Air Products 20,000 Gallon Liquid Nitrogen Storage Tank – 70 PSI – LOX Equipment

What is the current vacuum reading, and what is the NER?

The listing does not provide a current vacuum reading or NER (Normal Evaporation Rate) for this tank. Request these figures from the seller along with the date of last vacuum measurement, as vacuum degradation is the primary performance indicator on double-walled cryogenic tanks and determines whether the unit needs re-evacuation before service. On tanks of this vintage, NER above 1.5-2% per day typically indicates vacuum loss requiring service.

What product has it held, and what can it be converted to?

This tank was in liquid nitrogen service. Nitrogen tanks can generally be converted to liquid argon without modification, as both are inert and have similar temperature ranges (-320°F for nitrogen, -303°F for argon). Conversion to liquid oxygen requires ASME review and typically involves cleaning to oxygen service standards and possible materials compatibility assessment, as oxygen is highly reactive and requires rigorous contamination control.

Is the data plate legible, and is the U-1A available?

The listing confirms the serial number (30174) and National Board number (3723), which indicates the data plate information is readable. The listing does not state whether the ASME U-1A Manufacturer's Data Report is available; request a copy from the seller, as the U-1A is required for jurisdictional review and many states will not permit installation without it on file.

What is involved in relocating and re-commissioning it?

Relocation requires purging, warming to ambient temperature, vacuum relief, draining ancillary piping, crane lifting (typically 25,000-35,000 lbs for a 20,000-gallon horizontal tank including saddles and insulation), and transport on a lowboy or flatbed. Re-commissioning involves foundation preparation, saddle leveling and anchoring, vacuum integrity testing, pressure testing per ASME requirements, recalibration of relief devices set at 65 PSIG, and jurisdictional inspection if required by the state. Vacuum quality determines whether re-evacuation is needed before the tank can hold rated capacity without excessive boil-off.