4. Shipping weights as they affected the cost of delivery. 5. Probable maximum service-life requirements. 6. Type and function of buildings in which these materials were to be installed. 7. Availability as it affected delivery and progress of the installation. 8. Possibility of substitution in the event the selected items were not available. 9. Suitability of the selected items to fit conditions where field changes were to me made. As a result of these investigations the following criteria were set-up and, except in some specific instances, represented the type of installation: 1. Fixtures a, Aluminum reflectors with bare incandescent lamps were selected for general use because they were more economical than the vapor-proof type. Aluminum reflectors for all bed lights were originally specified but procurement efforts indicated that costs of manufacture would be inordinately high at the time. As a consequence, of the available steel or porcelain substitutes, steel was chosen because of considerations of weight, unbreakable character and very low cost. The last mentioned factor indicated economies in the use of steel even if frequent replacement was necessary. Glassteel diffusers were used in the dining portions of the mess halls to provide a high quality of light. Vapor-proof fixtures were used for outside bracket lights, in latrines and shower rooms, and elsewhere where excessive moisture conditions prevailed. Fluorescent fixtures were used only in areas specified by J-Division, as the initial cost of installation was considered to be too high to warrant general use. Class 1, Group D, explosion-proof fixtures were installed in hazardous areas along with rigid galvanized conduit, explosion-proof fittings, sealing fittings, etc. Security flood lighting was installed around the CMR and similar restricted areas on Parry and on each of the experiment locations. 5-125