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Understanding EPC Contracts: Key Phases of Engineering, Procurement, and Construction Projects

EPC contracts (Engineering, Procurement, Construction) play a key role in implementing large-scale infrastructure and industrial projects. These contracts encompass a complete suite of services and work, spanning from design to construction and commissioning. This article takes a detailed look at every stage of constructing a plant or facility under an EPC contract, as well as the specific aspects of supervising installation and startup operations.

Stage 1: Engineering

The first stage of any project carried out under an EPC contract is engineering. This involves preparing initial data for project development, analyzing customer requirements, and drafting the technical specifications. At this stage, the key parameters of the future facility are defined, laying the foundation for all subsequent work.

Technical Specification Development

The technical specification is a document that outlines the essential requirements for the facility, its functionality, technical characteristics, and standards that the finished product must meet. The client and contractor work together on the details of the technical specification before moving onto the next phase—design.

Designing the Facility

Based on the approved technical specification, design engineers develop the project solution, which includes architectural, structural, and engineering-technological components of the facility. Design requires multiple calculations and modeling various scenarios to ensure the safety and efficiency of the future operation of the facility.

Obtaining Permits

The next step in the engineering phase is ensuring legal support for the project, including obtaining all the necessary permits, approvals, and licenses. Project documentation approval is a crucial moment, as it paves the way for the actual construction work.

Stage 2: Procurement

After the project is approved, the procurement stage begins. This is a critical period, as the quality and timeliness of materials and equipment delivery affect the entire course of construction.

Purchasing Materials and Equipment

Selecting suppliers and purchasing the necessary materials and equipment for construction is a task that requires special attention to detail. The success of these actions affects the quality and reliability of the future facility. Moreover, it’s essential to organize logistics efficiently to ensure timely delivery without damage.

Selecting Contractors

An EPC contract allows the principal contractor to engage specialized subcontracting organizations for the works. Choosing reliable partners and managing them is also a crucial component of the project’s success.

We continue analyzing the EPC project process by transitioning to construction and the details of supervisory installation work.

Stage 3: Construction

The construction phase encompasses all procedures and operations necessary to build the facility according to the project documentation. This is a critical phase of the project, during which all the contractor’s resources are engaged to ensure the timely completion of the construction work.

Organization of the Construction Process

At the initial stage of construction, it’s crucial to properly organize all processes on-site. This requires clear planning, high coordination between contractors and suppliers, and control over adherence to the work schedule.

Installation of Structures and Equipment

The physical implementation of the project starts with the installation of load-bearing structures and the assembly of technological equipment and communications. The quality of these works directly affects the safety and functionality of the entire structure.

Finishing and Auxiliary Works

Upon completion of the main construction works, finishing works and installation of auxiliary systems and infrastructure elements are carried out. It’s vital to ensure that all components of the project fully meet the developed specifications.

Stage 4: Supervisory Installation Work

As soon as the main equipment is installed, supervisory installation work begins—one of the key stages during which equipment manufacturers’ specialists (supervisors) arrive on-site to oversee the correct installation and startup.

Supervision of Installation Work

Equipment manufacturers often provide supervisory installation services to ensure that their products are installed and configured correctly. Specialists conduct briefings for workers and monitor the progress of the work.

Training Client Personnel

Concurrent with installation, training of the client’s personnel takes place. This is necessary so that the client’s employees can efficiently manage and service the equipment after it is put into operation.

Adjustment and Calibration of Equipment

The supervisors perform precise adjustment and calibration of the equipment, verifying its functionality and compliance with technical parameters. These actions are necessary to minimize the likelihood of defects and accidents in the further operation of the facility.

Stage 5: Commissioning and Startup Works (CSW)

The final stage before commissioning the facility is commissioning and startup works. Their task is to ensure a continuous and safe launch of all systems and equipment of the facility.

Startup of Equipment and Systems

After equipment installation, it is gradually started up to verify and adjust all systems. Each system must be thoroughly checked to ultimately confirm the correctness of its assembly and installation.

Testing and Defect Rectification

This stage involves comprehensive testing of equipment operation in various modes and under loads. If discrepancies or defects are identified, they are analyzed and rectified. This guarantees that the equipment will operate correctly and safely during future exploitation.

Equipment Adjustment for Reliable Operation

The final step of the commissioning and startup works is the precise adjustment of the equipment to ensure its stable and long-term functioning. This is critically important for preventing downtime and minimizing wear during operation.

Stage 6: Acceptance by the Client

Upon completion of the startup and commissioning works, the facility must be accepted by the client. Acceptance is a procedure confirming that the work completed meets all the requirements and standards stipulated in the contract.

Verification of Compliance with Project Documentation

The client, together with specialists, conducts a thorough inspection and verification of the facility to ensure it complies with the project documentation and technical specifications.

Signing of Acceptance Acts

Following the verification, acts of acceptance for the completed work and the facility as a whole are signed. This document serves as the legal basis for putting the facility into operation.

Stage 7: Commercial Operation

After official acceptance, the facility is transferred to the client for commercial operation.

Transfer of the Facility to the Client

The client gains full control and responsibility for the operation of the facility. From this point, they can begin using it in accordance with the goals and objectives outlined in the project.

Warranty Service

For an established period, the contractor may provide warranty service, preventing potential issues and assisting in defect resolution when necessary.

Maintenance of Facility Operation

After completing all construction and startup works, it is essential to ensure proper technical maintenance of the facility for its efficient and safe operation throughout its service life.

EPC contracts require expertise, versatility, and well-organized project management for the successful implementation of complex infrastructure and industrial projects. They allow clients to minimize their risks by entrusting the entire cycle of work to one competent organization.


In conclusion, it should be emphasized that EPC contracts represent a comprehensive approach to project implementation, starting from the initial conceptual design to the commissioning of the facility. This allows clients to minimize their risks by transferring respon

Throughout every stage of the project, strict quality control is key. This is achieved through the development of a clear project plan, the involvement of qualified specialists, and the use of advanced technologies. It is also important to ensure uninterrupted interaction between all project participants for the prompt resolution of any issues and tasks that arise.

Effective management of an EPC project implies constructive interaction with the client, who should be informed about the progress of the work and ready to cooperate at each stage. Only through joint efforts can a successful outcome be achieved.

When deciding to implement a project based on an EPC contract, clients should carefully choose the contractor, assessing their experience, technical capabilities, financial stability, and market reputation. Ultimately, the success of the project depends on the quality of work of each team and every specialist involved in the construction process.

Thus, EPC contracts remain one of the most reliable and proven ways to implement large projects, ensuring a high level of integration of processes and quality of the final product for the client.

This article focuses on the technical aspects and does not cover the legal services required at all stages of preparing and signing an EPC contract. Nevertheless, selecting an experienced and proven legal advisor is crucial for the project’s success. Attempting to save on legal services and engaging a specialist with less than 15–20 years of experience can adversely affect the project’s results. Typically, both engineering and consulting teams consist of individuals with many years of successful careers. Deep knowledge and experience in key areas such as EPC can be decisive for efficient work on the project and its ultimate success.

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This material is intended for informational purposes only and does not constitute legal advice. If you have any questions or would like to learn more about the topics covered in this article or our global projects and EPC practice, please contact us at