Multi-discipline EPC projects require many different types of people with various skill sets who can work together in an integrated fashion to deliver the project on time and on budget.
This article gives an overview of the roles and responsibilities of the various engineering disciplines for EPC project teams.
Understanding the Roles and Responsibilities of Engineering Disciplines in EPC Project Teams
Whether small or large, for any project executed inside an existing facility, the following items, at minimum, are required prior to the execution phase of the project:
- Complete project piping and instrumentation diagram (P&ID)
- Major equipment drawings and specifications
- Preliminary equipment layout drawings
- Existing infrastructure surveys (as needed throughout the project)
Engineering Team During Detail Design: Common Disciplines
The following engineering and design disciplines are involved in most multidiscipline EPC projects during the execution phase: civil/structural, piping, mechanical, and instrumentation/electrical/controls (IEC). The process engineering team will be involved as necessary to confirm design details or basis, but most of their work happens at the beginning of the project. Other specialties will be involved as necessary (e.g., fire protection), but, for the bulk of the work, the aforementioned “three” groups represent the highest percentage of required labor hours.
Civil/Structural Engineering and Design
This team is responsible for the design and engineering of:
- Groundwork
- Drainage
- Foundations
- Steel supports and structures
To begin detail design work, the civil/structural engineering and design discipline will typically need:
- Soil samples/geotechnical investigations
- Existing drawings
- Equipment weights
Piping Design and Engineering
Piping designers are responsible for:
- Determining equipment locations in the plant
- 3D models of piping
- Locating nozzles on equipment
Piping engineers are responsible for:
- Stress analysis (finite elements analysis, or FEA) of piping systems
- Piping specifications
To begin detail design work, the piping engineering and design discipline will typically need:
- Complete project P&IDs
- Line list with piping sizes and process conditions
Instrument, Controls, and Electrical Design
The instrumentation, controls, and electrical disciplines are responsible for the following on the project:
- Instruments
- Cause and effect diagrams
- Loop diagrams
- Automation
- Power systems and distribution designs
- Load studies
To begin work, this discipline needs instrument requirements/specifications, control philosophy, and engineering specifications. It also requires existing plant drawings or information, such as available:
- One-line diagrams (also known as an electrical single-line diagram [SLD])
- Power sources
- Input/output information
Process/Mechanical Engineering
Most process and mechanical engineering should have been done prior to detail design when equipment is being identified and specified and process and mechanical data sheets are filled out. However, process and/or mechanical duties during detail design may include:
- Conformance verification of the final design with the design basis. For instance, a hydraulic analysis may be necessary to confirm initial assumptions after equipment is located and piping is routed.
- Any details that have been left until the detail design phase (relief valve calculations/specifications, vendor drawing reviews, etc.)
Project Team Composition
The project team will vary depending on project specifics, but a simple rule of thumb for a typical project is a labor hour composition of civil/structural (25%), piping (50%), and IEC (25%). Note that this can vary greatly depending on the unique characteristics of the project.

In addition to the core engineering disciplines, typical roles for the engineering phase of an EPC project will include:
- Project Manager: The project manager provides overall scope, schedule, and budget control for the project.
- Project Engineer: The project engineer works for the project manager and provides technical interface among the engineering disciplines, clients, and vendors.
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