CHAPTER 5.19 DEHUMIDIFICATION, AIR CONDITIONING & VENTILATION The original Reconnaissance Report contained information regarding new air-conditioning units for timing buildings and the possibility of salvaging any existing portions of air-conditioning units in these buildings for use in less important locations, Supplement No, 1 to the report contained additional information regarding air conditioning of all laboratory buildings to the extent of reducing relative oiumidity only, except the photo laboratory where a temperature of 70° F with 50 per cent relative humidity was required, The report also specified ventilated range hoods for use in mess halls. Preliminary estimates for air-conditioning loads and design out- door conditions were started ditions of 82° dry bulb and 80 May 1949. Design outdoor weather conFwet bulb weather conditions were based on data obtained from a U, S. Department of Commerce publication titled "Weather Conditions in the Marshall Islands with Special Emphasis on Eniwetok Areas", dated February 1948, Tentative calculations were made for the counting and sample laboratory, instrument laboratory, rad-safe building, and the photo laboratory on Parry Island. The result of the study (which included load calculations, vapor seal, design conditions, and maintenance problems) was the realization that the major obstacle was vapor sealing of buildings for air conditioning. H & N promptly set out on an investigation which covered materials of some fifteen manufacturers, The only acceptable material proved to be a vinyl resin plastic known as "cocoon", This material, which is transparent or white depending on the number of spray coats applied, successfully eliminated the vapor transmission, Extreme care was necessary in its application, however, because of the acitate content of the material. Problems confronting those concerned with dehumidification and allied matters at the Jobsite were relived only through the Engineering Division's intensified research and jobbers! full compliance with unusual demands, The following terms used generally throughout this chapter are defined for purposes of clarity: 1, Dehumidification, This term denotes the supplying cf a room or a building with air which has had some of its water content removed, thus lowering the humidity. The equipment used also controls the motion and distribution of air, in order to main- tain relative humidity at a predetermined level. 2. Airconditioning. This term is used to define the control of air, including the dehumidification as well as the control of the final air temperature. This process also includes the distribution and motion of air to maintain predetermined air temperature and relative humidity, 5-256