Static evaporation rate is the volume of liquid nitrogen a storage vessel loses per day under normal ambient conditions, with the vessel correctly filled and sealed and no samples being accessed. It is expressed in litres per day and is one of the key specifications to compare when selecting an LN2 storage vessel for an IVF laboratory.
The reason it matters operationally is straightforward: as the liquid nitrogen fill level drops, the temperature in the vapour column above the liquid rises. In a vessel with a high static evaporation rate, the fill level drops faster between top-ups, which means the safety margin above the critical -130°C biological threshold narrows faster. A vessel with a low evaporation rate holds its fill level longer and is therefore more tolerant of supply disruptions, delivery delays, or a gap in the laboratory’s LN2 replenishment schedule.
For labs making a capacity comparison between two vessels with similar canister capacity, the static evaporation rate is often the deciding specification. A vessel that requires top-up every four days imposes a more demanding supply and monitoring burden than one that holds its fill for eight days. When assessing a CryoNest or CryoCan vessel, Cryolab can provide static evaporation rate data for each model. Contact the team to compare specifications for your specific storage requirements.
