{"id":56671,"date":"2026-08-30T10:28:52","date_gmt":"2026-08-30T10:28:52","guid":{"rendered":"https:\/\/zobai.com\/?p=56671"},"modified":"2026-09-01T04:23:44","modified_gmt":"2026-09-01T04:23:44","slug":"ammonia-refrigeration-safety-valve-selection","status":"publish","type":"post","link":"https:\/\/zobai.com\/zh\/blog\/ammonia-refrigeration-safety-valve-selection\/","title":{"rendered":"Ammonia Refrigeration Safety Valve Selection"},"content":{"rendered":"<style>\n  .ammonia-safety-valve-article {\n    max-width: 100%;\n  }<\/p>\n<p>  .ammonia-safety-valve-article .asv-table-scroll {\n    width: 100%;\n    max-width: 100%;\n    overflow-x: auto;\n    -webkit-overflow-scrolling: touch;\n    margin: 1.25rem 0;\n  }<\/p>\n<p>  .ammonia-safety-valve-article .asv-table-scroll:focus {\n    outline: 2px solid currentColor;\n    outline-offset: 2px;\n  }<\/p>\n<p>  .ammonia-safety-valve-article .asv-table-scroll table {\n    width: 100%;\n    min-width: 640px;\n    border-collapse: collapse;\n  }<\/p>\n<p>  .ammonia-safety-valve-article th,\n  .ammonia-safety-valve-article td {\n    padding: 0.75rem;\n    text-align: left;\n    vertical-align: top;\n  }<\/p>\n<p>  .ammonia-safety-valve-article th {\n    font-weight: 600;\n  }<\/p>\n<p>  .ammonia-safety-valve-article aside {\n    margin: 1.25rem 0;\n    padding: 1rem;\n  }<\/p>\n<p>  .ammonia-safety-valve-article ul,\n  .ammonia-safety-valve-article ol {\n    padding-left: 1.4rem;\n  }<\/p>\n<p>  .ammonia-safety-valve-article h2,\n  .ammonia-safety-valve-article h3,\n  .ammonia-safety-valve-article p,\n  .ammonia-safety-valve-article li,\n  .ammonia-safety-valve-article td,\n  .ammonia-safety-valve-article th {\n    overflow-wrap: anywhere;\n  }\n<\/style>\n<article class=\"ammonia-safety-valve-article\">\n<p>\n    <strong>Ammonia refrigeration safety valve selection should start only after the relief duty is defined.<\/strong><br \/>\n    A candidate is not ready for engineering review simply because the refrigerant, connection, or intended pressure setting is known. The protected boundary, required relieving duty, ammonia relieving state, component-level compatibility, discharge conditions, and supplier evidence all need to align.\n  <\/p>\n<p>\n    In this article, \u201csafety valve candidate\u201d is practical search-language shorthand for a reclosing pressure-relief device being evaluated for a defined ammonia refrigeration duty. The exact device classification and final acceptance remain subject to the applicable project engineering basis. This page does not size the valve, establish the relief case, or design the refrigeration system. Its task is narrower: determine whether a candidate has enough relevant evidence to continue to engineering or RFQ review.\n  <\/p>\n<p>\n    For this article\u2019s candidate-screening engineering framework, the review ends in one of three controlled states:<br \/>\n    <strong>PROCEED<\/strong> when the candidate is ready for further engineering review,<br \/>\n    <strong>HOLD<\/strong> when decision-critical information is missing, or<br \/>\n    <strong>REJECT<\/strong> when a known mismatch has been identified.<br \/>\n    These are review states used in this article, not regulatory classifications. PROCEED does not mean final installation or project approval.\n  <\/p>\n<section>\n<h2>Is the Relief Duty Ready for Safety Valve Selection?<\/h2>\n<p>\n      <strong>Do not compare valve candidates until the pressure-protection duty is defined well enough to evaluate them.<\/strong><br \/>\n      The first question is therefore not which valve to buy, but whether the project has supplied the engineering inputs that make candidate selection meaningful.\n    <\/p>\n<p>\n      Ammonia refrigeration systems can contain different protected boundaries and different relief situations. Pressure-vessel protection, compressor protection, and protection of an isolated section containing trapped liquid are not interchangeable duties. A product search cannot safely close gaps that still belong to relief-duty definition.\n    <\/p>\n<p>\n      Before candidate review starts, the project basis should identify what is being protected, what relief condition governs the evaluation, and what relieving performance the device is expected to provide. That requirement must come from the system or equipment design basis rather than being inferred from nominal connection size or from an existing valve.\n    <\/p>\n<h3>Use a readiness gate before comparing candidates<\/h3>\n<div class=\"asv-table-scroll\" role=\"region\" aria-label=\"Relief-duty readiness gate\" tabindex=\"0\">\n<table>\n<thead>\n<tr>\n<th>Selection input<\/th>\n<th>Ready to review when<\/th>\n<th>If unresolved<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Protected boundary<\/td>\n<td>The equipment, vessel, line section, or other pressure boundary is identified.<\/td>\n<td>HOLD: the candidate has no defined protection target.<\/td>\n<\/tr>\n<tr>\n<td>Relief duty<\/td>\n<td>The governing duty has been established by the responsible project or system basis.<\/td>\n<td>HOLD: product selection cannot substitute for duty definition.<\/td>\n<\/tr>\n<tr>\n<td>Required relieving performance<\/td>\n<td>The required performance is available as an engineering input.<\/td>\n<td>HOLD: connection size is not an adequate substitute.<\/td>\n<\/tr>\n<tr>\n<td>Relieving state<\/td>\n<td>The relevant ammonia phase or state is known well enough to compare supplier evidence.<\/td>\n<td>HOLD: the evidence basis cannot yet be matched.<\/td>\n<\/tr>\n<tr>\n<td>Project acceptance basis<\/td>\n<td>The candidate can be reviewed against an identified project requirement set.<\/td>\n<td>HOLD: suitability cannot be closed against an unknown basis.<\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<p>\n      This separates two different engineering questions.<br \/>\n      <strong>Relief-duty definition establishes what protection is required.<\/strong><br \/>\n      <strong>Candidate selection checks whether a particular valve can satisfy that established requirement.<\/strong><br \/>\n      Comparing more supplier data does not resolve an incomplete upstream duty.\n    <\/p>\n<p>\n      The same distinction applies to setting and capacity. Evidence supporting setting or opening behavior does not by itself establish required relieving performance. Likewise, a matching nominal connection demonstrates mechanical similarity, not equivalent relieving capability.\n    <\/p>\n<aside>\n      <strong>Decision boundary:<\/strong><br \/>\n      if a missing input could change the required performance basis, relieving state, component requirements, discharge condition, or project acceptance basis, keep the candidate on HOLD rather than filling the gap with a product assumption.<br \/>\n    <\/aside>\n<\/section>\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" src=\"https:\/\/zobai.com\/wp-content\/uploads\/2026\/08\/ammonia-refrigeration-safety-valve-selection-img-01.webp\" alt=\"Neutral engineering decision flow showing that candidate selection begins only after the protected boundary, relief-duty basis, required relieving performance and relevant service inputs are defined; unresolved decision-critical inputs lead to HOLD.\" title=\"ZOBAI Ammonia Refrigeration Safety Valve Selection IMG-01\" width=\"1200\" height=\"900\" decoding=\"async\" class=\"wp-image-56681\" srcset=\"https:\/\/zobai.com\/wp-content\/uploads\/2026\/08\/ammonia-refrigeration-safety-valve-selection-img-01.webp 1200w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/08\/ammonia-refrigeration-safety-valve-selection-img-01-300x225.webp 300w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/08\/ammonia-refrigeration-safety-valve-selection-img-01-1024x768.webp 1024w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/08\/ammonia-refrigeration-safety-valve-selection-img-01-768x576.webp 768w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/08\/ammonia-refrigeration-safety-valve-selection-img-01-16x12.webp 16w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/08\/ammonia-refrigeration-safety-valve-selection-img-01-400x300.webp 400w\" sizes=\"auto, (max-width: 1200px) 100vw, 1200px\" \/><figcaption class=\"wp-element-caption\">Present as a duty-readiness gate, not a relief-sizing procedure. Preserve the distinction between established project duty and candidate-valve evaluation. Do not introduce numerical pressures, capacities, formulas, standard clauses, product models or project-specific values.<\/figcaption><\/figure>\n<section>\n<h2>Does the Candidate Evidence Match the Ammonia Relieving Phase and State?<\/h2>\n<p>\n      <strong>\u201cAmmonia service\u201d is not a complete relieving-condition description.<\/strong><br \/>\n      The supplier evidence must correspond to the state in which the defined relief duty is evaluated, rather than merely naming the refrigerant.\n    <\/p>\n<p>\n      Ammonia refrigeration does not have one universal relief context. A duty associated with vapor-containing equipment is not automatically equivalent to protection of an isolated section containing trapped liquid. The engineering basis remains distinct even though both situations involve ammonia.\n    <\/p>\n<p>\n      Relieving-performance evidence is also tied to a defined test or service basis. Valve size, refrigerant name, or a general application statement cannot by itself establish that the documented performance basis corresponds to the project duty.\n    <\/p>\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" src=\"https:\/\/zobai.com\/wp-content\/uploads\/2026\/08\/ammonia-refrigeration-safety-valve-selection-img-02.webp\" alt=\"Conceptual evidence-match diagram showing that ammonia\/R717 identifies the medium but does not by itself establish the relieving phase or state; the defined relieving state must be checked against the supplier's documented application and capacity evidence basis.\" title=\"ZOBAI Ammonia Refrigeration Safety Valve Selection IMG-02\" width=\"1200\" height=\"900\" decoding=\"async\" class=\"wp-image-56680\" srcset=\"https:\/\/zobai.com\/wp-content\/uploads\/2026\/08\/ammonia-refrigeration-safety-valve-selection-img-02.webp 1200w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/08\/ammonia-refrigeration-safety-valve-selection-img-02-300x225.webp 300w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/08\/ammonia-refrigeration-safety-valve-selection-img-02-1024x768.webp 1024w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/08\/ammonia-refrigeration-safety-valve-selection-img-02-768x576.webp 768w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/08\/ammonia-refrigeration-safety-valve-selection-img-02-16x12.webp 16w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/08\/ammonia-refrigeration-safety-valve-selection-img-02-400x300.webp 400w\" sizes=\"auto, (max-width: 1200px) 100vw, 1200px\" \/><figcaption class=\"wp-element-caption\">Emphasize phase\/state as an evidence-acceptance variable rather than a thermodynamics lesson. Defined and matched evidence may continue, unknown state is HOLD, and known mismatch is REJECT or requires different evidence. Do not include formulas, numerical values or project conditions.<\/figcaption><\/figure>\n<h3>Match the defined state to the supplier evidence basis<\/h3>\n<div class=\"asv-table-scroll\" role=\"region\" aria-label=\"Ammonia relieving-state evidence matching\" tabindex=\"0\">\n<table>\n<thead>\n<tr>\n<th>Project information<\/th>\n<th>Supplier evidence<\/th>\n<th>Review outcome<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Relieving state is defined.<\/td>\n<td>The evidence basis is clearly compatible with that state.<\/td>\n<td>Continue to the next selection gate.<\/td>\n<\/tr>\n<tr>\n<td>Relieving state is defined.<\/td>\n<td>The evidence basis is unclear.<\/td>\n<td>HOLD and request clarification.<\/td>\n<\/tr>\n<tr>\n<td>Relieving state is not defined.<\/td>\n<td>Supplier evidence exists for one or more conditions.<\/td>\n<td>HOLD because the project input is incomplete.<\/td>\n<\/tr>\n<tr>\n<td>Relieving state is defined.<\/td>\n<td>The documented evidence basis is known to conflict with the required condition.<\/td>\n<td>REJECT that evidence basis or candidate configuration.<\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<h3>Practical phase\/state evidence troubleshooting<\/h3>\n<ol>\n<li>\n        <strong>Start with the defined project duty.<\/strong><br \/>\n        Identify the relieving state the candidate must cover before reviewing the datasheet.\n      <\/li>\n<li>\n        <strong>Identify the supplier evidence basis.<\/strong><br \/>\n        Determine what service condition the documented relieving performance actually represents.\n      <\/li>\n<li>\n        <strong>Compare the two without bridging gaps by assumption.<\/strong><br \/>\n        If they cannot be matched, \u201cammonia service\u201d alone is not enough to close the review.\n      <\/li>\n<li>\n        <strong>Escalate conditions not represented by the available evidence.<\/strong><br \/>\n        Additional engineering verification is required rather than an unsupported conversion or sizing shortcut.\n      <\/li>\n<\/ol>\n<p>\n      Phase and state therefore act as candidate-evidence variables, not as a side lesson in refrigeration thermodynamics. If the state is unresolved, use HOLD. If a documented basis is known to be incompatible with the required condition, use REJECT or seek a different supported configuration.\n    <\/p>\n<\/section>\n<section>\n<h2>Are Materials, Seats and Seals Verified at Component Level?<\/h2>\n<p>\n      <strong>Ammonia compatibility should be verified across the relevant valve components, not inferred from body material alone.<\/strong><br \/>\n      The proposed assembly may contain different materials in the body, closure components, wetted trim, seat, seals, and other exposed internals.\n    <\/p>\n<p>\n      ASHRAE ammonia refrigeration guidance provides a public engineering basis for screening ammonia-related material compatibility concerns. That general guidance is useful for identifying risks, but it does not prove that a specific commercial valve assembly is suitable. Product suitability still depends on the actual components and configuration proposed by the supplier.\n    <\/p>\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" src=\"https:\/\/zobai.com\/wp-content\/uploads\/2026\/08\/ammonia-refrigeration-safety-valve-selection-img-03.webp\" alt=\"Simplified generic pressure-relief-valve component map highlighting separate verification zones for the pressure-containing body, wetted trim, closure\/seat area, seals and other relevant exposed internals; communicate that body material alone does not establish complete ammonia-service compatibility.\" title=\"ZOBAI Ammonia Refrigeration Safety Valve Selection IMG-03\" width=\"1200\" height=\"900\" decoding=\"async\" class=\"wp-image-56679\" srcset=\"https:\/\/zobai.com\/wp-content\/uploads\/2026\/08\/ammonia-refrigeration-safety-valve-selection-img-03.webp 1200w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/08\/ammonia-refrigeration-safety-valve-selection-img-03-300x225.webp 300w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/08\/ammonia-refrigeration-safety-valve-selection-img-03-1024x768.webp 1024w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/08\/ammonia-refrigeration-safety-valve-selection-img-03-768x576.webp 768w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/08\/ammonia-refrigeration-safety-valve-selection-img-03-16x12.webp 16w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/08\/ammonia-refrigeration-safety-valve-selection-img-03-400x300.webp 400w\" sizes=\"auto, (max-width: 1200px) 100vw, 1200px\" \/><figcaption class=\"wp-element-caption\">Present as a component-level compatibility evidence map. Keep seat and seal construction as independent verification items. Do not label specific alloys, polymers, elastomers, ZOBAI materials, product models, certifications, limits or project facts.<\/figcaption><\/figure>\n<h3>Verify compatibility as an evidence chain<\/h3>\n<div class=\"asv-table-scroll\" role=\"region\" aria-label=\"Component-level ammonia compatibility evidence\" tabindex=\"0\">\n<table>\n<thead>\n<tr>\n<th>Component area<\/th>\n<th>Evidence question<\/th>\n<th>Assumption to avoid<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Pressure-containing body<\/td>\n<td>What controlled material designation applies to the proposed configuration?<\/td>\n<td>An acceptable body material proves the complete assembly.<\/td>\n<\/tr>\n<tr>\n<td>Wetted trim and closure parts<\/td>\n<td>Which components contact ammonia, and what materials are actually specified?<\/td>\n<td>The trim automatically uses the same material as the body.<\/td>\n<\/tr>\n<tr>\n<td>Seat<\/td>\n<td>What exact seat construction is used, and what evidence supports its service applicability?<\/td>\n<td>A generic \u201csoft seat\u201d or \u201cmetal seat\u201d label establishes compatibility.<\/td>\n<\/tr>\n<tr>\n<td>Seals and other polymeric components<\/td>\n<td>What exact configuration is installed, and is its application scope documented?<\/td>\n<td>A generic compatibility chart proves suitability of the finished valve.<\/td>\n<\/tr>\n<tr>\n<td>Complete assembly<\/td>\n<td>Does controlled manufacturer evidence connect the full configuration to the required service?<\/td>\n<td>Individually acceptable materials automatically prove assembly-level suitability.<\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<p>\n      Seat and seal evidence must also remain separate from leakage evidence. A defined seat-tightness result can support a leakage-related question under its own test basis, but it does not establish relieving capacity and should not be treated as proof of long-term chemical compatibility.\n    <\/p>\n<h3>Troubleshoot incomplete component evidence<\/h3>\n<ul>\n<li>\n        <strong>Body documented, trim unknown:<\/strong><br \/>\n        use HOLD because the component compatibility chain is incomplete.\n      <\/li>\n<li>\n        <strong>Seat or seal description is generic:<\/strong><br \/>\n        request the exact construction or controlled material identification required for verification.\n      <\/li>\n<li>\n        <strong>Only generic material guidance is available:<\/strong><br \/>\n        use it for screening, not as proof that the proposed assembly is suitable.\n      <\/li>\n<li>\n        <strong>Components are identified but service applicability is not:<\/strong><br \/>\n        the evidence describes the construction but does not yet support PROCEED.\n      <\/li>\n<\/ul>\n<aside>\n      <strong>PROJECT_ONLY boundary:<\/strong><br \/>\n      no specific ZOBAI body, trim, seat, seal, or complete valve configuration is established here as suitable for ammonia service. Product-specific suitability requires controlled product evidence.<br \/>\n    <\/aside>\n<\/section>\n<section>\n<h2>Does the Discharge Interface Fit the Candidate Valve Evidence?<\/h2>\n<p>\n      <strong>The downstream condition is part of candidate review, even though full discharge-system design is not.<\/strong><br \/>\n      A valve may fit mechanically yet still lack evidence applicable to the actual outlet or back-pressure condition.\n    <\/p>\n<p>\n      IIAR ammonia relief-piping guidance supports treating inlet and outlet conditions as performance-relevant parts of pressure-relief system review. Valve configurations do not all respond to downstream pressure in the same way. The useful engineering question is therefore not whether back pressure matters in general, but whether the documented basis for the proposed candidate matches the downstream condition imposed by the installed system.\n    <\/p>\n<p>\n      This matters particularly when the relief path is not an independent discharge arrangement. Internal relief paths or shared relief systems may exist under an applicable engineering basis, but their complete design remains a system-level responsibility. Candidate selection requires enough downstream information only to determine whether the valve evidence is relevant to the actual installation.\n    <\/p>\n<h3>Separate candidate evidence from relief-system engineering<\/h3>\n<div class=\"asv-table-scroll\" role=\"region\" aria-label=\"Valve candidate and discharge-system responsibility boundary\" tabindex=\"0\">\n<table>\n<thead>\n<tr>\n<th>Candidate valve review<\/th>\n<th>Installed relief-system responsibility<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Identify the outlet condition assumed by the valve documentation.<\/td>\n<td>Determine the actual downstream condition created by the installed system.<\/td>\n<\/tr>\n<tr>\n<td>Determine whether documented behavior or performance depends on back pressure.<\/td>\n<td>Establish the downstream condition created by piping, headers, or other system elements.<\/td>\n<\/tr>\n<tr>\n<td>Check whether performance evidence uses a compatible discharge basis.<\/td>\n<td>Engineer the complete relief path and any shared discharge arrangement.<\/td>\n<\/tr>\n<tr>\n<td>Verify the documented outlet configuration.<\/td>\n<td>Confirm the final discharge destination and installed-system arrangement.<\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<h3>Back-pressure evidence troubleshooting<\/h3>\n<ol>\n<li>\n        <strong>Define the actual downstream condition.<\/strong><br \/>\n        If it has not been characterized, candidate review remains incomplete.\n      <\/li>\n<li>\n        <strong>Identify the candidate&#8217;s documented discharge basis.<\/strong><br \/>\n        Do not assume published performance applies to every outlet condition.\n      <\/li>\n<li>\n        <strong>Check configuration-specific assumptions or limits.<\/strong><br \/>\n        The actual valve construction matters.\n      <\/li>\n<li>\n        <strong>Compare evidence with the installation.<\/strong><br \/>\n        Marketing terminology is not a substitute for documented applicability.\n      <\/li>\n<\/ol>\n<p>\n      The decision boundary is straightforward:<br \/>\n      <strong>unknown downstream condition \u2192 HOLD<\/strong>;<br \/>\n      <strong>known condition but incomplete candidate evidence \u2192 HOLD<\/strong>;<br \/>\n      <strong>known documented conflict \u2192 REJECT<\/strong>;<br \/>\n      <strong>compatible evidence \u2192 continue to engineering review<\/strong>.\n    <\/p>\n<p>\n      This preserves the engineering boundary: valve suitability does not equal discharge-system approval, but the two cannot be reviewed as unrelated problems.\n    <\/p>\n<\/section>\n<section>\n<h2>What Does Each Supplier Document Actually Prove?<\/h2>\n<p>\n      <strong>Supplier evidence should be accepted claim by claim, not document by document.<\/strong><br \/>\n      A datasheet, test record, material record, or conformity document is useful only for the specific question it actually supports. None should be treated as automatic proof of complete ammonia-project suitability.\n    <\/p>\n<p>\n      National Board and ASME pressure-relief-device certification and testing frameworks distinguish different evidence scopes, including setting-related performance and relieving-capacity evidence. A defensible review therefore builds an evidence chain: each document should be tied to the proposed configuration, the engineering claim it supports, its stated scope or basis, and the project condition against which it is being checked.\n    <\/p>\n<div class=\"asv-table-scroll\" role=\"region\" aria-label=\"Supplier evidence scope for ammonia safety valve selection\" tabindex=\"0\">\n<table>\n<thead>\n<tr>\n<th>Supplier evidence<\/th>\n<th>What it can support<\/th>\n<th>What it does not automatically prove<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Controlled datasheet<\/td>\n<td>Documented configuration, stated application, and published limits.<\/td>\n<td>Suitability for every project condition.<\/td>\n<\/tr>\n<tr>\n<td>Capacity evidence<\/td>\n<td>Relieving performance under its defined basis.<\/td>\n<td>Material compatibility, installed discharge-system acceptance, or project approval.<\/td>\n<\/tr>\n<tr>\n<td>Set-pressure or calibration evidence<\/td>\n<td>Setting or opening performance under its defined test basis.<\/td>\n<td>Required relieving capacity.<\/td>\n<\/tr>\n<tr>\n<td>Seat-tightness evidence<\/td>\n<td>Leakage or tightness result under its defined test basis.<\/td>\n<td>Capacity, chemical compatibility, or service life.<\/td>\n<\/tr>\n<tr>\n<td>Component material records<\/td>\n<td>Material identity for the documented component or configuration.<\/td>\n<td>Complete-valve ammonia suitability by themselves.<\/td>\n<\/tr>\n<tr>\n<td>Manufacturer service statement<\/td>\n<td>Declared applicability of the documented configuration within its stated scope.<\/td>\n<td>Suitability for every relieving state, discharge condition, or project.<\/td>\n<\/tr>\n<tr>\n<td>Conformity or certification document<\/td>\n<td>The conformity or certification scope stated by that document.<\/td>\n<td>Automatic acceptance under every jurisdiction, specification, or installed condition.<\/td>\n<\/tr>\n<tr>\n<td>Drawing or bill of materials<\/td>\n<td>Configuration and component identity.<\/td>\n<td>Relieving performance.<\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<h3>Trace each document through five questions<\/h3>\n<ol>\n<li>\n        <strong>What claim is the document being used to support?<\/strong><br \/>\n        Capacity, component material, setting, seat tightness, service applicability, and conformity are separate questions.\n      <\/li>\n<li>\n        <strong>Which configuration does it describe?<\/strong><br \/>\n        Evidence for a different construction does not close the gap for the proposed candidate.\n      <\/li>\n<li>\n        <strong>What conditions or test basis limit the claim?<\/strong><br \/>\n        Keep the evidence scope attached to the result.\n      <\/li>\n<li>\n        <strong>Does that basis match the project duty?<\/strong><br \/>\n        A valid document can still be the wrong evidence for the current application.\n      <\/li>\n<li>\n        <strong>What remains unproven?<\/strong><br \/>\n        Build the package by closing individual engineering questions rather than expecting one document to prove everything.\n      <\/li>\n<\/ol>\n<h3>Distinguish three evidence failures<\/h3>\n<div class=\"asv-table-scroll\" role=\"region\" aria-label=\"Supplier evidence failure types\" tabindex=\"0\">\n<table>\n<thead>\n<tr>\n<th>Evidence problem<\/th>\n<th>What it means<\/th>\n<th>Review response<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Missing evidence<\/td>\n<td>The required document or controlled information has not been supplied.<\/td>\n<td>HOLD and request it.<\/td>\n<\/tr>\n<tr>\n<td>Scope mismatch<\/td>\n<td>The evidence exists but does not cover the proposed configuration or duty basis.<\/td>\n<td>HOLD and request evidence with the correct scope.<\/td>\n<\/tr>\n<tr>\n<td>Known technical conflict<\/td>\n<td>The documented limit or applicability conflicts with a mandatory requirement.<\/td>\n<td>REJECT the candidate or configuration.<\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<p>\n      Missing evidence and negative evidence are not the same thing. Treating both as a generic \u201cnot approved\u201d result can cause either unnecessary rejection or premature acceptance.\n    <\/p>\n<ul>\n<li><strong>Seat tightness is not capacity evidence.<\/strong><\/li>\n<li><strong>Set-pressure evidence is not capacity evidence.<\/strong><\/li>\n<li><strong>A material record is not complete service-suitability evidence.<\/strong><\/li>\n<li><strong>A conformity document is not automatic project approval.<\/strong><\/li>\n<li><strong>A matching connection is not proof of equivalent relieving performance.<\/strong><\/li>\n<\/ul>\n<\/section>\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" src=\"https:\/\/zobai.com\/wp-content\/uploads\/2026\/08\/ammonia-refrigeration-safety-valve-selection-img-04.webp\" alt=\"Integrated candidate-readiness flow linking defined duty and relieving state, component-level compatibility evidence, discharge\/back-pressure interface review, supplier-document scope, RFQ inputs and the final PROCEED\/HOLD\/REJECT decision.\" title=\"ZOBAI Ammonia Refrigeration Safety Valve Selection IMG-04\" width=\"1200\" height=\"900\" decoding=\"async\" class=\"wp-image-56678\" srcset=\"https:\/\/zobai.com\/wp-content\/uploads\/2026\/08\/ammonia-refrigeration-safety-valve-selection-img-04.webp 1200w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/08\/ammonia-refrigeration-safety-valve-selection-img-04-300x225.webp 300w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/08\/ammonia-refrigeration-safety-valve-selection-img-04-1024x768.webp 1024w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/08\/ammonia-refrigeration-safety-valve-selection-img-04-768x576.webp 768w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/08\/ammonia-refrigeration-safety-valve-selection-img-04-16x12.webp 16w, https:\/\/zobai.com\/wp-content\/uploads\/2026\/08\/ammonia-refrigeration-safety-valve-selection-img-04-400x300.webp 400w\" sizes=\"auto, (max-width: 1200px) 100vw, 1200px\" \/><figcaption class=\"wp-element-caption\">Show that valve suitability and discharge-system approval are separate responsibilities that still require interface checking; supplier evidence supports only its documented scope. PROCEED means continue to engineering\/RFQ review only, HOLD means decision-critical evidence is incomplete, and REJECT requires a known mismatch. Do not imply final design, code, installation or certification approval.<\/figcaption><\/figure>\n<section>\n<h2>What Should Go Into the RFQ, and When Is the Candidate PROCEED, HOLD or REJECT?<\/h2>\n<p>\n      <strong>A useful ammonia safety valve RFQ should connect each project input to a specific supplier response and evidence requirement.<\/strong><br \/>\n      It should not ask the supplier to infer an undefined relief duty or close missing system-design information.\n    <\/p>\n<h3>Build the RFQ around the selection gates<\/h3>\n<div class=\"asv-table-scroll\" role=\"region\" aria-label=\"Ammonia safety valve RFQ inputs and supplier evidence\" tabindex=\"0\">\n<table>\n<thead>\n<tr>\n<th>RFQ area<\/th>\n<th>Project input<\/th>\n<th>Supplier response needed<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Protected duty<\/td>\n<td>Protected boundary and project-defined relief requirement.<\/td>\n<td>Candidate performance evidence relevant to that duty.<\/td>\n<\/tr>\n<tr>\n<td>Ammonia relieving state<\/td>\n<td>Defined phase or state relevant to the duty.<\/td>\n<td>Evidence showing that the proposed configuration and performance basis are applicable.<\/td>\n<\/tr>\n<tr>\n<td>Materials and sealing<\/td>\n<td>Relevant project compatibility requirements.<\/td>\n<td>Controlled component, seat, seal, and configuration information needed for verification.<\/td>\n<\/tr>\n<tr>\n<td>Discharge interface<\/td>\n<td>Known downstream or back-pressure basis.<\/td>\n<td>Documented outlet assumptions, limitations, and relevant performance basis.<\/td>\n<\/tr>\n<tr>\n<td>Evidence package<\/td>\n<td>Required project review documentation.<\/td>\n<td>Documents tied to the proposed configuration and their stated scope.<\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<h3>Request evidence by purpose, not by document count<\/h3>\n<ul>\n<li>Controlled product or configuration datasheet<\/li>\n<li>Relieving-capacity evidence relevant to the proposed configuration and duty basis<\/li>\n<li>Component-level construction or material documentation where required<\/li>\n<li>Seat and seal construction or applicability evidence where relevant<\/li>\n<li>Set-pressure or calibration evidence required by the project<\/li>\n<li>Seat-tightness evidence where required<\/li>\n<li>Relevant conformity or certification documentation required by the project<\/li>\n<li>Configuration drawing or controlled identification needed to tie the evidence to the proposed candidate<\/li>\n<\/ul>\n<h3>Use this candidate-screening engineering framework from duty to RFQ<\/h3>\n<ol>\n<li>\n        <strong>Duty gate:<\/strong><br \/>\n        Is the protected boundary and required relief duty defined?\n      <\/li>\n<li>\n        <strong>State gate:<\/strong><br \/>\n        Is the ammonia relieving phase or state known, and does the candidate evidence use a compatible basis?\n      <\/li>\n<li>\n        <strong>Compatibility gate:<\/strong><br \/>\n        Are the relevant body, trim, seat, seal, and exposed-component requirements supported by controlled evidence?\n      <\/li>\n<li>\n        <strong>Discharge gate:<\/strong><br \/>\n        Does the candidate&#8217;s documented downstream or back-pressure basis fit the installed-system condition?\n      <\/li>\n<li>\n        <strong>Evidence gate:<\/strong><br \/>\n        Do the supplied documents answer the engineering claims they are being used to support?\n      <\/li>\n<li>\n        <strong>Decision gate:<\/strong><br \/>\n        Is the remaining review state PROCEED, HOLD, or REJECT?\n      <\/li>\n<\/ol>\n<div class=\"asv-table-scroll\" role=\"region\" aria-label=\"Article candidate-screening PROCEED HOLD REJECT framework\" tabindex=\"0\">\n<table>\n<thead>\n<tr>\n<th>\u51b3\u7b56<\/th>\n<th>Use it when<\/th>\n<th>Required next action<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><strong>PROCEED<\/strong><\/td>\n<td>\n              The relief duty is defined, the relieving-state basis is known, relevant compatibility evidence is available, the discharge interface is understood, and the supplier evidence is suitable for further review.\n            <\/td>\n<td>\n              Continue to engineering and RFQ review. Do not treat this status as final installation or project approval.\n            <\/td>\n<\/tr>\n<tr>\n<td><strong>HOLD<\/strong><\/td>\n<td>\n              A decision-critical project input, evidence scope, or document is missing or unclear.\n            <\/td>\n<td>\n              Resolve the specific project-data or evidence gap before making a suitability decision.\n            <\/td>\n<\/tr>\n<tr>\n<td><strong>REJECT<\/strong><\/td>\n<td>\n              A known mismatch exists between a mandatory requirement and the candidate&#8217;s documented service scope, performance basis, material configuration, discharge limitation, or another required condition.\n            <\/td>\n<td>\n              Stop review of that candidate unless the mismatch is removed through a different supported configuration or new applicable evidence.\n            <\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<h3>Diagnose a HOLD before sending the RFQ<\/h3>\n<div class=\"asv-table-scroll\" role=\"region\" aria-label=\"Ammonia safety valve evidence troubleshooting\" tabindex=\"0\">\n<table>\n<thead>\n<tr>\n<th>Observed review problem<\/th>\n<th>Likely evidence gap<\/th>\n<th>Next question to resolve<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>A valve size is being discussed before the duty is established.<\/td>\n<td>An upstream project input is missing.<\/td>\n<td>What relieving duty must the candidate actually satisfy?<\/td>\n<\/tr>\n<tr>\n<td>The supplier states ammonia suitability but the relieving state is unclear.<\/td>\n<td>Application evidence cannot yet be matched to the duty.<\/td>\n<td>What relieving state does the project require, and what basis does the supplier evidence represent?<\/td>\n<\/tr>\n<tr>\n<td>Body material is listed but seat or seal construction is absent.<\/td>\n<td>Component-level compatibility evidence is incomplete.<\/td>\n<td>What exact wetted and sealing components are used in the proposed configuration?<\/td>\n<\/tr>\n<tr>\n<td>Performance data exists but outlet assumptions are unclear.<\/td>\n<td>Discharge-interface evidence is incomplete.<\/td>\n<td>Under what downstream or back-pressure basis does the documented performance apply?<\/td>\n<\/tr>\n<tr>\n<td>Multiple documents are supplied but suitability remains unclear.<\/td>\n<td>Evidence has not been mapped to individual selection claims.<\/td>\n<td>Which document supports performance, materials, setting, tightness, service applicability, and conformity for the proposed configuration?<\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<p>\n      Within this article\u2019s candidate-screening framework, keep HOLD and REJECT distinct. Missing evidence does not automatically make a candidate technically unsuitable; it means the decision cannot yet be closed. REJECT is appropriate only when a known incompatibility or documented mismatch exists.\n    <\/p>\n<aside>\n<h3>Engineering \/ RFQ Next Step<\/h3>\n<p>\n        Once the protected duty, ammonia relieving state, component-level compatibility requirements, discharge conditions, and required evidence package are defined, send those inputs for engineering or supplier review. Ask the supplier to identify the proposed configuration and show which document supports each selection requirement.\n      <\/p>\n<p>\n        A PROCEED result remains a candidate-selection decision only. Final installation, complete relief-system design, project compliance, jurisdictional acceptance, and final engineering approval remain separate responsibilities.\n      <\/p>\n<\/aside>\n<\/section>\n<\/article>","protected":false},"excerpt":{"rendered":"<p>Ammonia refrigeration safety valve selection should start only after the relief duty is defined. A candidate is not ready for engineering review simply because the refrigerant, connection, or intended pressure setting is known. The protected boundary, required relieving duty, ammonia relieving state, component-level compatibility, discharge conditions, and supplier evidence all need to align. In this&#8230;<\/p>","protected":false},"author":2,"featured_media":56681,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[73],"tags":[],"class_list":["post-56671","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-valve-types-selection"],"_links":{"self":[{"href":"https:\/\/zobai.com\/zh\/wp-json\/wp\/v2\/posts\/56671","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/zobai.com\/zh\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/zobai.com\/zh\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/zobai.com\/zh\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/zobai.com\/zh\/wp-json\/wp\/v2\/comments?post=56671"}],"version-history":[{"count":1,"href":"https:\/\/zobai.com\/zh\/wp-json\/wp\/v2\/posts\/56671\/revisions"}],"predecessor-version":[{"id":56780,"href":"https:\/\/zobai.com\/zh\/wp-json\/wp\/v2\/posts\/56671\/revisions\/56780"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/zobai.com\/zh\/wp-json\/wp\/v2\/media\/56681"}],"wp:attachment":[{"href":"https:\/\/zobai.com\/zh\/wp-json\/wp\/v2\/media?parent=56671"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/zobai.com\/zh\/wp-json\/wp\/v2\/categories?post=56671"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/zobai.com\/zh\/wp-json\/wp\/v2\/tags?post=56671"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}