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1947-48 Theatre Catalog, 6th Edition, Page 155 (143)

1947-48 Theatre Catalog, 6th Edition
1947-48 Theatre Catalog
1947-48 Theatre Catalog, 6th Edition, Page 155
Page 155

1947-48 Theatre Catalog, 6th Edition, Page 155

situation that is generally covered by code and should be checked carefully in that relation.

Where the emergency exits feed into an exit court, the level of such a court can be adjusted by means of ramps to meet the level of the exit door sills. Such courts, hOWever, should follow as closely as possible the general outside grade. This is advantageous for reasons of construction cost and to ayid an exit court several feet below the natural outside grade, which will become filled with snow and ice in the winter, and be difficult as Well as costly to keep clean and passable at all times.

Picture Elevation

The next variable to consider in determining proper floor slope is the elevation of the bottom of the picture and the elevation of the stage or platform. The proper height of the bottom of the picture above the stage or platform is from 18 to 24 inches, which gives an opportunity for the installation of the bottom masking of the picture sheet. The bottom of the picture can be located at almost any height in relation to the elevation of the fioor at the last row, but the elevation of the floor at the first row will be fixed at a distance of 5 feet to 5 feet and 6 inches below the bottom of the picture.

With an assumed elevation of the bottom of' the picture, and the elevation of the floor at the first row fixed in relation to this figure, the sight line from the bottom of the picture over the heads of the seat occupants in the first row to the eye height of the occupants of the third row can be determined and consequently the elevation of the floor at the third row. This procedure is then repeated determining the sight line from the bottom of the picture over the third row heads and meeting the eye line of the fifth row. The average height of the eye of a seated person is 3 feet 8 inches and the average distance from the eye to the top of the head is 4% inches. By repeating this process for every second row until the level of the last row is determined, the proper curve

FIGURE 17-Orchestra floor seating layout, showing steppings in the rear rows. (Not drawn to scale: figured elevations are not necessarily typical.) The seat rows should be laid out on the arcs of concentric circles. The center of these circles will be determined by the width of the house, loca4



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FIGURE 16-The sill of the exit openings should be raised above the level of the sidewalk or exit

court by means of a ramp or, perhaps, a step a

t the building line. Since the aisles immediately

adjacent will be carpeted, it is necessary to make provision for the carpet and padding the recommendation for these sills is an angle set securely in the concrete. Doors should be weather-stripped.

of the floor will be obtained for variables which have been assumed.

Should the curve thusly determined fail to meet the fixed elevations, such as the side emergency exits and the

elevation of the standee foyer at the standee rail, it will be necessary to either raise or lower the assumed elevation of the bottom of the picture and start over, repeating this process until a curve results which will most nearly meet the requirements.

The process of figuring the floor curve may be reversed starting with the approximate required elevation of the last row and figuring the line from the eye height of these seats over the head height of the second row in front and continuing to the first row.

The preliminary trials may be made graphically but, due to the great probability of accumulated errors in this method, the final elevations of the curve should be figured. In this connection, considerable time will be saved if the elevation of the stage is taken as plus or minus no feet, no inches.

Floor Curves

Depending on the relation between the elevation of the bottom of the picture and that of the door at the last row of seats, varying types of curves will result, but if the calculations are correct the sight lines resulting will be


The usual curve is one which has the steepest inclination at the rear, gradually diminishing towards the stage. An other might be a reverse curve with the lowest point somewhere approximately two-thirds of the distance between the last and first rows, or it may result in a curve where the last row and the first row are at approximately the same elevation with the lowest point of curve somewhere near the center row. An extreme case can also result Where the slope of the curve is entirely reversed and although such a curve will produce the proper sight lines, it is not recommended.

In this connection attention is called to the fact that seat standards are available, and will be supplied by the seat tions 01 emergency exits, and so forth. The orchestra floor along each of these concentric arcs will be level in order to maintain the same sight line for all the seats in the row. In order to lay out the orchestra floor, several variables must be considered to establish the proper sight lines.
1947-48 Theatre Catalog, 6th Edition, Page 155