{"id":11645,"date":"2026-10-15T16:33:28","date_gmt":"2026-10-15T08:33:28","guid":{"rendered":"https:\/\/oxy-boss.com\/?p=11645"},"modified":"2026-10-15T16:33:29","modified_gmt":"2026-10-15T08:33:29","slug":"concentratori-ossigeno-5-vs-10-l-min-camera-iperbarica","status":"publish","type":"post","link":"https:\/\/oxy-boss.com\/it\/5-l-min-vs-10-l-min-concentrators-for-hyperbaric-chambers\/","title":{"rendered":"Concentratori da 5 L\/min vs 10 L\/min per la tua camera iperbarica: perch\u00e9 conta la portata"},"content":{"rendered":"\n
\"5<\/figure>\n\n\n\n

If you have ever stared at two oxygen concentrators sitting side by side \u2014 one rated 5 L\/min, one rated 10 L\/min \u2014 and wondered which one your hyperbaric chamber<\/a> actually needs, you are asking the right question. You are probably going to get the wrong answer, because a spec sheet compares apples to a different kind of apple.<\/p>\n\n\n\n

Here is the short version, before the detail: the number on the box is a lab number<\/strong>. It is the maximum flow the machine can push into open air at a tiny back-pressure. Your chamber is not open air. Your chamber is a sealed shell at pressure, with tubing, with occupants, with purge, and with a safety ceiling on how much oxygen can be in there at all. The question “5 or 10” only makes sense once you know what the chamber is pulling out the other end.<\/p>\n\n\n\n

So this is a flow-budget read, written from the chamber side. If you want to leave with only one takeaway, take this one: pick the concentrator the chamber needs, not the one the datasheet brags about.<\/strong><\/p>\n\n\n\n

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What the number on the box actually means<\/h2>\n\n\n\n

A 5 L\/min concentrator and a 10 L\/min concentrator are rated under the same two conditions, and both conditions are gentle:<\/p>\n\n\n\n

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  • Zero or ~7 kPa back-pressure at the outlet.<\/strong>\u00a0That is well below what most sealed chambers feel.<\/li>\n\n\n\n
  • Short tubing, no humidifier bowl in series, no mask resistance.<\/strong>\u00a0Clean plumbing.<\/li>\n<\/ul>\n\n\n\n

    Put the same machine against real back-pressure, add 10 to 50 feet of tubing, add a bubble humidifier, and the delivered flow at the chamber port is lower than the sticker. Nothing is wrong with the machine. The sticker was a number about a test bench, not about your setup. The DeVilbiss 5 L\/min family is literally rated “Maximum Recommended Flow at nominal outlet pressures of zero and 7 kPa” \u2014 the 10 L\/min family uses the same wording, and both spec a maximum tubing length as part of that rating. [1][2]<\/p>\n\n\n\n

    Two things fall out of this that a first-time buyer rarely sees spelled out:<\/p>\n\n\n\n

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    1. Nominal is not delivered.<\/strong>\u00a0A 10 L\/min machine can run at 10 L\/min \u2014 in its own test rig. In your rig it does whatever your rig lets it do.<\/li>\n\n\n\n
    2. Purity is tied to flow.<\/strong>\u00a0Pressure-swing adsorption concentrators are usually quoted at 90\u201396% O\u2082 purity, and that number is also measured near rated conditions. Push the machine toward its ceiling, add resistance, and the purity drifts down. The two numbers on the sticker \u2014 flow and purity \u2014 are both ideal-case, and they do not come together for free.<\/li>\n<\/ol>\n\n\n\n

      If a vendor hands you only a flow number and only a purity number, you have two ideal-case numbers and nothing about the setup they were measured in. Ask what the delivered flow is at your chamber’s working pressure, down your actual tubing length. That is the number that matters.<\/p>\n\n\n\n

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      The physics in one line<\/strong>: at a fixed temperature, pressure and volume of a gas move in opposite directions (Boyle’s law), total pressure is the sum of the partial pressures (Dalton’s law), and the amount of a gas that dissolves in a liquid rises with the partial pressure sitting on top of it (Henry’s law). That is the whole reason a sealed chamber is a different animal from a living room.<\/p>\n<\/blockquote>\n\n\n\n

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      Two very different jobs the concentrator can do<\/h2>\n\n\n\n

      Before you can even ask “5 or 10,” you need to say what the oxygen is doing in your chamber. There are two architectures and they ask for different flow budgets.<\/p>\n\n\n\n

      A) Enrich the whole shell.<\/strong> The concentrator feeds oxygen directly into the chamber envelope, and the occupant breathes the enriched air. Flow decides how fast you purge the shell, how fast you reach a steady oxygen level, and how fast CO\u2082 is diluted out through the release valves. There is also a hard safety ceiling here: fire-safety codes define an oxygen-enriched atmosphere as one above 23.5% O\u2082 by volume<\/strong>, and that threshold tightens further as total pressure rises. More source flow does not put more oxygen into the shell if the shell is already at the ceiling. [3]<\/p>\n\n\n\n

      B) Feed a mask, hood, or BIBS.<\/strong> The concentrator feeds a demand regulator, a non-rebreather mask, or a built-in breathing system (BIBS), and the shell itself is pressurized with ambient air. Flow decides per-person inhaled dose, not the shell’s chemistry. In this setup, the chamber side of the plumbing is air; the enriched oxygen stays inside the breathing circuit.<\/p>\n\n\n\n

      The practical answer swings on which architecture you own:<\/p>\n\n\n\n

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      • Enrich the whole shell<\/strong>\u00a0\u2192 the question is “how fast do I need to purge the shell, and how do I stay under 23.5%.” A 10 L\/min machine helps you reach steady state faster, but you are capped by chemistry, not by the machine.<\/li>\n\n\n\n
      • Mask \/ BIBS<\/strong>\u00a0\u2192 the question is “how much is this person breathing per minute, and what is the delivered flow after the regulator.” A 10 L\/min source gives you headroom for higher respiratory rates and for the pressure drop across the mask hardware.<\/li>\n<\/ul>\n\n\n\n

        If you cannot name which of the two your chamber is, no choice between 5 and 10 is going to be the right one.<\/p>\n\n\n\n

        \"Paper-cut<\/figure>\n\n\n\n
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        A working flow budget, said out loud<\/h2>\n\n\n\n

        Here is how to actually size the concentrator. It is deliberately conditional, because the numbers only mean something next to the setup around them. Read it as a working rule, not a hard spec.<\/p>\n\n\n\n

        Setup<\/th>Working pressure<\/th>Occupants<\/th>Reasonable concentrator rating<\/th>Why<\/th><\/tr><\/thead>
        Mask \/ BIBS, single-user chamber<\/td>1.3 \u2013 1.8 ATA<\/td>1<\/td>5 L\/min<\/strong><\/td>Fits a typical adult minute ventilation at rest with headroom. Delivered flow after regulator is close to source rating at modest back-pressure.<\/td><\/tr>
        Mask \/ BIBS, single-user chamber<\/td>1.5 \u2013 2.0 ATA<\/td>1<\/td>10 L\/min<\/strong><\/td>More ambient pressure means more mass of gas moved per breath; also absorbs mask \/ regulator losses.<\/td><\/tr>
        Mask \/ BIBS, two-user chamber<\/td>1.3 \u2013 2.0 ATA<\/td>2<\/td>Two sources, or one 10 L\/min with a splitter rated for it<\/strong><\/td>A single 5 L\/min source cannot feed two occupants without starving someone.<\/td><\/tr>
        Enrich-the-shell soft chamber<\/td>Low pressure<\/td>1 \u2013 2<\/td>5 L\/min is usually enough<\/strong><\/td>You are capped by the 23.5% O\u2082 ceiling, not by the source. More flow mostly shortens the purge time.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

        The reason this table reads honestly<\/strong>: a row only makes sense when the assumptions in the first three columns hold. Change the chamber size, the tubing, the mask, or the occupant count, and the “right” column changes. Do not read a row out of context.<\/p>\n\n\n\n

        A few numbers to keep in your head:<\/p>\n\n\n\n

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        • An adult at rest moves roughly\u00a06 \u2013 8 L\/min of air<\/strong>. Under exertion or stress, that climbs. A 5 L\/min source feeding a mask is already in the same range as resting ventilation \u2014 thin margin for anyone breathing above baseline.<\/li>\n\n\n\n
        • 1 ATA is 14.7 psi<\/strong>. Doubling to 2 ATA doubles the gas density. A given volumetric flow at the source delivers more molecules at pressure, but your tubing, humidifier, and mask resistance all go up too. That is why delivered flow at the chamber port is the number worth measuring.<\/li>\n\n\n\n
        • Tubing length is not free. The 10 L\/min class specifies a maximum tubing run as part of its rating, because the longer the run, the more pressure drop between the sieve bed and the chamber port. Short runs. Smooth bends. Good connectors. [2]<\/li>\n<\/ul>\n\n\n\n
          \"Man<\/figure>\n\n\n\n
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          Four things that quietly derate your flow<\/h2>\n\n\n\n

          Four variables sit between the number on the sticker and the number at the chamber port. If you are picking a concentrator and you are not accounting for all four, the choice is a guess.<\/p>\n\n\n\n

          Back-pressure.<\/strong> The sticker was measured at zero or 7 kPa. Your sealed chamber is above that. A 5 L\/min machine fighting elevated back-pressure delivers less than 5. A 10 L\/min machine fighting the same back-pressure gives you more absolute margin, because its rated outlet pressure is higher to begin with (the DeVilbiss 10 L\/min series is rated at 20 psi outlet, the 5 L\/min series at 8.5 psig). That difference is why you cannot just “turn the 5 up.” [1][2]<\/p>\n\n\n\n

          Tubing and connectors.<\/strong> Every meter of tubing is pressure drop. Every elbow is a little more. Every quick-connect fitting is a little more. Published ratings assume a specific length \u2014 the DeVilbiss 5 L\/min and 10 L\/min families both cap tubing at roughly 50 feet of crush-proof oxygen tubing plus about 7 feet of nasal cannula. Run longer than that and you are outside the setup the rating was measured in. [1][2]<\/p>\n\n\n\n

          Humidifier bowls and water traps.<\/strong> Bubbling oxygen through water adds measurable back-pressure. Rated flows assume the humidifier that was tested with the device; swapping in a different one, or stacking two, changes the delivered flow. If you must humidify, use the bowl the device was rated with.<\/p>\n\n\n\n

          Mask or regulator resistance.<\/strong> The last piece of plumbing is the user interface. A loose-fit non-rebreather, a demand regulator, and a BIBS mask all behave differently under load. “Flow at the port” and “flow at the lungs” are not the same number.<\/p>\n\n\n\n

          Add all four together and the realistic delivered flow at a sealed chamber port is routinely 20 \u2013 40% lower<\/strong> than the sticker. A 10 L\/min source that reads 10 on the knob is often delivering 6 \u2013 8 at the chamber port under real conditions. That is not failure; that is physics, and it is the single most important number to measure once your chamber is installed.<\/p>\n\n\n\n

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          Purity, and why it also slips when flow goes up<\/h2>\n\n\n\n

          Pressure-swing adsorption works by letting a sieve bed strip nitrogen from compressed air. The faster you ask the bed to work, the less time each adsorption cycle has, and the more residual nitrogen slips through. That is why PSA concentrators are quoted in a band \u2014 typically 90% to 96% \u2014 and that is why the top of the band belongs to lower flow settings<\/strong>, not the maximum.<\/p>\n\n\n\n

          Rules of thumb that hold up in the field:<\/p>\n\n\n\n