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Plant Commissioning

What Is Plant Commissioning, Exactly?

March 2, 2020
The ins and outs of the hand-off period between construction and production.

Commissioning is a vital step near the end of a plant’s construction, its purpose to hand over a safe, efficient and operation-ready facility to the owner. It is the planned coordination and execution of the final stages of construction and the beginning of production.

A detailed, systematic commissioning plan can reduce the overall time between completion of construction and the start of facility operations, and verify that the equipment and systems installed meet the design intent.

Over the years, I have led numerous commissioning efforts for industrial facilities across the U.S. and internationally. In this article, using a chemical process plant as an example, I lean into that experience, sharing some of the ins and outs of the commissioning process and the importance of developing a good commissioning plan.

It’s important to note that there is no clear definition as to when construction ends and commissioning begins, and no exact time when commissioning ends and operations take over.

Commissioning typically falls within three steps:

 1. Pre-commissioning: This stage involves activities that occur during the final stages of construction, including pre-functional test (PFT) inspections; end-of-construction punch lists and check sheets; factory and site acceptance testing of control systems; instrument loop checks and more.

 2. Commissioning: Sometimes referred to as “cold” commissioning, this second step (in the case of a chemical plant) involves running and testing the process without adding the chemicals or hazardous materials. For building commissioning systems, this step can include pre-functional testing of complete building systems, pre-commissioning focusing on equipment, and commissioning focusing on the system.

Depending on the complexity of the project, commissioning can be executed on individual systems, groups of systems or even partial systems. The commissioning timeline is a function of construction progress, and a commissioning team may be required to modify system commissioning as systems reach construction completion.

Cold commissioning is typically executed by the owner with support provided by the commissioning team. The commissioning team can support the owner with planning and scheduling of activities, manpower requirements for contractor support, and by providing engineering calculations required for various commissioning tests. Some standard tests that may require engineering support and calculations include water system flushing, compressed air blows, temporary support of piping for testing, and steam blows.

3. Startup: This final step is where the plant is finally brought into operation by the owner. During startup, the commissioning team will provide engineering support as required by the owner. A successful commissioning effort generates site-specific knowledge that can be used by the commissioning team to assist in the startup. Some common support functions include operator systems training, process systems troubleshooting, lockout-tagout practices and other safe work procedures, and pre-startup safety review participation.

Creating a Roadmap

Successful commissioning starts with a commissioning plan, which establishes a framework for how commissioning will be handled and managed on a project. Serving as a project roadmap, it identifies all parties involved, their roles and responsibilities, and the documentation required.

Planning begins with a solid schedule and process systemization. For instance, in a chemical plant, process systemization involves a commissioning process engineer taking the project’s piping and instrumentation diagrams (P&IDs) and identifing sub-systems that can be broken out and prioritized based on a logical sequence of events to start up the facility. The commissioning engineer will then work with the contractor to prioritize construction completion to meet this systemized startup sequence. This allows the contractor to refocus construction efforts in a way that permits an overlap of plant startup activities with construction, minimizing the overall time required to commission and start up the facility.

 Selecting the Team

For a chemical plant, a commissioning team should include a chemical process engineer, a mechanical engineer and an electrical, controls and instrumentation engineer. A chemical process engineer will help with understanding processes as they are designed. A mechanical engineer is mostly responsible for the full check and verification of all mechanical equipment in the field. The electrical, controls and instrumentation engineer handles all electrical power distribution systems and instrumentation testing and documentation. Of course, this is not a comprehensive list of all the responsibilities for every player on the team, as the scope of commissioning differs from plant to plant and client to client.

Document, Document, Document

The true value of commissioning documentation can easily go unnoticed. If the commissioning is a success, the commissioning documents may remain untouched for many years. However, if something does go awry, it is extremely important to have a detailed collection of all commissioning tests and procedures to verify that everything was done to the correct standards and practices. This will help solve the root cause of any machine or system failure. At the end of a project, when the question is asked: “Was that test completed?” a member of the compliance team should always be able to say with confidence: “Yes, I saw it with my own eyes, and I have the documentation to prove it.”

 Some teams use a cloud-based commissioning software program that allows them to add documentation remotely, giving the contractor immediate access to vital information such as PFT inspections, photos, equipment and piping drawings, systemized to match process systemization and schedule priorities.

 Every final approval and sign-off for cleaning, testing, inspection and acceptance flows through the commissioning team. They will record all documents, which will be compiled into a handover package. Handover serves as the sign-off on responsibility from the contractor to the owner, who will then be 100% responsible for operating each system.

Putting a Checklist Together

Another significant task of the commissioning team is to verify that construction is proceeding as necessary to start up the plant. Any deficiencies will be documented on a punch list and then distributed to the construction team for rectification. While conducting the walkthrough, the commissioning engineer won’t just be looking for loose bolts or missing valves. They will also be evaluating the system from an all-important operator’s perspective. This includes checking for safety issues around the work area, making sure that all valves and platforms are accessible to operators, and that the system can be operated safely.

Understanding How the Pieces Fit

A good commissioning plan can make or break a project’s budget and schedule. It can save a company time and money at every stage of a project, while preventing safety and operability issues, increasing productivity, lowering downtime, and perhaps most importantly, giving the person charged with starting up the plant the confidence to finally push that green button.

 Nathan Somerville, P.E., is a senior project manager in the industrial market with Gresham Smith. He has more than 15 years of experience in project management, engineering, commissioning and construction management.

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