Dry ice is available in solid blocks or as individual pellets of a few centimetres length. Pellet dry ice is most convenient for assembling dry ice shipping systems as it is easy to pour and naturally fills available space. Dry ice block would need to be prepared to the correct size to fit.
A dry ice shipping system for moving frozen product starts with an insulated box. The product being shipped is normally loaded into the box first. A temperature monitor may also be included and should be started at the correct time.
Now the dry ice needs to be loaded. Caution must be exercised when handling dry ice and all relevant Health & Safety procedures must be followed. Dry ice is very cold (around -80°C) so there is a risk of cold burns. It also gives off gaseous carbon dioxide – an asphyxiant – so must only be stored and used in appropriately ventilated and supervised areas.
Dry ice pellets are usually simply poured on top of the product and temperature monitor. Guidance from the packaging manufacturer will determine how much dry ice is to be added. The shipping system should have been correctly validated to meet pharmaceutical documentation needs.
Pellets usually come in 10kg bags – it’s worth bearing in mind that these bags will likely have a little more than 10kg in them when they arrive from the supplier but will lose weight in storage over time as carbon dioxide gas is given off. Thus a bag of dry ice used several days after delivery could have significantly less than 10kg inside. Thus weights may need to be checked against the expected bag contents.
Once the desired quantity of dry ice has been loaded in the lid can be sealed. It’s important at this time to check pellets aren’t stuck in the seal of the lid – this could keep the lid ajar and allow a warm draft into the internal of the box.
The sealed dry ice system is now ready to go off into the specialist logistics network.