01 October 2004
Project execution methods
By John C. Pfeiffer
Editor's note: Last month we looked at the traditional construction project method and the roles and responsibilities of the owner, engineer, and contractor. This month, we will review those same factors as they come into play in the design/build construction method.
In the design/build (D/B) method of implementing plant construction projects, the owner contracts with the engineer/contractor or contractor/engineer company or team—depending upon who takes the lead in the project to develop the project's drawings, purchase equipment, and construct the plant.
There is a fundamental difference in responsibility between the two types of project execution methods. Under the D/B approach there is a single point of responsibility: the engineer/contractor team. Using the traditional approach, the engineer has specific responsibilities, separate and different from the responsibilities of the contractor.
The differences in project execution methods apply equally to the design of a building, a chemical process, or a manufacturing system. Today, manufacturing systems are often highly integrated systems just as with a chemical process or a building. As we move to highly integrated systems, more and more of the systems are being purchased under single contracts rather than individual purchases.
In a D/B process, a contractor provides a single source of responsibility to the owner for project design and construction. Regard-less of whether design services come from in-house, joint-venture partners, or a subcontract to architects/engineers, system integrators, or others, the D/B entity cannot divorce itself from design responsibility.
The D/B method requires the owner to develop a detailed project scope document to define project needs. This scope definition often comes from the architect/engineer under the traditional project method, but must occur before the D/B project bids out.
The D/B contractor requires more initial information to develop its proposal than does the architectural/engineering firm. The looser the definition at the bid stage, the more changes you can expect as the project moves forward.
Often the owner will contract out this initial requirements-gathering effort along with the development of a functional specification. This is a far better practice than going out for bids with a very limited project scope document.
The success of every construction project depends as much on the project owner as it does on the engineers and contractors themselves. In addition to the responsibilities of the owner in the traditional construction project method, additional tasks assumed by the owner under D/B include:
- providing detailed definition of project requirements;
- setting the material, equipment and construction quality specifications;
- performing construction inspections;
- approving all materials and methods.
The engineer is no longer a separate entity working for the owner, but rather is part of the D/B team.
Meanwhile, the essence of the contractor's contractual responsibilities in the D/B method includes those tasks addressed under the traditional approach, but now has expanded to include the majority of the design aspects of the project.
Examples of these new duties of the contractor include:
- scheduling and coordinating the work by the contractor and its subcontractors;
- supervising (controlling, directing, and coordinating) the performance of the work;
- providing labor, material, and equipment for the work;
- initiating, maintaining, and supervising all safety precautions and programs;
- providing the means, methods, techniques, sequences, and procedures;
- warranting and guaranteeing that all work will be in accordance with the contract document.
Additional duties under the D/B method encompass responsibility for the design and performance of the project.
The different roles and responsibilities of the key players in a plant construction project—owner, engineer, and contractor—demand careful review of the pros and cons of the method used.
There is a right way for each project (possibly even with modification), but it needs to be resolved as early as possible in the project life cycle.
Behind the byline
John C. Pfeiffer is founder and president of Pfeiffer Engineering Co. Inc., a professional engineering company based in Louisville, Ky. The twenty-three-year-old system integrator provides engineering services for the chemical, petrochemical, plastics, metals, other industries. Pfeiffer Engineering is a registered member of the Control and Information System Integrators Association (CSIA). His e-mail is email@example.com.
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