From the website:
Bushbunker represents a concept that has been designed from scratch specifically as a bushfire bunker, and comprehensively engineered to withstand the severe environmental conditions that a major bushfire produces. It has been designed for maximum survivor ability no matter the intensity or type of fire.

A series of two fire doors is used to separate the entrance/storage area from the bunkers main interior to provide a fail safe, and to create an air lock which protects against the infiltration of radiant heat through the first steel fire door. This is an extremely important design feature, as some of the most severe burns to Black Saturday fire survivors were caused by radiant heat.

To outfit the interior, the design makes use of standard off the shelf components such as steel fire doors, steel frames and sealing, bench seating, compressed air cylinders, battery powered electric lighting, storage shelving, water drums, UHF radio and EPIRB, and fire blankets and first aid. This in turn allows for flexibility in the design, and reduces costs.

The Bushbunker has been designed to comfortably accommodate up to 6 adults for an extended period when equipped with compressed air cylinders. These air cylinders also have the additional feature of providing a positive internal air pressure inside the bunker making it impossible for noxious and poisonous outside gasses and smoke to enter.

Hanging above each seating area is a series of refillable standard 20 Litre water containers which provide a gravity fed source of clean water for drinking, cooling and first aid purposes.

Due to its standardized size and modular construction, and depending on the site conditions of a home, the Bushbunker can be specially incorporated into the structure of a house or home, free standing, set into an embankment or partially or totally buried underground.

From : Bushbunker

Designer : Jon S. Standing