{"id":7908,"date":"2020-06-24T15:24:00","date_gmt":"2020-06-24T13:24:00","guid":{"rendered":"https:\/\/www.idro-elettrica.it\/esperto-risponde\/open-top-fuel-tank-when-is-it-permitted\/"},"modified":"2026-07-01T09:46:00","modified_gmt":"2026-07-01T07:46:00","slug":"open-top-fuel-tank-when-is-it-permitted","status":"publish","type":"esperto-risponde","link":"https:\/\/www.idro-elettrica.it\/en\/esperto-risponde\/open-top-fuel-tank-when-is-it-permitted\/","title":{"rendered":"Open-top fuel tank: when is it permitted?"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\"><em>Open-top tank<\/em>: Whether this option can be used depends on the type of water supply planned. Below is a detailed response, including the case studies and requirements listed in the reference text. <\/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=\"#quando-e-ammesso-il-serbatoio-a-cielo-aperto\">When Is an Open-Top Tank Permitted?<\/a><\/li><li class=\"\"><a href=\"#quando-e-vietato-il-caso-dellalimentazione-idrica-singola-superiore\">When It Is Prohibited: The Case of a Single Upper Water Supply Line<\/a><\/li><li class=\"\"><a href=\"#alimentazioni-idriche-previste-quadro-dinsieme-utile-alla-scelta\">Planned Water Supplies: An Overview to Help You Choose<\/a><\/li><li class=\"\"><a href=\"#focus-alimentazioni-idriche-singole-superiori-e-perche-impattano-sulla-riserva\">Focus: Upper Individual Water Inlets (and Why They Affect the Reservoir)<\/a><\/li><li class=\"\"><a href=\"#requisiti-del-serbatoio-in-alcune-configurazioni-gravita-o-accumulo-con-2-pompe\">Tank Requirements in Certain Configurations (Gravity-Fed or Storage with 2 or More Pumps)<\/a><\/li><li class=\"\"><a href=\"#controlli-pratici-cosa-verificare-in-progetto-e-in-revisione-documentale\">Practical Checks: What to Verify in the Project and During Document Review<\/a><\/li><li class=\"\"><a href=\"#conclusione\">Conclusion<\/a><\/li><\/ul><\/nav><\/div>\n\n<h2 id=\"quando-e-ammesso-il-serbatoio-a-cielo-aperto\" class=\"wp-block-heading\">When Is an Open-Top Tank Permitted?<\/h2>\n\n<p class=\"wp-block-paragraph\">An <strong>open-top<\/strong> water storage <strong>tank<\/strong> may be installed <strong>only<\/strong> in <strong>presence of a single water supply<\/strong>.<\/p>\n\n<p class=\"wp-block-paragraph\">This point is crucial because it directly links the \u201cconstructive\u201d\/design choice of the (open-air) water reservoir to <strong>the type of water supply system<\/strong> being used. In practice, before discussing the details of the reservoir, it is necessary to verify and clearly state <em>what type of water supply system<\/em> is being implemented. <\/p>\n\n<h2 id=\"quando-e-vietato-il-caso-dellalimentazione-idrica-singola-superiore\" class=\"wp-block-heading\">When It Is Prohibited: The Case of a Single Upper Water Supply Line<\/h2>\n\n<p class=\"wp-block-paragraph\">This same approach also leads to a prohibition: <strong>open-air<\/strong> water reservoirs <strong>are prohibited<\/strong> when<strong>a single, larger water supply system<\/strong> is to be constructed.<\/p>\n\n<p class=\"wp-block-paragraph\">Therefore, if the project or conditions require a single, higher-category water supply, the \u201copen-air\u201d configuration is not among the permissible options. The practical consequence is that verifying the type of water supply (single vs. single-upper) becomes a key \u201cturning point\u201d in the design process: if the category changes, so does what is permitted for the tank. <\/p>\n\n<h2 id=\"alimentazioni-idriche-previste-quadro-dinsieme-utile-alla-scelta\" class=\"wp-block-heading\">Planned Water Supplies: An Overview to Help You Choose<\/h2>\n\n<p class=\"wp-block-paragraph\">The text refers to the <strong>planned water supplies<\/strong> and some of their <strong>characteristics<\/strong>. The list includes: <\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>Individual Water Supplies<\/strong><\/li>\n\n\n\n<li><strong>Upper Single Water Inlets<\/strong><\/li>\n\n\n\n<li><strong>Dual water supplies<\/strong><\/li>\n\n\n\n<li><strong>Combined Water Supplies<\/strong><\/li>\n<\/ul>\n\n<p class=\"wp-block-paragraph\">For the purposes of this application (open-top tank), the two key categories are the first two: <strong>single<\/strong> (where the solution is permissible) and <strong>upper single<\/strong> (where it is prohibited). The other two categories (double and combined) are listed, but they are not described in detail in the text available here; for this reason, when the goal is to \u201cselect the reservoir,\u201d it is best to first determine precisely which of the four categories is being used. <\/p>\n\n<h2 id=\"focus-alimentazioni-idriche-singole-superiori-e-perche-impattano-sulla-riserva\" class=\"wp-block-heading\">Focus: Upper Individual Water Inlets (and Why They Affect the Reservoir)<\/h2>\n\n<p class=\"wp-block-paragraph\"><strong>Upper-tier single water supplies<\/strong> are defined as those single water supplies that <strong>provide a high degree of reliability<\/strong>.<\/p>\n\n<p class=\"wp-block-paragraph\">The text provides examples of the following types of individual water supply systems:<\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>An aqueduct fed from both ends<\/strong><\/li>\n\n\n\n<li><strong>A gravity-fed tank without a pump<\/strong><\/li>\n\n\n\n<li><strong>A tank with TWO or more pumps<\/strong><\/li>\n\n\n\n<li><strong>An inexhaustible source with TWO or more pumps<\/strong><\/li>\n<\/ul>\n\n<p class=\"wp-block-paragraph\">The connection to the initial question is direct: <strong>if your case falls under the \u201cupper single\u201d category<\/strong>, then the water reservoir <strong>cannot<\/strong> be an <strong>open-air one<\/strong>. It is therefore essential not to confuse: <\/p>\n\n<ul class=\"wp-block-list\">\n<li>the presence of a tank (which may also appear in the \u201cupper single\u201d), with<\/li>\n\n\n\n<li>the feasibility of the \u201copen-air\u201d solution (which is, in fact, ruled out specifically when referring to a single upper level).<\/li>\n<\/ul>\n\n<h2 id=\"requisiti-del-serbatoio-in-alcune-configurazioni-gravita-o-accumulo-con-2-pompe\" class=\"wp-block-heading\">Tank Requirements in Certain Configurations (Gravity-Fed or Storage with 2 or More Pumps)<\/h2>\n\n<p class=\"wp-block-paragraph\">The text specifies that, <strong>in the case of a gravity-fed or storage tank with two or more pumps<\/strong>, the tank must meet the following conditions:<\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>It must be at least equal to the total capacity required by the project<\/strong><\/li>\n\n\n\n<li><strong>It must not allow light and\/or foreign matter to penetrate it<\/strong><\/li>\n\n\n\n<li><strong>Drinking water must be used<\/strong><\/li>\n\n\n\n<li><strong>It must be painted and protected against corrosion<\/strong> <em>(minimal maintenance required after 10 years)<\/em><\/li>\n<\/ul>\n\n<p class=\"wp-block-paragraph\">These requirements have practical implications: regardless of the solution adopted, the water reserve should not be treated as \u201cjust any volume of water,\u201d but as a component subject to clear constraints (capacity, protection, water quality, corrosion protection).<\/p>\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p class=\"wp-block-paragraph\">Consistency note to be verified: The phrase<strong>\u201copen-air\u201d<\/strong>and the requirement<strong>that \u201cit must not allow light to penetrate\u201d<\/strong>may give rise to interpretive doubts; it is advisable to clarify exactly what is meant by \u201copen-air\u201d in this specific case (see the final section, \u201cMissing Data \/ Questions\u201d).<\/p>\n<\/blockquote>\n\n<h2 id=\"controlli-pratici-cosa-verificare-in-progetto-e-in-revisione-documentale\" class=\"wp-block-heading\">Practical Checks: What to Verify in the Project and During Document Review<\/h2>\n\n<p class=\"wp-block-paragraph\">To correctly apply the rule \u201callowed only with a single space \/ prohibited with a single space at the beginning,\u201d it\u2019s a good idea in practice to create a short checklist of documents:<\/p>\n\n<ol class=\"wp-block-list\">\n<li><strong>Specify the type of water supply<\/strong> (single, single upper, double, combined).<\/li>\n\n\n\n<li>If you are evaluating an <strong>open-top tank<\/strong>, confirm that it is connected to <strong>a single water supply<\/strong>.<\/li>\n\n\n\n<li>If the situation requires or involves <strong>a single, higher-level water supply<\/strong>, do not use an open-air solution.<\/li>\n\n\n\n<li>If the tank is <strong>a gravity-fed<\/strong> or <strong>storage tank with two or more pumps<\/strong>, check the following <strong>conditions<\/strong> one by one (design capacity, absence of light penetration or foreign material, potable water, paint coating, and corrosion protection).<\/li>\n<\/ol>\n\n<h2 id=\"conclusione\" class=\"wp-block-heading\">Conclusion<\/h2>\n\n<p class=\"wp-block-paragraph\">An <strong>open-top tank<\/strong> is permitted <strong>only<\/strong> in presence of <strong>a single water supply<\/strong>; it is <strong>prohibited<\/strong>, however, when<strong>a single water supply of a higher capacity<\/strong> is installed. If the tank is a gravity-fed or storage tank with two or more pumps, the listed requirements (capacity, protective measures, potable water, corrosion protection) must also be met. <\/p>\n","protected":false},"excerpt":{"rendered":"<p>Open-top tanks and water reservoirs: when are they allowed, and when are they not? In this answer, I\u2019ll explain in which cases they\u2019re permitted only with a single water supply and why they\u2019re prohibited with a single water supply from a higher elevation. I\u2019ll conclude by outlining the requirements for the tank in certain configurations.  <\/p>\n","protected":false},"featured_media":7910,"parent":0,"template":"","meta":{"_acf_changed":false,"_angie_page":false,"footnotes":"","_members_access_role":[],"_members_access_error":""},"tags":[552,651,645,647,655,653,649,553,646],"class_list":["post-7908","esperto-risponde","type-esperto-risponde","status-publish","has-post-thumbnail","hentry","tag-fire-pumps","tag-gravity-tank","tag-open-air-reservoir","tag-single-water-supply","tag-tank-maintenance","tag-tank-requirements","tag-upper-single-water-supply","tag-water-supply","tag-water-supply-2"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.idro-elettrica.it\/en\/wp-json\/wp\/v2\/esperto-risponde\/7908","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\/7908\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.idro-elettrica.it\/en\/wp-json\/wp\/v2\/media\/7910"}],"wp:attachment":[{"href":"https:\/\/www.idro-elettrica.it\/en\/wp-json\/wp\/v2\/media?parent=7908"}],"wp:term":[{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.idro-elettrica.it\/en\/wp-json\/wp\/v2\/tags?post=7908"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}