Hyperbaric Chamber Pressure PSI: ATA Conversion andBuying Guide
Hyperbaric chamber pressure PSl is only clear when you know whether it refers to gauge pressure(PSIG) or absolute pressure (PSIA). Under standard atmospheric conditions, a chamber operating at2.0 ATA is approximately 14.7 PSIG or 29.4 PSIA-different readings for the same pressure
This guide explains PSI and ATA, provides a conversion table and shows which pressurespecifications to check before buying. At MACY-PAN, we help you verify your selected model’s operating pressure, available settings and supporting equipment before confirming a quotation.
Hyperbaric Chamber Pressure: PSI vs ATA
Hyperbaric chamber specifications may list pressure in PSI or ATA. Before comparing modelsconfirm whether the PSI figure represents gauge or absolute pressure. Different numbers can describe the same operating pressure.
What Do PSI and ATA Mean?
PSI means pounds per square inch, a unit of pressure. On its own, it does not tell you whether themeasurement includes atmospheric pressure.
ATA means atmospheres absolute. It expresses total pressure relative to a standard atmosphere,including atmospheric pressure. A rating of 2.0 ATA therefore means twice standard atmospheric pressure-not twice the pressure added above the surrounding air.
PSIG vs PSIA: Gauge and Absolute Pressure
PSIG measures pressure above the surrounding atmosphere. PSIA measures total pressurefrom a vacuum reference. When an unpressurized chamber is open to the room, its gaugepressure is zero, while its absolute pressure equals the local atmospheric pressure.
| Term | Meaning | What to Check |
| PSI | Pounds per square inch | Is the figure gauge or absolute? |
| PSIG | Gauge pressure above the local atmosphere | What ambient pressure is used for conversion? |
| PSIA | Absolute pressure, including atmospheric pressure | Is it consistent with the stated ATA rating? |
| ATA | Absolute pressure expressed in standard atmospheres | Does it describe the model’s rated operating pressure? |
For example, with the surrounding atmosphere at 1 ATA, a chamber operating at 2.0 ATA has approximately 29.4 PSIA of absolute pressure and 14.7 PSIG of gauge pressure. These describe the same chamber condition using different reference points.
When reviewing a MACY-PAN specification or quotation, ask us to confirm the pressure reference if it is listed only as “PSI.”
Hyperbaric Chamber Pressure Conversion: ATA to PSI
Use the table below to compare ATA ratings with absolute and gauge pressure. Confirm thepressure reference before converting any specification listed only in PSI.
ATA to PSI Conversion Table
PSIG values below assume the surrounding atmosphere is one standard atmosphere:approximately 14.696 PSIA. Values are rounded to two decimal places.
| Chamber Pressure | Absolute Pressure (PSIA) | Gauge Pressure (PSIG) |
| 1.0 ATA | 14.7 | 0 |
| 1.3 ATA | 19.1 | 4.41 |
| 1.5 ATA | 22.04 | 7.35 |
| 2.0 ATA | 29.39 | 14.7 |
For ATA-to-PSI conversion:
● PSIA = ATA × 14.696
● PSIG = (ATA × 14.696) − local atmospheric pressure in PSIA
How to Convert PSI to ATA
First, check whether your figure is PSIA or PSIG. Absolute pressure converts directly; gauge pressure requires adding the local atmospheric pressure.
From PSIA:
ATA = PSIA ÷ 14.696
Example: 29.392 PSIA ÷ 14.696 = 2.0 ATA.
From PSIG:
ATA = (PSIG + local atmospheric pressure in PSIA) ÷ 14.696
Example, under standard atmospheric conditions:
(7.348 PSIG + 14.696 PSIA) ÷ 14.696 = 1.5 ATA.
At higher elevations, local atmospheric pressure is lower, so the same gauge reading corresponds to a different absolute pressure. Use the site’s actual atmospheric pressure when an accurate conversion is required.
Once the units are clear, compare 1.5 ATA vs 2.0 ATA hyperbaric chambers to review the configuration details for your project.
Compare Hyperbaric Chamber Pressure Ratings
Once pressure units match, check what each rating describes. Compare the selected model’soperating limits, available settings and control functions-not just the highest number on aspecification sheet.
Operating Pressure vs Test Pressure
Rated operating pressure specifies the pressure permitted for normal use under the manufacturer’sstated conditions. Test pressure is applied during a defined verification procedure and must not betreated as an operating setting.
| Pressure Rating | What It Means |
| Rated operating pressure | The specified pressure or range permitted for normal operation. Confirm whether the figure is a maximum rating or a selectable setting. |
| Test pressure | Pressure applied during a specified test. Check the test method, conditions and corresponding record; it does not authorize operation at that pressure. |
If design pressure is also listed, ask the manufacturer to identify it separately and explain its relationship to the permitted operating pressure. Keep each rating clearly labeled in your technical comparison.
Pressure Settings and Controls
Two chambers with the same maximum pressure may offer different settings and control functions. For your selected model, confirm:
● Available settings: Which operating pressures are supported, and are they fixed or adjustable?
● Pressure display: Does the display show ATA, PSIG or another clearly identified unit?
● Cycle control: How are pressurization, pressure holding and depressurization controlled?
● Pressure relief: Which relief controls are provided, and where are they located?
● Abnormal conditions: What instructions apply to alarms, power interruptions or unexpected pressure changes?
At MACY-PAN, we help you review these details against the selected model’s specifications and operating instructions.
Chamber Pressure vs Oxygen Concentration
PSI and ATA describe pressure; they do not specify oxygen concentration. Review the oxygen source, delivery method, specified concentration and flow separately. Confirm where those values are measured and whether they apply under the intended operating conditions.
Review the complete hyperbaric chamber system to understand how air pressurization, oxygen delivery and pressure controls work together. Ask for these specifications to be listed separately in your equipment proposal.
Confirm Pressure Specifications Before Buying
Before ordering, confirm that the pressure specifications, model documents and quotation describe the same configuration. At MACY-PAN, we help you review these details before preparing your equipment proposal.
Check Your Model’s Pressure Documents
Request the specification sheet, operating instructions and available pressure inspection information for your selected model. Check that the pressure units, rated operating pressure and permitted settings are consistent across these documents.
We help you review applicable hyperbaric chamber certifications and documents for your model and destination. Confirm each document’s scope—a company-level certificate does not establish a particular model’s pressure rating.
Confirm Pressure Details in Your Quote
Confirm the following in your quotation or accompanying technical specification:
● Full model and configuration.
● Rated operating pressure in ATA, with PSI figures identified as PSIG or PSIA.
● Available pressure settings and control functions.
● Oxygen supply and delivery equipment.
● Included documents and project support.
Tell us about installation altitude or other special site conditions before confirming the configuration. For room planning, delivery and other purchasing checks, read our Hyperbaric Chamber Buying Guide.
Confirm Your Chamber Pressure with MACY-PAN
Send us your required pressure, intended use and installation location. Our sales and engineering team will review the available configurations and clarify the pressure specifications before quotation.
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