{"id":5520,"date":"2024-01-18T08:47:00","date_gmt":"2024-01-18T07:47:00","guid":{"rendered":"https:\/\/www.idro-elettrica.it\/esperto-risponde\/what-are-the-requirements-of-uni-en-12845-for-water-supplies-with-pumps-and-tanks-in-the-design-phase\/"},"modified":"2026-07-01T09:47:22","modified_gmt":"2026-07-01T07:47:22","slug":"what-are-the-requirements-of-uni-en-12845-for-water-supplies-with-pumps-and-tanks-in-the-design-phase","status":"publish","type":"esperto-risponde","link":"https:\/\/www.idro-elettrica.it\/en\/esperto-risponde\/what-are-the-requirements-of-uni-en-12845-for-water-supplies-with-pumps-and-tanks-in-the-design-phase\/","title":{"rendered":"UNI EN 12845 Water Supply Requirements: Design Review"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\"><em>The UNI EN 12845 requirements for water supply systems<\/em> essentially mean understanding <strong>what information<\/strong> must be included in the design when the supply system consists of <strong>a pump station<\/strong> and <strong>a tank<\/strong>.<\/p>\n\n<p class=\"wp-block-paragraph\">In this response, we organize the requested information so that it can be used as a practical checklist for project documentation.<\/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=\"#dove-la-norma-indica-cosa-fornire-in-progetto-punto-4-4-4\">Where the rules specify what must be included in the design (section 4.4.4)<\/a><\/li><li class=\"\"><a href=\"#requisiti-uni-en-12845-alimentazione-idrica-disegni-4-4-4-1\">UNI EN 12845 requirements for water supply: drawings (4.4.4.1)<\/a><\/li><li class=\"\"><a href=\"#calcolo-idraulico-4-4-4-2-cosa-deve-dimostrare\">Hydraulic Calculation (4.4.4.2): What It Must Demonstrate<\/a><\/li><li class=\"\"><a href=\"#gruppo-di-pompaggio-automatico-4-4-4-4-dati-richiesti\">Automatic Pumping Unit (4.4.4.4): Required Data<\/a><\/li><li class=\"\"><a href=\"#serbatoio-di-accumulo-4-4-4-5-dati-richiesti\">Storage Tank (4.4.4.5): Required Data<\/a><\/li><li class=\"\"><a href=\"#figure-4-e-5-prospetto-12-livelli-camere-e-distanze-minime\">Figures 4 and 5 + Table 12: Levels, Rooms, and Minimum Distances<\/a><ul><li class=\"\"><a href=\"#prospetto-12-distanze-minime-come-riportate\">Table 12 \u2014 Minimum Distances (as shown)<\/a><\/li><\/ul><\/li><li class=\"\"><a href=\"#checklist-finale-cosa-preparare-per-non-lasciare-buchi-in-progetto\">Final Checklist: What to Prepare to Avoid &#8220;Gaps&#8221; in the Project<\/a><\/li><li class=\"\"><a href=\"#conclusione\">Conclusion<\/a><\/li><\/ul><\/nav><\/div>\n\n<h2 id=\"dove-la-norma-indica-cosa-fornire-in-progetto-punto-4-4-4\" class=\"wp-block-heading\">Where the rules specify what must be included in the design (section 4.4.4)<\/h2>\n\n<p class=\"wp-block-paragraph\"><strong>Section 4.4.4<\/strong> of the rules specifies <strong>what information must be provided<\/strong> during the design phase regarding the selected water supply system.<\/p>\n\n<p class=\"wp-block-paragraph\">When the water supply system consists <strong>of a pump station and a tank<\/strong>, the specific sections to refer to are <strong>4.4.4.4<\/strong> and <strong>4.4.4.5<\/strong>, in addition to the general requirements for drawings and calculations (4.4.4.1 and 4.4.4.2).<\/p>\n\n<h2 id=\"requisiti-uni-en-12845-alimentazione-idrica-disegni-4-4-4-1\" class=\"wp-block-heading\">UNI EN 12845 requirements for water supply: drawings (4.4.4.1)<\/h2>\n\n<p class=\"wp-block-paragraph\"><strong>Water supply drawings<\/strong> must show:<\/p>\n\n<ul class=\"wp-block-list\">\n<li>the <strong>water supply<\/strong> lines and <strong>piping up to the control station<\/strong>;<\/li>\n\n\n\n<li>A <strong>key to the symbols<\/strong>.<\/li>\n<\/ul>\n\n<p class=\"wp-block-paragraph\">In addition, the drawings must also show:<\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>location and type<\/strong> of <strong>shut-off valves<\/strong> and <strong>check valves<\/strong>;<\/li>\n\n\n\n<li>any <strong>pressure-reducing valve<\/strong>;<\/li>\n\n\n\n<li><strong>water meters<\/strong>;<\/li>\n\n\n\n<li><strong>backflow prevention devices<\/strong>;<\/li>\n\n\n\n<li>any <strong>water supply connection for other services<\/strong>.<\/li>\n<\/ul>\n\n<p class=\"wp-block-paragraph\">The goal is to avoid ambiguity: it is not enough simply to \u201cknow\u201d that a component exists; it must also <strong>be located and identified<\/strong> in the drawings.<\/p>\n\n<h2 id=\"calcolo-idraulico-4-4-4-2-cosa-deve-dimostrare\" class=\"wp-block-heading\">Hydraulic Calculation (4.4.4.2): What It Must Demonstrate<\/h2>\n\n<p class=\"wp-block-paragraph\">In addition to the drawings, the <strong>hydraulic analysis<\/strong> must be included.<\/p>\n\n<p class=\"wp-block-paragraph\">The hydraulic calculation must demonstrate that the <strong>minimum specifications of the water supply<\/strong> are sufficient to provide <strong>the<\/strong> required <strong>pressure and flow rate<\/strong> <strong>to the control station<\/strong>.<\/p>\n\n<p class=\"wp-block-paragraph\">In practical terms, this step links the choice of fuel supply system (pumps\/tank) to the performance verification: the declared and\/or rated data are not \u201cisolated,\u201d but must be consistent with the performance required at the specified delivery point (inspection station).<\/p>\n\n<h2 id=\"gruppo-di-pompaggio-automatico-4-4-4-4-dati-richiesti\" class=\"wp-block-heading\">Automatic Pumping Unit (4.4.4.4): Required Data<\/h2>\n\n<p class=\"wp-block-paragraph\">For <strong>automatic pump groups<\/strong>, the following characteristics and curves (among others) must be specified:<\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>Q\/H characteristic curve<\/strong> of the pump, assuming an <strong>inlet level<\/strong> equal to the minimum level <strong>\u201cX\u201d<\/strong> (see <strong>Figures 4 and 5<\/strong> in Chapter 9).<\/li>\n\n\n\n<li><strong>Power consumption curve<\/strong>; for pumps with <strong>an increasing power curve<\/strong> (in short: <strong>centrifugal pumps<\/strong>), the power curve must be available up to <strong>NPSHr = 16 m.w.c.<\/strong><\/li>\n\n\n\n<li><strong>Required NPSH curve<\/strong>. For centrifugal pumps, the curve must be available up to <strong>NPSHr = 16 m.w.c.<\/strong> <\/li>\n\n\n\n<li><strong>Statement of the available power<\/strong> for each engine.<\/li>\n\n\n\n<li><strong>Available and required NPSH<\/strong> at <strong>the maximum expected flow rate<\/strong>.<\/li>\n\n\n\n<li><strong>Minimum submersion depth<\/strong> for <strong>VTP<\/strong> pumps and <strong>Submersible Electric Pumps<\/strong>.<\/li>\n\n\n\n<li>For <strong>fully calculated networks<\/strong>: the <strong>pressure-flow curve required<\/strong> for the <strong>most<\/strong> and <strong>least favorable<\/strong> <strong>hydraulic<\/strong> operating areas.<\/li>\n<\/ul>\n\n<p class=\"wp-block-paragraph\">Operational note: In the project documentation, it is advisable to keep this information as a single \u201cpackage\u201d (curves + statements), because these elements are interdependent: for example, the Q\/H value must be interpreted in conjunction with the conditions at level <strong>X<\/strong> and the NPSH data.<\/p>\n\n<h2 id=\"serbatoio-di-accumulo-4-4-4-5-dati-richiesti\" class=\"wp-block-heading\">Storage Tank (4.4.4.5): Required Data<\/h2>\n\n<p class=\"wp-block-paragraph\">For <strong>storage tanks<\/strong>, the following characteristics (among others) must be provided:<\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>Total volume<\/strong>.<\/li>\n\n\n\n<li><strong>Actual capacity and range<\/strong>.<\/li>\n\n\n\n<li><strong>Flow rate<\/strong> for tanks with <strong>reduced capacity<\/strong>.<\/li>\n\n\n\n<li><strong>Vertical distance<\/strong> between the pump shaft and the minimum level <strong>\u201cX\u201d<\/strong> in the tank (see <strong>Fig. 4<\/strong> in Chapter 9).<\/li>\n\n\n\n<li><strong>Design Features<\/strong> of the Tank and <strong>Cover<\/strong>.<\/li>\n\n\n\n<li><strong>Recommended frequency<\/strong> for scheduled maintenance that requires <strong>draining<\/strong> the tank.<\/li>\n\n\n\n<li><strong>Protection against freezing<\/strong>.<\/li>\n\n\n\n<li>Minimum <strong>level<\/strong> <strong>\u201cX\u201d<\/strong> and normal <strong>level<\/strong> <strong>\u201cN\u201d<\/strong> (see <strong>Fig. 4<\/strong> in Chapter 9).<\/li>\n<\/ul>\n\n<p class=\"wp-block-paragraph\">The key point here is that it\u2019s not just \u201cvolumes\u201d that are required: <strong>levels, distances, and maintenance management<\/strong> are also required\u2014that is, information useful for describing how the tank operates over time and under operating conditions (X\/N).<\/p>\n\n<h2 id=\"figure-4-e-5-prospetto-12-livelli-camere-e-distanze-minime\" class=\"wp-block-heading\">Figures 4 and 5 + Table 12: Levels, Rooms, and Minimum Distances<\/h2>\n\n<p class=\"wp-block-paragraph\"><strong>Figure 4<\/strong> is referenced for the <strong>effective capacity of the inlet tanks<\/strong> and the <strong>dimensions of the inlet chambers<\/strong>, distinguishing <strong>between<\/strong> conditions <strong>with and<\/strong> <strong>without<\/strong> <strong>an inlet well<\/strong>. The same figure also includes information such as: <\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>Effective capacity<\/strong><\/li>\n\n\n\n<li><strong>Minimum distance<\/strong> from the inlet pipe to <strong>the minimum water level<\/strong><\/li>\n\n\n\n<li><strong>Minimum distance<\/strong> from the inlet pipe to <strong>the bottom of the sump<\/strong><\/li>\n<\/ul>\n\n<p class=\"wp-block-paragraph\"><strong>Fig. 5<\/strong> illustrates the design <strong>of the sedimentation and inlet chambers<\/strong>, including components such as <strong>filters<\/strong>, water level <strong>\u201cX,\u201d<\/strong> the sedimentation chamber, the inlet chamber, and various feed methods (weir, open channel, conduit\/pipe).<\/p>\n\n<p class=\"wp-block-paragraph\">In addition, <strong>Table 12<\/strong> specifies the <strong>minimum distances<\/strong> for the placement of the inlet pipe (as shown in the figures). It is also noted that, if an <strong>anti-vortex plate<\/strong> with the minimum dimensions specified in Figure 12 is installed, dimension <strong>A<\/strong> may be reduced to <strong>0.10 m<\/strong>. It is also noted that a tank may be equipped with <strong>a socket<\/strong> to maximize its effective capacity.  <\/p>\n\n<h3 id=\"prospetto-12-distanze-minime-come-riportate\" class=\"wp-block-heading\">Table 12 \u2014 Minimum Distances (as shown)<\/h3>\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th class=\"has-text-align-right\" data-align=\"right\">Nominal pipe size (mm)<\/th><th class=\"has-text-align-right\" data-align=\"right\">Minimum B (m)<\/th><th class=\"has-text-align-right\" data-align=\"right\">Minimum without anti-vortex plate (m)<\/th><th class=\"has-text-align-right\" data-align=\"right\">Minimum with anti-vortex plate (m)<\/th><th class=\"has-text-align-right\" data-align=\"right\">Minimum size of anti-vortex plate A (m)<\/th><\/tr><\/thead><tbody><tr><td class=\"has-text-align-right\" data-align=\"right\">60<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.08<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.25<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.20<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.10<\/td><\/tr><tr><td class=\"has-text-align-right\" data-align=\"right\">80<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.08<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.31<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.20<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.10<\/td><\/tr><tr><td class=\"has-text-align-right\" data-align=\"right\">100<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.10<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.37<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.40<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.10<\/td><\/tr><tr><td class=\"has-text-align-right\" data-align=\"right\">150<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.10<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.50<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.60<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.10<\/td><\/tr><tr><td class=\"has-text-align-right\" data-align=\"right\">200<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.15<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.62<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.80<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.10<\/td><\/tr><tr><td class=\"has-text-align-right\" data-align=\"right\">250<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.20<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.75<\/td><td class=\"has-text-align-right\" data-align=\"right\">1.00<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.10<\/td><\/tr><tr><td class=\"has-text-align-right\" data-align=\"right\">300<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.20<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.90<\/td><td class=\"has-text-align-right\" data-align=\"right\">1.20<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.10<\/td><\/tr><tr><td class=\"has-text-align-right\" data-align=\"right\">400<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.30<\/td><td class=\"has-text-align-right\" data-align=\"right\">1.05<\/td><td class=\"has-text-align-right\" data-align=\"right\">1.20<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.10<\/td><\/tr><tr><td class=\"has-text-align-right\" data-align=\"right\">500<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.35<\/td><td class=\"has-text-align-right\" data-align=\"right\">1.20<\/td><td class=\"has-text-align-right\" data-align=\"right\">1.20<\/td><td class=\"has-text-align-right\" data-align=\"right\">0.10<\/td><\/tr><\/tbody><\/table><\/figure>\n\n<h2 id=\"checklist-finale-cosa-preparare-per-non-lasciare-buchi-in-progetto\" class=\"wp-block-heading\">Final Checklist: What to Prepare to Avoid &#8220;Gaps&#8221; in the Project<\/h2>\n\n<p class=\"wp-block-paragraph\">For a water supply system using <strong>pumps and a tank<\/strong>, the design documentation should include at least the following:<\/p>\n\n<ul class=\"wp-block-list\">\n<li>Complete <strong>drawings<\/strong> up to the <strong>control station<\/strong>, including a legend and components (valves, reducers, meters, backflow preventers, and other equipment).<\/li>\n\n\n\n<li><strong>Hydraulic calculation<\/strong> demonstrating the required pressure and flow rate at the control station.<\/li>\n\n\n\n<li>For the <strong>pump group<\/strong>: curves (Q\/H at level <strong>X<\/strong>, power consumption, required NPSH), power per motor, available\/required NPSH at maximum flow rate, submersion depth (VTP and submerged), and\u2014if the system has been fully calculated\u2014pressure\/flow rate curves for the most favorable and least favorable areas.<\/li>\n\n\n\n<li>For the <strong>tank<\/strong>: volume, effective capacity\/range, backup flow rate (if capacity is reduced), vertical distances and <strong>X\/N<\/strong> levels, construction\/coverage, maintenance involving draining, and freeze protection.<\/li>\n\n\n\n<li>Refer to <strong>Figures 4 and 5<\/strong> and <strong>Table 12<\/strong> when describing rooms, levels, and distances of the inlet piping.<\/li>\n<\/ul>\n\n<h2 id=\"conclusione\" class=\"wp-block-heading\">Conclusion<\/h2>\n\n<p class=\"wp-block-paragraph\">During the design phase, the requirements are translated into a coherent set of <strong>drawings<\/strong>, <strong>analyses (hydraulic calculations)<\/strong>, and <strong>technical data<\/strong> on pumps and tanks (curves, levels, distances, management). Organizing this information from the very beginning helps make the design process more manageable and verifiable. <\/p>\n","protected":false},"excerpt":{"rendered":"<p>UNI EN 12845 Requirements for Water Supply Systems During the Design Phase: What to Include in Drawings, Hydraulic Calculations, Pumping Units, and Tanks. A practical checklist to ensure you don\u2019t overlook any required data. <\/p>\n","protected":false},"featured_media":5521,"parent":0,"template":"","meta":{"_acf_changed":false,"_angie_page":false,"footnotes":"","_members_access_role":[],"_members_access_error":""},"tags":[1167,1170,1169,550,1171,607,1168,1172,549,646],"class_list":["post-5520","esperto-risponde","type-esperto-risponde","status-publish","has-post-thumbnail","hentry","tag-automatic-pump-system","tag-control-station","tag-hydraulic-calculation","tag-npsh","tag-q-h-curves","tag-sprinkler-systems","tag-storage-tank-2","tag-table-12","tag-uni-en-12845","tag-water-supply-2"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.idro-elettrica.it\/en\/wp-json\/wp\/v2\/esperto-risponde\/5520","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\/5520\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.idro-elettrica.it\/en\/wp-json\/wp\/v2\/media\/5521"}],"wp:attachment":[{"href":"https:\/\/www.idro-elettrica.it\/en\/wp-json\/wp\/v2\/media?parent=5520"}],"wp:term":[{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.idro-elettrica.it\/en\/wp-json\/wp\/v2\/tags?post=5520"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}