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Pre-Commissioning Versus Commissioning: Essential Differences For Modular Skid Commissioning

As part of the commissioning process, there are four crucial stages. The first stage is pre-commissioning, and the second is core commissioning. The third phase is start up commissioning, and the final phase is post-commissioning. But these phases can be confusing. It’s generally clear that commissioning must take place before plant facilities are provided for normal functions. Still, many people mix the pre-commissioning and commissioning stages up, and it’s easy to misunderstand the activities of the pre-commissioning process and the events of the commissioning process. So, suppose you’re not clear on the main differences. In that case, our article will outline the main commissioning activities in the pre-commissioning stage and those in the commissioning stage. It will also clarify why these stages are so crucial. Let’s take a look.

What is meant by pre-commissioning?

precommissioning Pre-commissioning involves testing to see whether the plant equipment has incurred any damage. It also involves checking whether the test results produced on the site are equal to the factory test results. Part of pre-commissioning involves mechanical completion (which occurs prior to pre-commissioning). The mechanical completion of the pre-commissioning stage focuses on handing the system over from the construction team to the commissioning team.  The commissioning team will be responsible for checking all equipment individually, including the components and the systems. They will test it and ensure that, at the installation phase, all the equipment aligns with the specs and drawings. Once the handover from the construction team to the commissioning team has occurred, a team responsible for operation will then take over. Pre-commissioning, therefore, involves preparing for commissioning and complying with safety requirements during the transference period. 

What are some examples of mechanical completion and pre-commissioning?

There are a few different mechanical completion pre-commissioning tests. The critical, most vital ones to keep in mind are:
  • Testing for leaks: this process focuses on ensuring the components and equipment do not leak.
  • Testing for pressure: this process involves making sure the piping can withstand the liquid’s pressure.
  • Rotational equipment verification: this process focuses on ensuring high levels of vibration do not occur when the first rotation occurs.

What are some examples of pre-commissioning activities that are electrical?

There are a few different examples of pre-commissioning activities that are electrical. A few  of the crucial ones that are featured on checklists and are tested include:
  • AC checks: during this phase, a rotation meter is used to check the installation of the phases of electrical setup in order.
  • Checks for open circuits: in this phase, tests for short circuits and current losses are carried out to assess the current losses.
  • Hi-pot, AC/DC tests: in which dielectric is measured in terms of its ability to handle the transient voltage.

When is pre-commissioning finished?

The pre-commissioning activities, also referred to as a vendor start up, are finished when each of the checklists has been fulfilled, and the equipment has been verified in terms of its ability to meet the project’s technical requirements. 

What is meant by a commissioning process?

Commissioning, or the commissioning process can be an overlapping stage to the pre-commissioning process. What the process involves are many tests that correspond to the equipment and components, making sure that all components can function together in the whole system. Although it involves a few commissioning activities that might overlap with the pre-commissioning process, they are specifically carried out to check whether the equipment works as one system for the plant facility prior to the startup. This is an important part that must be completed to ensure that even control systems of the plant projects, such as the quality ones offered by DG-SKID and other components such as the piping, pumps, valves, and controls, can all function as one system.

What are the key stages of the commissioning process?

Now, there are three main stages of the commissioning process for process plant equipment and skids. The main stages include:
  • Preparation for commissioning
  • Execution of the commissioning phase itself
  • Documentation of the commissioning phase and then the transition to the client for the operation phase
Let’s have a look at each of these stages in more detail. Commissioning

What does the preparation for the commissioning phase involve?

The preparation for the commissioning phase involves a few separate steps. As well as ensuring that the flow direction is verified and that the instruments are connected correctly, it also involves some activities such as verifying certificates of calibration and checking the installation. A checklist is often used for the preparation of the commissioning phase 

What does the execution of the commissioning phase involve?

The execution of the commissioning phase involves a few other steps, such as the instrument calibration and testing, control shutdown settings, industrial PLCs (offered by exceptional skid manufacturers) cable insulation, control systems function testing, and many other critical stages that will be included on a checklist.

What does the documentation of the commissioning phase involve?

The documentation of the commissioning phase involves preparing the relevant documentation for the handover to the operation team. This phase must happen before the startup and typically occurs towards the end of the commissioning process.

What are some examples of testing commissioning activities?

A key example of some commissioning activities might be for skids that are used for chemical dosing. These types of skid consist of piping and pumps, controls and a control system, valves, and gauges. Every one of these individual components must be assessed for whether they function altogether as a system, in the correct way, for the plant project.  Again, a checklist must be used to confirm that all equipment on site functions in the correct way.

Which procedures test and determine whether the components function?

In the commissioning process, a few procedures are used to test and determine whether the components function in the correct way. In relation to the skids that are used for chemical dosing, some examples of the procedures or types of tests used include:
  • Instrument calibration before installation
  • Close inspection to ensure the correct installation
  • Verification of the control system
  • Integration of each individual subsystems
  • Commissioning test process for the subsystems

Choose DG-SKID for exceptional pre-commissioning and commissioning of skids 

Pre-commissioning and commissioning are fundamental to the integration of a modular skid in your plant facility, so before it becomes operational, it’s vital that these activities are carried out by experts and professionals. Professional modular skid commissioning can ensure that there are no problems when you start up the skid and begin to use it for your process plant projects and its procedures.  To ensure your skid’s performance is of the best, highest quality, select the established industry leaders in skid performance DG-SKID for your modular skid commissioning and maintenance.

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