Typical share of instrumentation cost in modern chemical plants Instrumentation and control typically account for what percentage of total plant cost?

Introduction / Context:
Project cost estimation requires realistic allowances for instrumentation and control (I&C). This includes transmitters, analyzers, control systems (DCS/PLC), wiring, and installation.

Given Data / Assumptions:

• Modern chemical plant with standard DCS/PLC-based control.
• Total plant cost considered as the basis for percentage.

Concept / Approach:
Rule-of-thumb ranges for I&C cost share are typically on the order of single digits to low teens percentage of total installed cost for process plants. The exact value depends on process complexity, safety/automation level, and regulatory requirements, but a common planning estimate is around 5–10% of total plant cost.

Step-by-Step Solution:
List typical cost contributors: field devices, marshalling, control rooms, software, panels.Apply standard estimating ratios used in FEL and feasibility studies.Select 5–10% as the representative band for many chemical facilities.

Verification / Alternative check:
Industry estimating guides and historical cost studies place I&C costs commonly in single-digit percentages for average complexity plants.

Why Other Options Are Wrong:

• 20–30%, 40–50%, 60–70%: far above typical I&C contributions and would imply extremely instrumentation-heavy facilities (not representative for standard plants).

Common Pitfalls:

• Confusing I&C share with electrical + I&C combined totals or with specialized facilities (e.g., semiconductor fabs) where shares differ.

Final Answer:
5 to 10%