Cracking the Code: How Many Atmospheres Is 13 PSI in a Hyperbaric Chamber?

When people start looking into hyperbaric oxygen chambers, one of the most common questions we hear is:

“How many atmospheres is 13 PSI in a hyperbaric chamber?”

At first glance, it sounds simple. But once you dive into it, you realize that PSI, ATA, and bar can be confusing if you’re not used to working with pressure units. Understanding these numbers is key to choosing the right chamber and making sense of treatment protocols.

In this post, we’ll break it down in plain English: what these units mean, how to convert them, and why pressure settings matter depending on your health goals.

Pressure Units 101: ATA vs PSI vs Bar

Hyperbaric chambers usually list pressure in three different units:

• ATA (Atmospheres Absolute): The most common unit in the hyperbaric world.
  • 1 ATA = the air pressure at sea level.
  • It measures absolute pressure, meaning it includes the surrounding atmosphere.
• PSI (Pounds per Square Inch): Widely used in the U.S. for industrial and medical equipment.
  • 1 ATA ≈ 14.7 PSI.
  • If you’re used to PSI, think of it as the “American way” of describing pressure.
• Bar: More common in Europe and international standards.
  • 1 bar ≈ 1 ATA.

Key difference: Most hyperbaric chambers are labeled in ATA (absolute pressure), but pressure gauges on equipment often show PSIG (gauge pressure), which excludes the 1 ATA of natural air pressure around us. That’s why the same “13 PSI” can mean different things depending on whether it’s gauge or absolute.

Quick Conversion Guide

Here’s the easy math you need:

• 1 ATA = 14.7 PSI (absolute)
• Absolute Pressure (ATA) = Gauge Pressure (PSI) ÷ 14.7 + 1
• Gauge Pressure (PSI) = (ATA – 1) × 14.7

So, how many atmospheres is 13 PSI in a hyperbaric chamber?

If it’s gauge pressure (PSIG):

13 ÷ 14.7 + 1 = ~1.9 ATA absolute

That’s right around the sweet spot for many rehab and recovery protocols.

Common Pressure Conversion Table

Here’s a quick reference table showing how ATA, PSI, and bar compare at different levels, along with their typical applications in hyperbaric oxygen therapy:

Common Pressure Ranges and Their Uses

• Low Pressure (1.1 – 1.5 ATA):
  • Used in wellness and recovery centers.
  • Boosts energy, improves sleep, and supports anti-aging.
  • FDA-approved soft chambers in the U.S. max out at 1.3 ATA.

• Mid Pressure (1.5 – 2.5 ATA):
  • The most common range in medical-grade chambers.
  • Supports post-surgery recovery, sports injury healing, and chronic condition management.
  • 2.0 ATA is considered the “gold standard.”

• High Pressure (2.5 – 3.0+ ATA):
  • Used in hospitals and critical care settings.
  • Treats conditions like carbon monoxide poisoning and decompression sickness.

Why This Matters When Choosing a Chamber

Understanding these units isn’t just a math exercise — it’s the difference between getting a chamber that fits your needs and overspending on features you don’t need.

When comparing chambers:

• ✅ Check if the specs list ATA (absolute) or PSIG (gauge)
• ✅ Look for certifications (like CE approval)
• ✅ Match the pressure range with your intended use (wellness vs clinical treatment)

Final Thoughts

The short answer: 13 PSI (gauge) is about 1.9 ATA in a hyperbaric chamber.

But the bigger picture is this: there’s no single “best” pressure. The right setting depends on your goals — whether it’s general wellness, athletic recovery, or medical treatment.

Next time you’re comparing chambers, don’t get lost in the numbers. Just remember:

• 1 ATA = sea level
• 14.7 PSI = 1 ATA
• Always check whether it’s absolute (ATA) or gauge (PSIG)

Still have questions about pressure settings? Contact us — our team is happy to walk you through the details and help you choose the chamber that fits your needs.