Move the inputs to match your application — pressure, gas, cycles, weight envelope — and get a defensible recommendation across all five formats: Type I steel, Type II hoop-wrapped, Type III aluminium-lined, Type IV HDPE, and Type IV modified PET (Meyer HDRX). Each input has a help tooltip — click the ? to see what it means.
Already know the part you need? Browse the full COPV database → — 36 production cylinders with searchable specs, dimensions, and order forms.
COPVs are classified by how the pressure load is shared between the metal liner (if any) and the composite overwrap. The classification looks dry on paper, but it determines weight, cost, cycle life, and permeation.
| Liner | Wall thickness | H₂ permeation* | Cycle life | Best for |
|---|---|---|---|---|
| Steel (Type I) | Varies | < 0.01% / month | > 30,000 (steel) | Stationary, industrial, scuba |
| Aluminium (Type III) | ~3–6 mm | < 0.05% / month | 5,000–15,000 | SCBA, aerospace, breathing |
| Thin metal liner (Type IV-M) | ≤ 1 mm | ~0.05% / month | ~2,000–5,000 (metal fatigue, like Type III) | Zero-leak service where cycle count is low; weight-conscious |
| HDPE (Type IV) | ~4 mm | ~15% / month | 10,000+ | CNG, cost-led mobile gas |
| Modified PET | ~0.3 mm | ~30% / month | 10,000+, NLL | Weight-critical mobile (UAV, CubeSat, SCBA) where the cylinder is filled often |
*Indicative H₂ permeation at 300 bar, 20 °C. Each format has its place depending on the mission. Polymer-lined Type IV variants trade some permeation performance for the lowest mass and highest internal volume per outer diameter — the right choice for daily-fill mobile use (UAVs, vehicles, SCBA). Metal-lined formats lead on permeation and are the right choice for long-duration storage (helium pressurant, satellite missions on stored gas). Actual values depend on liner formulation, dome geometry, fill cycle profile, gas type, and temperature.
Pick the application closest to yours, then refine the inputs.
