Cold box design providing secondary containment

The present invention relates to cryogenic fluids. In another aspect, the present invention relates to additional protection of an apparatus containing equipment capable of operating at cryogenic temperatures and containing cryogenic materials. In one embodiment of the present invention, an apparatus includes a primary enclosure defining an internal volume. The primary enclosure includes primary walls, a primary ceiling, a primary floor, and a vapor venting system. The primary enclosure is fabricated from a low temperature alloy. At least of a portion of the primary floor forms a slope to a hydrocarbon outlet. A perforated plate is located on top of the hydrocarbon outlet. The perforated plate is fabricated from a low temperature alloy. A fire retardant agent applied to the exterior surface of the primary enclosure.