Formula Equations
Formula is an equation used to calculate the developed length for any radius or outside diameter (OD) that falls outside the range of the table data. Piping provides the following variables for use in the table:
L—Developed straight length of the bend.
T—Pipe outer diameter (OD).
ANGLE—Bend Angle (in degrees).
Formula Equation Rules
Follow these rules when you enter the formula equation in a bend table:
The formula must be the first equation in the table.
The formula must begin with the descriptor FORMULA, in the first column.
If an equation is simple, write it in the second column on the same line as the descriptor, as in the following examples:
FORMULA L = (0.55*T) + (PI*R)/2.0
FORMULA L = (ANGLE*PI/180)*(R+T/2)
If the formula is more complex and/or contains some logic statements, then the FORMULA descriptor must precede the actual formula on its own line. The formula must also be concluded by the descriptor END FORMULA, on its own line and in the first column. The following example illustrates this process:
FORMULA
IF (R/T) < 1.10 | (R/T) > 1.83
L = (PI*R*T)/2.0
ELSE
L = (PI/2)*(R + (T*0.35))
ENDIF
END FORMULA
In a multi-statement formula like this, you can enter the statements in columns other than column one.