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Why be Rigorous? – Part 1

In October, 2005, Getting it Right loosely defined levels of rigor for commissioning tests. That was intended to help building owners understand the wide variety of testing approaches available from commissioning providers. This month and next month (December, 2005) I’d like to present a qualitative discussion of the advantages and disadvantages associated with the various levels of rigor. The intent is to help building owners decide what is most appropriate for their projects prior to soliciting commissioning services.

To help this column stand on its own, I’ll repeat the definitions for each level of rigor. This month I’ll cover the three lowest levels, and next month I’ll complete the discussion with the two highest levels of rigor.

Low Rigor Testing

Preparation: Familiarization with design documents.

Execution: Cx Provider observes system operation and decides what sequences or modes to check out once in the field.

Documentation: Test report recommending acceptance or rejection.

This level of testing is best accomplished by Cx Providers who are very familiar with the owner’s operational requirements and priorities and who are well trusted by the owner. In fact, it is often the approach taken by owners performing commissioning on their own behalf. It is low cost and, perhaps, all that can be afforded for small projects. This level of rigor lacks the thoroughness of a better planned and documented testing process.

The primary benefit of this approach is to the project alone, i.e., it enhances the turnover and acceptance process. However, it leaves no tangible technical details for the owner’s operations staff to reference in the future. Also, there is little or no training benefit to the testing process, even if the owner’s staff witnesses the testing. Much of the process and reasoning behind the test steps remains in the Cx Provider’s head and may be difficult to extract and/or understand.

Medium Low Rigor Testing

Preparation: Generic test procedures selected based on review of design documents and system shop drawings.

Execution: Cx Provider uses generic test procedures to guide the testing of various system functions, deciding on applicability to the project’s systems once in the field.

Documentation: Test report documenting problems found and recommending acceptance or rejection.

Thoroughness and consistency is increased with this approach. This level of testing should be performed by knowledgeable and experienced Cx Providers who can quickly and appropriately assess the applicability of each test step in the field. As such, it is somewhat un-repeatable by others in the future, i.e., someone else might make different decisions with respect to what is necessary. If this approach is combined with low cost inexperienced field technicians it may be as inconclusive as no testing at all.

The test report is the beginning of something helpful to future building operators. The “problem” information provides a clue to the issues encountered during initial testing and what operating engineers might need to be alert to in the future. The test procedures can be used, by appropriately savvy operators, as guides to future system troubleshooting and/or recommissioning.

Medium Rigor Testing

Preparation: Generic test procedures customized for the systems to be commissioned.

Execution: Cx Provider decides in the field exactly how to execute the generic test procedures. Contractor performs test under Cx Provider direction.

Documentation: Test report documenting problems found and recommending acceptance or rejection.

The customization of the test procedures associated with this level of rigor relieves the need for high level decision makers in the field to determine the relevance of each step of the test. If decisions can be made prior to going into the field, the testing will be faster and smoother and will avoid last minute disagreements about testing procedures.

The requirement that the Contractor performs the test procedures helps the owner’s capital project team maintain clean lines of authority and liability. As soon as the Cx Provider starts “playing with” the system without the Contractor present, you can be sure there will be denials and finger pointing regarding any non-compliant results.

This level of rigor also enhances the benefit to future building operators. The customized test procedures can be an easy-to-use and meaningful tool to support future recommissioning or troubleshooting activities.

Next month, I’ll comment on the two highest levels of rigor, both of which involve substantially more preparation and the inclusion of acceptance criteria within the test procedures.



Engineered Systems, November, 2005

Rebecca Ellis, PE, LEED AP, CCP, CxA
Questions & Solutions Engineering
1079 Falls Curve
Chaska, MN  55318