weather hood easily removable for servicing and inspection, The fan shaft was stainless steel, and the fan blades were designed of heavy duty cast aluminum, balanced to insure vibrationless operation, The fan housing was made of heavy gauge aluminum adequately reinforced for maximum rigidity. Weight of these fan assemblies could not exceed 300 pounds because of building structural limitations. Exhaust hoods over ranges and friers designed for the installations of grease filters were constructed of stainless steel sheets reinforced with stainless steel angles. For ease of handling these hoods were sent to the Jobsite knocked down in sections. The grease filter assemblies for the range hoods were designed to withstand the salt air and excessive humidity, The filter media were corrosion resistant copper, and the filter frame was constructed of heavy silicon bronze. All filters used were stand~ ard sizes and of the cleanable type. Filters were placed in a V-type stainless steel adapter unit with removable drip pan, Exhaust hoods located over steam kettles, cookers, coffee urns, and dishwashers did not require grease filters, These hoods were designed similar to those located over ranges and friers, except that they were made of aluminun, The fume hoods used in the laboratory buildings were of standard construction similar to those used in commercial laboratories, - The three power house buildings on the test sites (Runit, the Aomon Group, and Engebi) were of solid reinforced concrete design, with the only openings those provided in the rear wall of the building. For this reason, it was necessary to ventilate these buildings whenever equipment was operating inside. The ventilation system for each building was designed so that the temperature inside the building would not rise above 110°F when outside air was 80°F, Air was supplied into each building through two identical ventilating systems with axial flow fans mounted inside the building. One system was designed so that blind flanges could be installed for seal-~ ing the inlet and outlet of the system a few hours before zero, The other ventilating system was designed with electric motor operated butterfly valves installed over the exhaust and supply openings. This system was to continue operation until shutoff at zero hour. The butterfly valve was an electric motor cperated two-position valve designed to close from wide open position in ten seconds, with an allowable variation of plus or minus 1 second, The valve was constructed of cast iron suitable for high humidity salt air at atmospheric temperature. The supply fan and other materials used for the construction of these ventilating systems were the best quality available for normal ventilation usage. A power house building was designed for Bogallua and its ventilation system was similar to the one described above with the exception that it was a single ventilation system with electric motor operated butterfly valves mounted inside the building over the supply and exhaust openings. The decision not to use this island for a test site made it unnecessary to construct this power plant. The ventilation for the scientific stations at various sites was in accordance with design criteria received from J-Division, 5 -260 The first