Straight answers, including the ones that cost us sales

No. And neither is any other product, from any manufacturer, anywhere. No such status exists to hold. NFPA writes and publishes codes; it does not operate a product certification, approval or listing scheme for breathing-air equipment. So a phrase like "NFPA 99 certified compressor" is not a claim we have declined to make — it is a claim that cannot be true of anything.

When you see it, you are looking at one of two things: a vendor who does not understand the document they are citing, or one who is counting on you not to check. Ask them which body issued the certificate and for the certificate number. There will not be one. What can legitimately be said about a product is narrower and more useful: that it is intended to help meet a named clause, that it was tested to a named standard by a named method, or that it holds a real approval from a body that issues them — a UL listing, a state pre-approval number, an ISO 17025 accredited test report. Those are checkable. "Certified" is not.

No, and we will not say otherwise. Compliance is a property of an entire installation — the chamber, the gas supply, the electrical work, the ventilation, the ignition source controls, the staffing, the written procedures and the maintenance records — as judged by your authority having jurisdiction. It is not a property of any box you can buy and bolt on.

A well-specified supply and purge system can help you satisfy specific requirements: the intake siting requirement, the air treatment and monitoring requirements on a lubricated compressor, the particulate filter, the ventilation rate, the alarm setpoints. That is a real and worthwhile contribution. It is not the same statement, and we have written a whole page on the difference at what the code requires. If a vendor tells you their product makes you compliant, that vendor has just told you they will not be much help when the inspector arrives.

Grade E under the hyperbaric code, per the accreditation manual's citation of NFPA 99 §14.2.9.6.1 (UHMS accreditation manual, 4th Ed.). That is a specific, published numeric specification, and the single most surprising thing about it is what it leaves out: Grade E sets no dew point or moisture limit at all. Our breathing air grades page lays out the full parameter set, the differences from Grade D, and why the moisture number you still need comes from OSHA rather than from the grade.

At least every six months, and after any major repair or modification of the compressor. That is the only mandated interval we were able to locate for hyperbaric chamber breathing air, from NFPA 99 §14.2.9.6.1 as quoted in the UHMS accreditation manual.

The quarterly figure that circulates widely is not a hyperbaric requirement. It comes either from a recommendation inside a professional-society article, from recreational diving practice, or from fire-service breathing air under NFPA 1989 — a different document that does not apply to chambers. Quarterly is a perfectly defensible choice if your insurer or your own risk assessment wants it. It is not what the code says. Full breakdown, with the sources for each tier, on the testing page.

No. NFPA 99 §14.2.4.2.4 permits an oil-lubricated compressor fitted with an air treatment package and a monitoring package, and §14.2.4.2.4.1 requires automatic safeguards on such an installation (UHMS, 4th Ed., criteria HBOV 3.1 and 3.3). Both routes are open. Oil-free removes a contamination source; lubricated keeps it and requires equipment to manage it. Our oil-free versus lubricated page compares the published datasheets and, more importantly, the maintenance ledger each choice commits you to.

If your compressor is oil-lubricated and the air is being used for supplied-air respirator service, OSHA requires a high-temperature alarm, a CO alarm, or both, and if you fit only the high-temperature alarm you must monitor the supply at intervals sufficient to keep CO below 10 ppm (29 CFR 1910.134(i)(7)). For a non-oil-lubricated compressor the same rule sets the 10 ppm limit but does not mandate an instrument (i)(6).

Our own view, independent of what is mandated: fit one anyway. A hopcalite CO catalyst degrades with humidity, with heat and with sulphur compounds, and has a published intake CO overload ceiling of roughly 50–100 ppm above which it simply stops converting (DAN, Alert Diver). Nothing about that failure is visible from outside the housing. See monitoring instruments for published models and prices, including the calibration consumables most budgets miss. One caution about that DAN source: it is a diving cylinder-fill case, not a chamber case. We cite it for the compressor physics, which is identical, not to imply a chamber incident occurred.

No, and it was never meant to be. NFPA 99 requires a particulate filter of 66 micron or finer per criterion HBOV 14.0 (UHMS, 4th Ed., citing §14.2.10.3). For scale, that is 6,600 times coarser than the 0.01 micron coalescing stage on a published breathing-air filtration panel. A 66 µm screen stops rust flakes, thread sealant, swarf and insects. It does nothing about oil aerosol, oil vapour, water vapour or carbon monoxide.

Both requirements are real and they are different requirements. The 66 µm provision protects the chamber and its plumbing from debris. Air quality is addressed by the code in a different way entirely: by naming an outcome, Grade E, and requiring a laboratory sample twice a year to prove you reached it. See where bad air comes from.

Not in any published record we were able to locate. We think you should know that, even though it slightly weakens our own sales case.

We searched the verifiable incident record. An FDA MAUDE report on a 1989-built chamber records device problem "Fire," and fire investigators found the operator had placed a battery-operated fan inside the chamber during use; no air supply, compressor, contamination or oxygen-concentration finding is recorded (FDA MAUDE report 5855494). A Michigan criminal prosecution over a January 2025 chamber fire and explosion that killed a five-year-old child records a safety director pleading no contest to involuntary manslaughter for deliberately discarding published safety protocols and allowing an outdated device to operate; air supply, compressor, contamination and ignition source are not mentioned (Michigan Attorney General). FDA's August 2025 letter to health care providers states it is aware of "recent reports of fires that occurred with HBOT devices that resulted in serious injuries and deaths" and that "the root cause of these events is not known" (FDA). Australia's regulator issued a fire advisory after a child's death overseas and noted no similar events reported there, recommending grounding and clothing-material controls (TGA).

Every verified fire record points to oxygen concentration plus an introduced ignition source, or to protocol non-compliance with an out-of-life device. So we do not claim that a supply and purge system prevents chamber fires. The honest case for doing this properly rests on code requirements and measurable contaminant limits, not on an incident narrative that does not exist. Anyone selling you air-supply equipment on a fire-prevention story is telling you something the public record does not support.

No. FDA recognises consensus standards for use in device review. For product code CBF, "Chamber, hyperbaric," regulation 868.5470, the recognised standards include NFPA 99:2021, ASME PVHO-1-2019, NFPA 99:2024 and ASME PVHO-1-2023 (FDA Product Classification database). Recognition means FDA will accept conformity to that standard as part of a submission. It is not NFPA certifying a product, and it is not FDA certifying that any given installation complies with the code.

No. NFPA 99 Chapter 14 contains no ISO 8573 requirement. ISO 8573 shows up in this subject for two legitimate reasons — it is the standard filter manufacturers measure their elements against, and a professional-society article uses its classification when comparing international practice — but neither of those makes it a hyperbaric code requirement. If a proposal presents an ISO 8573 class as an NFPA 99 obligation, it has invented a link between two unrelated documents.

Possibly, and if so you should — buying a second compressor you do not need is the most expensive mistake available here. What you would need to add is treatment and monitoring: coalescing and activated-carbon filtration, moisture control, CO monitoring, and an intake sited away from vehicle, engine and building exhaust as §14.2.4.2.2 requires. Published panel products exist for exactly this, including a filtration and CO-monitor kit at $4,950 and three-stage panels from a second vendor, both listed on our alternatives page.

The honest caveats: a shop compressor's duty cycle may not suit continuous chamber ventilation, an oil-lubricated one triggers the OSHA alarm duty above, and you still owe the six-monthly laboratory sample that proves the result. Get one sample taken on the existing machine with a panel fitted before you commit either way — a kit in the low hundreds is a cheap way to answer a question worth thousands.

No. This site is operated by Hyperbaric Service Pros, a hyperbaric equipment and service business, and it exists in part to sell a product. Every page says so in the footer, and our about page states it plainly.

What we can offer instead of independence is that every factual claim here is linked to a primary source you can open — code criteria to the accreditation manual, regulations to the eCFR and OSHA, specifications and prices to manufacturer datasheets and vendor pages. Where a number is not published, we write "Not published" rather than estimating. Where a competitor's product suits you better, the alternatives page says which one and why. Check the links rather than trusting the site.

The published price is $4,000 plus $100 shipping, built to order, with a 12-month warranty. On specifications, the honest answer is that our published product page does not currently list an SCFM figure, a discharge pressure, a horsepower, a filtration micron rating, a dew point, or a CO monitoring specification. Those are Not published, and that is a genuine weakness next to the competitor datasheets we link to.

We would rather write that sentence than invent numbers. Ask us for the figures for your configuration in writing before you buy, and hold us to the same standard we apply to everyone else on the alternatives page. If we cannot produce a number, that tells you something worth knowing.

No. We publish nothing about medical or therapeutic outcomes, we do not make health claims, and nothing on this site is medical advice. This site is about the engineering and code requirements for a chamber's breathing-air supply — compressors, filtration, contaminant limits, alarm setpoints and testing. Clinical questions belong with a qualified clinician.