Factory Acceptance Testing for Hyperbaric Chambers: A Buyer's Guide

Who this page is for: people buying a chamber — wellness operators, clinic procurement leads, or someone outfitting a recovery space — who want to verify, before paying, that the unit they're getting has actually been tested.

What's in it: what's worth asking for, what each document should look like, what to do when a supplier says no, and how to read the paper afterward when an inspector or insurer comes asking.

1. Is a Factory Acceptance Test Actually Required?

Short answer: nobody makes you do one. Not the standard, not the regulator, not the brand.

A factory acceptance test, or FAT, is something you choose to require on your purchase order. It can be a single pressure check, or a multi-day witnessed program covering welds, electricals, oxygen cleanliness, and paperwork. The breadth is up to you.

What you don't want to do is confuse what comes by default with what's been verified.

• Many chambers ship with a "test certificate" that documents one or two items — usually a leak-down hold and a visual check.
• That certificate is not the same as a FAT. It's a sample.
• The brand's logo on the certificate doesn't mean a third party witnessed it.

So the first decision isn't "FAT or no FAT?" It's “what do I want verified for this serial number, by whom, with what paper?” ​ Everything else on this page is about answering that one question.

A chamber FAT is only as good as the paper it produces — ask for the data report for this serial number, not a certificate for the brand.

2. What a Chamber FAT Should Test

The scope question is where most buyers get lost, because the same word "FAT" gets stretched to cover very different things.

In practice, a FAT that actually proves anything runs through five families:

1. Pressure integrity — a leak-down or hydrostatic hold at the rated working pressure, with hold time and pressure drop both recorded.
2. Weld and seam quality — visual on 100% of seams, plus nondestructive examination on the critical ones (per ASME PVHO-1 §1-7.3).
3. Pressure relief devices — set pressure verified, nameplate recorded, vent path clear (PVHO-1 §1-8).
4. Electrical outfitting — interlock check on doors and valves, grounding, alarm and shutoff sequence (PVHO-1 §1-7.4).
5. Oxygen cleanliness — residue and particulate per ASTM G93 Level A or a comparable written limit, with a logged flush and UV or particle count.

That's the floor. Optional items include viewing window pressure-cycle records (PVHO-1 §1-7.5), door interlock force testing, and a third-party witness present on the shop floor.

If your supplier says "yes, we do FAT" but can't name which of the five families they cover, the answer wasn't really yes.

3. FAT, SAT, Commissioning: Who Does What, and Where

Three tests, three places, three sets of paper. They overlap enough that buyers mix them up.

The trap is paying for one and calling it the other. A SAT cannot prove weld quality — by the time the unit is on your floor, the welds are inside the chamber behind cosmetic panels. If weld quality matters, the inspection has to happen at FAT.

A useful rule: anything that's hidden after delivery (welds, relief devices, oxygen plumbing inside the shell, internal cleanliness) belongs in FAT. Anything that depends on your site (power, ventilation, room size, fire separation) belongs in commissioning.

A clean SAT cannot catch a bad weld. If weld quality matters, it has to be inspected at FAT.

4. The Document Package: Ask for These by Name

This is the part most buyers walk away from with a folder of generic PDFs. You want per-serial-number evidence, not a brochure that says "we comply with everything."

Below is the table to send. It maps what to ask for, what the evidence should look like, which standard it ties to, the pass criterion, and — the part almost nobody gives you — what to do if it's missing.

If a supplier can't hand you items in the first three rows, walk away from the PO. If they can hand you items 1–3 but skip 5–7, you're paying for a chamber that wasn't fully verified — price that risk before you sign.

Test: after reading a row above, can the buyer send an email based on it? If no, it's an index. If yes, it's a tool.

5. Oxygen Cleanliness: The One Most Buyers Never Ask About

This is the gap that costs the most in post-delivery disputes.

A chamber breathes. The interior surfaces see pressurized oxygen at elevated partial pressure. Any hydrocarbon residue, oil mist, or particulate from manufacturing can ignite under those conditions. Standards address this — ASTM G93 specifies cleanliness levels from A through D, with Level A the cleanest and the right reference for oxygen service; CGA G-4.1 covers cleaning methods.

The problem: buyers ask for a "test report" and get a pressure-hold. They never ask for an oxygen clean verification, and the supplier never volunteers one, because a fail costs the supplier a re-flush and a re-test.

What to ask for:

• A written flush procedure (cycles, duration, gas source).
• A UV or particle-count reading before and after, in particles or gas and measurement unit.
• An NVR (non-volatile residue) gravimetric result, in mg/m² or mg/ft².
• The acceptance criterion the procedure was compared to (most commonly ASTM G93 Level A or B).

If the supplier says "we clean it during assembly and we don't have residue problems," the useful follow-up is: “Can you send me the flush log and the gravimetric result for the last three units?” ​ If the answer is no, treat the chamber as unverified for oxygen service.

Oxygen clean verification is not a bonus. It's the only test that catches what would otherwise show up as a post-delivery fire risk.

6. Which Standard Answers Which Question

Standards confuse buyers because there are several, and they overlap. Here's the routing:

• “What was it built to?” ​ → ASME PVHO-1 (pressure vessels for human occupancy). The current version cited by FDA is PVHO-1-2023, recognition number 1-181. The prior version, PVHO-1-2019, was accepted by FDA only through 2026-12-26 (FDA Recognized Consensus Standards database).
• “How is it being kept safe while in use?” ​ → ASME PVHO-2 (in-service inspection).
• “What about the room it sits in?” ​ → NFPA 99 Chapter 14 (hyperbaric facilities). Always cite the edition with the chapter — the 2024 edition places hyperbaric facilities in Chapter 14. Older editions used a different number, and any document that names the chapter without the edition is out of date.
• “Is it registered with FDA?” ​ → FDA 21 CFR §868.5470, product code CBF, Class II. The mild hyperbaric chamber itself as a non-medical device may or may not require FDA listing depending on intended use and labeling; registration is not the same as approval (FDA 21 CFR §868.5470).
• “What's the quality system behind the build?” ​ → ISO 9001 (general) or ISO 13485 (medical devices). For non-medical chambers, ISO 9001 is the usual reference; ISO 13485 applies only if the device is labeled and intended for medical use.
• “How clean is the oxygen side?” ​ → ASTM G93 (cleanliness levels) and CGA G-4.1 (cleaning methods).

The mistake to avoid: asking "is it ASME?" — that's not a question. Ask "which edition, which sections, which forms?" — that's a question you can verify.

If the only standard a supplier can name is the brand's own internal document, the conversation isn't about compliance. It's about whether any third party has reviewed the build.

7. Two Product Lines, Two Acceptance Boundaries

Here's the honest part most suppliers duck.

ASME PVHO-1's scope turns on pressure differential. Above a stated threshold, a pressure vessel for human occupancy falls inside the standard. Below it, the standard doesn't apply — but the standard still has provisions for non-rigid and flexible chambers, so the standard's applicability to a fabric chamber is not decided by the fabric alone.

What this means for the buyer:

• For a rigid chamber built to a rated working pressure above the standard's threshold, the full PVHO-1 document package applies. Ask for Form GR-1 or GR-1S data report tied to the serial number, NDT records on critical seams, relief device set-pressure records, marking per §1-9.
• For a soft or flexible chamber, the standard does not automatically exempt the chamber from scrutiny. Ask instead for the supplier's engineering basis: which sections they applied, which they treated as not applicable, and why. Ask for the documentation they did produce (often: fabric specifications, seam test records, valve cycle tests, oxygen clean log, electrical interlock check, control system verification).

The useful follow-up if a supplier says fabric chambers are automatically outside the standard: “Which edition are you reading, and what's your engineering basis?” ​ That's not a gotcha — it's the question that separates suppliers who actually engaged with the standard from suppliers who decided not to.

Whether PVHO-1 applies to a fabric chamber is not decided by the fabric. It's decided by which edition the supplier is reading and what their engineering basis is.

8. When the Test Fails: Hold Points, Retest, and Your Options

A FAT that never fails is suspicious. Things get caught — a relief device set one psi high, a weld indication flagged on NDT, a door interlock that's slow to latch. What matters is the response, not whether something went wrong.

Three questions to ask before signing the PO:

1. Where are the hold points?​ A hold point is a stage in the FAT at which work stops until the buyer (or witness) signs off. If there are no declared hold points, the only "hold point" is your payment.
2. What triggers a retest?​ A relief device set pressure out of tolerance, a weld repair, a flush cycle redone — each should map to a documented retest, not a verbal "we'll fix it."
3. Who pays for the retest?​ Default should be the supplier when the failure is in their work scope. Get it in writing.

The contract language that does the work:

Any item failing acceptance criteria shall be documented as a hold point. Resolution shall be by retest at the supplier's cost, with the retest report attached to the original FAT record. Release for shipment shall not occur until all hold points are cleared in writing.

That single paragraph gives you more leverage than any standard citation.

The FAT isn't about whether something fails. It's about whether the response to a failure is in writing before the failure happens.

9. Before You Release Payment

The single most common buyer mistake is paying on delivery confirmation rather than on FAT acceptance. By the time the unit shows up at your door, the leverage is gone.

Three rules:

1. Tie final payment to FAT acceptance, not to shipment. Standard practice is 30% on PO, 30% on FAT acceptance, 30% on delivery, 10% on commissioning or 30-day operation, depending on acceptance milestones.
2. Acceptance is documented, not verbal. The acceptance record is signed by the named inspector of record, references the serial number, and references the standards cited in the contract.
3. Punch list before payment. If there's a list of open items at FAT, the punch list becomes part of the acceptance record, with a date for closure. Payment on the unresolved items is held back.

If the contract says "net 30 on delivery," you have no FAT. You have a shipment.

10. The Paper You Keep: What Your AHJ, Insurer, and Inspector Will Ask For Later

The FAT record isn't only for you. Years from now, when the local authority having jurisdiction (AHJ) inspects the facility, or when your insurer renews, or when a window is due for replacement, the FAT record is the document that proves the chamber was built right.

What to keep, where, and for how long:

• Original data report (Form GR-1, GR-1S, or equivalent) — keep the physical original; scan and store a copy off-site.
• FAT record — signed, with hold points and resolutions.
• NDT records — radiographs or alternative method outputs, with the inspector's interpretation.
• Cleaning log — flush cycles, UV or particle counts, NVR results.
• PVHO-2 in-service inspection log — starts at commissioning, runs for the chamber's life.
• Marking and nameplate photo — useful if the plate is ever damaged or repainted.

Storage: digital is fine, but the inspector wants the paper trail that matches the serial number. If the digital copies don't reconcile to the unit, the inspector has questions. If the records are missing at all, the conversation gets uncomfortable.

The FAT record is the only document that proves the chamber was verified. Everything else is opinion.

11. Questions to Ask Any Supplier — Including Us

Below are the questions to send, in order. A supplier who answers all of them with paper, not promises, is a supplier worth working with. The list applies to any supplier, including us.

1. What edition of ASME PVHO-1 are your rigid chambers built to?​ (Current FDA-recognized version is PVHO-1-2023.)
2. For soft chambers: which sections of PVHO-1 did you apply, and what is your engineering basis for the sections you didn't apply?​
3. Send me the data report (Form GR-1 or GR-1S) for the serial number I'm ordering.
4. Send me the FAT scope, including the five families (pressure, weld, relief, electrical, oxygen clean) and any optional items you include.
5. Send me the oxygen clean verification: flush procedure, UV or particle count, NVR result, acceptance criterion.
6. Where are the hold points in your FAT, and who signs them?​
7. What is your retest policy, and who pays?​
8. Can I or a third party witness the FAT? What is the cost?​
9. What marking appears on the nameplate, and how do I reconcile it to the data report?​
10. What PVHO-2 in-service inspection schedule do you recommend, and what records will you accept from my inspector?​
11. What documentation will you keep on file for this serial number, and for how long?​

If a supplier can't or won't answer these in writing, the FAT conversation hasn't really started — and the chamber isn't really verified.

Sources

The claims above map to the following primary references. Each entry shows what the source supports and the URL where you can verify it.

• ASME PVHO-1 scope and structure (pressure vessels for human occupancy; design, fabrication, inspection, testing, cleaning, marking; Forms GR-1, GR-1S, VP-1) — asme.org/codes-standards/find-codes-standards/pressure-vessels-human-occupancy
• FDA Recognized Consensus Standards: PVHO-1-2019, recognition #1-154, transition end 2026-12-26 — accessdata.fda.gov/scripts/cdrh/cfdocs/cfStandards/detail.cfm?standard__identification_no=45594
• FDA 21 CFR §868.5470 — Hyperbaric chamber product code CBF, Class II — ecfr.gov/current/title-21/section-868.5470
• NFPA 99 Chapter 14 (2024 edition) — Hyperbaric Facilities — nfpa.org codes and standards page
• ASTM G93 — Standard Guide for Cleanliness Levels and Cleaning Methods for Oxygen Service — astm.org/standards/g93.htm
• CGA G-4.1 — Cleaning Equipment for Oxygen Service — cgagroup.org
• NAVFAC MO-406 (military chambers): test and acceptance program — navfac.navy.mil MO-406
• Idaho DEQ hyperbaric facility review and maintenance sampling — Idaho DEQ document B23-01
• UHMS Accreditation Manual (4th ed.) — facility accreditation reference — uhms.org accreditation manual

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