Cryogenic dewars contain no moving parts and in normal use simply sit holding liquid nitrogen. This can create a false impression that they require little maintenance. In fact, dewars in active IVF clinical use should be subject to regular inspection and periodic servicing to maintain safe performance and HFEA compliance.
At minimum, a visual inspection should be conducted monthly. This involves checking for external damage including dents, scratches, or any visible deformation that might indicate the vacuum jacket has been compromised. It also involves checking that fittings, couplings, and level sensing equipment are secure and functioning correctly.
The measured evaporation rate should be monitored and compared against the baseline for each dewar. An increase in evaporation rate is one of the earliest indicators of vacuum jacket degradation. If a dewar that previously lost 0.15 litres per day begins losing 0.3 litres per day, this should prompt investigation.
A more thorough engineering inspection by a qualified cryogenic equipment technician should be conducted annually at minimum, including checking all seals and joints and assessing the general structural condition of the vessel.
When dewars approach the end of their expected service life, typically 10 to 15 years for a quality clinical dewar, the decision to replace rather than continue servicing should be made proactively.
All service records must be maintained as part of the HFEA-required documentation for cryogenic storage equipment.
Cryolab provides service support alongside equipment supply for UK fertility clinic cryogenic storage. Visit cryolab.co.uk“>Cryolab
