There are many reasons legacy control systems migration projects go bad. These include incomplete or inaccurate drawings, the wrong team, lack of guidance, poor methodology, poor communications, and lack of teamwork. A FEED (front-end engineering & design) study is the starting point for preventing and avoiding these issues. The FEED Plus study takes this process to the next level.
A typical FEED study will address the I/O list, current drawings and control system layout, scope of work description, and potential problem areas. These functions are basic to preparing for a migration project. But the typical study also has some shortcomings.
The scope of work description, while describing the “what” of a project, generally does not describe the “how.” Identification of potential problem areas does not usually include possible solutions. And such typical FEED studies are often engineering-centric, meaning they tend to be unaware of installation and construction issues.
Other aspects of a typical FEED study may involve the use of catch phrases such as “other instruments as required for automation of the process” or “include reporting as required.” These phrases are risk enabling and force a prospective service provider to add dollars to their estimate in order to cover the potential risk. There is also a failure in typical studies to properly address schedule requirements in a realistic manner.
The FEED Plus study addresses these shortcomings. The I/O list is developed from a full site audit, and all stakeholders are consulted in determining control system requirements. The scope of work description goes beyond the “what” to describe the “how,” providing a high degree of clarity. It also presents solutions to the identified problems. Risks are mitigated by detailing specifics instead of using catch phrases. For example, “the I/O list contains all current and required instruments and devices and the path forward for each,” and “included are examples of required reports.” And an achievable schedule is established and agreed upon by the stakeholders.
One of the reasons we refer to it as a FEED Plus study is because of the degree to which constructability issues are addressed, compared to a typical FEED study. Failure to understand and account for construction requirements such as where panels can be located and how cable runways will be routed can often result in major delays and cost overruns if changes have to be made on the fly during the construction phase of the project. Other constructability issues that are addressed with FEED Plus are identification of the marshalling area, which equipment will need to be replaced, and which equipment can be modified and kept.
Because of the importance of constructability issues to the successful project, it is crucial that the site survey team include field savvy engineering and constructability knowledge in addition to the control system engineering expertise and the plant support input. The FEED Plus site survey will typically produce scanned field data, extensive photographs of in-place equipment, a complete drawing index, and as-found drawings. These items are backed up daily and they are made accessible to all survey team members.
A FEED Plus study will typically involve about 3 weeks by a team of 4 people. Once the site survey is completed, it is done thoroughly enough that the remainder of the study can be completed off site.
The essential elements of a successful FEED Plus study include the following:
- Understand from the beginning every stakeholder’s definition of success
- Be clear about project expectations from each stakeholder
- Do not rely on assumptions
- Dive deep into the details
- Have comprehensive, accurate, and concise documentation
- Communicate clearly and often with all team members
- Clearly address both the what and the how of all parts of the scope of work
A FEED Plus study will typically be about 20% of the total engineering cost of a legacy migration project. But this is a small price to pay for the peace of mind and confidence of success that a FEED Plus study will deliver.
Download a copy of Tom York's recent FEED Plus presentation at Rockwell Automation on the Move event.