Document ID: chunk:federal_register_of_legislation:F2015L00160:body:0:p7
Version: federal_register_of_legislation:F2015L00160
Segment Type: other
Provision Reference: 
Character Range: 16272–19181

effect of the clamping rods was to sandwich the several layers of cladding together.
The first building constructed at Mawson using this method was the Electricians' Workshop (originally the Works Hut). Mark III buildings also featured:
       * improved insulation, including double-glazed perspex box windows and heavy 'cold room' doors with clamp handles;
       * greater comfort by virtue of coke-stove heating and exhaust fan ventilation, and purpose-designed furnishing;
       * improved access through the inclusion of a roof hatch; and
       * reduced exterior maintenance through the use of aluminium sheeting to protect against snow blast.
The Mark III huts also looked quite different, having a simple box appearance rather than pitched rooves and gabled ends.
The first Mark IV was built in 1955. While structurally very similar to the Mark III, the internal configuration was markedly different; Ross Hut contained six individual sleeping cubicles. Balleny Hut, a larger version of Ross, was built in 1956 and became the model for sleeping quarters at Australian Antarctic stations, until a rebuilding project commenced in the 1970s.
Gradually, faults in the PTBs became evident and cladding materials changed from bare plywood to aluminium, asbestos cement sheeting and zincanneal (used exclusively from 1959 on). The original stone base foundations gave way to timber sleepers, wooden chocks, steel scaffolding (from 1960 onwards), and eventually concrete. Structural details such as door and window types also changed over time, as did internal building materials. Onazote insulation, which was not fire retardant, was replaced by polystyrene foam and asbestos cement.
The PTB series was followed by a style known as the 'Gimesey' – until deficiencies (primarily complexities of shipping and construction, and failures of insulation) led to its abandonment.
Consistent with Mawson's development as a research facility, buildings and structures were also purpose built to house or prepare equipment. Sledge-dogs bore field parties on regular routes over sea ice to emperor penguin colonies as far as 210 km from the station, and supported one or two long inland journeys per year between 1954 and the late 1960s. While dogs were phased out elsewhere in favour of more efficient mechanical alternatives—they were removed from Davis station in 1965 and from Casey station in 1970—they remained in use at Mawson until 1993.
In 1956, Antarctica's first hangar was built to accommodate Royal Australian Air Force De Havilland Beaver (A95) and Auster (A11) aircraft which in that year served as platforms for surveying areas up to 800 km from the station from a 2500 m blue ice airstrip. RAAF pilots and engineers were stationed year-round at Mawson until 1960. After a storm destroyed two Beaver aircraft in December 1959 and their replacements (a Beaver and an ex-US Air Corps Dakota DC3) in the