fieri debet et ad valvam aperiendam et ad eam claudendam. Diagnostica valvae provectior etiam adhibenda est, si praesto est. Hoc adiuvare potest te dicere utrum functiones valvae tuae deteriores sint, comparando signaturas valvae probationis subsequentes et diagnostica cum linea fundamentali tua. Hoc genus probationis adiuvare potest compensare pro non probatione valvae sub pessimis pressionibus operationis.
Signatura valvulae per probationem etiam tempus responsum cum signis temporalibus notare potest, ita ut horologium temporis non amplius necesse sit. Tempus responsum auctum signum est deteriorationis valvulae et oneris frictionis aucti ad valvulam movendam. Quamquam nullae normae de mutationibus in tempore responsus valvulae exstant, exemplar mutationum negativum inter probationes indicat potentialem iacturam marginis salutis et functionis valvulae. Probationes modernae valvulae SIS signaturam valvulae includere debent, ut res bonae praxis ingeniariae.
Pressio aeris instrumenti valvae metiri debet in probatione. Quamquam fons valvae pro valva revertentis valvam claudit, vis sive momentum torquens implicatum determinatur quantum fons valvae a pressione valvae comprimitur (secundum Legem Hooke, F = kX). Si pressio aeris humilis est, fons non tam comprimetur, ergo minor vis praesto erit ad valvam movendam cum opus erit. Quamquam non inclusiva, quaedam ex rebus considerandis in creando parte valvae processus probationis in Tabula 2 dantur.
Tempus publicationis: XIII Novembris MMXIX