{"id":638,"date":"2026-10-02T13:11:13","date_gmt":"2026-10-02T11:11:13","guid":{"rendered":"https:\/\/www.valfonta.com\/safety-valves\/"},"modified":"2026-10-05T15:13:24","modified_gmt":"2026-10-05T13:13:24","slug":"safety-valves","status":"publish","type":"page","link":"https:\/\/www.valfonta.com\/en\/safety-valves\/","title":{"rendered":"Safety valves"},"content":{"rendered":"<div class=\"wp-block-group vf-raiz vf-pl-hub is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group vf-cat-wrap is-layout-flow wp-block-group-is-layout-flow\"><article class=\"wp-block-group vf-pdp vf-cat vf-c2 is-layout-flow wp-block-group-is-layout-flow\"><nav class=\"wp-block-group vf-breadcrumbs vfa-aria-label--Breadcrumbs is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-envolt wp-block-paragraph\"><a href=\"\/en\/\">Home<\/a><span class=\"vf-sep\">\u203a<\/span><span aria-current=\"page\">Safety valves<\/span><\/p><\/nav><div class=\"wp-block-group vf-cat-hero vf-c2-hero is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-pdp-eyebrow wp-block-paragraph\">Overpressure protection \u00b7 Badalona, since 1962<\/p><h1 class=\"wp-block-heading\">Safety valves<\/h1><p class=\"vf-lead wp-block-paragraph\">They detect overpressure in tanks, boilers, or pipelines and discharge the excess fluid without auxiliary power; once the pressure returns to normal, they close again. Models with full, instantaneous opening and with progressive opening, plus atmospheric valves for sealed vessels.<\/p><ul class=\"vf-pdp-keys wp-block-list\"><li><span>Sizes<\/span><b>\u00bc\u2033 to 4\u2033 \u00b7 DN15 to DN100<\/b><\/li><li><span>Pressure<\/span><b>up to PN25<\/b><\/li><li><span>Temperature<\/span><b>up to 280 \u00b0C<\/b><\/li><li><span>Material<\/span><b>Brass, bronze, or 316L stainless<\/b><\/li><\/ul><div class=\"wp-block-group vf-pdp-cta is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-envolt wp-block-paragraph\"><a class=\"vf-btn vf-btn--pri\" href=\"#solicitar\">Request a quote<\/a><a class=\"vf-btn vf-btn--sec\" href=\"#modelos\" data-vf-view-go=\"table\">Compare models<\/a><\/p><\/div><p class=\"vf-pdp-contact wp-block-paragraph\">Questions about the set pressure? Call <a href=\"tel:+34933720888\">933 720 888<\/a> or email <a href=\"mailto:valfonta@valfonta.com\">valfonta@valfonta.com<\/a>.<\/p><\/div><div class=\"wp-block-group vf-c2-finder vfa-role--group vfa-aria-labelledby--vf-c2-fh is-layout-flow wp-block-group-is-layout-flow\"><p id=\"vf-c2-fh\" class=\"vf-fh wp-block-paragraph\">Find your safety valve<\/p><div class=\"wp-block-group vf-grp is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-envolt wp-block-paragraph\"><span class=\"vf-lab\">What you need<\/span><\/p><div class=\"wp-block-group vf-chips is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-envolt wp-block-paragraph\"><button type=\"button\" class=\"vf-chip\" data-vf-filter=\"fun\" data-v=\"sobre\" aria-pressed=\"false\">Protect against overpressure<\/button><button type=\"button\" class=\"vf-chip\" data-vf-filter=\"fun\" data-v=\"vacio\" aria-pressed=\"false\">Balance pressure and vacuum<\/button><\/p><\/div><\/div><div class=\"wp-block-group vf-grp is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-envolt wp-block-paragraph\"><span class=\"vf-lab\">Opening<\/span><\/p><div class=\"wp-block-group vf-chips is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-envolt wp-block-paragraph\"><button type=\"button\" class=\"vf-chip\" data-vf-filter=\"ap\" data-v=\"total\" aria-pressed=\"false\">Full, instantaneous<\/button><button type=\"button\" class=\"vf-chip\" data-vf-filter=\"ap\" data-v=\"prog\" aria-pressed=\"false\">Progressive<\/button><\/p><\/div><\/div><div class=\"wp-block-group vf-grp is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-envolt wp-block-paragraph\"><span class=\"vf-lab\">Inlet size<\/span><\/p><div class=\"wp-block-group vf-chips is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-envolt wp-block-paragraph\"><button type=\"button\" class=\"vf-chip\" data-vf-filter=\"dn\" data-v=\"8-20\" aria-pressed=\"false\">Up to \u00be\u2033<\/button><button type=\"button\" class=\"vf-chip\" data-vf-filter=\"dn\" data-v=\"25-80\" aria-pressed=\"false\">1\u2033 to 3\u2033<\/button><button type=\"button\" class=\"vf-chip\" data-vf-filter=\"dn\" data-v=\"100-100\" aria-pressed=\"false\">4\u2033 or DN100<\/button><\/p><\/div><\/div><div class=\"wp-block-group vf-fbar is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-envolt wp-block-paragraph\"><a class=\"vf-btn vf-btn--pri\" href=\"#modelos\"><span>View <b data-vf-count=\"\">4<\/b> <span data-vf-count-txt=\"\" data-one=\"model\" data-many=\"models\">models<\/span><\/span><\/a><button type=\"button\" class=\"vf-reset\" data-vf-reset=\"\" hidden>Clear filters<\/button><\/p><\/div><\/div><\/div><ul class=\"vf-pdp-trust wp-block-list\"><li>Bench-tested safety valves<\/li><li>Supplied preset to the pressure you specify<\/li><li>Material and heat certificates on request<\/li><li>Valfonta, Badalona, since 1962<\/li><\/ul><nav class=\"wp-block-group vf-pdp-nav vfa-aria-label--Datasheet%20contents is-layout-flow wp-block-group-is-layout-flow\"><ul class=\"wp-block-list\"><li><a href=\"#modelos\">Models<\/a><\/li><li><a href=\"#como-funciona\">Safety or relief<\/a><\/li><li><a href=\"#preguntas\">FAQ<\/a><\/li><li><a href=\"#solicitar\">Request a quote<\/a><\/li><\/ul><\/nav><section id=\"modelos\" class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><h2 class=\"wp-block-heading\">Safety valve models<\/h2><p class=\"vf-c2-intro wp-block-paragraph\">Filter with the search tool in the header or switch to the comparison table. Each product page includes specifications, available figures and sizes, and the PDF datasheet.<\/p><div class=\"wp-block-group vf-c2-bar is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-count vfa-aria-live--polite wp-block-paragraph\"><b data-vf-count=\"\">4<\/b> <span data-vf-count-txt=\"\" data-one=\"model\" data-many=\"models\" data-fit=\"1\">models<\/span><\/p><p class=\"vf-envolt wp-block-paragraph\"><button type=\"button\" class=\"vf-reset\" data-vf-reset=\"\" hidden>Clear filters<\/button><\/p><div class=\"wp-block-group vf-view vfa-role--tablist vfa-aria-label--View is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-envolt wp-block-paragraph\"><button type=\"button\" role=\"tab\" aria-selected=\"true\" data-vf-view=\"cards\">Cards<\/button><button type=\"button\" role=\"tab\" aria-selected=\"false\" data-vf-view=\"table\">Comparison table<\/button><\/p><\/div><\/div><div class=\"wp-block-group vf-c2-cardsview is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group vf-c2-group vfd-group--seg is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group vf-ghead is-layout-flow wp-block-group-is-layout-flow\"><h3 class=\"wp-block-heading\">Safety valves<\/h3><p class=\"wp-block-paragraph\">They protect tanks, boilers, and pipelines: they open when the set pressure is exceeded and close again once the pressure returns to normal.<\/p><\/div><div class=\"wp-block-group vf-c2-cards vf-t-ul is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group vf-c2-card vfd-vf-item--p vfd-fun--sobre vfd-ap--total vfd-dnmin--8 vfd-dnmax--100 vf-t-li is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group vf-img is-layout-flow wp-block-group-is-layout-flow\"><figure class=\"wp-block-image vf-img-suelta\"><a href=\"\/en\/product\/alper-fully-open-safety-valve\/\"><img decoding=\"async\" src=\"https:\/\/www.valfonta.com\/wp-content\/uploads\/2026\/10\/alper-1-700x700-1.jpg\" alt=\"ALPER full-opening safety valve with lever and 90\u00b0 piped discharge\" class=\"wp-image-184\" width=\"160\" height=\"160\" loading=\"lazy\"><\/a><\/figure><\/div><div class=\"wp-block-group vf-body is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-tag wp-block-paragraph\">Full, instantaneous opening<\/p><h3 class=\"wp-block-heading\"><a href=\"\/en\/product\/alper-fully-open-safety-valve\/\">ALPER<\/a><\/h3><p class=\"vf-sub wp-block-paragraph\">Spring-loaded safety valve, available in lever or sealed figures and with piped discharge.<\/p><div class=\"wp-block-group vf-t-dl is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-t-dt vf-p0 wp-block-paragraph\">Sizes<\/p><p class=\"vf-t-dd vf-p0 wp-block-paragraph\">\u00bc\u2033 to 4\u2033 threaded \u00b7 DN15\u2013100 flanged<\/p><\/div><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-t-dt vf-p0 wp-block-paragraph\">Pressure<\/p><p class=\"vf-t-dd vf-p0 wp-block-paragraph\">PN25 metal seat \u00b7 PN16 PTFE<\/p><\/div><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-t-dt vf-p0 wp-block-paragraph\">Temperature<\/p><p class=\"vf-t-dd vf-p0 wp-block-paragraph\">up to 280 \u00b0C <small>stainless; 240 \u00b0C bronze<\/small><\/p><\/div><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-t-dt vf-p0 wp-block-paragraph\">Material<\/p><p class=\"vf-t-dd vf-p0 wp-block-paragraph\">RG5 bronze or 316L stainless<\/p><\/div><\/div><p class=\"vf-fit wp-block-paragraph\"><b>Choose it if<\/b> you need full, instantaneous opening in medium or large sizes, threaded or flanged.<\/p><div class=\"wp-block-group vf-act is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-envolt wp-block-paragraph\"><a class=\"vf-btn vf-btn--sec\" href=\"\/en\/product\/alper-fully-open-safety-valve\/\">View product<\/a><a class=\"vf-btn vf-btn--pri\" href=\"#solicitar\" data-vf-model=\"ALPER safety valve\">Request a quote<\/a><\/p><\/div><\/div><\/div><div class=\"wp-block-group vf-c2-card vfd-vf-item--p vfd-fun--sobre vfd-ap--total vfd-dnmin--8 vfd-dnmax--20 vf-t-li is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group vf-img is-layout-flow wp-block-group-is-layout-flow\"><figure class=\"wp-block-image vf-img-suelta\"><a href=\"\/en\/product\/safety-valves-for-boilers-jas\/\"><img decoding=\"async\" src=\"https:\/\/www.valfonta.com\/wp-content\/uploads\/2026\/10\/jas-1-700x700-1.jpg\" alt=\"JAS brass safety valve with lever and threaded piped discharge\" class=\"wp-image-195\" width=\"160\" height=\"160\" loading=\"lazy\"><\/a><\/figure><\/div><div class=\"wp-block-group vf-body is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-tag wp-block-paragraph\">Full, instantaneous opening<\/p><h3 class=\"wp-block-heading\"><a href=\"\/en\/product\/safety-valves-for-boilers-jas\/\">JAS<\/a><\/h3><p class=\"vf-sub wp-block-paragraph\">Compact threaded safety valve in brass with a Viton seat.<\/p><div class=\"wp-block-group vf-t-dl is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-t-dt vf-p0 wp-block-paragraph\">Sizes<\/p><p class=\"vf-t-dd vf-p0 wp-block-paragraph\">\u00bc\u2033 to \u00be\u2033<\/p><\/div><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-t-dt vf-p0 wp-block-paragraph\">Pressure<\/p><p class=\"vf-t-dd vf-p0 wp-block-paragraph\">PN16<\/p><\/div><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-t-dt vf-p0 wp-block-paragraph\">Temperature<\/p><p class=\"vf-t-dd vf-p0 wp-block-paragraph\">up to 180 \u00b0C<\/p><\/div><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-t-dt vf-p0 wp-block-paragraph\">Figures<\/p><p class=\"vf-t-dd vf-p0 wp-block-paragraph\">310 with lever \u00b7 311 sealed<\/p><\/div><\/div><p class=\"vf-fit wp-block-paragraph\"><b>Choose it if<\/b> you need a compact threaded safety valve, from \u00bc\u2033 to \u00be\u2033, up to PN16 and 180 \u00b0C.<\/p><div class=\"wp-block-group vf-act is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-envolt wp-block-paragraph\"><a class=\"vf-btn vf-btn--sec\" href=\"\/en\/product\/safety-valves-for-boilers-jas\/\">View product<\/a><a class=\"vf-btn vf-btn--pri\" href=\"#solicitar\" data-vf-model=\"JAS safety valve\">Request a quote<\/a><\/p><\/div><\/div><\/div><div class=\"wp-block-group vf-c2-card vfd-vf-item--p vfd-fun--sobre vfd-ap--prog vfd-dnmin--10 vfd-dnmax--80 vf-t-li is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group vf-img is-layout-flow wp-block-group-is-layout-flow\"><figure class=\"wp-block-image vf-img-suelta\"><a href=\"\/en\/product\/progressive-opening-safety-valve\/\"><img decoding=\"async\" src=\"https:\/\/www.valfonta.com\/wp-content\/uploads\/2026\/10\/alivio-368-700x700-1.jpg\" alt=\"Figure 368 progressive-opening safety valve in brass with lever and threaded connection\" class=\"wp-image-196\" width=\"160\" height=\"160\" loading=\"lazy\"><\/a><\/figure><\/div><div class=\"wp-block-group vf-body is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-tag wp-block-paragraph\">Progressive opening<\/p><h3 class=\"wp-block-heading\"><a href=\"\/en\/product\/progressive-opening-safety-valve\/\">368\u2013371<\/a><\/h3><p class=\"vf-sub wp-block-paragraph\">Progressive-opening safety valve, with open discharge (368) or piped discharge (371).<\/p><div class=\"wp-block-group vf-t-dl is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-t-dt vf-p0 wp-block-paragraph\">Sizes<\/p><p class=\"vf-t-dd vf-p0 wp-block-paragraph\">3\/8\u2033 to 3\u2033<\/p><\/div><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-t-dt vf-p0 wp-block-paragraph\">Set pressure<\/p><p class=\"vf-t-dd vf-p0 wp-block-paragraph\">0\u20131 \u00b7 1\u201311 \u00b7 11\u201316 bar<\/p><\/div><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-t-dt vf-p0 wp-block-paragraph\">Temperature<\/p><p class=\"vf-t-dd vf-p0 wp-block-paragraph\">up to 180 \u00b0C<\/p><\/div><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-t-dt vf-p0 wp-block-paragraph\">Discharge<\/p><p class=\"vf-t-dd vf-p0 wp-block-paragraph\">open (368) \u00b7 piped (371)<\/p><\/div><\/div><p class=\"vf-fit wp-block-paragraph\"><b>Choose it if<\/b> you want progressive opening rather than instantaneous pop action.<\/p><div class=\"wp-block-group vf-act is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-envolt wp-block-paragraph\"><a class=\"vf-btn vf-btn--sec\" href=\"\/en\/product\/progressive-opening-safety-valve\/\">View product<\/a><a class=\"vf-btn vf-btn--pri\" href=\"#solicitar\" data-vf-model=\"368\u2013371 safety valve\">Request a quote<\/a><\/p><\/div><\/div><\/div><\/div><\/div><div class=\"wp-block-group vf-c2-group vfd-group--atm is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group vf-ghead is-layout-flow wp-block-group-is-layout-flow\"><h3 class=\"wp-block-heading\">Atmospheric valves<\/h3><p class=\"wp-block-paragraph\">They let air in under vacuum and, in the double-regulation version, let excess pressure out, within very small ranges.<\/p><\/div><div class=\"wp-block-group vf-c2-cards vf-t-ul is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group vf-c2-card vfd-vf-item--p vfd-fun--vacio vfd-ap--prog vfd-dnmin--15 vfd-dnmax--100 vf-t-li is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group vf-img is-layout-flow wp-block-group-is-layout-flow\"><figure class=\"wp-block-image vf-img-suelta\"><a href=\"\/en\/product\/alper-atmospheric-valves\/\"><img decoding=\"async\" src=\"https:\/\/www.valfonta.com\/wp-content\/uploads\/2026\/10\/alperatmos-2-700x700-1.jpg\" alt=\"ALPER double-regulation atmospheric valve with 90\u00b0 piped discharge and protective mesh\" class=\"wp-image-197\" width=\"160\" height=\"160\" loading=\"lazy\"><\/a><\/figure><\/div><div class=\"wp-block-group vf-body is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-tag wp-block-paragraph\">Pressure and vacuum<\/p><h3 class=\"wp-block-heading\"><a href=\"\/en\/product\/alper-atmospheric-valves\/\">ALPER atmospheric<\/a><\/h3><p class=\"vf-sub wp-block-paragraph\">Atmospheric valve for sealed vessels: single regulation (vacuum) or double regulation (pressure and vacuum).<\/p><div class=\"wp-block-group vf-t-dl is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-t-dt vf-p0 wp-block-paragraph\">Sizes<\/p><p class=\"vf-t-dd vf-p0 wp-block-paragraph\">\u00bd\u2033 to 4\u2033 threaded \u00b7 DIN flanges<\/p><\/div><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-t-dt vf-p0 wp-block-paragraph\">Positive pressure<\/p><p class=\"vf-t-dd vf-p0 wp-block-paragraph\">+0.080 to +8 bar<\/p><\/div><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-t-dt vf-p0 wp-block-paragraph\">Vacuum<\/p><p class=\"vf-t-dd vf-p0 wp-block-paragraph\">\u22120.050 to \u22120.650 bar<\/p><\/div><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-t-dt vf-p0 wp-block-paragraph\">Temperature<\/p><p class=\"vf-t-dd vf-p0 wp-block-paragraph\">up to 280 \u00b0C <small>stainless<\/small><\/p><\/div><\/div><p class=\"vf-fit wp-block-paragraph\"><b>Choose it if<\/b> you need to balance a sealed tank with the atmosphere, against vacuum or pressure.<\/p><div class=\"wp-block-group vf-act is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-envolt wp-block-paragraph\"><a class=\"vf-btn vf-btn--sec\" href=\"\/en\/product\/alper-atmospheric-valves\/\">View product<\/a><a class=\"vf-btn vf-btn--pri\" href=\"#solicitar\" data-vf-model=\"ALPER atmospheric valve\">Request a quote<\/a><\/p><\/div><\/div><\/div><\/div><\/div><\/div><div class=\"wp-block-group vf-c2-table vfa-hidden-- is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group vf-tbl-wrap is-layout-flow wp-block-group-is-layout-flow\"><figure class=\"wp-block-table vf-tbl vf-tbl--grid\"><table><thead><tr><th scope=\"col\"><button type=\"button\" data-vf-sort=\"0\" data-type=\"t\">Model<\/button><\/th><th scope=\"col\"><button type=\"button\" data-vf-sort=\"1\" data-type=\"t\">Opening<\/button><\/th><th scope=\"col\"><button type=\"button\" data-vf-sort=\"2\" data-type=\"t\">Inlet sizes<\/button><\/th><th scope=\"col\"><button type=\"button\" data-vf-sort=\"3\" data-type=\"t\">Connection<\/button><\/th><th scope=\"col\"><button type=\"button\" data-vf-sort=\"4\" data-type=\"t\">Material<\/button><\/th><th scope=\"col\"><button type=\"button\" data-vf-sort=\"5\" data-type=\"t\">Pressure<\/button><\/th><th scope=\"col\"><button type=\"button\" data-vf-sort=\"6\" data-type=\"n\">Max. T (\u00b0C)<\/button><\/th><\/tr><\/thead><tbody><tr><th scope=\"row\"><span class=\"vf-dato vf-dato-fila\" hidden data-vf-item=\"t\" data-fun=\"sobre\" data-ap=\"total\" data-dnmin=\"8\" data-dnmax=\"100\"><\/span><span class=\"vf-dato\" hidden data-s=\"ALPER\"><\/span><a href=\"\/en\/product\/alper-fully-open-safety-valve\/\">ALPER<\/a><\/th><td><span class=\"vf-dato\" hidden data-s=\"Full, instantaneous\"><\/span>Full, instantaneous<\/td><td><span class=\"vf-dato\" hidden data-s=\"\u00bc\u2033\u20134\u2033 \u00b7 DN15\u2013100\"><\/span>\u00bc\u2033\u20134\u2033 \u00b7 DN15\u2013100<\/td><td><span class=\"vf-dato\" hidden data-s=\"BSP threaded or DIN flanged\"><\/span>BSP threaded or DIN flanged<\/td><td><span class=\"vf-dato\" hidden data-s=\"RG5 bronze or 316L stainless\"><\/span>RG5 bronze or 316L stainless<\/td><td><span class=\"vf-dato\" hidden data-s=\"PN25 (PN16 with PTFE)\"><\/span>PN25 (PN16 with PTFE)<\/td><td><span class=\"vf-dato\" hidden data-s=\"280\"><\/span>280 stainless \u00b7 240 bronze<\/td><\/tr><tr><th scope=\"row\"><span class=\"vf-dato vf-dato-fila\" hidden data-vf-item=\"t\" data-fun=\"sobre\" data-ap=\"total\" data-dnmin=\"8\" data-dnmax=\"20\"><\/span><span class=\"vf-dato\" hidden data-s=\"JAS\"><\/span><a href=\"\/en\/product\/safety-valves-for-boilers-jas\/\">JAS<\/a><\/th><td><span class=\"vf-dato\" hidden data-s=\"Full, instantaneous\"><\/span>Full, instantaneous<\/td><td><span class=\"vf-dato\" hidden data-s=\"\u00bc\u2033\u2013\u00be\u2033\"><\/span>\u00bc\u2033\u2013\u00be\u2033<\/td><td><span class=\"vf-dato\" hidden data-s=\"BSP threaded\"><\/span>BSP threaded<\/td><td><span class=\"vf-dato\" hidden data-s=\"Brass, Viton seat\"><\/span>Brass, Viton seat<\/td><td><span class=\"vf-dato\" hidden data-s=\"PN16\"><\/span>PN16<\/td><td><span class=\"vf-dato\" hidden data-s=\"180\"><\/span>180<\/td><\/tr><tr><th scope=\"row\"><span class=\"vf-dato vf-dato-fila\" hidden data-vf-item=\"t\" data-fun=\"sobre\" data-ap=\"prog\" data-dnmin=\"10\" data-dnmax=\"80\"><\/span><span class=\"vf-dato\" hidden data-s=\"368\u2013371\"><\/span><a href=\"\/en\/product\/progressive-opening-safety-valve\/\">368\u2013371<\/a><\/th><td><span class=\"vf-dato\" hidden data-s=\"Progressive\"><\/span>Progressive<\/td><td><span class=\"vf-dato\" hidden data-s=\"3\/8\u2033\u20133\u2033\"><\/span>3\/8\u2033\u20133\u2033<\/td><td><span class=\"vf-dato\" hidden data-s=\"BSP threaded\"><\/span>BSP threaded<\/td><td><span class=\"vf-dato\" hidden data-s=\"Brass \/ bronze\"><\/span>Brass \/ bronze<\/td><td><span class=\"vf-dato\" hidden data-s=\"Set pressure 0\u201316 bar (PN16 bronze \u00b7 PN12 Viton)\"><\/span>Set pressure 0\u201316 bar (PN16 bronze \u00b7 PN12 Viton)<\/td><td><span class=\"vf-dato\" hidden data-s=\"180\"><\/span>180<\/td><\/tr><tr><th scope=\"row\"><span class=\"vf-dato vf-dato-fila\" hidden data-vf-item=\"t\" data-fun=\"vacio\" data-ap=\"prog\" data-dnmin=\"15\" data-dnmax=\"100\"><\/span><span class=\"vf-dato\" hidden data-s=\"ALPER atmospheric\"><\/span><a href=\"\/en\/product\/alper-atmospheric-valves\/\">ALPER atmospheric<\/a><\/th><td><span class=\"vf-dato\" hidden data-s=\"Progressive\"><\/span>Progressive<\/td><td><span class=\"vf-dato\" hidden data-s=\"\u00bd\u2033\u20134\u2033 \u00b7 DN15\u2013100\"><\/span>\u00bd\u2033\u20134\u2033 \u00b7 DN15\u2013100<\/td><td><span class=\"vf-dato\" hidden data-s=\"BSP threaded or DIN flanged\"><\/span>BSP threaded or DIN flanged<\/td><td><span class=\"vf-dato\" hidden data-s=\"RG5 bronze or 316L stainless\"><\/span>RG5 bronze or 316L stainless<\/td><td><span class=\"vf-dato\" hidden data-s=\"+0.080 to +8 bar \u00b7 \u22120.050 to \u22120.650 bar\"><\/span>+0.080 to +8 bar \u00b7 \u22120.050 to \u22120.650 bar<\/td><td><span class=\"vf-dato\" hidden data-s=\"280\"><\/span>280 stainless<\/td><\/tr><\/tbody><\/table><\/figure><\/div><p class=\"vf-note wp-block-paragraph\">Data from each model\u2019s datasheet. All of them work with liquids, compressed air, inert gases, and steam. On the ALPER, DIN flanges go up to DN32 in the stainless steel figures.<\/p><\/div><div class=\"wp-block-group vf-c2-empty vfa-hidden-- is-layout-flow wp-block-group-is-layout-flow\"><p class=\"wp-block-paragraph\"><b>No model matches these filters.<\/b> Tell us about your installation in the <a href=\"#solicitar\" data-vf-model=\"I don&#x27;t know \/ I need advice\">form<\/a> and we will recommend the right valve.<\/p><\/div><\/section><section id=\"como-funciona\" class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><h2 class=\"wp-block-heading\">Safety valve vs. relief valve: how they differ<\/h2><div class=\"wp-block-group vf-c2-how vf-solo is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group vf-txt is-layout-flow wp-block-group-is-layout-flow\"><p class=\"wp-block-paragraph\">The main difference is how they open. The <a href=\"\/en\/product\/alper-fully-open-safety-valve\/\">ALPER<\/a> and the <a href=\"\/en\/product\/safety-valves-for-boilers-jas\/\">JAS<\/a> are <strong>full, instantaneous opening<\/strong> (A.I.T.) valves: when the set pressure is exceeded, they open fully and discharge the excess fluid. The <a href=\"\/en\/product\/progressive-opening-safety-valve\/\">368\u2013371<\/a> is a <strong>progressive opening<\/strong> valve: it starts to open when the set pressure is exceeded, and its datasheet also calls it a relief valve.<\/p><p class=\"wp-block-paragraph\">Valfonta <a href=\"\/en\/pressure-relief-valve\/\">relief valves<\/a> and excess pressure valves open in proportion to the pressure rise and hold the upstream pressure at the set value. Their manuals warn that they are not safety valves: if the installation needs overpressure protection, a safety valve must also be installed. We explain it in <a href=\"\/en\/blog\/what-difference-between-safety-valve-and-relief-valve\/\">the difference between a safety valve and a relief valve<\/a>.<\/p><p class=\"wp-block-paragraph\"><a href=\"\/en\/product\/alper-atmospheric-valves\/\">ALPER atmospheric valves<\/a> serve another purpose: they let air into or out of sealed vessels. Single-regulation models act against vacuum, and double-regulation models also act against positive pressure, within very small ranges.<\/p><\/div><\/div><\/section><section id=\"normativa\" class=\"wp-block-group vf-c2-norm is-layout-flow wp-block-group-is-layout-flow\"><h2 class=\"wp-block-heading\">Certification<\/h2><div class=\"wp-block-group vf-norm vf-t-ul is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group vf-t-li is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-envolt wp-block-paragraph\"><b>Pressure Equipment Directive<\/b><\/p><p class=\"wp-block-paragraph\">The 368\u2013371 is certified to PED 2014\/68\/EU. On the ALPER, threaded figures 375, 376, 385, 386, 395, and 396 carry CE certification; for flanged figures, please ask us. Atmospheric valves do not carry CE certification.<\/p><\/div><div class=\"wp-block-group vf-t-li is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-envolt wp-block-paragraph\"><b>Certificates on request<\/b><\/p><p class=\"wp-block-paragraph\">For the ALPER, the JAS, and the 368\u2013371, material, heat, and output certificates are delivered with the valve if requested in advance.<\/p><\/div><\/div><p class=\"wp-block-paragraph\">View and download <a href=\"\/en\/certificates\/\">Valfonta\u2019s certificates<\/a>.<\/p><\/section><section id=\"preguntas\" class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><h2 class=\"wp-block-heading\">Frequently asked questions about safety valves<\/h2><details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary>What is the difference between a safety valve and a relief valve?<\/summary><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"wp-block-paragraph\">How they open and what they do. ALPER and JAS safety valves open fully and instantaneously when the set pressure is exceeded; the 368\u2013371 opens progressively, and its datasheet also calls it a relief valve. <a href=\"\/en\/pressure-relief-valve\/\">Relief valves and excess pressure valves<\/a> open in proportion to the pressure rise and do not replace a safety valve.<\/p><\/div><\/details><details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary>Are they supplied preset?<\/summary><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"wp-block-paragraph\">Yes. ALPER, JAS, and 368\u2013371 safety valves are tested on a test bench and supplied preset to the pressure specified by the customer.<\/p><\/div><\/details><details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary>What fluids do they handle?<\/summary><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"wp-block-paragraph\">Liquids, compressed air, inert gases, and steam. The maximum temperature is 180 \u00b0C for the JAS and the 368\u2013371, and 280 \u00b0C for the stainless steel ALPER valves.<\/p><\/div><\/details><details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary>What is an atmospheric valve used for?<\/summary><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"wp-block-paragraph\">To balance the pressure in a sealed vessel with atmospheric pressure: it lets air in under vacuum and, in the double-regulation version, lets excess pressure out.<\/p><\/div><\/details><details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary>What information does Valfonta need to prepare a quote?<\/summary><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"wp-block-paragraph\">The fluid and its temperature, the set pressure, the size and connection (threaded or flanged), the material, and whether you want it with a lever or sealed.<\/p><\/div><\/details><\/section><section id=\"guias\" class=\"wp-block-group vf-c2-more is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><h2 class=\"wp-block-heading\">Technical guides on safety and relief<\/h2><div class=\"wp-block-group vf-arts vf-t-ul is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group vf-t-li is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-envolt wp-block-paragraph\"><a href=\"\/en\/blog\/what-difference-between-safety-valve-and-relief-valve\/\">Difference between a safety valve and a relief valve<\/a><\/p><\/div><div class=\"wp-block-group vf-sin-idioma vf-t-li is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-envolt wp-block-paragraph\"><a data-vf-href=\"\/blog\/tarado-de-valvulas-de-alivio\/\">Relief valve set pressure safety audit<\/a><\/p><\/div><\/div><\/div><p class=\"vf-fams wp-block-paragraph\"><b>Other families:<\/b> <a href=\"\/en\/pressure-relief-valve\/\">Pressure relief valves<\/a> \u00b7 <a href=\"\/en\/pressure-reducing-valves\/\">Pressure reducing valves<\/a> \u00b7 <a href=\"\/en\/control-valve\/\">Control valves<\/a> \u00b7 <a href=\"\/en\/liquid-steam-ejectors\/\">Ejectors<\/a><\/p><\/section><section id=\"solicitar\" class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group vf-quote is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><h2 class=\"wp-block-heading\">Request a quote for a safety valve<\/h2><p class=\"wp-block-paragraph\">Give us your installation details and we will recommend the right model, figure, and size.<\/p><ul class=\"wp-block-list\"><li>Fluid and temperature<\/li><li>Set pressure (or vacuum setting)<\/li><li>Size and connection (threaded or flanged)<\/li><li>Material and whether you want it with a lever or sealed<\/li><\/ul><p class=\"vf-pdp-contact wp-block-paragraph\">You can also call <a href=\"tel:+34933720888\">933 720 888<\/a>.<\/p><\/div>\n<div class=\"wpcf7 no-js\" id=\"wpcf7-f543-o1\" lang=\"en-US\" dir=\"ltr\" data-wpcf7-id=\"543\">\n<div class=\"screen-reader-response\"><p role=\"status\" aria-live=\"polite\" aria-atomic=\"true\"><\/p> <ul><\/ul><\/div>\n<form action=\"\/en\/wp-json\/wp\/v2\/pages\/638#wpcf7-f543-o1\" method=\"post\" class=\"wpcf7-form init vf-form wpcf7-acceptance-as-validation\" aria-label=\"Contact form\" novalidate=\"novalidate\" data-status=\"init\" toolname=\"solicitar_oferta\" tooldescription=\"Request a quote from Valfonta for the models on this page (model, size, fluid and pressures); a member of the team will reply.\">\n<fieldset class=\"hidden-fields-container\"><input type=\"hidden\" name=\"_wpcf7\" value=\"543\" \/><input type=\"hidden\" name=\"_wpcf7_version\" value=\"6.2.3\" \/><input type=\"hidden\" name=\"_wpcf7_locale\" value=\"en_US\" \/><input type=\"hidden\" name=\"_wpcf7_unit_tag\" value=\"wpcf7-f543-o1\" \/><input type=\"hidden\" name=\"_wpcf7_container_post\" value=\"0\" \/><input type=\"hidden\" name=\"_wpcf7_posted_data_hash\" value=\"\" \/><input type=\"hidden\" name=\"_vf_t\" value=\"1792698943.a677e3f00a8b9796\" \/>\n<\/fieldset>\n<input class=\"wpcf7-form-control wpcf7-hidden\" value=\"V\u00e1lvulas de seguridad\" type=\"hidden\" name=\"familia\" \/><label>Name *<span class=\"wpcf7-form-control-wrap\" data-name=\"nombre\"><input size=\"40\" maxlength=\"400\" class=\"wpcf7-form-control wpcf7-text wpcf7-validates-as-required\" autocomplete=\"name\" aria-required=\"true\" aria-invalid=\"false\" value=\"\" type=\"text\" name=\"nombre\" \/><\/span><\/label><label>Company<span class=\"wpcf7-form-control-wrap\" data-name=\"empresa\"><input size=\"40\" maxlength=\"400\" class=\"wpcf7-form-control wpcf7-text\" autocomplete=\"organization\" aria-invalid=\"false\" value=\"\" type=\"text\" name=\"empresa\" \/><\/span><\/label><label>Email *<span class=\"wpcf7-form-control-wrap\" data-name=\"email\"><input size=\"40\" maxlength=\"400\" class=\"wpcf7-form-control wpcf7-email wpcf7-validates-as-required wpcf7-text wpcf7-validates-as-email\" autocomplete=\"email\" aria-required=\"true\" aria-invalid=\"false\" value=\"\" type=\"email\" name=\"email\" \/><\/span><\/label><label>Phone<span class=\"wpcf7-form-control-wrap\" data-name=\"telefono\"><input size=\"40\" maxlength=\"400\" class=\"wpcf7-form-control wpcf7-tel wpcf7-text wpcf7-validates-as-tel\" autocomplete=\"tel\" aria-invalid=\"false\" value=\"\" type=\"tel\" name=\"telefono\" \/><\/span><\/label><label class=\"vf-full\">Model<span class=\"wpcf7-form-control-wrap\" data-name=\"modelo\"><select class=\"wpcf7-form-control wpcf7-select\" aria-invalid=\"false\" name=\"modelo\"><option value=\"\">Select<\/option><option value=\"ALPER safety valve\">ALPER safety valve<\/option><option value=\"JAS safety valve\">JAS safety valve<\/option><option value=\"368\u2013371 safety valve\">368\u2013371 safety valve<\/option><option value=\"ALPER atmospheric valve\">ALPER atmospheric valve<\/option><option value=\"I don&#039;t know \/ I need advice\">I don&#039;t know \/ I need advice<\/option><\/select><\/span><\/label><label>Set pressure (bar)<span class=\"wpcf7-form-control-wrap\" data-name=\"tarado\"><input size=\"40\" maxlength=\"400\" class=\"wpcf7-form-control wpcf7-text\" aria-invalid=\"false\" value=\"\" type=\"text\" name=\"tarado\" \/><\/span><\/label><label>Temperature (\u00b0C)<span class=\"wpcf7-form-control-wrap\" data-name=\"temperatura\"><input size=\"40\" maxlength=\"400\" class=\"wpcf7-form-control wpcf7-text\" aria-invalid=\"false\" value=\"\" type=\"text\" name=\"temperatura\" \/><\/span><\/label><label class=\"vf-full\">Message<span class=\"wpcf7-form-control-wrap\" data-name=\"mensaje\"><textarea cols=\"40\" rows=\"4\" maxlength=\"2000\" class=\"wpcf7-form-control wpcf7-textarea\" aria-invalid=\"false\" name=\"mensaje\"><\/textarea><\/span><\/label><label class=\"vf-chk vf-full\"><span class=\"wpcf7-form-control-wrap\" data-name=\"privacidad\"><span class=\"wpcf7-form-control wpcf7-acceptance\"><span class=\"wpcf7-list-item\"><input type=\"checkbox\" name=\"privacidad\" value=\"1\" aria-invalid=\"false\" \/><\/span><\/span><\/span> <span>I have read and accept the <a href=\"\/en\/privacy-policy\/\">privacy policy<\/a> *<\/span><\/label><input class=\"wpcf7-form-control wpcf7-submit has-spinner vf-btn vf-btn--pri\" type=\"submit\" value=\"Send request\" \/><span class=\"vf-hp\" aria-hidden=\"true\"><label>Web <input type=\"text\" name=\"vf_web\" value=\"\" tabindex=\"-1\" autocomplete=\"off\" toolparamdescription=\"Campo de control: d\u00e9jalo vac\u00edo\"><\/label><\/span><div class=\"wpcf7-response-output\" aria-hidden=\"true\"><\/div>\n<\/form>\n<\/div>\n\n<\/div><\/section><div class=\"wp-block-group vf-pdp-bar is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-envolt wp-block-paragraph\"><a class=\"vf-btn vf-btn--sec\" href=\"tel:+34933720888\">Call<\/a><a class=\"vf-btn vf-btn--pri\" href=\"#solicitar\">Request a quote<\/a><\/p><\/div><\/article><\/div><\/div>","protected":false},"excerpt":{"rendered":"<p>Home\u203aSafety valves Overpressure protection \u00b7 Badalona, since 1962 Safety valves They detect overpressure in tanks, boilers, or pipelines and discharge the excess fluid without auxiliary power; once the pressure returns to normal, they close again. Models with full, instantaneous opening and with progressive opening, plus atmospheric valves for sealed vessels. Request a quoteCompare models Questions ... <a title=\"Safety valves\" class=\"read-more\" href=\"https:\/\/www.valfonta.com\/en\/safety-valves\/\" aria-label=\"Read more about Safety valves\">Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"_generate-full-width-content":"true","_generate-disable-headline":"true","rank_math_title":"Safety and atmospheric valves | Valfonta","rank_math_description":"ALPER, JAS, and 368\u2013371 safety valves with full or progressive opening, from \u00bc\u2033 to 4\u2033 or DN100, and ALPER atmospheric valves for pressure and vacuum.","rank_math_focus_keyword":"","vf_jsonld":"[{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"Organization\",\"@id\":\"https:\/\/www.valfonta.com\/#organization\",\"name\":\"Valfonta\",\"legalName\":\"Val Fonta, S.L.\",\"taxID\":\"B59935718\",\"url\":\"https:\/\/www.valfonta.com\/en\/\",\"logo\":{\"@type\":\"ImageObject\",\"url\":\"https:\/\/www.valfonta.com\/wp-content\/uploads\/2026\/10\/valfonta-logo.webp\"},\"foundingDate\":\"1962\",\"email\":\"valfonta@valfonta.com\",\"telephone\":\"+34 933 720 888\",\"address\":{\"@type\":\"PostalAddress\",\"streetAddress\":\"C\/ Bronze 26, Pol. Ind. Les Guixeres\",\"postalCode\":\"08915\",\"addressLocality\":\"Badalona\",\"addressRegion\":\"Barcelona\",\"addressCountry\":\"ES\"},\"description\":\"Design, manufacture, and sale of pressure reducing valves, pressure relief valves, and control valves.\"},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/www.valfonta.com\/#website\",\"url\":\"https:\/\/www.valfonta.com\/en\/\",\"name\":\"Valfonta\",\"publisher\":{\"@id\":\"https:\/\/www.valfonta.com\/#organization\"},\"inLanguage\":\"en\"},{\"@type\":\"CollectionPage\",\"@id\":\"https:\/\/www.valfonta.com\/en\/safety-valves\/#webpage\",\"url\":\"https:\/\/www.valfonta.com\/en\/safety-valves\/\",\"name\":\"Safety and atmospheric valves | Valfonta\",\"description\":\"ALPER, JAS, and 368\u2013371 safety valves with full or progressive opening, from \u00bc\u2033 to 4\u2033 or DN100, and ALPER atmospheric valves for pressure and vacuum.\",\"isPartOf\":{\"@id\":\"https:\/\/www.valfonta.com\/#website\"},\"about\":{\"@id\":\"https:\/\/www.valfonta.com\/#organization\"},\"inLanguage\":\"en\",\"datePublished\":\"2020-03-11T11:01:53+02:00\",\"dateModified\":\"2026-01-13T10:37:53+02:00\",\"breadcrumb\":{\"@id\":\"https:\/\/www.valfonta.com\/en\/safety-valves\/#breadcrumb\"},\"mainEntity\":{\"@id\":\"https:\/\/www.valfonta.com\/en\/safety-valves\/#modelos\"},\"primaryImageOfPage\":{\"@type\":\"ImageObject\",\"url\":\"https:\/\/www.valfonta.com\/wp-content\/uploads\/2026\/10\/alper-1.jpg\"}},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/www.valfonta.com\/en\/safety-valves\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/www.valfonta.com\/en\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Safety valves\",\"item\":\"https:\/\/www.valfonta.com\/en\/safety-valves\/\"}]},{\"@type\":\"ItemList\",\"@id\":\"https:\/\/www.valfonta.com\/en\/safety-valves\/#modelos\",\"name\":\"Safety valves\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"url\":\"https:\/\/www.valfonta.com\/en\/product\/alper-fully-open-safety-valve\/\",\"name\":\"ALPER safety valve\"},{\"@type\":\"ListItem\",\"position\":2,\"url\":\"https:\/\/www.valfonta.com\/en\/product\/safety-valves-for-boilers-jas\/\",\"name\":\"JAS safety valves\"},{\"@type\":\"ListItem\",\"position\":3,\"url\":\"https:\/\/www.valfonta.com\/en\/product\/progressive-opening-safety-valve\/\",\"name\":\"368 \u2013 371 progressive-opening safety valve\"},{\"@type\":\"ListItem\",\"position\":4,\"url\":\"https:\/\/www.valfonta.com\/en\/product\/alper-atmospheric-valves\/\",\"name\":\"ALPER atmospheric valves\"}]},{\"@type\":\"FAQPage\",\"@id\":\"https:\/\/www.valfonta.com\/en\/safety-valves\/#faq\",\"mainEntity\":[{\"@type\":\"Question\",\"name\":\"What is the difference between a safety valve and a relief valve?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"How they open and what they do. ALPER and JAS safety valves open fully and instantaneously when the set pressure is exceeded; the 368\u2013371 opens progressively, and its datasheet also calls it a relief valve. Relief valves and excess pressure valves open in proportion to the pressure rise and do not replace a safety valve.\"}},{\"@type\":\"Question\",\"name\":\"Are they supplied preset?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Yes. ALPER, JAS, and 368\u2013371 safety valves are tested on a test bench and supplied preset to the pressure specified by the customer.\"}},{\"@type\":\"Question\",\"name\":\"What fluids do they handle?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Liquids, compressed air, inert gases, and steam. 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