Fa'ailo mo le tetete o le leo mo le (ＨＯＭＥ)

O le su'ega o fa'amaoniga o se vaega taua tele lea o le tausiga o le saogalemu o a tatou faiga fa'ameafaigaluega saogalemu (SIS) ma faiga e feso'ota'i ma le saogalemu (e pei o fa'ailo taua, faiga afi ma kesi, faiga loka fa'ameafaigaluega, ma isi mea fa'apena). O se su'ega o fa'amaoniga o se su'ega fa'avaitaimi e iloa ai fa'aletonu mata'utia, su'e galuega e feso'ota'i ma le saogalemu (e pei o le toe setiina, fa'asolosolo, fa'ailo, su'esu'ega, tapunia lima, ma isi mea fa'apena), ma ia mautinoa o lo'o ausia e le faiga tulaga fa'atonuina a le kamupani ma fafo. O taunu'uga o su'ega o fa'amaoniga o se fua fo'i lea o le aoga o le polokalame fa'amaoni fa'amekanika a le SIS ma le fa'atuatuaina o le faiga i le fanua.

O taualumaga o suega fa'amaonia e aofia ai la'asaga o suega mai le mauaina o pemita, faia o fa'asilasilaga ma le aveesea o le polokalama mai le fa'aogaina mo le su'eina i le fa'amautinoaina o suega atoatoa, fa'amaumauina le suega fa'amaonia ma ona taunuuga, toe fa'aogaina le polokalama, ma le iloiloina o taunuuga o suega o lo'o iai nei ma taunuuga o suega fa'amaonia muamua.

O le ANSI/ISA/IEC 61511-1, Fuaiupu 16, e aofia ai suega fa'amaonia o le SIS. O le lipoti fa'atekinolosi a le ISA TR84.00.03 – “Mechanical Integrity of Safety Instrumented Systems (SIS),” e aofia ai suega fa'amaonia ma o lo'o fa'agasolo nei le toe teuteuina ma o lo'o fa'amoemoe e vave ona fa'alauiloa se lomiga fou. O le lipoti fa'atekinolosi a le ISA TR96.05.02 – “In-situ Proof Testing of Automated Valves” o lo'o fa'agasolo nei le atina'eina.

Lipoti a le HSE a le UK CRR 428/2002 – “Mataupu faavae mo suega faamaoniga o faiga fa'ameafaigaluega saogalemu i le alamanuia o vaila'au” o lo'o tu'uina atu ai fa'amatalaga e uiga i suega faamaoniga ma mea o lo'o faia e kamupani i le UK.

O se faiga o suega fa'amaonia e fa'avae i luga o se su'esu'ega o faiga fa'aletonu mata'utia ua iloa mo vaega ta'itasi i le ala o le saogalemu (SIF), le galuega a le SIF o se faiga, ma le auala (ma pe afai) e su'e ai le faiga fa'aletonu mata'utia. E tatau ona amata le atina'eina o faiga i le vaega o le mamanu o le SIF fa'atasi ai ma le mamanu o le faiga, filifilia o vaega, ma le fuafuaina o le taimi ma le auala e su'e ai le suega fa'amaonia. O meafaigaluega SIS e eseese tulaga faigata o suega fa'amaonia e tatau ona mafaufau i ai i le mamanu o le SIF, fa'agaioiga ma le tausiga. Mo se fa'ata'ita'iga, o mita orifice ma masini fa'asalalau mamafa e faigofie ona su'eina nai lo mita tafe mamafa a Coriolis, mita mag po'o masini fa'alogo leo i luga o le ea. O le fa'aogaina ma le mamanu o le valve e mafai fo'i ona a'afia ai le atoatoa o le suega fa'amaonia o le valve e fa'amautinoa ai o fa'aletonu mata'utia ma amata ona o le fa'aleagaina, poloka po'o fa'aletonu e fa'alagolago i le taimi e le o'o atu ai i se fa'aletonu taua i totonu o le vaitaimi o suega ua filifilia.

E ui o faiga fa'ata'ita'i fa'amaoniga e masani ona atia'e i le taimi o le vaega o le inisinia SIF, ae e tatau fo'i ona toe iloiloina e le Pulega Fa'atekinolosi a le SIS, le Pulega o Galuega ma le au tekinisia o meafaigaluega o le a faia le su'ega. E tatau fo'i ona faia se su'esu'ega o le saogalemu o galuega (JSA). E taua le maua o le lagolago a le fale gaosi i po'o a su'ega o le a faia ma le taimi, fa'apea fo'i ma lo latou gafatia fa'aletino ma le saogalemu. Mo se fa'ata'ita'iga, e le aoga le fa'amaotiina o su'ega fa'asolosolo pe a le malilie le vaega o Galuega e fai. E fautuaina fo'i le toe iloiloina o faiga fa'ata'ita'i fa'amaoniga e se tagata tomai fa'apitoa tuto'atasi (SME). O su'ega masani e mana'omia mo se su'ega fa'amaoniga atoatoa o lo'o fa'aalia i le Ata 1.

Manaʻoga atoa mo le suʻega o le faʻamaoniga o galuega faatino Ata 1: O se faʻamatalaga atoa mo le suʻega o le faʻamaoniga o galuega faatino mo se galuega faatino ua faʻaaogaina meafaigaluega saogalemu (SIF) ma lana faiga faʻaaogaina meafaigaluega saogalemu (SIS) e tatau ona faʻamatala auiliili pe faʻasino i laʻasaga i le faasologa mai sauniuniga o suʻega ma faʻagasologa o suʻega i faʻasilasilaga ma pepa faʻamaonia.

Ata 1: O se faʻamatalaga atoa o le suʻega o le faʻamaoniga o galuega faatino mo se galuega faatino faʻaeletoroni saogalemu (SIF) ma lana faiga faʻaeletoroni saogalemu (SIS) e tatau ona faʻamatala auiliili pe faʻasino i laʻasaga i le faasologa mai sauniuniga o suʻega ma faʻagasologa o suʻega i faʻasilasilaga ma pepa faʻamaonia.

O le su'ega o fa'amaoniga o se gaioiga tausiga fuafuaina e tatau ona faia e tagata faigaluega agavaa ua a'oa'oina i su'ega SIS, le faiga o le su'ega, ma fa'asologa o le SIS o le a latou su'eina. E tatau ona i ai se fa'ata'ita'iga o le faiga a'o le'i faia le su'ega muamua o le su'ega, ma tu'uina atu se fa'amatalaga i le Pulega Fa'atekinolosi a le SIS i le nofoaga mulimuli ane mo ni fa'aleleiga po'o ni fa'asa'oga.

E lua auala autū o le faaletonu (saogalemu pe matautia), e vaevaeina i ni auala e fa—matautia e leʻi iloa, matautia ua iloa (e ala i suʻesuʻega), saogalemu e leʻi iloa ma saogalemu ua iloa. O upu o le faaletonu matautia ma le matautia e leʻi iloa o loʻo faʻaaogaina fesuiaʻi i lenei tusiga.

I le su'ega o le fa'amaoniga o le SIF, matou te fiafia tele i faiga fa'aletonu mata'utia e le'i iloa, ae afai e iai ni su'esu'ega a tagata fa'aoga e iloa ai ni fa'aletonu mata'utia, e tatau ona su'eina nei su'esu'ega. Ia manatua e le pei o su'esu'ega a tagata fa'aoga, o su'esu'ega i totonu o le masini e masani lava e le mafai ona fa'amaonia e le tagata fa'aoga pe aoga, ma e mafai ona a'afia ai le filosofia o su'ega o le fa'amaoniga. A fa'aaogaina le fa'afetai mo su'esu'ega i fa'atusatusaga o le SIL, e tatau ona su'eina fa'ailo su'esu'ega (e pei o fa'ailo i fafo atu o le laina) o se vaega o le su'ega o le fa'amaoniga.

E mafai ona vaevaeina atili auala o le toilalo i ni auala na tofotofoina i le taimi o se suega faamaoniga, o auala e le'i tofotofoina, ma ni faaletonu amata pe faaletonu e faalagolago i le taimi. O nisi auala matautia o le toilalo atonu e le tofotofoina sa'o mo ni mafuaaga eseese (e pei o le faigata, faaiuga faainisinia po o le faagaoioiga, le iloa, le agavaa, le amanaiaina po o le faia o mea sese faatulagaina, maualalo le avanoa e tupu ai, ma isi mea faapena). Afai ei ai ni auala ua iloa o le a le tofotofoina, e tatau ona faia se taui i le mamanuina o masini, faiga o suega, suiina o masini i lea taimi ma lea taimi po o le toe fausiaina, ma/po o suega faaiu e tatau ona faia ina ia faaitiitia ai le aafiaga i le faamaoni o le SIF ona o le le tofotofoina.

O se faaletonu amata o se tulaga po o se tulaga ua faaleagaina ai e mafai ona faamoemoeina se faaletonu matuia ma matautia pe afai e le faia ni gaioiga faasa'o i se taimi talafeagai. E masani ona iloa e ala i le faatusatusaina o le faatinoga i suega faamaonia talu ai nei po o suega muamua (e pei o faailoga o le valve po o taimi tali o le valve) po o le siakiina (e pei o se uafu o le faagasologa ua poloka). O faaletonu amata e masani ona faalagolago i le taimi—o le umi o le faaaogaina o le masini po o le faapotopotoga, o le tele foi lea o lona faaleagaina; o tulaga e faafaigofie ai se faaletonu faafuasei e sili atu ona ono tupu, o le poloka o le uafu o le faagasologa po o le faaputuputuina o le sensor i le aluga o taimi, ua uma le umi aoga, ma isi mea faapena. O le mea lea, o le umi o le vaitaimi o suega faamaonia, o le tele foi lea o le ono tupu o se faaletonu amata po o se faaletonu faalagolago i le taimi. So'o se puipuiga mai faaletonu amata e tatau foi ona tofotofoina faamaoniga (faamamaina o le port, su'esu'ega o le vevela, ma isi mea faapena).

E tatau ona tusia ni fa'agasologa e fa'amaonia ai ni fa'aletonu mata'utia (e le'i iloa). O metotia o le Failure Mode and Effect Analysis (FMEA) po'o le Failure Mode, Effect and Diagnosis Analysis (FMEDA) e mafai ona fesoasoani e fa'ailoa ai ni fa'aletonu mata'utia e le'i iloa, ma pe o fea e tatau ona fa'aleleia atili ai le ufiufi o su'ega fa'amaonia.

O le tele o faiga o suega fa'amaoniga e fa'avae i tusitusiga e fa'avae i luga o le poto masani ma fa'ata'ita'iga mai faiga o lo'o iai nei. O faiga fou ma SIF e sili atu ona faigata e mana'omia ai se auala sili atu ona fa'ainisinia e fa'aaoga ai le FMEA/FMEDA e iloilo ai mo ni fa'aletonu mata'utia, fuafua pe fa'apefea ona tofotofoina pe leai fo'i e le faiga o suega na fa'aletonu, ma le aofia ai o suega. O lo'o fa'aalia i le Ata 2 se ata poloka o le auiliiliga o le faiga o le fa'aletonu i le tulaga lautele mo se masini fa'alogo. E masani lava e na'o le fa'atasi ona mana'omia le faia o le FMEA mo se ituaiga masini fa'apitoa ma toe fa'aaoga mo masini fa'apena ma le mafaufauina o latou auaunaga fa'agasologa, fa'apipi'iina ma le gafatia o suega i le nofoaga.

Iloiloga o le faaletonu i le tulaga lautele Ata 2: O lenei ata poloka o le auiliiliga o le faaletonu i le tulaga lautele mo se sensor ma se pressure transmitter (PT) o loʻo faʻaalia ai galuega autu e masani ona vaevaeina i ni auiliiliga o faaletonu laiti e faʻamatalaina atoatoa ai faaletonu e ono tulaʻi mai e foia i suega o galuega.

Ata 2: O lenei ata poloka o le au'ili'iliga o le faiga o le faaletonu i le tulaga lautele mo se masini fa'alogo ma se masini fa'asalalau mamafa (PT) o lo'o fa'aalia ai galuega tetele e masani ona vaevaeina i ni au'ili'iliga o le faaletonu laiti e fa'amatalaina atoatoa ai faaletonu e ono tula'i mai e tatau ona fa'atalanoaina i su'ega o galuega.

O le pasene o fa'aletonu ua iloa, mata'utia, ma le le iloa ua fa'amaonia ua ta'ua o le proof test coverage (PTC). E masani ona fa'aaogaina le PTC i fuafuaga SIL e "taui" ai le le manuia e sili atu ona atoatoa le su'eina o le SIF. E iai le talitonuga sese a tagata ona ua latou mafaufau i le leai o se proof test coverage i la latou fuafuaga SIL, ua latou mamanuina ai se SIF fa'atuatuaina. O le mea moni faigofie, afai o lau proof test coverage e 75%, ma afai e te fa'aopoopoina lena numera i lau fuafuaga SIL ma su'e mea ua uma ona e su'eina soo, e 25% o fa'aletonu mata'utia e mafai lava ona tutupu fa'amaumauga. Ou te le mana'o e i ai i lena 25%.

O lipoti fa'amaonia a le FMEDA ma tusi lesona saogalemu mo masini e masani ona tu'uina atu ai se faiga fa'ata'ita'i maualalo ma le ufiufi o faiga fa'ata'ita'i. O nei mea e na'o ni ta'iala e tu'uina atu, ae le o la'asaga uma o faiga fa'ata'ita'i e mana'omia mo se faiga fa'ata'ita'i atoatoa. O isi ituaiga o au'ili'iliga o fa'aletonu, e pei o le au'ili'iliga o le la'au fa'aletonu ma le tausiga e fa'atotonugalemu i le fa'atuatuaina, e fa'aaogaina fo'i e au'ili'ili ai mo fa'aletonu mata'utia.

E mafai ona vaevaeina suega fa'amaonia i ni suega atoatoa (mai le pito i luma i le pito) po'o ni suega fa'amaonia vaega (Ata 3). E masani ona faia suega fa'amaonia vaega pe a eseese taimi e faia ai suega i vaega o le SIF i fuafuaga a le SIL e le ogatasi ma tapunia fuafuaina po'o ni suiga. E taua tele le fa'atasia o fa'agasologa o suega fa'amaonia vaega ina ia mafai ona latou fa'ata'ita'iina fa'atasi gaioiga uma o le saogalemu o le SIF. I suega fa'amaonia vaega, e fautuaina pea le faia e le SIF o se suega fa'amaonia muamua mai le pito i luma i le pito, ma isi suega mulimuli ane i le taimi o suiga.

E tatau ona fa'aopoopoina su'ega fa'amaoniga vaega Ata 3: O su'ega fa'amaoniga vaega tu'ufa'atasi (pito i lalo) e tatau ona aofia ai galuega uma o se su'ega fa'amaoniga atoatoa (pito i luga).

Ata 3: O suega fa'amaoniga fa'avaega tu'ufa'atasi (pito i lalo) e tatau ona aofia ai galuega uma o se suega fa'amaoniga atoatoa (pito i luga).

O se suega fa'amaonia fa'apitoa e na'o le fa'ata'ita'iina o se pasene o faiga fa'aletonu o se masini. O se fa'ata'ita'iga masani o le suega fa'amaonia fa'apitoa o le valve, lea e fa'agaoioi ai le valve i sina vaega itiiti (10-20%) e fa'amaonia ai e le o pipii. E maualalo le ufiufi o lenei suega fa'amaonia nai lo le suega fa'amaonia i le vaitaimi muamua o le suega.

E mafai ona eseese le lavelave o faiga o suega fa'amaonia e fa'atatau i le lavelave o le SIF ma le filosofia o faiga o suega a le kamupani. O nisi kamupani e tusia ni faiga auiliili o suega ta'itasi, ae o isi e fai si pu'upu'u. O fa'asinomaga i isi faiga, e pei o se fa'atulagaga masani, e fa'aaogaina i nisi taimi e fa'aitiitia ai le tele o le faiga o suega fa'amaonia ma fesoasoani e fa'amautinoa le tutusa o suega. O se faiga lelei o suega fa'amaonia e tatau ona maua ai ni fa'amatalaga auiliili e fa'amautinoa ai o suega uma ua mae'a ma fa'amaumauina, ae le o le tele o fa'amatalaga auiliili e mafua ai ona manana'o tagata fa'atekinolosi e fa'ase'e la'asaga. O le i ai o le tagata fa'atekinolosi, o ia lea e nafa ma le fa'atinoina o le la'asaga o suega, e amata le la'asaga o suega ua mae'a e mafai ona fesoasoani e fa'amautinoa o le a faia sa'o le suega. O le sainia o le suega fa'amaonia ua mae'a e le Supavaisa o Meafaigaluega ma sui o Galuega Fa'atino o le a fa'amamafaina ai fo'i le taua ma fa'amautinoa ai se suega fa'amaonia ua mae'a lelei.

E tatau ona vala'aulia i taimi uma ni manatu fa'apitoa e fesoasoani e fa'aleleia atili ai le faiga. O le manuia o se faiga o su'ega fa'amaonia e tele lava ina faalagolago i lima o le tagata tomai faapitoa, o lea e matua fautuaina ai lava se taumafaiga fa'atasi.

O le tele o suega fa'amaonia e masani ona faia i fafo atu o le initaneti i le taimi o le tapunia po'o le toe fa'afo'isia o le feso'ota'iga. I nisi tulaga, atonu e mana'omia le faia o suega fa'amaonia i luga ole initaneti a'o fa'agaoioia e fa'amalieina ai fuafuaga a le SIL po'o isi mana'oga. O suega i luga ole initaneti e mana'omia ai le fuafuaina ma le fa'amaopoopoina ma le Operations ina ia mafai ai ona faia le suega fa'amaonia ma le saogalemu, e aunoa ma se fa'alavelaveina o se faiga, ma e aunoa ma le mafua ai o se malaga sese. E na'o le tasi le malaga sese e fa'aaoga ai au attaboys uma. I le taimi o lenei ituaiga suega, pe a le o atoatoa le avanoa o le SIF e fa'atino lana galuega saogalemu, o le 61511-1, Fuaiupu 11.8.5, o lo'o ta'ua ai "O fua fa'atatau e fa'amautinoa ai le fa'aauau pea o le saogalemu o le fa'agaioiga e tatau ona tu'uina atu e tusa ai ma le 11.3 pe a fa'aletonu le SIS (toe fa'aleleia po'o le su'ega)." O se faiga e pulea ai tulaga e le masani ai e tatau ona o fa'atasi ma le faiga o suega fa'amaonia e fesoasoani e fa'amautinoa ai ua faia lelei lenei mea.

E masani ona vaevaeina se SIF i ni vaega autū se tolu: o masini fa'alogo (sensors), o masini fofo fa'alogika (logic solvers) ma elemene mulimuli. E iai fo'i masini fesoasoani e mafai ona fa'afeso'ota'i i totonu o nei vaega ta'itasi e tolu (e pei o IS barriers, trip amps, interposing relays, solenoids, ma isi) e tatau fo'i ona fa'ata'ita'iina. O vaega taua o le fa'ata'ita'iina o fa'amaoniga o nei tekinolosi ta'itasi e mafai ona maua i le itu pa, "Testing sensors, logic solvers ma elemene mulimuli" (i lalo).

O nisi mea e faigofie ona fa'amaonia le su'ega nai lo isi. O le tele o tekinolosi fa'aonaponei ma nai tekinolosi tuai o le tafe ma le tulaga o lo'o i totonu o le vaega e sili atu ona faigata. E aofia ai mita tafe Coriolis, mita vortex, mita mag, radar e fa'aogaina ai le ea, tulaga ultrasonic, ma ki o le faiga i totonu, e na'o ni nai mea e ta'ua. O le mea e lelei ai, o le tele o nei mea ua i ai nei fa'aleleia atili o su'ega e mafai ai ona fa'aleleia atili su'ega.

E tatau ona mafaufau i le faigata o le fa'ata'ita'iina o se masini fa'apea i le fanua i le mamanu o le SIF. E faigofie mo inisinia ona filifili masini SIF e aunoa ma se mafaufau loloto i mea e mana'omia e fa'ata'ita'i ai le masini, aua o le a le avea i latou ma tagata o lo'o fa'ata'ita'iina. E moni fo'i lenei mea i le fa'ata'ita'iina o le partial-stroke, o se auala masani e fa'aleleia ai le averesi o le SIF o le ono fa'aletonu i le taimi e mana'omia ai (PFDavg), ae mulimuli ane e le mana'o le vaega o lo'o fa'agaoioia le la'au e fai, ma e tele taimi atonu e le faia. Ia tu'uina atu i taimi uma le va'ava'aiga a le la'au i le inisinia o SIF e tusa ai ma le fa'ata'ita'iga o le fa'ata'ita'iga.

E tatau ona aofia i le suega fa'amaonia se asiasiga o le fa'apipi'iina ma le toe fa'aleleia o le SIF pe a mana'omia e ausia ai le 61511-1, Fuaiupu 16.3.2. E tatau ona i ai se asiasiga mulimuli e fa'amautinoa ai ua mae'a mea uma, ma se siaki faalua ua toe tu'u lelei le SIF i totonu o le fa'agasologa o galuega.

O le tusiaina ma le faʻatinoina o se faiga lelei o suʻega o se laʻasaga taua e faʻamautinoa ai le saʻo o le SIF i lona olaga atoa. E tatau i le faiga o suʻega ona tuʻuina atu faʻamatalaga auiliili e faʻamautinoa ai o suʻega manaʻomia e faʻatinoina ma faʻamaumauina i se auala faifai pea ma saogalemu. O faʻaletonu mataʻutia e le faʻataʻitaʻiina e ala i suʻega faʻamaonia e tatau ona faʻaleleia ina ia mautinoa o loʻo tausia lelei le saʻo o le saogalemu o le SIF i lona olaga atoa.

O le tusiaina o se faiga lelei o suega fa'amaonia e mana'omia ai se auala fa'apitoa i le au'ili'iliga fa'ainisinia o fa'aletonu mata'utia e ono tula'i mai, filifilia o auala, ma tusia la'asaga o suega fa'amaonia o lo'o i totonu o le gafatia o le la'au e faia ai suega. I le aluga o le taimi, ia maua le lagolago a le la'au i tulaga uma mo le faia o suega, ma a'oa'o tagata tomai fa'apitoa e fa'atino ma fa'amaumauina le suega fa'amaonia fa'apea fo'i ma le malamalama i le taua o le suega. Tusi fa'atonuga e peisea'ī o oe o le tagata tomai fa'apitoa o meafaigaluega o le a faia le galuega, ma e fa'alagolago ola i le faia sa'o o le suega, aua latou te faia.

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

E masani ona vaevaeina se SIF i ni vaega autu se tolu, o masini fa'alogo (sensors), masini fofo fa'alogika (logic solvers) ma elemene mulimuli. E masani fo'i ona iai ni masini fesoasoani e mafai ona fa'afeso'ota'i i totonu o nei vaega ta'itasi e tolu (e pei o IS barriers, trip amps, interposing relays, solenoids, ma isi) e tatau fo'i ona fa'ata'ita'iina.

Su'ega e fa'amaonia ai le sensor: E tatau i le su'ega e fa'amaonia ai le sensor ona fa'amautinoa e mafai e le sensor ona lagona le fesuia'iga o le fa'agasologa i lona lautele atoa ma tu'uina atu le fa'ailo talafeagai i le SIS logic solver mo le iloiloga. E ui e le o aofia ai, o nisi o mea e mafaufau i ai i le fatuina o le vaega o le sensor o le fa'agasologa o le su'ega o le fa'amaoniga o lo'o tu'uina atu i le Laulau 1.

Su'ega fa'amaonia o le fofo fa'alogika: A faia le su'ega fa'amaonia atoa-galuega, o le a faia le su'ega a le fofo fa'alogika i le fa'ataunu'uina o le gaioiga saogalemu a le SIF ma gaioiga e feso'ota'i i ai (e pei o fa'ailo, toe setiina, fa'asolosolo, fa'ama'i o tagata fa'aoga, toe fa'aaogaina, HMI, ma isi mea). O su'ega fa'amaonia o galuega fa'atino e le atoatoa pe fa'asolosolo e tatau ona fa'ataunu'uina nei su'ega uma o se vaega o su'ega fa'amaonia ta'itasi e fe'avea'i. E tatau i le kamupani gaosi oloa fofo fa'alogika ona i ai se faiga fa'ata'ita'i fa'amaonia fautuaina i le tusi lesona saogalemu o le masini. A leai ma o se mea itiiti ifo, e tatau ona toe fa'ata'amilomilo le malosiaga o le fofo fa'alogika, ma e tatau ona siakiina resitala fa'amaonia o le fofo fa'alogika, moli o le tulaga, voltages o le sapalai o le eletise, so'otaga feso'ota'iga ma le toe fa'aaogaina. E tatau ona faia nei siaki a'o le'i faia le su'ega fa'amaonia atoa-galuega.

Aua le faia se manatu faapea e lelei pea le polokalama faakomepiuta e faavavau ma e le manaomia ona tofotofoina le mafuaaga pe a uma le suega muamua o faamaoniga aua o suiga ma faafouga o polokalama faakomepiuta ma masini e le'i faamaumauina, e le'i faatagaina ma e le'i tofotofoina e mafai ona sosolo atu i totonu o polokalama i le aluga o taimi ma e tatau ona aofia i lau filosofia atoa o suega faamaoniga. E tatau ona toe iloiloina le puleaina o suiga, tausiga, ma faamaumauga o toe teuteuga ina ia mautinoa o loo lata mai ma tausia lelei, ma afai e mafai, e tatau ona faatusatusa le polokalama faakomepiuta i le faaleoleo lata mai.

E tatau fo'i ona fa'aeteete i le fa'ata'ita'iina o galuega fesoasoani uma a le tagata fa'aoga e fo'ia ai fa'afitauli ma galuega fa'apitoa (e pei o leoleo, feso'ota'iga, masini fa'asaienisi i luga o le initaneti, ma isi mea fa'apena).

Su'ega fa'amaonia o elemene mulimuli: O le tele o elemene mulimuli o valves, peita'i, o masini fa'ata'amilomilo e amata ai afi, ta'avale e fesuisuia'i le saoasaoa ma isi vaega eletise e pei o feso'ota'iga ma circuit breakers e fa'aaogaina fo'i o ni elemene mulimuli ma e tatau ona iloiloina a latou faiga fa'aletonu ma fa'ata'ita'i le fa'amaoniga.

O auala autū e fa'aletonu ai valve o le pipi'i, telegese tele pe vave tele le taimi e tali atu ai, ma le tafe o le vai, o nei mea uma e a'afia i le feso'ota'iga o le fa'agaioiga o le valve i le taimi e motusia ai. E ui o le su'eina o le valve i tulaga fa'agaioiga o le tulaga sili lea ona mana'omia, ae o le fa'agaioiga e masani lava ona tete'e i le motusia o le SIF a'o fa'agaioiga le la'au. O le tele o valve SIS e masani ona su'eina a'o fa'aitiitia le la'au i le zero differential pressure, o le tulaga sili lea ona itiiti le faigata o tulaga fa'agaioiga. E tatau i le tagata fa'aoga ona nofouta i le tulaga sili ona leaga o le eseesega o le mamafa fa'agaioiga ma le fa'aleagaina o le valve ma le fa'agaioiga, lea e tatau ona mafaufau i ai i le mamanu ma le tele o le valve ma 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).

E mafai fo'i e le vevela o le si'osi'omaga ona a'afia ai avega fe'ese'esea'iga o valve, o lea o le fa'ata'ita'iina o valve i le tau mafanafana o le a avea ma avega fe'ese'esea'iga e sili ona itiiti pe a fa'atusatusa i le fa'agaioiga i le tau malulu. O le i'uga, o le fa'amaoniga o valve i se vevela tutusa e tatau ona mafaufauina e maua ai fa'amaumauga tutusa mo su'ega fa'ai'u mo le fuafuaina o le fa'aletonu o le fa'atinoga o valve.

O valves e iai ni smart positioner po'o se digital valve controller e masani ona iai le gafatia e fatu ai se valve saini e mafai ona fa'aaogaina e mata'ituina ai le fa'aletonu o le fa'atinoga o le valve. E mafai ona talosagaina se valve baseline saini o se vaega o lau fa'atonuga fa'atau pe e mafai fo'i ona e fatuina se tasi i le taimi o le su'ega fa'amaonia muamua e fai ma fa'avae. E tatau ona faia le valve saini mo le tatalaina ma le tapunia o le valve. E tatau fo'i ona fa'aaoga le fa'amaoniga fa'apitoa o le valve pe a maua. E mafai ona fesoasoani lea e ta'u atu ia te oe pe ua fa'aletonu le fa'atinoga o lau valve e ala i le fa'atusatusaina o fa'amaoniga ma fa'amaoniga o valve i lau baseline. O lenei ituaiga su'ega e mafai ona fesoasoani e fa'aleleia ai le le su'eina o le valve i le mamafa o le fa'agaioiga sili ona leaga.

O le fa'ailoga o le valve i le taimi o se suega fa'amaonia e mafai fo'i ona fa'amaumauina le taimi tali atu i fa'ailoga taimi, ma ave'ese ai le mana'omia o se uati taofi. O le fa'ateleina o le taimi tali atu o se fa'ailoga lea o le fa'aleagaina o le valve ma le fa'ateleina o le mamafa o le fe'ese'esea'i e fa'agaoioi ai le valve. E ui e leai ni tulaga fa'atonuina e uiga i suiga i le taimi tali atu o le valve, o se mamanu leaga o suiga mai le suega fa'amaonia i le suega fa'amaonia o lo'o fa'ailoa mai ai le ono leiloa o le saogalemu o le valve ma le fa'atinoga. O suega fa'amaonia o valve SIS fa'aonaponei e tatau ona aofia ai se fa'ailoga o le valve e avea o se mataupu o faiga fa'ainisinia lelei.

E tatau ona fuaina le mamafa o le sapalai o le ea i le meafaigaluega o le valve i le taimi o se suega fa'amaonia. E ui o le valve spring mo se valve e toe fo'i mai ai le spring e tapunia ai le valve, o le malosi po'o le torque e a'afia ai e fuafua i le tele o le fa'apipi'iina o le valve spring e le mamafa o le sapalai o le valve (e tusa ai ma le Tulafono a Hooke, F = kX). Afai e maualalo lau mamafa o le sapalai, o le a le tele se fa'apipi'iina o le spring, o lea o le a itiiti ai le malosi e maua e fa'agaoioi ai le valve pe a mana'omia. E ui e le o aofia ai, o nisi o mea e mafaufau i ai i le fatuina o le vaega o le valve o le faiga o suega fa'amaonia o lo'o tu'uina atu i le Laulau 2.