{"id":56812,"date":"2026-09-11T08:27:53","date_gmt":"2026-09-11T08:27:53","guid":{"rendered":"https:\/\/zobai.com\/?p=56812"},"modified":"2026-09-11T10:14:57","modified_gmt":"2026-09-11T10:14:57","slug":"pilot-operated-safety-valve-for-lng-service-low-temperature-and-pilot-circuit-risks","status":"publish","type":"post","link":"https:\/\/zobai.com\/es\/blog\/pilot-operated-safety-valve-for-lng-service-low-temperature-and-pilot-circuit-risks\/","title":{"rendered":"Pilot Operated Safety Valve for LNG Service: Low Temperature and Pilot Circuit Risks"},"content":{"rendered":"<style> .zobai-posv-lng-article { width: 100%; max-width: 100%; overflow-wrap: anywhere; } .zobai-posv-lng-article .zobai-table-scroll { width: 100%; max-width: 100%; overflow-x: auto; -webkit-overflow-scrolling: touch; margin: 1.25rem 0; } .zobai-posv-lng-article .zobai-table-scroll table { width: 100%; min-width: 640px; border-collapse: collapse; } .zobai-posv-lng-article .zobai-table-scroll th, .zobai-posv-lng-article .zobai-table-scroll td { padding: 0.75rem; vertical-align: top; text-align: left; } .zobai-posv-lng-article blockquote { margin: 1.25rem 0; padding-left: 1rem; } @media (max-width: 390px) { .zobai-posv-lng-article .zobai-table-scroll table { min-width: 600px; } .zobai-posv-lng-article h2, .zobai-posv-lng-article h3, .zobai-posv-lng-article p, .zobai-posv-lng-article li { overflow-wrap: anywhere; } } <\/style>\n<article class=\"zobai-posv-lng-article\">\n<p> A <strong>pilot-operated safety valve for LNG service<\/strong> can be a valid candidate, but the main valve&#8217;s low-temperature rating alone does not establish suitability. The complete pilot-operated system has to be reviewed: the main valve, pilot, pressure-sensing path, tubing, seals and other soft goods, pilot vent arrangement, and the conditions under which the pilot receives its pressure signal. <\/p>\n<p> The pilot circuit is part of the valve&#8217;s pressure-control function. A main valve may appear suitable for cryogenic service while an unresolved pilot component, sensing path or seal limitation still prevents a defensible selection. <\/p>\n<p>The practical question is not simply, \u201cIs this a cryogenic pilot-operated valve?\u201d It is:<\/p>\n<blockquote>\n<p> <strong> Has the complete configured pilot-operated safety valve been shown suitable for the defined LNG relief duty, temperature exposure, fluid state, sensing arrangement and downstream conditions? <\/strong> <\/p>\n<\/blockquote>\n<p> This guide uses that question to screen a candidate before model-specific engineering or RFQ review. <\/p>\n<section>\n<h2>Can a Pilot-Operated Safety Valve Be Used for LNG Service?<\/h2>\n<p>\n  Yes\u2014as a <strong>candidate architecture for defined LNG duties, subject to<br \/>\n  project-specific verification<\/strong>.\n<\/p>\n<p>\n  Pilot-operated safety valves are used in defined LNG applications.<br \/>\n  <a href=\"https:\/\/www.iso.org\/standard\/61632.html\" target=\"_blank\" rel=\"noopener noreferrer\"><br \/>\n    ISO 18154<br \/>\n  <\/a>,<br \/>\n  for example, specifically addresses diaphragm-type pilot-operated safety valves for<br \/>\n  LNG-carrier cargo tanks. That confirms the architecture can be appropriate within a<br \/>\n  defined LNG application while also showing why scope matters: the standard does not<br \/>\n  apply automatically to every LNG terminal, liquefaction train, transfer line or other<br \/>\n  installation.\n<\/p>\n<p>\n  A<br \/>\n  <a href=\"https:\/\/www.leser.com\/en\/products\/high-efficiency-posv\/\" target=\"_blank\" rel=\"noopener noreferrer\"><br \/>\n    documented LNG cryogenic POSV application from LESER<br \/>\n  <\/a><br \/>\n  likewise shows that pilot-operated relief valves can be engineered for cryogenic duty.<br \/>\n  That evidence establishes application feasibility, not universal suitability for every<br \/>\n  pilot-operated valve or every LNG service.\n<\/p>\n<p>\n  For broader LNG pressure-relief scenarios beyond this article&#8217;s narrow pilot-circuit scope,<br \/>\n  see the<br \/>\n  <a href=\"https:\/\/zobai.com\/es\/applications\/lng\/\">LNG safety valve application guide<\/a>.\n<\/p>\n<p>\n  Keep three states separate:\n<\/p>\n<p>\n  <strong>Architecture is used in LNG service<\/strong><br \/>\n  does not mean<br \/>\n  <strong>this product family is suitable for LNG<\/strong><br \/>\n  and neither automatically means<br \/>\n  <strong>this exact configuration is suitable for this relief duty.<\/strong>\n<\/p>\n<p>\n  Before the candidate moves forward, the relief duty, relieving state, temperatures,<br \/>\n  back pressure, materials, pilot arrangement and applicable project evidence still need<br \/>\n  to be defined.\n<\/p>\n<p>\n  La palabra <strong>candidate<\/strong> is deliberate. At this stage it means the<br \/>\n  architecture deserves further technical review; it does not mean the valve has been<br \/>\n  finally sized, certified or approved for the project.\n<\/p>\n<p>\n  Readers who need the broader product-family context can review<br \/>\n  <a href=\"https:\/\/zobai.com\/es\/safety-valves\/pilot-operated-safety-valves\/\"><br \/>\n    v\u00e1lvulas de seguridad pilotadas<br \/>\n  <\/a><br \/>\n  separately from this LNG-specific screening guide.\n<\/p>\n<\/section>\n<section>\n<h2>Why Main-Valve Low-Temperature Capability Is Not Enough<\/h2>\n<p>\n  A pilot-operated safety valve is not one temperature-rated object. It is a system of<br \/>\n  components that can have different materials, seals, exposure conditions and allowable limits.\n<\/p>\n<p>\n  The main relieving assembly may include the pressure-retaining body, nozzle, disc or piston<br \/>\n  and main-valve sealing components. The control side adds the pilot valve, sensing path,<br \/>\n  tubing, pilot seals, filters or restrictions where used, and the dome\/control-pressure circuit.\n<\/p>\n<p>\n  <a href=\"https:\/\/dam.bakerhughes.com\/m\/a3504148807a8e1\/original\/Consolidated-3900-3900-TM-POSRV-Tech-Spec-English.pdf\" target=\"_blank\" rel=\"noopener noreferrer\"><br \/>\n    Baker Hughes Consolidated 3900 technical data<br \/>\n  <\/a><br \/>\n  illustrate why this distinction matters. The documentation separates pilot\/modulator<br \/>\n  soft-goods limits from main-valve soft-goods limits and notes that media conditioning<br \/>\n  may be needed when applicable limits are exceeded; such arrangements remain<br \/>\n  application-specific.\n<\/p>\n<p>\n  A cryogenic LNG application can go further by deliberately controlling what the pilot<br \/>\n  experiences. The<br \/>\n  <a href=\"https:\/\/www.leser.com\/en\/products\/high-efficiency-posv\/\" target=\"_blank\" rel=\"noopener noreferrer\"><br \/>\n    LESER LNG cryogenic POSV example<br \/>\n  <\/a><br \/>\n  shows that purpose-built cryogenic configurations may manage the pilot environment rather<br \/>\n  than relying on a generic main-valve temperature rating alone.\n<\/p>\n<div class=\"zobai-table-scroll\"\n     role=\"region\"\n     aria-label=\"Pilot-operated safety valve component verification table\"\n     tabindex=\"0\"><\/p>\n<table>\n<thead>\n<tr>\n<th scope=\"col\">Part of the configured system<\/th>\n<th scope=\"col\">Qu\u00e9 debe verificarse<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Main relieving assembly<\/td>\n<td>Materials and allowable limits for the exact configuration<\/td>\n<\/tr>\n<tr>\n<td>Pilot<\/td>\n<td>Pilot type, internal materials, seals and applicable limits<\/td>\n<\/tr>\n<tr>\n<td>Pressure-sensing path<\/td>\n<td>What pressure and fluid condition actually reach the pilot<\/td>\n<\/tr>\n<tr>\n<td>Pilot tubing and fittings<\/td>\n<td>Material, routing and expected exposure<\/td>\n<\/tr>\n<tr>\n<td>Seals and other soft goods<\/td>\n<td>Component-specific temperature and compatibility evidence<\/td>\n<\/tr>\n<tr>\n<td>Filters or restrictions, if used<\/td>\n<td>Service suitability and effect on the sensing\/control path<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<blockquote>\n<p>\n    <strong><br \/>\n      Do not use one temperature number as evidence for the whole pilot-operated valve<br \/>\n      unless the supplier documentation actually supports that scope.<br \/>\n    <\/strong>\n  <\/p>\n<\/blockquote>\n<p>\n  The same caution applies to product-family tables. The most extreme low-temperature<br \/>\n  value visible anywhere in a catalog should not be assigned to every pilot, seal,<br \/>\n  material combination or valve configuration.\n<\/p>\n<figure class=\"wp-block-image size-full zobai-figure\" data-image-slot=\"IMG-01\"><img loading=\"lazy\" src=\"https:\/\/zobai.com\/wp-content\/uploads\/2026\/09\/pilot-operated-safety-valve-lng-img-01.webp\" alt=\"Conceptual LNG pilot-operated safety valve verification map showing main valve, pilot, sensing path, tubing and sealing components.\" title=\"Pilot Operated Safety Valve for LNG Service: Low Temperature and Pilot Circuit Risks - IMG-01\" width=\"1200\" height=\"900\" class=\"wp-image-56877\" decoding=\"async\" srcset=\"https:\/\/zobai.com\/wp-content\/uploads\/2026\/09\/pilot-operated-safety-valve-lng-img-01.webp 1200w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/09\/pilot-operated-safety-valve-lng-img-01-300x225.webp 300w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/09\/pilot-operated-safety-valve-lng-img-01-1024x768.webp 1024w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/09\/pilot-operated-safety-valve-lng-img-01-768x576.webp 768w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/09\/pilot-operated-safety-valve-lng-img-01-16x12.webp 16w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/09\/pilot-operated-safety-valve-lng-img-01-400x300.webp 400w\" sizes=\"auto, (max-width: 1200px) 100vw, 1200px\" \/><figcaption>Conceptual LNG pilot-operated safety valve verification map showing main valve, pilot, sensing path, tubing and sealing components.<\/figcaption><\/figure>\n<\/section>\n<section>\n<h2>How Low Temperature Can Threaten Pilot Pressure-Signal Integrity<\/h2>\n<p>\n  Low temperature becomes a pilot-circuit issue when it interferes with the pressure signal<br \/>\n  the pilot needs to perform its control function.\n<\/p>\n<p>At a simplified level, the functional chain is:<\/p>\n<p>\n  <strong><br \/>\n    protected system pressure \u2192 pressure pickup \u2192 sensing path \u2192 pilot \u2192<br \/>\n    dome\/control pressure \u2192 main-valve response<br \/>\n  <\/strong>\n<\/p>\n<p>\n  That small sensing path can therefore be decision-critical even though it carries far less<br \/>\n  flow than the main relief path.\n<\/p>\n<p>\n  <a href=\"https:\/\/dam.bakerhughes.com\/m\/6b2933aeddb3989a\/original\/Consolidated-2900-Gen-II-POSRV-Manual-English.pdf\" target=\"_blank\" rel=\"noopener noreferrer\"><br \/>\n    Baker Hughes Consolidated POSRV operating instructions<br \/>\n  <\/a><br \/>\n  document the risk directly: if a pilot sensing line becomes clogged or frozen, system<br \/>\n  pressure can be isolated from the pilot so that the pilot cannot correctly detect the<br \/>\n  protected-system pressure and perform the intended relief response.\n<\/p>\n<p>\n  Readers who need the complete generic operating sequence can review<br \/>\n  <a href=\"https:\/\/zobai.com\/es\/blog\/how-does-a-pilot-operated-safety-valve-work\/\"><br \/>\n    c\u00f3mo funciona una v\u00e1lvula de seguridad pilotada<br \/>\n  <\/a>;<br \/>\n  this article only uses the operating principle needed to explain LNG risk.\n<\/p>\n<figure class=\"wp-block-image size-full zobai-figure\" data-image-slot=\"IMG-02\"><img loading=\"lazy\" src=\"https:\/\/zobai.com\/wp-content\/uploads\/2026\/09\/pilot-operated-safety-valve-lng-img-02.webp\" alt=\"Pressure-signal path from protected LNG equipment through the sensing line and pilot to the main valve, highlighting a possible sensing-path restriction.\" title=\"Pilot Operated Safety Valve for LNG Service: Low Temperature and Pilot Circuit Risks - IMG-02\" width=\"1200\" height=\"900\" class=\"wp-image-56878\" decoding=\"async\" srcset=\"https:\/\/zobai.com\/wp-content\/uploads\/2026\/09\/pilot-operated-safety-valve-lng-img-02.webp 1200w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/09\/pilot-operated-safety-valve-lng-img-02-300x225.webp 300w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/09\/pilot-operated-safety-valve-lng-img-02-1024x768.webp 1024w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/09\/pilot-operated-safety-valve-lng-img-02-768x576.webp 768w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/09\/pilot-operated-safety-valve-lng-img-02-16x12.webp 16w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/09\/pilot-operated-safety-valve-lng-img-02-400x300.webp 400w\" sizes=\"auto, (max-width: 1200px) 100vw, 1200px\" \/><figcaption>Pressure-signal path from protected LNG equipment through the sensing line and pilot to the main valve, highlighting a possible sensing-path restriction.<\/figcaption><\/figure>\n<h3>Do not merge different mechanisms into one risk<\/h3>\n<p><strong>Blockage<\/strong> describes a restricted or closed pressure path.<\/p>\n<p><strong>Congelaci\u00f3n<\/strong> can be one cause of blockage under applicable conditions.<\/p>\n<p>\n  Other deposits or contamination can produce restriction through different mechanisms.\n<\/p>\n<p>\n  Manufacturer guidance also discusses hydrate formation in some hydrocarbon applications,<br \/>\n  but that does not justify describing hydrates as a routine LNG pilot-circuit failure.<br \/>\n  Likewise, steam-condensate freezing examples are useful for the underlying freeze mechanism<br \/>\n  but should not be presented as LNG-specific events.\n<\/p>\n<p>\n  Current evidence also does not support a universal statement that flashing or two-phase<br \/>\n  flow in every LNG sensing line will cause a particular pilot failure.\n<\/p>\n<blockquote>\n<p>\n    <strong><br \/>\n      The pressure condition presented to the pilot must remain representative of the<br \/>\n      protected system under the defined operating and relieving conditions.<br \/>\n    <\/strong>\n  <\/p>\n<\/blockquote>\n<p>\n  If the proposed design depends on a sensing path whose local temperature, fluid state or<br \/>\n  blockage risk is unresolved, that uncertainty should stay visible in the selection review.\n<\/p>\n<\/section>\n<section>\n<h2>What Must Be Checked in the Pilot and Sensing Circuit?<\/h2>\n<p>\n  Once the pilot path is treated as part of the pressure-protection function, the review<br \/>\n  can move from generic \u201ccryogenic suitability\u201d to specific verification questions.\n<\/p>\n<div class=\"zobai-table-scroll\"\n     role=\"region\"\n     aria-label=\"Pilot and sensing circuit verification matrix\"\n     tabindex=\"0\"><\/p>\n<table>\n<thead>\n<tr>\n<th scope=\"col\">Verify<\/th>\n<th scope=\"col\">Por qu\u00e9 cambia la decisi\u00f3n<\/th>\n<th scope=\"col\">Evidencia a obtener<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Pressure pickup location<\/td>\n<td>Determines which system pressure the pilot actually senses<\/td>\n<td>P&amp;ID, connection point or supplier arrangement<\/td>\n<\/tr>\n<tr>\n<td>Detecci\u00f3n integral o remota<\/td>\n<td>Changes the physical pressure-sensing path<\/td>\n<td>Exact valve configuration<\/td>\n<\/tr>\n<tr>\n<td>Remote sensing-line route, where used<\/td>\n<td>Adds tubing length, elevation and routing variables<\/td>\n<td>Routing\/configuration data<\/td>\n<\/tr>\n<tr>\n<td>Pilot supply filter, where used<\/td>\n<td>Becomes part of the sensing\/control path<\/td>\n<td>Filter configuration and service basis<\/td>\n<\/tr>\n<tr>\n<td>Pilot vent destination<\/td>\n<td>Can interact with downstream\/back-pressure conditions<\/td>\n<td>Vent arrangement<\/td>\n<\/tr>\n<tr>\n<td>Backflow-prevention arrangement, where applicable<\/td>\n<td>May matter under particular pressure relationships<\/td>\n<td>Supplier application review<\/td>\n<\/tr>\n<tr>\n<td>Pilot materials and internals<\/td>\n<td>Can have different service limits from the main valve<\/td>\n<td>Material\/configuration documents<\/td>\n<\/tr>\n<tr>\n<td>Pilot and main-valve seals<\/td>\n<td>Soft-good limits may differ<\/td>\n<td>Material and allowable-condition evidence<\/td>\n<\/tr>\n<tr>\n<td>Tubos y accesorios<\/td>\n<td>The complete control circuit must remain suitable<\/td>\n<td>Material\/configuration evidence<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<h3>Remote sensing is an engineered arrangement, not an automatic upgrade<\/h3>\n<p>\n  Remote pressure sensing is a legitimate configuration, but it should not be recommended<br \/>\n  simply because the application is LNG.\n<\/p>\n<p>\n  <a href=\"https:\/\/dam.bakerhughes.com\/m\/a3504148807a8e1\/original\/Consolidated-3900-3900-TM-POSRV-Tech-Spec-English.pdf\" target=\"_blank\" rel=\"noopener noreferrer\"><br \/>\n    Original POSV technical documentation<br \/>\n  <\/a><br \/>\n  treats remote sensing as a defined system-pressure connection rather than a generic<br \/>\n  feature. The useful project question is therefore:\n<\/p>\n<blockquote>\n<p>\n    <strong><br \/>\n      Where must the pilot sense representative protected-system pressure, and what physical<br \/>\n      path connects that point to the pilot?<br \/>\n    <\/strong>\n  <\/p>\n<\/blockquote>\n<p>The answer depends on the installation.<\/p>\n<h3>Filters solve a defined problem, not \u201cLNG service\u201d in general<\/h3>\n<p>\n  Pilot supply filters appear as options in documented POSV configurations. They can be<br \/>\n  relevant when particulate contamination is a concern, but a filter should not become a<br \/>\n  mandatory LNG checkbox.\n<\/p>\n<p>\n  If a filter is proposed, verify what condition it addresses and how it fits into the<br \/>\n  selected sensing\/control arrangement.\n<\/p>\n<h3>Review pilot venting together with back pressure<\/h3>\n<p>\n  Pilot venting and outlet pressure belong in the same configuration review. Manufacturer<br \/>\n  technical data show that back-pressure behavior can vary with pilot design and vent<br \/>\n  arrangement; the numerical limits are product-specific.\n<\/p>\n<blockquote>\n<p>\n    <strong><br \/>\n      The selected pilot vent arrangement has to be checked against the actual downstream-<br \/>\n      pressure conditions.<br \/>\n    <\/strong>\n  <\/p>\n<\/blockquote>\n<h3>Backflow prevention is conditional<\/h3>\n<p>\n  Backflow-preventer arrangements are documented as optional configurations rather than<br \/>\n  universal equipment.\n<\/p>\n<p>\n  The engineering question is whether the actual system pressure relationships make a<br \/>\n  backflow-prevention arrangement necessary for the selected pilot configuration.\n<\/p>\n<p>\n  The same logic applies to the rest of the circuit: configuration names should trigger<br \/>\n  engineering verification, not automatic purchasing decisions.\n<\/p>\n<\/section>\n<section>\n<h2>What Do Standards Prove\u2014and What Do They Not Prove?<\/h2>\n<p>\n  Standards are essential evidence, but different standards answer different questions.\n<\/p>\n<blockquote>\n<p>\n    <strong><br \/>\n      standard relevance \u2260 certification or conformity evidence \u2260 application suitability<br \/>\n      \u2260 project acceptance<br \/>\n    <\/strong>\n  <\/p>\n<\/blockquote>\n<p>\n  <a href=\"https:\/\/www.iso.org\/standard\/50827.html\" target=\"_blank\" rel=\"noopener noreferrer\"><br \/>\n    ISO 4126-4<br \/>\n  <\/a><br \/>\n  is a useful example. ISO describes it as a general product standard for pilot-operated<br \/>\n  safety valves and explicitly states that it is not an application standard. ISO also<br \/>\n  states that the standard itself places no temperature limitation. Those statements have<br \/>\n  to be interpreted together.\n<\/p>\n<p>Therefore this reasoning is not valid:<\/p>\n<blockquote>\n<p>\n    \u201cISO 4126-4 places no temperature limitation, so a valve associated with ISO 4126-4 is<br \/>\n    automatically suitable for LNG temperature.\u201d\n  <\/p>\n<\/blockquote>\n<p>\n  The standard&#8217;s scope does not make that service-specific decision.\n<\/p>\n<h3>LNG-specific standards can be much narrower<\/h3>\n<p>\n  <a href=\"https:\/\/www.iso.org\/standard\/61632.html\" target=\"_blank\" rel=\"noopener noreferrer\"><br \/>\n    ISO 18154<br \/>\n  <\/a><br \/>\n  is application-specific, but narrowly so: it covers diaphragm-type pilot-operated safety<br \/>\n  valves used on LNG-carrier cargo tanks. It is useful evidence for that defined application,<br \/>\n  not a blanket rule for every LNG facility or pilot architecture.\n<\/p>\n<h3>Where API 520 fits<\/h3>\n<p>\n  <a href=\"https:\/\/www.api.org\/products-and-services\/standards\/standards-plan\" target=\"_blank\" rel=\"noopener noreferrer\"><br \/>\n    API 520<br \/>\n  <\/a><br \/>\n  provides recognized sizing, selection and installation context within its applicable scope.<br \/>\n  That makes it relevant to the engineering basis, but citing API 520 is still different from<br \/>\n  demonstrating LNG-specific product certification or project acceptance.\n<\/p>\n<p>\n  For a deeper standards overview without expanding this article beyond its scope, see the<br \/>\n  <a href=\"https:\/\/zobai.com\/es\/blog\/safety-valve-standards-guide\/\"><br \/>\n    Gu\u00eda de normas para v\u00e1lvulas de seguridad<br \/>\n  <\/a>.\n<\/p>\n<p>For supplier evaluation, separate four questions:<\/p>\n<ol>\n<li>Which technical standards are relevant to the pressure-relief design or product?<\/li>\n<li>What conformity or certification evidence exists for the exact proposed configuration?<\/li>\n<li>Does that configuration satisfy the defined LNG duty?<\/li>\n<li>Does the project or applicable jurisdiction accept the resulting evidence package?<\/li>\n<\/ol>\n<p>\n  A long standards list does not substitute for those answers.\n<\/p>\n<\/section>\n<section>\n<h2>When Should an LNG POSV Candidate Proceed, Be Held, or Be Rejected?<\/h2>\n<p>\n  The following <strong>PROCEED \/ HOLD \/ REJECT<\/strong> logic is an engineering screening<br \/>\n  framework used in this article. It is not an ISO, API, ASME or regulatory classification.\n<\/p>\n<h3>PROCEDER<\/h3>\n<p>\n  Usar <strong>PROCEDER<\/strong> when there is enough defined information to continue into<br \/>\n  detailed model-specific engineering or supplier review.\n<\/p>\n<p>Typical decision inputs include:<\/p>\n<ul>\n<li>relief duty and required capacity;<\/li>\n<li>fluid and relieving state;<\/li>\n<li>temperatura de operaci\u00f3n y alivio;<\/li>\n<li>expected back pressure;<\/li>\n<li>pilot type and configuration;<\/li>\n<li>disposici\u00f3n de sensado;<\/li>\n<li>main-valve and pilot materials;<\/li>\n<li>seals and other soft goods;<\/li>\n<li>pilot vent arrangement where relevant;<\/li>\n<li>applicable standards and required project evidence.<\/li>\n<\/ul>\n<p>\n  <strong>PROCEED does not mean approved.<\/strong> It means the candidate is sufficiently<br \/>\n  defined to continue a technically meaningful review.\n<\/p>\n<h3>EN ESPERA<\/h3>\n<p>\n  Usar <strong>EN ESPERA<\/strong> when a missing fact could materially change suitability.\n<\/p>\n<ul>\n<li>actual pilot temperature exposure is unknown;<\/li>\n<li>pilot or main-valve soft-good limits are unresolved;<\/li>\n<li>the pressure pickup or sensing arrangement is undefined;<\/li>\n<li>a proposed remote sensing path has not been defined;<\/li>\n<li>pilot venting and back-pressure interaction remain unresolved;<\/li>\n<li>a product-family temperature range cannot be tied to the exact proposed configuration;<\/li>\n<li>required conformity or certification evidence has not been supplied.<\/li>\n<\/ul>\n<blockquote>\n<p><strong>Unknown is not the same as unsuitable.<\/strong><\/p>\n<\/blockquote>\n<h3>RECHAZAR<\/h3>\n<p>\n  Usar <strong>RECHAZAR<\/strong> only when a known mismatch has been established.\n<\/p>\n<p>\n  Examples include a component expected to operate outside its documented limit,<br \/>\n  a configuration that cannot satisfy a required project condition, or a candidate<br \/>\n  that fails the required relieving-duty verification.\n<\/p>\n<div class=\"zobai-table-scroll\"\n     role=\"region\"\n     aria-label=\"LNG POSV candidate screening status\"\n     tabindex=\"0\"><\/p>\n<table>\n<thead>\n<tr>\n<th scope=\"col\">Estado de cribado<\/th>\n<th scope=\"col\">Significado<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><strong>PROCEDER<\/strong><\/td>\n<td>Enough evidence exists to continue detailed engineering\/model review<\/td>\n<\/tr>\n<tr>\n<td><strong>EN ESPERA<\/strong><\/td>\n<td>A decision-critical fact or evidence item remains unresolved<\/td>\n<\/tr>\n<tr>\n<td><strong>RECHAZAR<\/strong><\/td>\n<td>A known mismatch with the defined service has been established<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p>\n  This framework helps organize the engineering review without pretending to replace formal<br \/>\n  sizing, certification, purchaser acceptance or responsible-engineer approval.\n<\/p>\n<\/section>\n<section>\n<h2>What Should an LNG Pilot-Operated Valve RFQ Include?<\/h2>\n<p>\n  An LNG POSV RFQ should define the <strong>relief duty, process state and pilot-system<br \/>\n  conditions<\/strong>, not only valve size, medium and set pressure.\n<\/p>\n<p>\n  Original manufacturer ordering data support this approach: meaningful POSV selection<br \/>\n  normally requires service inputs such as fluid state, required capacity, operating and<br \/>\n  relieving temperatures, set pressure, back pressure and pilot\/sensing configuration.\n<\/p>\n<h3>Information the buyer should provide<\/h3>\n<p><strong>Servicio de alivio<\/strong><\/p>\n<ul>\n<li>protected equipment or service;<\/li>\n<li>credible relief case;<\/li>\n<li>capacidad de alivio requerida;<\/li>\n<li>base de presi\u00f3n de tarado;<\/li>\n<li>applicable project overpressure basis where defined.<\/li>\n<\/ul>\n<p><strong>Condiciones de proceso<\/strong><\/p>\n<ul>\n<li>LNG composition or defined fluid basis;<\/li>\n<li>presi\u00f3n de operaci\u00f3n;<\/li>\n<li>temperatura de operaci\u00f3n;<\/li>\n<li>temperatura de alivio;<\/li>\n<li>expected relieving fluid state.<\/li>\n<\/ul>\n<p><strong>Sistema instalado<\/strong><\/p>\n<ul>\n<li>contrapresi\u00f3n acumulada;<\/li>\n<li>contrapresi\u00f3n superpuesta;<\/li>\n<li>relevant discharge-system conditions.<\/li>\n<\/ul>\n<p><strong>Pilot and sensing basis<\/strong><\/p>\n<ul>\n<li>proposed pressure pickup location;<\/li>\n<li>integral or remote sensing requirement, if already defined;<\/li>\n<li>known sensing-path configuration;<\/li>\n<li>project constraints affecting routing or temperature exposure.<\/li>\n<\/ul>\n<p><strong>Project evidence<\/strong><\/p>\n<ul>\n<li>applicable design standard;<\/li>\n<li>especificaci\u00f3n del comprador;<\/li>\n<li>required conformity, certification or test documentation.<\/li>\n<\/ul>\n<h3>Evidence the supplier should return<\/h3>\n<p>\n  The supplier should identify the exact candidate configuration rather than respond only<br \/>\n  at product-family level.\n<\/p>\n<ul>\n<li>exact model and configuration;<\/li>\n<li>pilot type or operating action;<\/li>\n<li>main-valve materials;<\/li>\n<li>pilot materials and internals;<\/li>\n<li>seat and seal materials;<\/li>\n<li>tubing and fitting configuration;<\/li>\n<li>disposici\u00f3n de sensado de presi\u00f3n;<\/li>\n<li>pilot vent arrangement;<\/li>\n<li>filter or backflow configuration where used;<\/li>\n<li>applicable temperature limits for the relevant components\/configuration;<\/li>\n<li>sizing or capacity evidence for the defined duty;<\/li>\n<li>project-required test, conformity or certification documentation.<\/li>\n<\/ul>\n<blockquote>\n<p>\n    <strong><br \/>\n      Buyer inputs define the problem. Supplier evidence shows whether the proposed<br \/>\n      configuration can solve that problem.<br \/>\n    <\/strong>\n  <\/p>\n<\/blockquote>\n<p>\n  \u201cService: LNG\u201d is not enough information to complete either side of that exchange.<br \/>\n  Likewise, the word <strong>criog\u00e9nico<\/strong> is not a substitute for defining which<br \/>\n  configuration, which pilot, which soft goods and which actual temperatures the supplier<br \/>\n  is confirming.\n<\/p>\n<p>\n  Readers who need the broader valve-selection workflow can continue with the<br \/>\n  <a href=\"https:\/\/zobai.com\/es\/blog\/safety-valve-selection-guide\/\"><br \/>\n    Gu\u00eda de selecci\u00f3n de v\u00e1lvulas de seguridad<br \/>\n  <\/a>.\n<\/p>\n<p>\n  Preparing an LNG POSV inquiry?<br \/>\n  <a href=\"https:\/\/zobai.com\/es\/contacts\/\"><br \/>\n    Send the defined relief duty, operating and relieving conditions, expected back pressure,<br \/>\n    fluid state and pilot\/sensing requirements to ZOBAI<br \/>\n  <\/a><br \/>\n  for supplier review and RFQ preparation against the actual service conditions.\n<\/p>\n<\/section>\n<\/article>\n<p> <script type=\"application\/ld+json\">{\n    \"@context\": \"https:\\\/\\\/schema.org\",\n    \"@type\": \"BlogPosting\",\n    \"headline\": \"Pilot Operated Safety Valve for LNG Service: Low Temperature and Pilot Circuit Risks\",\n    \"description\": \"Screen a pilot-operated safety valve for LNG service by checking low-temperature exposure, sensing lines, pilot seals, back pressure, standards and RFQ evidence.\",\n    \"mainEntityOfPage\": {\n        \"@type\": \"WebPage\",\n        \"@id\": \"https:\\\/\\\/zobai.com\\\/blog\\\/pilot-operated-safety-valve-for-lng-service-low-temperature-and-pilot-circuit-risks\\\/\"\n    },\n    \"publisher\": {\n        \"@type\": \"Organization\",\n        \"name\": \"ZOBAI\",\n        \"url\": \"https:\\\/\\\/zobai.com\\\/\"\n    }\n}<\/script><\/p>","protected":false},"excerpt":{"rendered":"<p>Seleccione una v\u00e1lvula de seguridad pilotada para servicio de LNG verificando la exposici\u00f3n a baja temperatura, las l\u00edneas de detecci\u00f3n, los sellos del piloto, la contrapresi\u00f3n, las normas y la evidencia de la solicitud de cotizaci\u00f3n.<\/p>","protected":false},"author":2,"featured_media":56877,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[77],"tags":[],"class_list":["post-56812","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-applications-industry-guides"],"_links":{"self":[{"href":"https:\/\/zobai.com\/es\/wp-json\/wp\/v2\/posts\/56812","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/zobai.com\/es\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/zobai.com\/es\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/zobai.com\/es\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/zobai.com\/es\/wp-json\/wp\/v2\/comments?post=56812"}],"version-history":[{"count":2,"href":"https:\/\/zobai.com\/es\/wp-json\/wp\/v2\/posts\/56812\/revisions"}],"predecessor-version":[{"id":56900,"href":"https:\/\/zobai.com\/es\/wp-json\/wp\/v2\/posts\/56812\/revisions\/56900"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/zobai.com\/es\/wp-json\/wp\/v2\/media\/56877"}],"wp:attachment":[{"href":"https:\/\/zobai.com\/es\/wp-json\/wp\/v2\/media?parent=56812"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/zobai.com\/es\/wp-json\/wp\/v2\/categories?post=56812"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/zobai.com\/es\/wp-json\/wp\/v2\/tags?post=56812"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}