Selection of column spacing

It is necessary to select last/end column center to building outer distance. If a normal shed building is to be constructed which has brick wall of certain height (it may be 8 ft to 10 ft or more), the spacing is kept according to the thickness of the brick wall. The suggestion is following.
1. for 10 in (around 250 mm)  thick brick wall, the distance is kept 475 mm. See figure 1
2. for 5 in (around 125 mm) thick brick wall, the distance is kept 350 mm. See figure 2

Figure 1

Figure 2

Spacing of steel column, bay spacing will be kept in between 25 ft to 30 ft, member such as beam, column, purlin, girt etc should be kept under 30 ft for easy transport. In case of mezzanine floor or any other floor it is economical to keep column spacing in between 20-22 ft.

Standard practice in column rotation
Column rotation is kept according to following figure 3. This figure is only for I-shaped column of single storied pre-fabricated steel building.

Figure 3

But in case of the building having floors/floor column rotation is kept according to the following figure 4.

Figure 4

To construct a steel building it is necessary to keep unit in mm. And for easy construction the spacing should be round in number. Standard practice to round the numbers in 100, 500 and 1000. For example if clear height of a building is 18 ft, in mm unit it is 18X304.8=5486.4 mm, but it should be kept 5500 mm.
In a frame it is standard practice to keep column spacing in between 50 ft.
As maximum clients are non technical they give you out to out (O/O) dimension of their building. So this article may help you to give column spacing.