these cases, special consideration of detail was required to accomplish the desired results. aluminum structure, Standard building parts were used for every Because of the high relative humidity, it was necessary to dehumidify buildings that were to house instruments, telephone equipment, and other delicate equipment. Dehumidifications posed a serious problen, because the prefabricated aluminum buildings, although excellent in most other respects, were not inherently airtight. After considerable study, 2 gprayed-on vapor seal was selected for use in making buildings airtight. This method was used with good results. The Instrument Laboratory, the Counting and Sampling Building, and other buildings requiring dehumidification were treated in this manner, with the vapor seal sprayed directly on interior aluminum surfaces. Wherever possible, single buildings of rectangular plan were designed and sized to conform with the established standard width of 24 feet inside dimension, and the lengths of the buildings were developed in increments of four feet. In the design of the mess hall and galley at Parry, a cross-shaped plan was deemed the most functionally efficlient layout. The inside width of 24 feet was restrictive and made extremely careful planning necessary to include equipment and at the same time provide adequate work space and passage. In the course of the preparation of the plans for this building, it was decided that only the north dining wing would be constructed, but provisions were made for the addition of the south wing when and if it was required. The north dining wing was constructed in the first increment of work, and the south wing was added under the second increment. Later plans called for 32-foot extensions for both wings, but changes were made Which ultimately resulted in an additional dining room adjacent and parallel to the north wing. The introduction of plans requiring the intersecting and paralleling of standard building units produced the problem of designing satisfactory weatherproofing at intersections and between paralleled units. The general building construction did not lend itself to usual methods of intersecting roof surfaces, but this difficulty was overcome at buildings intersecting at right angles by placing the individual building wings in the desired positions, slightly separated from ona ancther, The intervening space was then closed with a special gutter installed at eave height and pitched to downspouts at one or both ends, as conditions warranted. The remaining open vertical spaces in the walls above the gutter were closed by means of special filler panels and, in conjunction with the roof gutter, formed a neat and weathertight installa- tion, Where standard buildings were placed in parallel, they were separated by approximately two feet and an aluminum gutter was suspended between the building eaves. For uniformity of construction and LVapor seal is described in Chapter 5.21, Dehumidification, AirConditioning, and Ventilation. 5-107