IrriNex Store publishes worked example on planning cuts before ordering irrigation pipe rolls

8 October 2026, IrriNex Store has published a free practical guide explaining why a total-metres calculation can understate the number of rolls needed when irrigation runs must remain continuous. The guide, "Why Total Pipe Length Can Understate How Many Rolls You Need," is available without registration on IrriNex Store Practical Irrigation Notes.

The hypothetical example uses seven finished runs of 38 metres, a 0.5-metre allowance per run, and rolls containing 100 metres of usable material. The resulting seven cuts are each 38.5 metres long. Dividing their combined 269.5 metres by the roll length and rounding up suggests three rolls. However, each roll can supply only two complete cuts. Three rolls provide six cuts, so four rolls are required under the example's no-join assumption.

The article provides a roll-by-roll allocation and spreadsheet formulas for equal-length runs. It distinguishes the 130.5 metres left uncut from the 3.5 metres reserved for trimming and connections, without assuming that all remaining material is waste. It also explains why mixed run lengths require a separate allocation and why different product specifications cannot be treated as interchangeable stock.

The figures are an illustrative purchasing exercise, not a product specification or an installation recommendation. The allowance is not a standard, and readers must confirm actual routes, connection requirements, usable roll lengths and whether joints are appropriate for their system. The guide does not claim that a particular roll specification is stocked or suitable for a particular installation.

Read the guide: https://irrinex-store-notes.blogspot.com/2026/10/why-total-pipe-length-can-understate.html