I needed to use a medical oxygen concentrator for a short period, and I found it strange that it came with a warning label I was supposed to put in the window so firefighters would know it was there. I don't understand why firefighters would care. I would understand why they'd care if I used oxygen tanks; as they could add oxygen to a fire. But an oxygen concentrator doesn't add any extra oxygen, it just moves it. The same amount of O2 would be in the room either way.

Is there something about oxygen concentrators that's extremely flammable? Or is this more of a legal issue where they're just being overly cautious?

I apologize if this is the wrong SE.

  • $\begingroup$ Oxygen helps things burn and a concentrator does exactly what it says on the tin - concentrates oxygen in a particular space... $\endgroup$
    – Solar Mike
    Jun 12, 2021 at 22:11
  • $\begingroup$ But its the same amount of O2 in the room, it just moves it from one part of the room to another. $\endgroup$
    – Ryan_L
    Jun 12, 2021 at 22:30
  • $\begingroup$ Yes, and I'm not sure I see how it makes a fire more dangerous. Sure, the flames near the concentrator might be hotter, but the flames in the rest of the room should actually be cooler. $\endgroup$
    – Ryan_L
    Jun 12, 2021 at 22:55
  • $\begingroup$ @StainlessSteelRat I doubt it, because the fire will use most of the oxygen in the room. The concentrator won't be concentrating much. $\endgroup$
    – Ryan_L
    Jun 13, 2021 at 2:50
  • 1
    $\begingroup$ @Ryan-L how are you keeping additional oxygen from infiltrating into the area of lower oxygen concentration $\endgroup$
    – jsotola
    Jun 13, 2021 at 4:01

2 Answers 2


The zeolite in the concentrator is a hazardous material if the concentrator is damaged by fire. At high temperatures it decomposes into hazardous compounds. Zeolite dust released by damage is also hazardous if breathed in, ingested, or is in contact with skin.

Zeolite may also react with some fire extinguishing systems.

So the fire department needs to know it is there for their own safety, regardless of what effect the "concentrated" oxygen may have on the fire.

  • $\begingroup$ so how do they deal with it when when enter through a door? $\endgroup$
    – Tiger Guy
    Jun 13, 2021 at 19:52
  • $\begingroup$ That may be but the warning isn't about zeolite dust, "oxygen in use" is too vague to infer that, so I doubt that's the intention. $\endgroup$
    – Drew
    Jun 15, 2021 at 7:06

No good reason

My guess is that this was included because some idiot lawyer thought up a non-existent risk and decided the company needed to include a sticker. The whole idea is ridiculous. 10 lpm (2 is normal) isn't going to cause a huge blaze like an O2 plant at a factory. Plus, fire fighters come in through doors because doors are people sized and windows aren't. Does anyone think firefighters are like "Bob, I was going to bust this door open with my Halligan, but could you first circle the house to see if any windows have oxygen warnings on them? I'll wait."

  • $\begingroup$ This could be written in a nicer way, but I think you are correct. The small flow of oxygen from the concentrator isn't going to effect a fire, and the warning is specifically about oxygen, not other aspects of the equipment. I don't think it's the manufacturer being stupid though. I'd wager there is some general rule about medical devices that contain oxygen, and they're just following it even though in this case it's nonsensical. $\endgroup$
    – Drew
    Jun 15, 2021 at 7:12

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