{"id":8736,"date":"2023-11-01T08:44:54","date_gmt":"2023-11-01T07:44:54","guid":{"rendered":"https:\/\/www.idro-elettrica.it\/esperto-risponde\/fire-pump-performance-curve-yes-no-140q\/"},"modified":"2026-07-01T09:47:19","modified_gmt":"2026-07-01T07:47:19","slug":"fire-pump-performance-curve-yes-no-140q","status":"publish","type":"esperto-risponde","link":"https:\/\/www.idro-elettrica.it\/en\/esperto-risponde\/fire-pump-performance-curve-yes-no-140q\/","title":{"rendered":"Fire pump performance curve: yes\/no 140%Q"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\"><em>Fire pump performance curve<\/em>: Verification at the point <strong>where Q is 140%<\/strong> and <strong>H is 70%<\/strong> is not \u201calways\u201d mandatory. The answer depends on how the system is classified under UNI EN 12845. <\/p>\n\n<h2 id=\"in-breve-la-risposta-si-no-dipende-dal-tipo-di-sistema\" class=\"wp-block-heading\">In short: the \u201cyes\/no\u201d answer (it depends on the type of system)<\/h2>\n\n<p class=\"wp-block-paragraph\">If the system is <strong>precalculated<\/strong>, the characteristic curve of the main pumps must <strong>also<\/strong> cover the point corresponding to <strong>140% of Q<\/strong>, while maintaining <strong>70% of H<\/strong>.<\/p>\n\n<p class=\"wp-block-paragraph\">If the system is <strong>calculated in its entirety<\/strong>, this requirement is not stated in those terms; instead, the rules specify certain conditions related to <strong>the most favorable and least favorable areas<\/strong> and to performance during <strong>testing<\/strong>.<\/p>\n\n<div class=\"wp-block-rank-math-toc-block\" id=\"rank-math-toc\"><h2>Table of Contents<\/h2><nav><ul><li class=\"\"><a href=\"#in-breve-la-risposta-si-no-dipende-dal-tipo-di-sistema\">In short: the \u201cyes\/no\u201d answer (it depends on the type of system)<\/a><\/li><li class=\"\"><a href=\"#normativa-di-riferimento-uni-en-12845-cap-10-7-2-e-10-7-3\">Applicable standard: UNI EN 12845 (sections 10.7.2 and 10.7.3)<\/a><\/li><li class=\"\"><a href=\"#sistemi-precalcolati-quando-la-curva-deve-coprire-140-di-q-e-70-di-h\">Pre-calculated systems: when the curve must cover 140% of Q and 70% of H<\/a><\/li><li class=\"\"><a href=\"#sistemi-calcolati-integralmente-la-richiesta-e-diversa-collaudo-aree-riserva-idrica\">Fully calculated systems: the requirements are different (inspection, areas, water reserve)<\/a><\/li><li class=\"\"><a href=\"#perche-la-norma-distingue-tra-precalcolato-e-calcolato-integralmente\">Why do the rules distinguish between pre-calculated and fully calculated?<\/a><\/li><li class=\"\"><a href=\"#come-interpretare-correttamente-la-regola-140-di-q-70-di-h\">How to Correctly Interpret the 140% Q \/ 70% H Rule<\/a><\/li><li class=\"\"><a href=\"#cosa-verificare-in-pratica-senza-confondere-i-due-casi\">What to Check in Practice (Without Confusing the Two Cases)<\/a><\/li><li class=\"\"><a href=\"#conclusione\">Conclusion<\/a><\/li><\/ul><\/nav><\/div>\n\n<h2 id=\"normativa-di-riferimento-uni-en-12845-cap-10-7-2-e-10-7-3\" class=\"wp-block-heading\">Applicable standard: UNI EN 12845 (sections 10.7.2 and 10.7.3)<\/h2>\n\n<p class=\"wp-block-paragraph\">The stated reference is <strong>UNI EN 12845<\/strong>, specifically:<\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>10.7.2<\/strong>: <strong>Q\/H<\/strong> characteristics of the <strong>main pumps<\/strong> for <strong>pre-calculated systems<\/strong>.<\/li>\n\n\n\n<li><strong>10.7.3<\/strong>: <strong>Q\/H<\/strong> characteristics of <strong>the main pumps<\/strong> for the <strong>systems calculated in their entirety<\/strong>.<\/li>\n<\/ul>\n\n<p class=\"wp-block-paragraph\">These two articles are not interchangeable: the standard defines different criteria depending on the design method used (precalculated vs. fully calculated).<\/p>\n\n<h2 id=\"sistemi-precalcolati-quando-la-curva-deve-coprire-140-di-q-e-70-di-h\" class=\"wp-block-heading\">Pre-calculated systems: when the curve must cover 140% of Q and 70% of H<\/h2>\n\n<p class=\"wp-block-paragraph\">For <strong>PRECALCULATED systems<\/strong> (and <strong>only<\/strong> for them), the rules require that:<\/p>\n\n<ol class=\"wp-block-list\">\n<li>The pump\u2019s <strong>rated<\/strong> <strong>flow rate<\/strong> and <strong>pressure<\/strong> values must comply with Section <strong>7.3.2<\/strong> of UNI EN 12845, that is, they must be consistent with the <strong>design Q\/H<\/strong> point derived from the tables in the standard.<\/li>\n\n\n\n<li>The <strong>performance curve<\/strong> of the main pumps covers:<\/li>\n<\/ol>\n\n<ul class=\"wp-block-list\">\n<li>the <strong>estimated design flow rate in Q\/H<\/strong>, and<\/li>\n\n\n\n<li><strong>as well as<\/strong> the point corresponding to <strong>140% of Q<\/strong>, while maintaining <strong>70% of H<\/strong>.<\/li>\n<\/ul>\n\n<p class=\"wp-block-paragraph\">In other words: in the preliminary calculation, one does not limit oneself to the \u201ctable\u201d operating point alone, but requires additional coverage of the curve at a point where the flow rate is higher.<\/p>\n\n<h2 id=\"sistemi-calcolati-integralmente-la-richiesta-e-diversa-collaudo-aree-riserva-idrica\" class=\"wp-block-heading\">Fully calculated systems: the requirements are different (inspection, areas, water reserve)<\/h2>\n\n<p class=\"wp-block-paragraph\">For <strong>FULLY CALCULATED systems<\/strong>, the requirement (Section <strong>10.7.3<\/strong>) is phrased differently and focuses on specific performance checks:<\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>During testing at the manufacturer&#8217;s test facility<\/strong>, the pump must deliver a pressure that is <strong>0.5 bar higher<\/strong> than that required for<strong>the most unfavorable area<\/strong>.<\/li>\n\n\n\n<li>The pump must be capable of maintaining the <strong>Q\/H<\/strong> operating point <strong>of the most favorable range<\/strong> even when <strong>the water level<\/strong> in the reservoir is <strong>at its lowest<\/strong>.<\/li>\n<\/ul>\n\n<p class=\"wp-block-paragraph\">Therefore, as a general rule, we are not talking here about \u201calways covering\u201d <strong>140% of Q with 70% of H<\/strong>: the regulation links this requirement to <strong>system conditions<\/strong> (favored\/disadvantaged areas) and <strong>water supply conditions<\/strong> (minimum reserve level).<\/p>\n\n<h2 id=\"perche-la-norma-distingue-tra-precalcolato-e-calcolato-integralmente\" class=\"wp-block-heading\">Why do the rules distinguish between pre-calculated and fully calculated?<\/h2>\n\n<p class=\"wp-block-paragraph\">The difference stems from the fact that:<\/p>\n\n<ul class=\"wp-block-list\">\n<li>In <strong>the fully calculated scenario<\/strong>, the network is modeled in greater detail:<strong>the most favorable area<\/strong> and<strong>the least favorable area<\/strong> (typically the area closest to the pump room and the one farthest away) are clearly identified. For this reason, the rules may require targeted checks: \n<ul class=\"wp-block-list\">\n<li>pressure margin at the most unfavorable location (during testing),<\/li>\n\n\n\n<li>Guarantee of the Q\/H point in the most favorable area, even at the minimum water storage level.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li>In <strong>the pre-calculated method<\/strong>, however, favorable and unfavorable areas are <strong>not<\/strong> identified: the tables lead to the identification of a <strong>single<\/strong> <strong>design Q\/H<\/strong> point. Precisely for this reason, the standard \u201cerrs on the side of caution\u201d and requires that the pump be capable of delivering performance that exceeds the point calculated using the tables, also mandating coverage of that point at <strong>140% of Q<\/strong> with at least <strong>70% of H<\/strong>. <\/li>\n<\/ul>\n\n<h2 id=\"come-interpretare-correttamente-la-regola-140-di-q-70-di-h\" class=\"wp-block-heading\">How to Correctly Interpret the 140% Q \/ 70% H Rule<\/h2>\n\n<p class=\"wp-block-paragraph\">The rule is explained in the text as follows:<\/p>\n\n<ul class=\"wp-block-list\">\n<li>The maximum flow rate to be observed: <strong>Q1 = Q \u00d7 1.4<\/strong><\/li>\n\n\n\n<li>At that flow rate: <strong>H1 \u2265 H \u00d7 0.7<\/strong><\/li>\n<\/ul>\n\n<p class=\"wp-block-paragraph\">This specification should be interpreted as a requirement based on <strong>the<\/strong> pump\u2019s <strong>performance curve<\/strong> for the <strong>specific<\/strong> case <strong>considered<\/strong>, not as a \u201cuniversal\u201d guideline applicable to every system and every calculation method.<\/p>\n\n<h2 id=\"cosa-verificare-in-pratica-senza-confondere-i-due-casi\" class=\"wp-block-heading\">What to Check in Practice (Without Confusing the Two Cases)<\/h2>\n\n<p class=\"wp-block-paragraph\">To avoid errors in configuration or verification, it is best to clearly separate the checks:<\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>If the system is precalculated<\/strong>: verify that the <strong>fire pump performance curve<\/strong> covers both the design Q\/H point and the point at <strong>140% of Q<\/strong> while maintaining <strong>70% of H<\/strong>.<\/li>\n\n\n\n<li><strong>If the system is designed on a full-scale basis<\/strong>: verify the conditions required during <strong>testing<\/strong> (additional pressure relative to the most unfavorable area) and the ability to maintain the Q\/H point of the most favorable area even when the water reserve is at <strong>its minimum level<\/strong>.<\/li>\n<\/ul>\n\n<p class=\"wp-block-paragraph\">For a visual reference, the text refers readers to <strong>Figures 7a and 7b<\/strong> in Chapter 10 of UNI EN 12845.<\/p>\n\n<h2 id=\"conclusione\" class=\"wp-block-heading\">Conclusion<\/h2>\n\n<p class=\"wp-block-paragraph\">The answer to the initial question is clear only after specifying the type of system: <strong>yes<\/strong> (precalculated) and <strong>no<\/strong> (fully calculated), because UNI EN 12845 establishes different criteria for verifying pump performance in the two approaches.<\/p>\n\n<p class=\"wp-block-paragraph\">If you are unsure about which classification your system falls under and which tests to apply (the 140%\/70% curve or testing under favorable\/unfavorable conditions), it is advisable to establish a documentation and technical review process that complies with the standard.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Fire pump performance curve: Is it really mandatory to also verify the point at 140% of the flow rate while maintaining 70% of the head? It depends on the type of system (pre-calculated or fully calculated) according to UNI EN 12845. In this article, I\u2019ll clarify the \u201cyes\/no\u201d answer and explain why.  <\/p>\n","protected":false},"featured_media":8738,"parent":0,"template":"","meta":{"_acf_changed":false,"_angie_page":false,"footnotes":"","_members_access_role":[],"_members_access_error":""},"tags":[551,552,554,1196,1195,1197,1171,549],"class_list":["post-8736","esperto-risponde","type-esperto-risponde","status-publish","has-post-thumbnail","hentry","tag-engineering-insights","tag-fire-pumps","tag-fire-safety-regulations","tag-fully-computed-systems","tag-pre-configured-systems","tag-pump-testing","tag-q-h-curves","tag-uni-en-12845"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.idro-elettrica.it\/en\/wp-json\/wp\/v2\/esperto-risponde\/8736","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.idro-elettrica.it\/en\/wp-json\/wp\/v2\/esperto-risponde"}],"about":[{"href":"https:\/\/www.idro-elettrica.it\/en\/wp-json\/wp\/v2\/types\/esperto-risponde"}],"version-history":[{"count":0,"href":"https:\/\/www.idro-elettrica.it\/en\/wp-json\/wp\/v2\/esperto-risponde\/8736\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.idro-elettrica.it\/en\/wp-json\/wp\/v2\/media\/8738"}],"wp:attachment":[{"href":"https:\/\/www.idro-elettrica.it\/en\/wp-json\/wp\/v2\/media?parent=8736"}],"wp:term":[{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.idro-elettrica.it\/en\/wp-json\/wp\/v2\/tags?post=8736"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}