What is Pre-Commissioning and What Does it Include?

Pre-commissioning is a critical project phase that takes place following the construction of piping and process systems, but before those process products are introduced into the systems. The purpose of pre-commissioning is to safeguard the integrity of your systems and ensure they don’t have debris or contaminants that can damage equipment and delay system startup.


  • Helps ensure project ROI
  • Reduces startup delays
  • Ensures the operability of critical equipment, which maximizes system uptime

In this post, we cover the most common pre-commissioning methods for cleaning your system of mill scale, debris and other contaminants. It’s important to note, when you enlist a service provider to handle pre-commissioning for your system, these techniques should be customized to your system.

Air Blow Cleaning

  • In air blowing, air is pumped through your system at more than 1.5 times PSI above normal operation, creating a drag force that removes debris
  • The process involves specialty equipment to pressurize the system, including: air receivers, quick-opening valves, oil-free, dry compressed air and fittings and hoses
  • Once pressurized, stored energy pushes out debris in a controlled manner so it doesn’t damage expensive equipment downstream
  • Air blowing is the simplest, fastest, and least expensive cleaning method

Learn more about our air blowing services.

Steam Blow Cleaning

  • Steam blows are necessary for most steam lines and turbine systems
  • In this process, high-pressure steam is blown through temporary piping toward steam receivers to remove debris, usually at 1.2 times PSI above normal operation
  • There are multiple approaches to steam blows, including the puffing method and the continuous blowing method
  • There are significant noise and temperature hazards that require a strong process to control — learn more in this article

Learn more about our steam blowing services

High-Velocity Oil Flushing (HVOF)

  • All rotating equipment must be cleaned and prepared before going into operation
  • For large-scale operations, a high-velocity oil flush (HVOF) is the most common method
  • In this approach, lube oil is run through your systems and filtered out, bringing contaminants with it
  • This requires system and turbulent flow analysis as well as a detailed flushing plan to ensure success
  • System cleanliness is proven using automatic particle counters or manual microscope analysis on filter paper, depending on the system

Learn more about oil flushing

Hydrostatic/Leak Testing

  • Following cleaning of tanks, piping and vessels, it’s crucial to test the system’s structural integrity and ensure there aren’t leaks
  • This can include pneumatic testing, hydrotesting, helium leak detection and other approaches

Learn more about hydrostatic testing services

Chemical Cleaning

  • Chemical cleaning is used on pipe systems to remove surface contaminants
  • It dissolves soluble debris and absorbs them into a solution
  • It’s crucial to get this procedure right, as without proper planning, filtration and removal, it’s easy to leave debris behind
  • It’s particularly important to select the correct, OEM-approved cleaner for your system

Learn more about the chemical cleaning process from this guide

Fluid Pumping

  • High-velocity flushing can also be used on large bore piping to remove debris
  • The same approach is used for boiler feed water flushing, glycol flushing and water flushing


  • Dewatering is the process of removing water from solid material
  • There are several approaches, including: centrifugation, filtration and other liquid separation approaches
  • Dewatering is a simple process, but must be handled with care in order to protect the environment from unexpected spills

System Filtration

  • Many pre-commissioning services require filtration
  • One approach is to set up a slip stream on a live system
  • Sometimes, if heavier-duty filtration is required, it’s necessary to connect external filters full bore into the system

Selecting a Pre-Commissioning Service Provider

As pre-commissioning is such a crucial part of a project process, it’s best to use a professional services provider. We recommend selecting a professional partner to:

  • Design, manage and execute pre-commissioning strategies
  • Achieve cost-effectiveness, scheduling, quality and reduction of project risk
  • Bring experience, knowledge and integrity
  • Have an experienced, professional team of field staff
  • Have experience working with companies like yours

At RIG, we take pride in delivering excellent pre-commissioning services and ensuring our clients’ success.

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