Underfloor heating (frost heave protection)
Also known as: frost heave protection, frost heave, under-floor heating
Short definitionHeating cable, warm glycol pipe or ventilation pipe laid under the insulation so that the ground beneath a freezer room does not freeze and lift the floor. It keeps the sub-floor between +5 and +10 °C.
Insulation does not stop heat, it slows it. The ground under a room that runs permanently below zero reaches the freezing limit within months or years. Freezing water draws up more water from below, ice lenses grow and push the floor upward. The concrete cracks, racks lean, the door will not close. Repair means emptying the store and breaking out the floor, so the matter is settled during construction.
It is considered for every frozen storage and blast freezing room that sits on the ground; a room on an upper floor or on an open platform does not need it. Electric cable of 10–20 W/m² is common in small and medium rooms, and glycol pipe warmed by condenser heat in large stores. Cables and sensors are laid in conduit, with spares, so they can be replaced. A fault alarm is fitted; a heating failure can go unnoticed for months.