nitrogen tires

nitrogen. supposedly doesn't leak out as fast as air. fact or fiction?

 

Nitrogen, not hydrogen. Hydrogen goes BOOM. But, really:

What are the effects of using pure nitrogen to inflate tires?

• Nitrogen is a gas and is still affected by changes in ambient temperature (about one psi for every 10° Fahrenheit). Nitrogen filled tires will require pressure be added during the fall/winter months as ambient temperatures and tire pressures drop. Nitrogen is good but can't change the laws of physics.
• Nitrogen reduces the loss of tire pressure due to permeation through rubber over time by about 1/3. This helps maintain the vehicle's required tire pressures a little longer, but doesn't eliminate the need for monthly tire pressure checks. This is good for people who don't maintain their vehicles well.
• Nitrogen is a dry gas and will not support moisture that could contribute to corrosion of the tire's steel components (bead, sidewall reinforcement and belts) due to the absence of moisture over extended periods of time. However it's important to remember that atmospheric pressure is constantly pushing oxygen and moisture into the rubber from the outside of the tire. This is especially good for low mileage drivers who don't wear out their tires quickly or those that run average annual mileages but use long wearing radial (60K and 80K warranted) tires.
• Nitrogen assures more consistent pressure increases due to increases in operating temperatures in a racing environment because of the absence of moisture. This is especially good for participants in track days, high-performance drivers education schools and road racing.
• Drivers should use standard air if pressure adjustments are required when a local source of nitrogen can't be found during a trip. While this reduces the benefit of higher nitrogen content, it is far better than running the tires underinflated in search of a source. Often the original nitrogen provider will refill the tires for free or a nominal cost when the driver returns to his hometown.

 

I swear that myth will never go away.

Yes, hydrogen is flammable compared to nitrogen. But it doesn't explode, and it won't even light in such a situation because there's no oxygen.

You know the big utility generators at power plants? A lot of them are cooled by hydrogen gas. That's right, people are combining hot components, high velocities and hydrogen gas. Ever hear of one exploding? Hydrogen is used because it reduces "windage" losses in the generators (low drag), is very thermally conductive, has a very high specific heat capacity, and can be easily generated on-site.

Nitrogen is used in tires primarily to avoid oxidation. Of course, the outsides oxidize the same either way.

 

Only when they develop a leak. Such as in my sister's unit on her very first week in a job at a major oil refinery.

Fortunately the emergency response was led the by the experienced folks, not dumped in the lap of a college new-hire.

 

Hydrogen is also the smallest molecule on the chart and will leak out of a tire at a very impressive rate.

 

Another myth.

Helium leaks faster than hydrogen. This is because the hydrogen molecule is diatomic (H2) while helium only has one atom (He).

 

We'll have to agree to disagree on this point as hydrogen has the widest range of oxygen ratio for combustion: https://www.safety.caltech.edu/documents/57-hydrogen.pdf

Hydrogen (H2) is a colorless, odorless, flammable gas which is compressed to high pressure. The flammable range of hydrogen is 4.0% - 75.0 % in air. High-pressure leaks can ignite spontaneously and burn with a colorless flame. This Safety Bulletin discusses precautions that should be taken when using Hydrogen. ​

NASA has a lot of experience with hydrogen gas operations and it is pretty wicked stuff. It also has a bad habit of changing the mechanical properties of high-pressure containers. I don't have a problem with reformulated, use on site but really don't want it outside of well designed, closed systems.

Bob Wilson

 

LeeJay,

You need have a drink (or whatever) and relax a bit. Are you one of those guys that need to put out a detailed analysis of every part of a movie that doesn't match reality? You can't just read something and have a chuckle? I'm pretty content with my knowledge of various gases, but thanks for your input. You did read the part of my post that said: "But really:"?

Based on your posts in this thread, remind me to never invite you to a party. You seem like a major buzz-kill. No disrespect meant toward your senior member status.

 

And since a tire filled with hydrogen would be at essentially 99+% H2, it wouldn't even ignite, much less explode.

No, it really isn't. NASA has even more experience with far more wicked stuff.

Hydrogen is safe enough that they let us make our own, play with it, and even burn it in 10th grade chemistry class. Think they'd do that with Monomethylhydrazine?

Name a rocket related loss-of-vehicle or loss-of-life caused by hydrogen. I can name some from hypergols and even Nitrous Oxide, but none from hydrogen (and Challenger 51L wasn't from hydrogen).

 

Um,,,,no. I added that 3 minutes before your post. Look at the times.

Anyway, what does it really matter. Try to relax and enjoy the world a bit before you get caught up in trivial details and get dropped by a heart attack.

 

Hydrogen's flammability and leakage misconception have stymied its use as an energy carrier for decades. I wouldn't call that a "trivial detail" at all.

 

Very likely they're just green valve caps, and it's nitrogen fill. Costco for one does this when installing new tires: inflates them with nitrogen, and supplies green valve caps.

The atmosphere is (roughly) 4/5 nitrogen, 1/5 oxygen, and various trace gases. Maybe instead of saying "nitrogen-filled" tires, it would be more succinct to say "oxygen-free". Just like gluten-free, lol.

 

OK, let me rephrase: Hydrogen is #1 on the chart. Sheesh.....

Hydrogen flammability and leakage are not myths.

"The storage and use of hydrogen poses unique challenges due to its ease of leaking as a gaseous fuel, low-energy ignition, wide range of combustible fuel-air mixtures, buoyancy, and its ability to embrittle metals that must be accounted for to ensure safe operation. "

Hydrogen safety - Wikipedia

 

Neither is gasoline's.

"U.S. fire departments responded to an estimated average of 152,300 automobile fires per year in 2006-2010. These fires caused an average of 209 civilian deaths, 764 civilian injuries, and $536 million in direct property damage. Automobile fires were involved in 10% of reported U.S. fires, 6% of U.S. fire deaths."


Vehicles


Overall, hydrogen is a far safer fuel than gasoline. One reason is that it escapes from the area and disperses rapidly upward, in the event of a leak, rather than pooling under the vehicle while ignited.

 

This is why if a hydrogen-filled electrical generator needs to have the casing removed for maintenance, it is first purged with CO2 to a certain percentage (I forget the exact %) of CO2 in H2, then the CO2 is purged to a certain percentage with air. Reverse the process after the casing is buttoned up --- Purge the air with CO2, then purge the CO2 with H2 until you get to >98% pure H2.

 

I crewed gas balloons one year at Albuquerque Balloon Fiesta, and those who chose to inflate with hydrogen had a giant roped off area, no fleece or static prone clothes and those aircraft had a giant ohmmeter to check balloon fabric for static electricity or something.

No accidents fortunately, but I was giving them a wide berth.

 

Fiction.
Post #3 covers it pretty good.
Fact is that it allows the service shops to take more of your money.......and the margin is VERY high.

 

And yet you perpetuate your own myth.