How to assess ROI in pipe prefabrication

The machine investment is one part of the decision. Start with the cost of producing the same workpiece in the current and proposed processes, and the capacity of the complete production route.

Collect the inputs

• Annual volume and batch sizes.
• Time spent cutting, fitting, welding, finishing and inspecting each workpiece.
• The number of operators involved in that time.
• The fully loaded labour cost per operator-hour.
• Purchased fittings and other additional components per workpiece.
• Average rework and scrap cost per workpiece.
• Changeover time, utilisation and the expected production mix.

Use a like-for-like comparison

Keep the annual volume and workpiece requirements the same for both options. Use measured current-process data and clearly identified assumptions for the proposed process. Avoid counting the same welding labour in both process time and a separate cost entry.

What does the calculator include?

Annual labour hours equal annual volume × process minutes per workpiece × operators ÷ 60. Annual process cost combines labour cost with additional components and rework. The difference between the current and proposed costs gives the annual cost saving in the scenario.

Simple payback equals investment divided by a positive annual saving. The five-year result equals five times the annual saving, less the initial investment. Weld reduction is a separate process indicator: it is not added to savings again.

What needs a separate assessment?

This initial model does not calculate discounted cash flow, tax, financing costs, inflation or changes in output. Account for installation and tooling in your investment input where relevant. Assess differences in energy, maintenance, downtime and other ongoing costs separately before making an investment decision.

Test conservative assumptions

Compare a base case with lower utilisation, a slower target cycle or higher implementation costs. A trial or proof of concept can help verify achievable cycle time and workpiece quality. The result is a scenario, not a quotation or a guaranteed return.

Need help preparing the inputs? Use the workpiece assessment checklist.