4,000 PSI ASME High-Pressure Storage CNG/ Nitrogen/Argon/Helium – 105 Cu Ft| 32,000 SCF | 1998

Is this ASME or DOT rated, and what does that allow me to do with it?

This is ASME Section VIII, Division 1 certified, National Board registered, and U-stamped. ASME stationary vessels are intended for fixed installation at a single location and cannot be transported filled like DOT cylinders; they are designed for permanent or semi-permanent skid-mounted applications where the gas is delivered to the vessel rather than the vessel transported to the point of use.

What is the MAWP and capacity at service pressure?

The MAWP is 4,000 PSIG. At working pressure this vessel holds 32,000 SCF of CNG or 25,000 SCF of nitrogen; the difference reflects the compressibility factors of the gases, and capacity for argon or helium would similarly depend on their respective Z-factors at 4,000 PSIG and storage temperature.

What is the requalification or inspection status?

The listing does not state the date of the last inspection, National Board R-stamp status, or remaining certification validity. ASME vessels in continuous service typically require external inspection every 3–5 years and internal inspection every 5–10 years depending on jurisdiction and service; you should request documentation showing the last NB-23 inspection, pressure test results, and thickness measurements.

What should I inspect before putting it into service?

Verify the epoxy lining for cracking, delamination, or holidays, especially at nozzles and welds, since compromised coatings can lead to localized corrosion in CNG or sour gas service. Check the data plate, nameplate legibility, and National Board number for traceability, then perform ultrasonic thickness testing at multiple zones to confirm no loss below the minimum required thickness stamped on the vessel. Review the previous service history carefully—CNG, nitrogen, argon, and helium are generally compatible, but if sour gas, hydrogen sulfide, or oxygen service occurred, embrittlement or contamination concerns may limit reuse without specialized cleaning and metallurgical evaluation.