Integrated Operation and Control

This checklist identifies Key Commissioning Test Requirements and Key Preparations and Cautions for testing the integrated operation and control of a building's HVAC systems. When writing a test, use this checklist to help ensure that these key areas have been covered. The buttons following the checklist items link to supporting information within the Functional Testing Guide and the Control System Design Guide.

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Control System Design Guide

Key Commissioning Test Requirements

Integration testing will be unique to each building, so key requirements will also be unique. The process for integration, however, can be generalized to start at the component level, and proceed to the subsystem, system, and building level. Refer to the Air Handler Module, Chiller Module, Boiler Module, and Pumping Module for individual component/subassembly and system acceptance criteria.

• ___ 1. During design review, the following items should be addressed to avoid issues during functional testing:
  • a) The sequence of operation for each system has been carefully examined for interactions among systems
  • b) The control system architecture allows for trending of all essential control and monitoring points at the specified frequency without slowing down the network communications.
  • c) Sensor selection is sufficient to achieve the design control strategies.
  • d) The HVAC process is integrated with requirements for temperature, humidity, and static pressure.
• ___ 2. The following are considered “prefunctional” checks that should be completed and verified prior to performing a functional test (note that this is not a comprehensive list of all prefunctional checks):
  • a) A points list that shows the point type, function, and physical location in the building has been created.
  • b) Sensor installation and calibration is sufficient to achieve the design control strategies.
  • c) All safeties, interlocks, and alarms are programmed (or hard-wired, if applicable) and functioning correctly.
• ___ 3. A system diagram has been created and field verified.
• ___ 4. The potential for simultaneous heating and cooling is minimized.
• ___ 5. The HVAC system operation and pressure requirements are integrated with the building envelope.
• ___ 6. The performance of the system is matched to the actual load (vs. the design load).
• ___ 7. Detailed trend analysis helps discover operational inefficiencies that may not be obvious from common environmental indicators.
• ___ 8. Control loops are tuned and stable, as shown by trend analysis with a frequent sampling rate (1 minute data or less).
• ___ 9. System instability due to interaction of multiple independent control loops or slow network communications is avoided.
• ___ 10. Nuisance problems that could be causing the systems to operate in a more energy-intensive manner are uncovered and mitigated.

Key Preparations and Cautions

• 1. Integrated testing can only occur after all other components in the system are deemed complete and in a state of operational readiness. If the responsible parties do not feel they are ready to have their particular component tested in relationship to the system-wide interactions, then proceeding with integrated testing may produce inconclusive results because problems may be blamed on equipment that was not fully commissioned. However, integrated testing may reveal that a component that was certified as being ready for test was not ready. This problem is one reason for performing integrated testing.
• 2. Active system testing (response to a forced stimulation) for scheduled start-up and shut down, power failure recovery, fire alarm response and recovery, as well as other safeties/interlocks, should be completed prior to extended system operation. Active testing can be a safer arrangement since potential problems can be anticipated in a test mode.
• 3. While some tests will provide adequate results through active testing, other tests are best accomplished by observing system operation over time. Passive testing (i.e. trend data analysis) is recommended to check the response of the system to changes in weather and daily usage patterns, since it may be impossible to achieve a full range of operating conditions through active testing.
• 4. Often, functional testing must be conducted with a building in a state of partial or full occupancy. This is especially true for renovation work and retro-commissioning. Testing in this manner may adversely impact occupant comfort for brief periods or require additional time or non-standard working hours to avoid causing problems with the normal use of the building. This contingency should be anticipated and discussed with the project team well in advance of its occurrence.
• 5. Because functional testing targeted at integrated operation relies heavily on trend data, loss of data could be a major testing setback, especially if the loss occurred before problems were identified and documented. Thus, the contractor and commissioning provider should take steps to ensure data integrity, including backing up databases, maintaining an off-site copy of the data, and making sure the data is actually being logged after the test is initiated.
• 6. Due to the extended time frame associated with passive testing and seasonal testing, it is often difficult to keep contractors engaged in the process. This potential circumstance should be discussed with the owner well before contractors are hired. This will enable contract documents to reflect the expectations and financial incentives deemed necessary to keep the contractors involved with the project.
• 7. When a test fails, the commissioning provider will have to revisit the site and retest systems. The implications of this can be quite significant if the site is not in the provider's home territory or if multiple retests are necessary. Thus the provider's contract with the owner and the owner's contract with the construction team should address how retesting will be handled.
• 8. Phased start-ups and temporary system operation can place a system at risk.
• 9. System start-up and shut-down are major events. When a system is started up or restarted (for example recovery from a power failure), a major step change is introduced into virtually every control loop in the system. Given the interactive nature of these processes, escalating instability and even damage to equipment can occur if adequate attention is not paid to such operational changes.

Page last updated: September 11, 2006