Elevation Datum Elevation data are used to indicate a level line control point. An elevation datum has three parts. Farthest from the drawing is a ¼” diameter circle with two lines crossing inside horizontally and vertically, and the upper right part and lower left part are filled with solid black. Above the horizontal line stretched out from the middle of the circle is a description of a point where a level is measured such as ceiling line, grade, or finished floor plan. The actual elevation that is the height of the point is described below the horizontal line (Figure 21). An elevation datum is generally used for exterior elevations.
P oint w here a level is m easured
FIN IS H ED FLO O R LE VE L 16'-7"
Elevation Figure 21. Elevation Datum
Door Number Symbol Doors are identified by a door number symbol. A door number symbol has a 3/8” diameter circle and a number inside (Figure 22). The number indicates either door number or door type, depending on the project. The number is then referenced to the door schedule.
Figure 22. Door number symbol
Window Letter Symbol Windows are identified by a window number symbol. A window letter symbol has a 3/8” diameter hexagon and a letter inside (Figure 23). The letter indicates either door number or door type, depending on the project. The letter is then referenced to the window schedule.