How to Fill an HPA Tank Correctly (2026 Guide)
An HPA tank is filled with dry, filtered compressed air up to the working pressure stamped on the tank neck by the manufacturer — typically 3000 psi (207 bar) or 4500 psi (310 bar). Overfilling past that number is the fastest way to turn sports gear into a hazard. ⭐
What pressure does my tank take?
| Tank type | Rated pressure | Typical use |
|---|---|---|
| Low-pressure tank | 3000 psi / 207 bar | Entry-level markers |
| High-pressure tank | 4500 psi / 310 bar | Tournament markers |
The rating is stamped directly on the tank neck. If it's missing or worn off, the tank needs inspection before it goes near a fill station, not another fill.
What are the actual fill steps?
- Check the tank for cracks, dents, and a valid inspection date.
- Connect the tank's fill nipple to the station adapter.
- Fill slowly while watching the pressure gauge.
- Stop the moment the rated pressure is reached.
- Bleed the line, disconnect, and check the tank for heat buildup.
Fast filling heats the compressed air, and air contracts as it cools — so a tank filled quickly often reads lower pressure once it settles than it did mid-fill. Slow filling is boring, which is exactly why it's the safer method.
What do the rules say?
There's no single global standard, so requirements shift by region:
- United States: Tanks fall under DOT/TC cylinder specifications. Steel and aluminum cylinders (DOT 3AL) typically need hydrostatic retesting every 5 years; carbon-composite tanks carry a manufacturer-set service life, often around 15 years, after which they must be retired regardless of test results.
- United Kingdom: Compressed gas cylinders fall under HSE guidance on pressure systems, requiring periodic examination by a competent person at intervals set by a written scheme of examination.
- International/general: Look for the pressure rating and last test date stamped on the tank, and follow the manufacturer's retest interval — this is the one detail that varies least across borders.
What happens if you get it wrong?
An overfilled or damaged tank can fail violently under sudden pressure release. Only fill at stations with a calibrated gauge, and never use a tank past its stamped inspection date — no exception is worth the risk.
Bottom line: know your rated pressure, fill slowly, respect the inspection date. Everything else is routine.