crazy people!

[angrybear]

My work is the biggest consumer of liquid nitrogen in the country.
It's bloody cold at -196 degrees C and 1 litre expands to 694 litres of gas.

Glad I got that off my chest :-)

Whilst in the RAF I was Q LOX/LIN production, good fun but LOX is not to be treated lightly.

[ChrisC]

Whilst in the RAF I was Q LOX/LIN production, good fun but LOX is not to be treated lightly.

We used to fill the LOX pots for the Dominie's.

[Shedder]

My recollection is that the air we breathe is 80% nitrogen, so it isn't very dangerous as a gas.

[Rob Edge]

My recollection is that the air we breathe is 80% nitrogen, so it isn't very dangerous as a gas.

Nitrogen at higher percentages will suffocate you. This is what happens to people at altitude where the air is described as thin due to the lower percentage of oxygen and higher percentage of nitrogen. Nitrogen is used in tyres due to it being more temperature stable. It has a much lower expansion rate than air as it is heated.

[tinbum]

The range of gasses that could be tried is quite large, many are inert, but some are plenty nert!

The best and only advice must be "breathing air only" to avoid confusion.

[DedIdick]

No boom....

But if your air cylinder leaks under your bed no massive drama.... if your nitrogen cylinder leaks you might not wake up.... ever

My recollection is that the air we breathe is 80% nitrogen, so it isn't very dangerous as a gas.

Correct, so a slightly leaking nitrogen cylinder under your bed should be no problem.

Only play with compressed gases IF you're COMPETENT & know what you're doing!

(So if the guy, talked about in the OP, works with compressed gases & is competent, then HE should have no issues.)

[eyebull]

If it troubles you that much to pay £1 to fill your PCP up, you should probably chop it in for a springer.

[secretagentmole]

BOOM !!!

Nitrogen is inert and makes up about 78% of the air we breathe, nothing wrong in using it at all.....

[zephyr]

Combustion requires the correct ratios of ‘fuel’ and oxygen, by using nitrogen that ratio is managed. Hence why nitrogen is sometimes used for:
a) drilling hydrocarbon (oil/gas) wells
b) fire extinguishant

The ‘BOOM’ comment isn’t completely wrong. While the ‘explosion’ won’t be caused by combustion, there could be a catastrophic mechanical failure of the pressure vessel if liquid nitrogen is allowed to warm and become nitrogen gas - the pressure would massively increase. But we aren’t talking of liquid nitrogen, are we?

The unwanted characteristics of nitrogen are, as said before, the potential for asphyxiation (although extreme cold is associated with liquid nitrogen) in addition there can be damage to some of the materials used in seals. Nitrogen molecules are much smaller than oxygen molecules and can get ‘inside’ the material of the seals. This results in (1) a very slow (insignificant) loss of pressure, (2) failure of the seals if there is rapid depressurisation.

To give some perspective of the dangers of nitrogen and the effect of the nitrogen molecule being smaller - ever wondered why crisp bags went from being transparent plastic to the silvery material used today? It’s because the gas inside the bag is nitrogen (no water moisture, as said before), which will leak through the transparent plastic!

[angrybear]

Correct, so a slightly leaking nitrogen cylinder under your bed should be no problem.

Only play with compressed gases IF you're COMPETENT & know what you're doing!

(So if the guy, talked about in the OP, works with compressed gases & is competent, then HE should have no issues.)

If he was competent he wouldn't have needed to ask in the first place

[ballisticboy]

No one seems to have pointed out that if he uses nitrogen to fill his rifle he will be committing an offence as only air and CO2 are permitted, all other gasses I believe are excluded.

[WILBA]

No boom....

But if your air cylinder leaks under your bed no massive drama.... if your nitrogen cylinder leaks you might not wake up.... ever

But that would depend on the following also rich. 1. Room is sealed.2. Size of cylinder v room size. We breath 78% nitrogen in with air.

[Gareth W-B]

See this is why I use a pump, because I'm waaay too thick to be buggering about with air cylinders

Lol. Ditto here, too. I only have one PCP among my mini collection, a single-shot BSA Scorpion .177 in a Tactical stock, which I keep charged with an FX Four-Stage pump. Had this as my token PCP set-up since 2012, and got no plans on changing it -- or my M.O. -- any time soon.

[Gareth W-B]

Nitrogen is inert and makes up about 78% of the air we breathe, nothing wrong in using it at all.....

..... err, we know, we established that twenty two posts ago, and I flagellated myself for my error nineteen posts ago.

[Rob Edge]

No one seems to have pointed out that if he uses nitrogen to fill his rifle he will be committing an offence as only air and CO2 are permitted, all other gasses I believe are excluded.

No offence committed because no law has been broken.