Most standard procurement models — including most inventory-management and supplier-evaluation approaches — are built for repeat purchasing: the same item, bought again and again, from the same supplier. In construction and EPC (Engineering, Procurement, Construction) projects, a large share of purchasing runs the opposite way: project-specific equipment and materials are often bought once, and the next project may need something entirely different. That fundamental difference renders many standard procurement tools ineffective in this industry.
Lead times for key EPC equipment — turbines, large heat exchangers, custom-fabricated units — can run from several months to over a year. That means the purchasing decision for these items has to be made early in the engineering design phase, before the final design is complete. Delaying that decision — often because teams wait for final technical specifications to be confirmed — directly impacts the project's overall completion date, since these items typically sit on the project's critical path.
Coordinating subcontractors adds a layer of procurement complexity that doesn't exist in typical manufacturing. Unlike a component supplier who just delivers goods, a subcontractor brings both resources (labor, equipment) and their own schedule into the project — and one subcontractor's delay can directly hit the schedule of other contractors whose work depends on them. Managing these interdependencies turns project-based procurement into a multi-layered scheduling problem, not just a purchasing one.
Volatility in base material prices (steel, cement, copper) creates meaningful financial risk on long-duration projects that's far less prominent in short-cycle repeat purchasing. A two-year project that assumes material prices fixed at contract-signing day offers no protection against market swings. Managing that risk usually requires either price-adjustment clauses in the contract, or early purchasing of critical items ahead of physical need — a decision that itself requires extra warehouse space and working capital.
Supplier evaluation in this industry also needs different criteria than repeat purchasing. For a repeat supplier, past performance history is the best predictor of the future. For a one-off, custom-fabricated equipment supplier, that history is limited or nonexistent; evaluation needs to focus more on technical capacity, financial capability to complete a large order, and verifiable references from comparable past projects.
A common mistake is applying the same procurement approval process — built for small, repeat purchases — to large, critical project purchases: the result is either excessive slowness on urgent decisions, or excessive speed on high-risk ones. Project-based procurement needs a separate approval path calibrated to each purchase's actual size and risk, not a single fixed dollar threshold applied to everything.
The practical starting point is segmenting project procurement items along two axes: lead time and impact on the critical path. Items that are both long-lead-time and on the critical path need to be identified and ordered during the earliest design phase, through a dedicated fast-track decision process — not left waiting in the project's normal procurement queue.
Across SCM LAB's engagements with EPC contractors and construction firms, the main difference between projects that deliver on time and those that slip almost always traces back to this exact point: whether long-lead-time items were identified and ordered in the project's first weeks, or left waiting for the design to be fully finalized.