CO2 vs HPA

Last Updated Feb. 19, 2008

There are Advantages and Disadvantages of CO₂ vs HPA
Written by George A. Lewko print friendly version of article

Advantages CO₂

Cheapest propellant source and usually the most available.
CO₂ takes up less room, as most of the CO₂ is stored as liquid and it convert gas (pressure) with ambient heat. (More shots per tank).
CO₂ tanks are cheaper to purchase.
Smaller CO₂ tanks are exempt from Hydrotesting, but do expire after 15 years.

Disadvantages CO₂

Limited ambient heat (under 5oC), will not convert enough liquid to gas for most markers.
Not all markers work on CO₂ anymore, especially higher rates of fire semis.
Tanks can over pressurize (with higher temperatures) and blow out rupture disks.
Tanks can increase their pressure with high ambient temperatures, to over 1,300 p.s.i. (normally 800-1,000 p.s.i.), which will cause unregulated markers to shoot too fast for safety.
Unless you remove the tank and weigh it, you don't know how much CO₂is left in the tank.

Advantages HPA

HPA refers to Compressed Air or Nitrogen gas up to 4,500 p.s.i.
Under our (Canada) temperatures, it's a more stable source of propellant. Which means that the velocity is stable for most of the day.
Can be used to play "Winter" paintball outside, we play down to -15oC, but markers seem to work at colder temperatures. (However, batteries don't work well at these temperatures.)
You don't freeze the markers seals or o-rings with every shot.
Easy fills, usually without removing the tank from the marker.
Works on all markers, but might need special outputs (high or low) for some.
Safer source generally than CO₂. (Could do a whole article on this alone).
Full 4,500 p.s.i. fills are not offered everywhere, and sometimes not even 3,000 p.s.i. fills, which limit your shots per tanks.
Gauge on tank lets you see how much pressure you have left.

Disadvantages HPA

Higher pressures than CO₂.
Not as available as CO₂.
Higher cost to use per shot.
Tanks must be hydrotested every 5 years (generally) , and expire after 15 years, or so many Hrydotests.
Fiber wrapped tanks can have their fibers damaged, and then are unsafe to fill, and will NOT pass Hyrdotesting. These all should be used with a protective cover over the fibers.
Oil or petroleum based products can flash under HPA pressures (3,000 p.s.i. +) and explode, so none of these products can be used to repair fill nipples that leak, air lines, etc. Leaking fill nipples should be replaced.
Fill nipples should be covered and protected against debris.