Mechanical Engineering Quality Control - Part III

By Vince Carucci

Previous articles in this series introduced the concept of engineering quality control, why it is important on capital projects and a general approach that may be used to implement it. This article provides more ideas for how the mechanical engineering specialist can perform this function.

As stated in an earlier article, engineering quality control does not duplicate the contractor's work. Instead, it uses a “spot-check” approach of the contractor's work in order to develop an assessment of his overall performance. It also involves spot-checking the work of major equipment vendors to assess both their performance and that of the contractor in his checking of their work. The following provides some overall guidelines that may be used to perform engineering quality control on a major capital project.

• Review the process design specifications for the project in order to develop a good understanding of the equipment and design conditions that are involved. Also, review the owner company's engineering standards that will apply.
• Based on this initial review, prepare a list of equipment items and systems that will be included in your later spot-checks. This list would include items that have the most severe design conditions, those that have unusual design features, items that are especially critical to the operations, and those that may have been troublesome in the past on other projects. For example, in the pressure vessel area on a major capital project, 10-20% of the total number of vessels might be included on this list.
• Soon after the contract has been awarded, have initial meetings with the contractor's technical specialists. During these meetings, be sure that the contractor's engineers understand the technical requirements of the job, provide them with any needed clarifications, and establish a basic working relationship with them.
• Review the engineering specifications that the contractor has prepared for general equipment categories, such as pressure vessels. Also review the detailed technical specifications and vendor bid conditioning documentation for critical equipment items, such as heavy-wall reactors.
• During the course of the job, in general, review the submitted vendor information after the contractor has done his review. For example, in the pressure vessel area, you should see the vendor drawings and calculations after the contractor has already marked them up with his comments. Remember, you are checking his work, not doing it for him.
• Adjust the number of items on your checklist based on what you've found in your review (e.g., decrease the number if you've developed confidence in the contractor's work). Also, on a large project where multiple vendors are supplying particular equipment items, be sure to check at least one item from each vendor regardless of whether they were on your original checklist.
• The prime contractor will generally do all the piping design work himself. Review the pipe material specification for acceptability.
• Review the engineering design and stress analysis for selected piping systems, including the procedures that are used to ensure that the system “as-analyzed” will be correctly installed in the field.

Remember that even for the items being reviewed, you are not completely redoing the contractor's work. Your intent is to concentrate on what you feel to be the most critical details, features, and calculations in each situation.

While the previous discussion was not meant to be complete and detailed, we hope that it has given you a good general idea of an approach that may be taken in performing mechanical engineering quality control on a capital project.