a. The importance
Exterior design should be considered throughout the design process. In general, the design should receive most attention once the general arrangement of the powerhouse including floor and crane rail elevations and crane clearances is determined. It should utilize scale, proportion, rhythm, and composition to achieve an aesthetically pleasing structure which fits in with its natural surroundings. In achieving these ends economy is important, and, although decoration and complexity are not to be ruled out, simplicity should be the keynote.
b. Aesthetic appearance
The arrangement and dimensions of the various masses is determined by the physical requirements of the powerhouse components. However, in the design of the ensemble of these masses, the architect should be allowed freedom consistent with an efficient and economical plant layout. In addition, some of the devices that may be used to define and compose the masses and give scale, proportion, and rhythm are changes in texture and materials, emphasis of horizontal pour joints and vertical contraction joints, and placement and sizing of fenestration and openings. The exact size and location of openings should be determined from the standpoint of aesthetics after the structural, mechanical, and functional requirements have been investigated.
Windows need not be used, but they may be desirable in order to let in natural light and increase employee morale. When used, their form and location should relate to their function and the aesthetic appearance of the structure. In general, large glass areas in operating portions of the powerhouse should be avoided to minimize blast damage, but small windows high in the powerhouse walls may have value in this respect as blast pressure relief openings.
c. Final selection
Selection of the final powerhouse design should be made after a careful study of at least three designs having basically different exterior treatments. Each proposed design should be carefully developed and perspective drawings prepared. The point of vision for the perspectives should be a point from which the general public will view the structure. The sketches, which are to be used for the selection of exterior treatment, should include all of the adjacent structures and surroundings.