CHAPTER Ili, SECTION 3 nected by a commoncorridor at one end which led to an L-shaped tunnel leading out of thefill. Room D was added to the structure. It was 26 feet square by 17 feet high with 3%foot-thick walls and 4-foot-thick slabs. This room supported the 150-foot tower, Station 2250. Although the new room was in contact with the existing structure, new walls were placed to re- duce vibration in the room,to isolate the heavy reactions from the tower to a single structure, and to avoid excessive breaking of existing concrete to establish continuity. An opening was madein the existing corridor wall to place a lead door for a shielded entry. The earth-fill over the station was extended to a 15-foot depth for with blast door. An opening in the existing wall was provided for the blast door. The roof and floor slabs were 4 feet thick, and the walls were 344 feet thick, except for the exposed 54-foot wall which was 41% feet thick. This wall was heavier because of the numerous exhaust and intake openings required for generator cooling. Room E contained two 214-foot-square openings with blast doors for air intake and exhaust for each of three generators. Room F contained two 314-foot-square openings with blast doors for air intake and exhaust for each of the two generators. The generators were mounted on raised foundations 6 inches high. Retaining walls were located on each end shielding purposes. of the Generator Station to provided ventilation Rooms E and F of the Generator Station Addition were located adjacent to Room D and taining wall was located at the tunnel end. parallel to the tunnel entry. The Generator Sta- tion Addition was a structure, 30x54x18 feet high, divided into two rooms with outside entry into Room F, and entry from Room F to the existing tunnel corridor utilizing a 5-foot corridor for the generators and for entry. Another reRoom D was air-conditioned utilizing the main equipment in the existing building with one additional compressor and condenser required. The two dehumidification units required in Room D were also provided. Two new salt- (Neg. No. W-V-263-5) Figure No, 2-57. Interior of Generator Room ‘“F’ — Station 2200. Page 115