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Commissioning: Design Phase Commissioning Activities

Last month we introduced the design intent document (D.I.D.) as being integral to the commissioning process.  The D.I.D. is the goal all designers and contractors should be working toward through all phases of the project.  The performance standards defined in the D.I.D. are quantifiable and objectively “testable,” so that at the end of the construction the testing process can definitively prove that the goals have been realized.

As the project moves from the planning, predesign stage into the design phase, the D.I.D. provides the basis from which design engineers can perform their work.  As the design progresses, the commissioning agent will be involved in the standard milestone reviews (schematic design, design development, and prebid construction documents).  The commissioning agent will review the design documents with three objectives in mind.

First, the commissioning agent will need to become intimately familiar with the systems being designed in preparation for developing test procedures, which will confirm that those systems are operating properly at the end of construction.

Second, the commissioning agent will make recommendations to the designers for system enhancements, which will be important to the testing process.  Examples of such enhancements include water or airflow meters, temperature and pressure gauges, and additional control system monitoring points.  If such components are deemed too costly to include in the design, provisions for the temporary “installation” of these devices need to be included.

These enhancements will not only prove valuable during the verification testing phase of the project, but also will be beneficial for maintenance and troubleshooting throughout the life of the systems.

Finally, the commissioning agent will provide a peer review of the designers’ work in order to confirm that, if constructed and operated as specified, the building systems will meet the goals detailed in the D.I.D..

Writing It All Down

Simultaneous with the designers’ preparation of the construction documents, the commissioning agent will develop a commissioning specification section for inclusion in the official project manual.  The commissioning section is typically a separate section inserted into “Division 0,” or treated as a separate division at the end of the specification.  This section details the commissioning activities required of the contractors, so they can properly bid their work.

The commissioning agent works closely with the design engineers, coordinating the commissioning section requirements for such things as equipment submittals, operation and maintenance manuals, training, etc.  In addition, it is imperative that the technical sections impacted by commissioning (“Division 15” and “Division 16” sections for mechanical and electrical system commissioning) refer the respective contractor to the separate commissioning section for full details of the commissioning requirements.

The commissioning specification section should also include, to the greatest extent possible, the step-by-step test procedures and required results of those tests, for final verification that the systems are installed and operating as intended.  It is critical that the contractors see these procedures before bidding the job, in order to understand exactly what will be required of them and the systems for which they’re responsible.  (Refer to Engineered Systems’ monthly “Back to Basics” feature for examples of commissioning test procedures.)

While developing the verification test procedures for the specification, the commissioning agent will be able to confirm the clarity of the designers’ drawings and specs, particularly with regards to system operation sequences.  If ambiguities exist, the commissioning agent can work with the designers to clear them up.  In this way, the designers are making the final decisions regarding the details of operation, instead of relying on the contractors to “fill in the blanks” without fully understanding the design intent or the owner’s operational preferences.

At the end of a commissioned project’s design phase, the construction documents will represent systems that meet the owner’s requirements (as detailed in the D.I.D.), and will include all features necessary for properly testing and verifying system operation at the end of the project.

In addition, the project manual will include the contractors’ responsibilities in the commissioning process, so they can accurately estimate the time and effort involved.

Having the contractors enter the construction phase fully informed as to what commissioning will be, goes a long ways toward ensuring their cooperation, attention, and enthusiasm throughout the project.

 

Commissioning: Getting It Right

Engineered Systems, March, 1998

by
Rebecca Ellis, PE, LEED AP, CCP, CxA
President
Questions & Solutions Engineering
1079 Falls Curve
Chaska, MN  55318
rteesmag@QSEng.com