Ice-lined refrigerators are widely used in immunisation programmes, including in India, at health facilities where electricity is not available round the clock. A layer of water-filled containers or tubes lines the walls of the cabinet. When power is on, the system freezes this lining; when power fails, the frozen lining keeps the storage compartment within the vaccine range for many hours. The time it can do so is called the hold-over time.
The design is top-opening, like a chest freezer, so cold air stays inside when the lid is lifted. Vaccines are kept in baskets, not directly against the walls, because contact with the ice lining could freeze freeze-sensitive vaccines. ILRs used in national programmes are generally chosen from models assessed against WHO PQS specifications, and handling follows programme guidelines.
A primary health centre in rural Odisha might store its routine immunisation stock in an ILR, with a temperature logger inside and twice-daily checks recorded by the cold chain handler. During long power cuts in the monsoon, the ice lining carries the vaccines through.