How dangerous is my new dehumidifier?
November 10, 2021 8:41 AM Subscribe
Our new dehumidifier comes with this warning: "This dehumidifier uses about 65 grams of R290 refrigerant, which is flammable... Do not use in a room with any continuous sources of ignition, for example, open flames, gas fires or hobs, cigarettes or any other sources of ignition." We have a gas hob, a gas boiler, and candles that we sometimes light. Our flat is small enough that we can only station the dehumidifier so far away from any of these things. Should we return this dehumidifier, or can we use it safely?
Three more details:
• Our flat is roughly 950 square feet;
• In order of preference, we'd prefer to keep the dehumidifier in the kitchen (where the hob is); the hallway (which contains the boiler closet); or the living room (where we sometimes light candles.) The only other alternative is the bedrooms (but their doors open onto the hallway and are close to the kitchen.)
• I'm in the UK, if that's relevant.
Three more details:
• Our flat is roughly 950 square feet;
• In order of preference, we'd prefer to keep the dehumidifier in the kitchen (where the hob is); the hallway (which contains the boiler closet); or the living room (where we sometimes light candles.) The only other alternative is the bedrooms (but their doors open onto the hallway and are close to the kitchen.)
• I'm in the UK, if that's relevant.
R290 is commonly used in food service where there are a lot of open flames. It's propane so in the event of a leak you're dealing with propane issues, but it shouldn't leak under normal circumstances. I think the warning is a CYA move.
posted by mikesch at 8:52 AM on November 10, 2021
posted by mikesch at 8:52 AM on November 10, 2021
Propane is flammable in air in a proportion of 2-10%.
There’s way more than 3kg of air in your room (Google says 1.22 kg per cubic meter), so lighting a slow leak is going to be essentially impossible.
Don’t put a nail through the coil, and you’ll be fine.
posted by doomsey at 9:32 AM on November 10, 2021 [1 favorite]
There’s way more than 3kg of air in your room (Google says 1.22 kg per cubic meter), so lighting a slow leak is going to be essentially impossible.
Don’t put a nail through the coil, and you’ll be fine.
posted by doomsey at 9:32 AM on November 10, 2021 [1 favorite]
It's not just that propane (R290) is flammable, it's also heavier than air and thus can collect in low spots that lack adequate ventilation. Boats exploding suddenly are a prime example of the hazards of propane (and butane), and caravans and campers will nearly always have their gas bottles in a compartment or box ventilating to the outside.
That said, as long as the circuit in your dehumidifier doesn't leak (and as long as it actually works, it's not leaking) there's no risk.
posted by Stoneshop at 9:49 AM on November 10, 2021 [3 favorites]
That said, as long as the circuit in your dehumidifier doesn't leak (and as long as it actually works, it's not leaking) there's no risk.
posted by Stoneshop at 9:49 AM on November 10, 2021 [3 favorites]
With regard to low spots: this is mitigated by quantity of flammable gas available (very small) and air exchange. The most likely loss off coolant from something like this is a pinhole leak - the entire 65g won’t go out at the same time, and it’s unlikely to collect in a single low spot due to air motion in the area.
I mean, it’s good to take basic precautions (don’t smoke next to the unit) but worrying about a gas stove in the next room is probably overcautious. A candle is more dangerous - I don’t mean that in terms of a candle lighting the propane, I mean that if the candle falls over it can light a whole bunch of other stuff!
posted by doomsey at 10:11 AM on November 10, 2021
I mean, it’s good to take basic precautions (don’t smoke next to the unit) but worrying about a gas stove in the next room is probably overcautious. A candle is more dangerous - I don’t mean that in terms of a candle lighting the propane, I mean that if the candle falls over it can light a whole bunch of other stuff!
posted by doomsey at 10:11 AM on November 10, 2021
I concur. To light a candle indoors at all is to accept a level of risk of hideous flaming death compared to which the added risk posed by a possible propane leak from your dehumidifier is a rounding error.
posted by flabdablet at 10:16 AM on November 10, 2021 [4 favorites]
posted by flabdablet at 10:16 AM on November 10, 2021 [4 favorites]
I actually know someone whose house burned down because of a lit candle on her kitchen table. The table was crowded, and a window curtain caught fire and burned away while the family was at dinner in the next room. By the time the family returned to the kitchen the entire back wall of the house was ablaze and all they could do was evacuate and call the fire brigade. They lost everything. Lit candles that are unattended are surprisingly dangerous.
posted by citygirl at 10:50 AM on November 10, 2021
posted by citygirl at 10:50 AM on November 10, 2021
Propane is flammable in air in a proportion of 2-10%.
Propane is explosive in air in a proportion of 2-10%.
posted by jamjam at 11:25 AM on November 10, 2021 [2 favorites]
Propane is explosive in air in a proportion of 2-10%.
posted by jamjam at 11:25 AM on November 10, 2021 [2 favorites]
The difference between flammable and explosive is containment, so in a sealed pressure vessel 2-10% of propane would be explosive, but in an open space we'd just call it flammable.
Agree it's probably just a CYA warning, but honestly that would piss me off enough that I would return it.
posted by Lady Li at 7:10 PM on November 11, 2021
Agree it's probably just a CYA warning, but honestly that would piss me off enough that I would return it.
posted by Lady Li at 7:10 PM on November 11, 2021
It definitely exceeds MY risk tolerance, is what I'm saying. I don't store my propane cylinders near flames either.
posted by Lady Li at 7:34 PM on November 11, 2021
posted by Lady Li at 7:34 PM on November 11, 2021
It definitely exceeds MY risk tolerance, is what I'm saying.
Planning to get rid of your fridge then? If it uses R600a, isobutane, propane's close nephew, as is currently common you would be dealing with the same flammability risk when it's leaking. And fridges contain more refrigerant than those 65 grams in this dehumidifier.
posted by Stoneshop at 1:25 PM on November 12, 2021 [1 favorite]
Planning to get rid of your fridge then? If it uses R600a, isobutane, propane's close nephew, as is currently common you would be dealing with the same flammability risk when it's leaking. And fridges contain more refrigerant than those 65 grams in this dehumidifier.
posted by Stoneshop at 1:25 PM on November 12, 2021 [1 favorite]
The difference between flammable and explosive is containment
For stoichiometric gas mixtures, not so much.
posted by flabdablet at 10:50 PM on November 12, 2021
For stoichiometric gas mixtures, not so much.
posted by flabdablet at 10:50 PM on November 12, 2021
Response by poster: Thanks, everybody! I really appreciate your helpful and thoughtful responses.
posted by yankeefog at 3:36 AM on November 29, 2021
posted by yankeefog at 3:36 AM on November 29, 2021
This thread is closed to new comments.
posted by Mr. Yuck at 8:51 AM on November 10, 2021