Within the fixed-capital investment (FCI) of a chemical process plant, the purchased cost of major equipment typically accounts for what percentage range of FCI?

Introduction / Context:
Understanding how fixed-capital investment (FCI) breaks down helps in early estimates and in sanity-checking vendor quotes. Purchased equipment cost is a large, visible component but is only a portion of the total installed cost once foundations, piping, instrumentation, and other direct/indirect costs are included.

Given Data / Assumptions:

• We refer to major process equipment (reactors, separators, heat exchangers, etc.).
• FCI includes direct costs (equipment, installation, piping, electrical) and indirect costs (engineering, construction, contingencies).
• Rule-of-thumb ranges are sought for conceptual estimating.

Concept / Approach:
In many chemical plants, purchased equipment constitutes roughly one-fifth to two-fifths of total fixed capital. Installation, piping, electrical, buildings, and services roughly double to triple the bare equipment cost. Thus, a 20–40 percent share for purchased equipment within FCI is a commonly taught range for preliminary estimates.

Step-by-Step Solution:
Recall common cost fractions from conceptual estimating methods.Link bare equipment cost to installed cost multipliers (e.g., Lang factors).Conclude purchased equipment is typically 20–40% of FCI.

Verification / Alternative check:
Using a Lang factor of about 4–5 for fluids/solids processing projects: installed cost ≈ 4 * purchased equipment. Therefore, purchased equipment ≈ 1/4 to 1/5 of total plant investment, consistent with 20–40% of FCI when definitions differ slightly among sources.

Why Other Options Are Wrong:
10–20%: Too low for many chemical process plants.45–60% or 65–75%: Unrealistically high; would leave insufficient room for installation and indirect costs.

Common Pitfalls:

• Confusing purchased cost with installed cost (which includes erection and auxiliaries).
• Applying a single fraction universally; actual fractions vary by project complexity.

Final Answer:
20 to 40