Precommissioning

When specifying equipment to fabricators, it should be remembered that equipment may well lie exposed on-site before erection and temporary corrosion protective measures should be considered. Any equipment precommissioning treatments specified by the design, e.g. descaling, must be carried out. 

Control of foulants and corrosion debris Because of the very large volume in these HW systems, there is an obvious reluctance to unnecessarily drain them down because of the development of waterside problems. Therefore, it is important to ensure that before regular operation they are provided with a proper precommission cleaning procedure. This process removes silt, mill-scale, grease, and other foulants, thus enabling passivation and subsequent maintenance inhibition to take place. 

Chemically cleaning new boilers before they are put into service is termed preoperational cleaning (POC), precommission cleaning, (PCC), or sometimes simply a boil-out. 

Organics such as oil or grease occasionally are present in process boilers as a result of either improper precommission cleaning procedures or... 

The concept of precommission cleaning and passivation is not new it has been promoted since the earliest days of water treatment. However, in the global marketplace, it continues to be a deplorable situation in that there are still far too many newly constructed cooling systems inadequately precleaned (if cleaned at all), or given proper passivation protection, prior to start-up and plant commissioning trials. Poor standards of cleaning may,... 

To be fair, poor or limited precommission cleaning is not always the case the development of fast-track mechanical services, for HVAC and similar built environment projects, in the mid 1980s (especially for office tower blocks in the United Kingdom and other parts of Europe) is a case in point. 

Precommission Cleaning of Closed-Loop Systems to Include Fast-Track HVAC Projects)... 

Precommission Cleaning and Passivation of Open Recirculating Systems... 

Complete operating manuals and startup plans well before precommissioning. 

Complete training before pre-commissioning starts. When precommissioning starts there will be too much going on to allow time away from the job site. 

The portion of the resolution allowance allocated to punchout / precommissioning (see Table I. 1) should be left intact until the work is at least 95 % complete. 

The last step in a properly run control project is to conduct a post audit. Collect postcommissioning data and compare them to precommissioning data. Make sure the new operating point is economically better than the old one. Check to ensure that the standard deviations of economically important CVs (often associated with product specifications) have decreased significantly. Evaluate whether the MV bounds are still set correctly. Can they be widened Is the controller forcing the process to run at the best set of constraints most of the time ... 

A very large project may not require that a PSSR be carried out because it will have its own precommissioning, commissioning, and start-up procedures. However, a PSSR may be used to coordinate changes with other operating units. 

---