Estimation of tubes in a tubesheet

By providing the effective Tube Sheet diameter (outer tube limit), the tube layout and Pitch the number of tubes fitting in the tube sheet are estimated. For an accurate result it is always advized to draw the tube sheet in detail including the spaces required for other internals that influence the space available for tubes. The estimation as shown below is based on a mathematical approximation and will be less correct when tube sheet diameters are small.