Teko ea bopaki ke karolo ea bohlokoa ea paballo ea ts'ireletso ea ts'ireletso ea lisebelisoa tsa rona tsa polokeho (SIS) le litsamaiso tse amanang le polokeho (mohlala, lialamo tsa bohlokoa, litsamaiso tsa mollo le khase, li-interlock tse nang le lisebelisoa, joalo-joalo). Teko ea bopaki ke teko ea nako le nako ho bona ho hloleha ho kotsi, ts'ebetso e amanang le ts'ireletso (mohlala, ho seta bocha, lipallo, lialamo, tlhahlobo, ho tima ka letsoho, joalo-joalo), le ho netefatsa hore sistimi e kopana le litekanyetso tsa k'hamphani le kantle. Liphetho tsa tlhahlobo ea bopaki hape ke tekanyo ea katleho ea lenaneo la SIS le ts'epahalo ea sebaka sa sistimi.
Mekhoa ea tlhahlobo ea bopaki e akaretsa mehato ea tlhahlobo ho tloha ho fumana mangolo a tumello, ho etsa litsebiso le ho ntša sistimi ts'ebetsong bakeng sa tlhahlobo ho netefatsa tlhahlobo e felletseng, ho ngola tlhahlobo ea bopaki le liphetho tsa eona, ho khutlisetsa sistimi ts'ebetsong, le ho lekola liphetho tsa liteko tsa hajoale le bopaki bo fetileng. liphetho tsa liteko.
ANSI/ISA/IEC 61511-1, Clause 16, e akaretsa teko ea bopaki ba SIS. Tlaleho ea tekheniki ea ISA TR84.00.03 - "Mechanical Integrity of Safety Instrumented Systems (SIS)," e akaretsa tlhahlobo ea bopaki 'me hajoale e ntse e ntlafatsoa 'me ho lebelletsoe hore ho tla tsoa mofuta o mocha haufinyane. Tlaleho ea tekheniki ea ISA TR96.05.02 - "In-situ Proof Testing of Automated Valves" e ntse e ntlafatsoa hajoale.
UK HSE tlaleho CRR 428/2002 - "Melao-motheo ea tlhahlobo ea bopaki ba lisebelisoa tsa ts'ireletso indastering ea lik'hemik'hale" e fana ka tlhahisoleseding mabapi le tlhahlobo ea bopaki le seo lik'hamphani li se etsang UK.
Ts'ebetso ea tlhahlobo ea bopaki e ipapisitse le tlhahlobo ea mekhoa e tsebahalang e kotsi ea ho hloleha ho karolo e 'ngoe le e 'ngoe ea tsela ea ts'ebetso ea ts'ireletso (SIF), ts'ebetso ea SIF joalo ka sistimi, le mokhoa (le haeba) ho etsa tlhahlobo e kotsi. mokgoa. Ntlafatso ea ts'ebetso e lokela ho qala mokhahlelong oa moralo oa SIF ka moralo oa sistimi, khetho ea likarolo, le qeto ea hore na tlhahlobo ea bopaki e etsoa neng le joang. Lisebelisoa tsa SIS li na le maemo a fapaneng a bothata ba tlhahlobo ea bopaki bo lokelang ho nahanoa moralong, ts'ebetsong le tlhokomelong ea SIF. Mohlala, orifice metres le li-transmitters tsa khatello li bonolo ho lekoa ho feta Coriolis mass flowmeters, mag metres kapa lisensor tsa boemo ba radar ea moea. Moralo oa ts'ebeliso le li-valve le ona o ka ama botlalo ba tlhahlobo ea bopaki ba li-valve ho netefatsa hore liphoso tse kotsi le tse qalang ka lebaka la ho senyeha, ho koala kapa ho hloleha ho itšetlehileng ka nako ha li lebise ho hloleheng ho hoholo nakong ea tlhahlobo e khethiloeng.
Le hoja mekhoa ea tlhahlobo ea bopaki e atisa ho etsoa nakong ea mohato oa boenjiniere oa SIF, e lokela ho hlahlojoa hape ke sebaka sa SIS Technical Authority, Operations le litsebi tsa lisebelisoa tse tla beng li etsa tlhahlobo. Tlhahlobo ea polokeho ea mosebetsi (JSA) le eona e lokela ho etsoa. Ho bohlokoa ho fumana hore na semela se reke eng mabapi le hore na liteko li tla etsoa neng le neng, le bokhoni ba tsona ba 'mele le polokeho. Mohlala, ha ho thuse letho ho hlakisa tlhahlobo e sa fellang ea setorouku ha sehlopha sa Ts'ebetso se hana ho se etsa. Ho boetse ho khothaletsoa hore mekhoa ea tlhahlobo ea bopaki e hlahlojoe ke setsebi se ikemetseng sa litaba (SME). Teko e tloaelehileng e hlokahalang bakeng sa tlhahlobo e felletseng ea bopaki ba ts'ebetso e bontšitsoe setšoantšong sa 1.
Litlhoko tsa tlhahlobo ea bopaki bo felletseng ba ts'ebetso Setšoantšo sa 1: Tlhaloso e felletseng ea tlhahlobo ea ts'ebetso bakeng sa ts'ebetso ea ts'ireletso (SIF) le sistimi ea eona ea ts'ireletso (SIS) e lokela ho bolela kapa ho bua ka mehato ka tatellano ho tloha litokisetsong tsa liteko le lits'ebetso tsa liteko ho ea ho litsebiso le litokomane. .
Setšoantšo sa 1: Tlhaloso e feletseng ea tlhahlobo ea bopaki ba ts'ebetso bakeng sa ts'ebetso ea lisebelisoa tsa polokeho (SIF) le sistimi ea eona ea ts'ireletso (SIS) e lokela ho hlalosa kapa ho bua ka mehato ka tatellano ho tloha litokisetsong tsa liteko le mekhoa ea liteko ho ea ho litsebiso le litokomane.
Teko ea bopaki ke ts'ebetso e reriloeng ea tlhokomelo e lokelang ho etsoa ke basebetsi ba nang le bokhoni ba koetliselitsoeng liteko tsa SIS, mokhoa oa ho netefatsa, le li-loops tsa SIS tseo ba tla li etsa liteko. Ho lokela hore ho be le mokhoa oa ho tsoela pele pele ho etsoa tlhahlobo ea pele ea bopaki, le maikutlo ho sebaka sa SIS Technical Authority ka mor'a moo bakeng sa lintlafatso kapa litokiso.
Ho na le mekhoa e 'meli e ka sehloohong ea ho hlōleha (e bolokehileng kapa e kotsi), e arotsoeng ka mekhoa e mene-e kotsi e sa lemohueng, e kotsi e fumanoeng (ka ho hlahloba), e bolokehileng e sa lemohuoe ebile e sireletsehile. Mantsoe a kotsi le a kotsi a sa bonahaleng a ho hloleha a sebelisoa ka mokhoa o fapaneng sengolong sena.
Tekong ea bopaki ba SIF, re thahasella haholo mekhoa e kotsi ea ho hloleha e sa lemoheng, empa haeba ho na le tlhahlobo ea mosebelisi e hlokomelang liphoso tse kotsi, tlhahlobo ena e lokela ho hlahlojoa. Hlokomela hore ho fapana le tlhahlobo ea mosebelisi, tlhahlobo ea kahare ea sesebelisoa hangata e ke ke ea netefatsoa hore e sebetsa ke mosebelisi, 'me sena se ka ama filosofi ea tlhahlobo ea bopaki. Ha mokitlane bakeng sa tlhahlobo ea mafu o nkuoa lipalong tsa SIL, lialamo tsa tlhahlobo (mohlala, lialamo tse sa sebetseng) li lokela ho lekoa e le karolo ea tlhahlobo ea bopaki.
Mekhoa ea ho hloleha e ka aroloa hape ka e lekiloeng nakong ea tlhahlobo ea bopaki, e sa lekoang, le mefokolo ea pele kapa liphoso tse itšetlehileng ka nako. Mekhoa e meng e kotsi ea ho hloleha e kanna ea se hlahlojoe ka kotloloho ka mabaka a fapaneng (mohlala, bothata, qeto ea boenjiniere kapa ts'ebetso, ho hloka tsebo, ho hloka tsebo, ho se sebetse kapa ho etsa liphoso tse hlophisitsoeng, monyetla o tlase oa ho etsahala, joalo-joalo). Haeba ho na le mekhoa e tsebahalang ea ho hloleha e ke keng ea lekoa, matšeliso a tlameha ho etsoa moralong oa sesebelisoa, ts'ebetsong ea tlhahlobo, ho nchafatsa sesebelisoa nako le nako kapa ho hahuoa bocha, le/kapa tlhahlobo e tlase e lokela ho etsoa ho fokotsa sephetho sa botšepehi ba SIF ea ho se etse liteko.
Ho hloleha ha pele ke boemo bo nyenyefatsang kapa boemo boo ho ka lebelloang ho hloleha ho hoholo, ho kotsi ka mokhoa o utloahalang haeba mehato ea ho lokisa e sa nkuoe ka nako. Hangata li bonoa ka ho bapisa ts'ebetso le liteko tsa morao-rao kapa tsa pele tsa bopaki (mohlala, li-signature tsa li-valve kapa linako tsa karabo ea li-valve) kapa ka tlhahlobo (mohlala, boema-kepe bo kentsoeng). Ho hlōleha ha pele hangata ho itšetlehile ka nako-ha sesebelisoa kapa kopano e ntse e sebetsa nako e telele, e ntse e senyeha le ho feta; maemo a thusang ho hloleha ho sa reroang ho ba bonolo, ho kenya li-port plug kapa sensor buildup ha nako e ntse e feta, bophelo ba bohlokoa bo felile, joalo-joalo. Tšireletso leha e le efe khahlanong le ho hlōleha ha pele le eona e tlameha ho lekoa ka bopaki (ho hloekisa boema-kepe, ho batla mocheso, joalo-joalo).
Mekhoa e tlameha ho ngolloa tlhahlobo ea bopaki bakeng sa liphoso tse kotsi (tse sa lemoheng). Mokhoa oa ho hloleha le tlhahlobo ea phello (FMEA) kapa mokhoa oa ho hloleha, mekhoa ea tlhahlobo ea phello le tlhahlobo ea mafu (FMEDA) e ka thusa ho tseba liphoso tse kotsi tse sa lemoheng, le moo ho tlameha ho ntlafatsoa ts'ebetso ea tlhahlobo ea bopaki.
Mekhoa e mengata ea tlhahlobo ea bopaki e ngotsoe ka boiphihlelo le litempele tse tsoang lits'ebetsong tse teng. Mekhoa e mecha le li-SIF tse thata ho feta li hloka mokhoa o tsoetseng pele o sebelisang FMEA/FMEDA ho sekaseka liphoso tse kotsi, ho fumana hore na mokhoa oa tlhahlobo o tla etsa liteko life kapa o ke ke oa etsa liteko bakeng sa liphoso tseo, le tšireletso ea liteko. Setšoantšo sa "macro-level failure analysis" bakeng sa kutlo se bontšoa ho Setšoantšo sa 2. FMEA hangata e hloka ho etsoa hanngoe feela bakeng sa mofuta o itseng oa sesebelisoa le ho sebelisoa hape bakeng sa lisebelisoa tse tšoanang ho nahanoa ka ts'ebeletso ea bona ea ts'ebetso, ts'ebetso ea ts'ebetso le bokhoni ba ho hlahloba sebaka. .
Tlhahlobo ea ho hloleha ha boemo ba macro Setšoantšo sa 2: Sets'oants'o sena sa ho hloleha ha maemo a macro-level bakeng sa sensor le khatello ea khatello (PT) e bonts'a mesebetsi e meholo eo ka tloaelo e tla aroloa ka litlhahlobo tse ngata tsa ho hloleha hoa ho hlalosa ka botlalo liphoso tse ka rarolloang. litekong tsa tšebetso.
Setšoantšo sa 2: Setšoantšo sena sa "macro-level failure mode analysis block" bakeng sa sensor le khatello ea khatello (PT) e bonts'a mesebetsi e meholo eo ka tloaelo e tla aroloa ka litlhahlobo tse ngata tsa ho hlōleha ho hlalosa ka botlalo mefokolo e ka 'nang ea sebetsanoa le liteko tsa mosebetsi.
Peresente ea liphoso tse tsejoang, tse kotsi, tse sa lemohuoang tse lekotsoeng li bitsoa proof test coverage (PTC). PTC e sebediswa ka tlwaelo dipalong tsa SIL ho “feela” ho hloleha ho lekola SIF ka botlalo. Batho ba na le tumelo e fosahetseng ea hore kaha ba nahanne ka khaello ea khaso ea tlhahlobo palong ea bona ea SIL, ba thehile SIF e tšepahalang. Taba e bonolo ke hore, haeba tlhahlobo ea hau ea tlhahlobo e le 75%, 'me haeba u kentse palo eo lipalong tsa hau tsa SIL le lintho tseo u seng u ntse u li leka hangata, 25% ea liphoso tse kotsi li ntse li ka etsahala ka lipalo. Ruri ha ke batle ho ba ho 25% eo.
Litlaleho tsa tumello ea FMDA le libuka tsa polokeho ea lisebelisoa hangata li fana ka mokhoa o fokolang oa tlhahlobo ea bopaki le tšireletso ea tlhahlobo ea bopaki. Tsena li fana ka tataiso feela, eseng mehato eohle ea tlhahlobo e hlokahalang bakeng sa ts'ebetso e felletseng ea tlhahlobo ea bopaki. Mefuta e meng ea tlhahlobo ea ho hloleha, joalo ka tlhahlobo ea sefate sa phoso le ho ts'epahala ho tsepamisitsoeng tlhokomelo, le tsona li sebelisetsoa ho sekaseka liphoso tse kotsi.
Liteko tsa bopaki li ka aroloa ka ts'ebetso e feletseng (bofelo-ho-qetellong) kapa tlhahlobo ea karolo e itseng (Setšoantšo sa 3). Teko e sa fellang e etsoa hangata ha likarolo tsa SIF li e-na le linako tse fapaneng tsa liteko lipalong tsa SIL tse sa tsamaellaneng le ho koala kapa ho fetoha ho reriloeng. Ho bohlokoa hore mekhoa ea teko ea bopaki bo sa fellang e tsamaisane hoo hammoho li lekang ts'ebetso eohle ea polokeho ea SIF. Ka tlhahlobo e sa fellang ea ts'ebetso, ho ntse ho khothaletsoa hore SIF e be le tlhahlobo ea bopaki ea ho qetela, le tse latelang nakong ea liphetoho.
Liteko tsa bopaki bo sa fellang li lokela ho eketsa Setšoantšo sa 3: Liteko tse kopantsoeng tsa bopaki bo sa fellang (ka tlaase) li lokela ho akaretsa mesebetsi eohle ea tlhahlobo e feletseng ea bopaki bo sebetsang (holimo).
Setšoantšo sa 3: Liteko tse kopantsoeng tsa bopaki bo sa fellang (ka tlaase) li lokela ho koahela mesebetsi eohle ea tlhahlobo e feletseng ea bopaki bo sebetsang (holimo).
Teko e sa fellang ea bopaki e leka feela liperesente tse itseng tsa mekhoa e hlolehileng ea sesebelisoa. Mohlala o tloaelehileng ke tlhahlobo ea li-valve tsa karoloana, moo valve e tsamaisoang ka chelete e nyane (10-20%) ho netefatsa hore ha e ea khomarela. Sena se na le khaso e tlase ea tlhahlobo ea bopaki ho feta tlhahlobo ea bopaki nakong ea tlhahlobo ea mantlha.
Mekhoa ea tlhahlobo ea bopaki e ka fapana ka ho rarahana le ho rarahana ha SIF le filosofi ea ts'ebetso ea tlhahlobo ea k'hamphani. Likhamphani tse ling li ngola lits'ebetso tsa tlhahlobo tse qaqileng tsa mohato ka mohato, ha tse ling li na le lits'ebetso tse khutšoane. Lits'oants'o tsa lits'ebetso tse ling, joalo ka tekanyo e tloaelehileng, ka linako tse ling li sebelisoa ho fokotsa boholo ba ts'ebetso ea tlhahlobo ea bopaki le ho thusa ho netefatsa ho tsitsa ha tlhahlobo. Ts'ebetso e ntle ea tlhahlobo ea bopaki e lokela ho fana ka lintlha tse lekaneng ho netefatsa hore liteko tsohle li phethoa hantle le ho ngoloa, empa eseng lintlha tse ngata ho etsa hore litsebi li batle ho tlola mehato. Ho ba le setsebi, se ikarabellang bakeng sa ho etsa mohato oa tlhahlobo, qalong mohato oa tlhahlobo o phethiloeng ho ka thusa ho netefatsa hore tlhahlobo e tla etsoa ka nepo. Ho tekenoa ha tlhahlobo e phethiloeng ea bopaki ke Mookameli oa Lisebelisoa le baemeli ba Ts'ebetso ho tla hatisa bohlokoa le ho netefatsa tlhahlobo ea bopaki e phethiloeng hantle.
Maikutlo a litsebi a lokela ho lula a memeloa ho thusa ho ntlafatsa ts'ebetso. Katleho ea ts'ebetso ea tlhahlobo ea bopaki e lutse haholo matsohong a litsebi, kahoo boiteko ba tšebelisano bo khothaletsoa haholo.
Liteko tse ngata tsa bopaki hangata li etsoa kantle ho marang-rang nakong ea ho koala kapa ho fetola. Maemong a mang, tlhahlobo ea bopaki e ka 'na ea hlokoa hore e etsoe inthaneteng ha u ntse u matha ho khotsofatsa lipalo tsa SIL kapa litlhoko tse ling. Teko ea Marang-rang e hloka ho rala le ho hokahana le Ts'ebetso ho lumella tlhahlobo ea bopaki hore e etsoe ka mokhoa o bolokehileng, ntle le ts'ebetso e ferekaneng, le ntle le ho baka leeto la bohata. Ho nka leeto le le leng feela la bohata ho sebelisa li-attaboys tsa hau kaofela. Nakong ea teko ea mofuta ona, ha SIF e se e le sieo ka botlalo ho etsa mosebetsi oa eona oa polokeho, 61511-1, Clause 11.8.5, e re “Compensation procedures that sure continue safe operation shall be given in according to 11.3 when the SIS is in in bypass (ho lokisa kapa ho etsa liteko)." Tsamaiso ea maemo a sa tloaelehang e lokela ho tsamaea le mokhoa oa tlhahlobo ea bopaki ho thusa ho netefatsa hore sena se etsoa ka nepo.
SIF hangata e arotsoe likarolo tse tharo tse kholo: li-sensor, logic solvers le likarolo tsa ho qetela. Ho boetse ho na le lisebelisoa tse thusang tse ka amahanngoang le karolo ka 'ngoe ea likarolo tsena tse tharo (mohlala, IS barriers, trip amps, interposing relays, solenoids, joalo-joalo) tse tlamehang ho lekoa. Lintlha tsa bohlokoa tsa tlhahlobo ea bopaki e 'ngoe le e' ngoe ea mahlale ana li ka fumanoa ka har'a lehlakore, "Li-sensor tsa liteko, li-logical solvers le likarolo tsa ho qetela" (ka tlase).
Lintho tse ling li bonolo ho etsa tlhahlobo ea bopaki ho feta tse ling. Litheknoloji tse ngata tsa sejoale-joale le tse seng kae tsa khale tsa phallo le maemo li maemong a thata haholoanyane. Tsena li kenyelletsa li-flowmeters tsa Coriolis, li-vortex metres, mag metres, radar ea moea, boemo ba ultrasonic, le li-switches tsa in-situ, ho bolela tse 'maloa. Ka lehlohonolo, tse ngata tsa tsena joale li na le tlhahlobo e ntlafalitsoeng e lumellang tlhahlobo e ntlafalitsoeng.
Bothata ba tlhahlobo ea bopaki sesebelisoa se joalo tšimong bo tlameha ho nahanoa ka moralo oa SIF. Ho bonolo ho boenjiniere ho khetha lisebelisoa tsa SIF ntle le ho nahana ka botebo hore na ho tla hlokahala eng ho netefatsa sesebelisoa, kaha e ke ke ea e-ba batho ba li lekang. Sena ke 'nete hape ka tlhahlobo e sa fellang ea stroke, e leng mokhoa o tloaelehileng oa ho ntlafatsa monyetla oa ho hloleha ho latela tlhoko ea SIF (PFDavg), empa hamorao polanteng Ts'ebetso ha e batle ho e etsa, 'me hangata e kanna ea se ke ea e etsa. Kamehla fana ka tlhokomelo ea polante ea boenjiniere ba li-SIF mabapi le tlhahlobo ea bopaki.
Teko ea bopaki e lokela ho kenyelletsa tlhahlobo ea ho kengoa le ho lokisoa ha SIF ha ho hlokahala ho kopana le 61511-1, Clause 16.3.2. Ho lokela hore ho be le tlhahlobo ea ho qetela ho netefatsa hore ntho e 'ngoe le e 'ngoe e koetsoe, le ho hlahloba habeli hore SIF e khutliselitsoe hantle ts'ebetsong ea ts'ebetso.
Ho ngola le ho kenya tshebetsong mokgwa o motle wa teko ke mohato wa bohlokwa ho netefatsa botshepehi ba SIF bophelong bohle ba yona. Mokhoa oa teko o lokela ho fana ka lintlha tse lekaneng ho netefatsa hore liteko tse hlokahalang li etsoa ka mokhoa o tsitsitseng le ka mokhoa o sireletsehileng le ho ngoloa. Liphoso tse kotsi tse sa lekoang ka liteko tsa bopaki li lokela ho lefshoa bakeng sa ho netefatsa hore botšepehi ba SIF bo bolokoa ka mokhoa o lekaneng bophelong bohle ba eona.
Ho ngola mokhoa o motle oa tlhahlobo ea bopaki ho hloka mokhoa o utloahalang oa tlhahlobo ea boenjiniere ea liphoso tse ka bang kotsi, ho khetha mekhoa, le ho ngola mehato ea tlhahlobo ea bopaki e ka har'a bokhoni ba tlhahlobo ea polante. Ha u ntse u le tseleng, fumana lisebelisoa tsa limela maemong ohle bakeng sa tlhahlobo, 'me u koetlise litsebi tsa theknoloji ho etsa le ho ngola tlhahlobo ea bopaki hammoho le ho utloisisa bohlokoa ba tlhahlobo. Ngola litaelo joalokaha eka ke uena setsebi sa lisebelisoa se tla tlameha ho etsa mosebetsi, 'me bophelo bo itšetlehile ka ho fumana tlhahlobo e nepahetseng, hobane ba etsa joalo.
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 hangata e arotsoe likarolo tse tharo tse kholo, li-sensor, logic solvers le likarolo tsa ho qetela. Ho boetse ho na le lisebelisoa tse thusang tse ka amahanngoang ka har'a karolo ka 'ngoe ea likarolo tsena tse tharo (mohlala, IS barriers, trip amps, interposing relays, solenoids, joalo-joalo) tse tlamehang ho lekoa.
Liteko tsa bopaki ba kutlo: Teko ea bopaki ba sensor e tlameha ho etsa bonnete ba hore sensor e khona ho utloa phetoho ea ts'ebetso ho feta mefuta eohle ea eona mme e fetisetse letšoao le nepahetseng ho SIS logic solver bakeng sa tlhahlobo. Leha e sa kenyelelitsoe, tse ling tsa lintho tse lokelang ho nahanoa ha u theha karolo ea sensor ea ts'ebetso ea tlhahlobo ea bopaki li fanoe ho Lethathamo la 1.
Teko ea bopaki ba ho rarolla bothata: Ha tlhahlobo ea bopaki bo felletseng e etsoa, karolo ea logic solver ho phethahatsa ts'ebetso ea ts'ireletso ea SIF le liketso tse amanang le tsona (mohlala, lialamo, reset, lipallo, tlhahlobo ea mosebelisi, bofokoli, HMI, jj.) lia lekoa. Liteko tsa bopaki ba tšebetso e sa fellang kapa tse nyane li tlameha ho fihlela liteko tsena kaofela e le karolo ea liteko tsa bopaki tse fetang. Moetsi oa logic solver o lokela ho ba le mokhoa o khothaletsoang oa tlhahlobo ea bopaki bukeng ea polokeho ea sesebelisoa. Haeba ho se joalo, 'me bonyane, matla a "logic solver" a lokela ho tsamaisoa ka baesekele, 'me libuka tsa tlhahlobo ea logic solver, mabone a boemo, li-voltage tsa phepelo ea motlakase, likhokahano tsa puisano le ho hloka mosebetsi li lokela ho hlahlojoa. Liteko tsena li lokela ho etsoa pele ho tlhahlobo ea bopaki bo felletseng.
U se ke ua etsa maikutlo a hore software e ntle ka ho sa feleng 'me logic ha ea lokela ho lekoa ka mor'a tlhahlobo ea pele ea bopaki e le lisebelisoa tse sa ngolisoang, tse sa lumelloeng le tse sa hlahlojoang le liphetoho tsa hardware le lisebelisoa tsa software li ka kena lits'ebetsong ka nako' me li tlameha ho kenngoa ka kakaretso ea hau. filosofi ea tlhahlobo ea bopaki. Tsamaiso ea liphetoho, tlhokomelo, le lintlha tsa ntlafatso li lokela ho hlahlojoa ho netefatsa hore li nakong le ho hlokomeloa ka nepo, 'me haeba li khonahala, lenaneo la ts'ebeliso le lokela ho bapisoa le bekapo ea morao-rao.
Tlhokomelo e boetse e lokela ho nkoa ho leka likarolo tsohle tse thusang le tsa tlhahlobo ea mosebelisi (mohlala, lintja tsa balebeli, likhokahano tsa puisano, lisebelisoa tsa cybersecurity, jj.).
Teko ea ho qetela ea bopaki: Lintho tse ngata tsa ho qetela ke li-valve, leha ho le joalo, lisebelisoa tse potolohang tsa motlakase, li-drive tse lebelo le likarolo tse ling tsa motlakase joalo ka li-contactor le li-circuit breaker le tsona li sebelisoa e le likarolo tsa ho qetela mme mekhoa ea bona ea ho se atlehe e tlameha ho hlahlojoa le ho hlahlojoa bopaki.
Mekhoa ea mantlha ea ho hloleha ha li-valve e ntse e ts'oaroa, nako ea karabelo butle haholo kapa e potlakile haholo, le ho lutla, tseo kaofela li angoang ke sebopeho sa ts'ebetso ea valve nakong ea leeto. Le hoja ho hlahloba valve maemong a ts'ebetso e le nyeoe e lakatsehang ka ho fetisisa, Ts'ebetso e ka 'na ea e-ba khahlanong le ho khoptjoa ha SIF ha semela se ntse se sebetsa. Boholo ba li-valve tsa SIS hangata lia lekoa ha polante e le tlase ka khatello ea zero, e leng boemo bo sa hlokeng letho maemong a ts'ebetso. Mosebelisi o lokela ho tseba ka khatello e mpe ka ho fetesisa ea ts'ebetso le li-valve le litlamorao tsa ts'ebetso, tse lokelang ho kengoa molemong oa moralo le boholo ba valve le actuator.
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).
Lithempereichara tsa tikoloho le tsona li ka ama likhohlano tsa li-valve, e le hore li-valve tsa tlhahlobo maemong a leholimo a futhumetseng hangata e be tsona tse sa hlokeng letho ha li bapisoa le ts'ebetso ea boemo ba leholimo bo batang. Ka lebaka leo, tlhahlobo ea bopaki ba li-valve ka mocheso o tsitsitseng o lokela ho nkoa e le ho fana ka lintlha tse tsitsitseng bakeng sa tlhahlobo e fokolang bakeng sa ho etsa qeto ea ho senyeha ha ts'ebetso ea valve.
Li-valve tse nang le li-positioners tse bohlale kapa se laolang li-valve tsa dijithale ka kakaretso li na le bokhoni ba ho etsa signature ea valve e ka sebelisoang ho lekola ho senyeha ha tšebetso ea li-valve. Saeno ea li-valve tsa motheo e ka koptjoa e le karolo ea odara ea hau ea theko kapa u ka e etsa nakong ea tlhahlobo ea pele ea bopaki ho sebetsa joalo ka motheo. Signature ea valve e lokela ho etsoa bakeng sa ho bula le ho koala valve. Tlhahlobo e tsoetseng pele ea li-valve le eona e lokela ho sebelisoa haeba e le teng. Sena se ka u thusa ho u joetsa hore na ts'ebetso ea valve ea hau e ntse e mpefala ka ho bapisa li-signature tse latelang tsa tlhahlobo ea bopaki le tlhahlobo le lintlha tsa hau tsa motheo. Mofuta ona oa teko o ka thusa ho lefella ho se leke valve maemong a mabe ka ho fetisisa a ho sebetsa.
Saeno ea valve nakong ea tlhahlobo ea bopaki e ka boela ea khona ho rekota nako ea ho arabela ka litempe tsa nako, ho tlosa tlhokahalo ea stopwatch. Nako e eketsehileng ea ho arabela ke pontšo ea ho senyeha ha valve le ho eketseha ha moroalo oa likhohlano ho tsamaisa valve. Le hoja ho se na litekanyetso tse mabapi le liphetoho nakong ea karabo ea valve, mokhoa o fosahetseng oa liphetoho ho tloha tekong ea bopaki ho ea tekong ea bopaki ke pontšo ea tahlehelo e ka bang teng ea moeli oa ts'ireletso ea valve le ts'ebetso. Teko ea sejoale-joale ea li-valve tsa SIS e lokela ho kenyelletsa signature ea valve e le taba ea ts'ebetso e ntle ea boenjiniere.
Khatello ea moea ea sesebelisoa sa valve e lokela ho lekanyetsoa nakong ea tlhahlobo ea bopaki. Le hoja mohloli oa valve bakeng sa valve ea ho khutlela nakong ea selemo ke oona o koalang valve, matla kapa torque e amehang e khethoa ke hore na mohloli oa valve o hatelloa hakae ke khatello ea phepelo ea valve (ho ea ka Molao oa Hooke, F = kX). Haeba khatello ea hau ea phepelo e le tlase, selemo se ke ke sa hatella haholo, kahoo matla a fokolang a tla ba teng ho tsamaisa valve ha ho hlokahala. Leha e sa kenyelelitsoe, tse ling tsa lintho tse lokelang ho nahanoa ha u theha karolo ea valve ea mokhoa oa tlhahlobo ea bopaki li fanoe ho Lethathamo la 2.
Nako ea poso: Nov-13-2019
