1. ATA: Verify the Working Pressure

ATA means atmospheres absolute. Normal pressure near sea level is about 1.0 ATA. Gauge pressure can be estimated as (ATA − 1) × 14.7 psig, so 1.5 ATA is about 7.4 psig. ATA does not state oxygen purity or delivery.

Ask the supplier to separate these values

• Working range and maximum operating pressure

• Design and test pressure

• Control accuracy and pressure-change rates

• Relief devices, emergency procedures, and cycle records

Higher ATA is not automatically better. The appropriate range depends on the intended setting, model, protocol, and local requirements.

2. Oxygen Delivery: Trace the Gas Path

Pressure and oxygen delivery are separate. In an air-pressurized system, a compressor raises chamber pressure while oxygen reaches the user through a mask or Built-In Breathing System (BIBS). The chamber itself is not filled with oxygen.

Outlet purity is not a guaranteed inhaled concentration. Flow, back pressure, mask fit, breathing demand, and exhalation design can affect delivery.

Information to request

• Source and rated purity at the stated flow

• Flow and pressure per station

• Performance at maximum chamber pressure

• Number of masks used simultaneously

• Exhaled-gas route, monitoring, and backup

3. Size: Plan Beyond the Chamber

Chamber dimensions are not the required room size. Allow for oxygen equipment, a compressor, climate control, hoses, door movement, and service access.

Request a model-specific installation drawing. Confirm power, ventilation, delivery access, turning clearance, and hose limits.

4. Noise: Compare Like With Like

System sound can come from compressors, concentrators, fans, valves, airflow, ventilation, and pressure release. A value such as “under 60 dB” is not fully comparable unless the test conditions are stated.

Ask whether the reading is dB(A), where and how far away it was measured, the operating phase, and which modules were running. Research on 41 multiplace chambers found that sound varied by phase and ventilation status. Those figures do not apply directly to other chamber types, but they show why test conditions matter.

5. Materials: Ask for Evidence

Hard chambers may use pressure-vessel steel, aluminum alloy, acrylic viewing sections, coatings, and engineered seals. Flexible chambers may use reinforced substrates with gas-barrier coatings, flexible windows, seams, and zipper assemblies. Construction varies by model, so a broad label such as “medical grade” is not enough.

Documentation to review

• Material grade, thickness, and traceability

• Certificates and test reports

• Inspection and pressure-test records

• Rated cycle life

• Viewport, cleaning, and replacement requirements

ISO 13485 covers a medical-device quality management system; it does not by itself prove a model’s pressure rating, material grade, or market authorization.

6. Commercial RFQ Checklist

For the U.S. medical-device market, verify the exact model. FDA establishment registration is not model-level 510(k) clearance.

7. Frequently Asked Questions

References

U.S. FDA: Safe Use of HBOT Devices · 21 CFR 868.5470 · NOAA: Understanding Pressure · In-Chamber Sound-Level Study · ISO 13485