Schedule pipe falls and stock cuts independently

A pipe route has at least three separate quantities: horizontal run, vertical level difference and physical pipe length. For an order, fittings and joint details also matter. Keep a route sketch alongside the arithmetic.

Calculate a stated gradient

For an illustrative 12 m horizontal run at a specified 1:80 fall, the level change is 12 ÷ 80 = 0.15 m, or 150 mm. This calculation does not say that 1:80 is suitable or permitted for the proposed system. The required gradient must come from the applicable design and requirements.

Keep the direction clear

Identify upstream and downstream levels and write down the reference datum. A positive numerical drop is not enough to establish that a route slopes the intended way. Check connecting invert levels before interpreting the fall as feasible.

Test the stock cuts

Three required 2.2 m straight pieces total 6.6 m. A 3 m stock length yields only one such piece, so three lengths are required even though total-length division rounds to three as well. With two 3.6 m stock lengths, total material would be 7.2 m but only two complete pieces could be cut. A cut list resolves this distinction.

Schedule fittings separately

Sockets, bends, branches, supports and connection allowances depend on the actual system. Their presence can change cut lengths. A quantity calculator cannot replace those connection details or establish hydraulic adequacy.

Found a measurement or calculation issue? Send the example and your correction.