Why does access reduce hold time?

Each opening introduces heat and vapor loss, increasing boil-off.

Should I use observed boil-off?

Yes. Replace defaults with measured consumption once the vessel is in service.

ToolsLN2 Dewar Hold-Time Estimator

LN2Free in-browser calculator

LN2 Dewar Hold-Time Estimator.

Estimate refill intervals from static hold time, fill level, access frequency, ambient temperature, and safety reserve.

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Validated2026-05-24

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Load example LN2 Dewar Hold-Time Estimator data to see the full workflow

Dewar assumptions

Static hold time

days

Fill level

Access events/day

Ambient temperature

Safety reserve

Refill plan

Adjusted hold

66 d

Refill target

50 d

Evap multiplier

1.09x

Use the interval as a refill planning target, then verify against observed boil-off.

When to use

LN2 refill planning
Cryogenic storage sizing
Access-policy review

Do not use for

Validated hold-time claims without observed boil-off data for the actual vessel

Static hold is idealized

Published static hold assumes limited access and controlled conditions.

Reserve protects weekends

A safety reserve prevents refill schedules from landing too close to empty.

Method

Static hold time is adjusted by fill percentage and an evaporation multiplier from access frequency and warm ambient conditions. The refill target subtracts the selected safety reserve.

Validated

Last validated 2026-05-24. Calculations are designed for planning and documentation support; verify procurement decisions against manufacturer specifications or institutional SOPs.

How to cite

How to Cite

ConductScience LN2 Dewar Hold-Time Estimator (v1.0.0). ConductScience, Inc. 2026. Available at: https://conductscience.com/tools/ln2-dewar-hold-time-estimator

ConductScience cold-storage calculator assumptions are deterministic planning aids and should be verified against selected equipment specifications.

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