2. Functional Testing for Integrated Operation and Control

The following tables outline the benefits and background information associated with testing for integrated operation and control of interrelated HVAC system during initial commissioning. However, these tests can be also used in a retro-commissioning process to define and correct existing operational issues. The tables are linked to related information throughout the Guide. Refer to Functional Testing Basics section for guidance on all functional testing activities, regardless of the component or system being tested.

2.1 Functional Testing Field Tips

Key Commissioning Test Requirements

General

Integrated functional testing of control strategies adds an additional level of reliability to the performance of the system by verifying that each independently commissioned component also functions as intended when interacting with the rest of the system. Integrated functional testing carries functional testing beyond the individual system elements and into the complex interactions that will occur during the system's operating cycles. The ultimate goal is to integrate the components of each system to work in harmony. The process then proceeds to the integration of all building systems with each other, the envelope, the occupants, the building functions, and the environment.

In general terms, the system will be acceptable if it can function efficiently in an integrated fashion and reliably navigate the day-to-day changes that are introduced by the dynamics of building use and the ambient environment. At best, the criteria are moving targets and can be very difficult to contractually define. Using team-building skills to obtain a consensus of acceptable and unacceptable protocol from all involved parties prior to testing is highly desirable. As the operations-savvy expert, the commissioning provider can set the stage for anticipating unexpected problems and correcting them, rather than anticipating perfection. Most buildings and systems will reveal some unexpected surprises in the course of integration testing.

When performing integrated functional testing on a system, it is important that sensor selection, installation, and calibration are sufficient to achieve the design control strategies and that all safeties, interlocks, and alarms are programmed (or hard-wired, if applicable) and functioning correctly. It is also important that the control system architecture allows for trending of all essential control and monitoring points at the specified frequency without slowing down the network communications.

Refer to the Air Handler Module, Chiller Module, Boiler Module, and Pumping Module for individual component/subassembly and system acceptance criteria.

Common Objectives

Verify the integrated functionality of the air handling system to ensure the system will operate at peak efficiency and to the fullest extent of its design intent. Pay careful attention to the following aspects of integration:

• Minimize the potential for simultaneous heating and cooling.

• Integrate the HVAC system and pressure requirements with the building envelope.

• Integrate HVAC process with temperature, humidity, and static pressure requirements.

• Identify operational inefficiencies using trend analyses common to integrated control system functional testing. These inefficiencies are often masked, preventing the problem from being observed from more common indicators, such as occupant comfort.

• Uncover nuisance problems that could be causing the systems to operate in a more energy-intensive manner. Resolving these nuisances helps ensure the persistence of the system’s efficiency, especially when supplemented by training and smart alarms that alert operators to selected conditions.

• Optimize interactive relationships among the components of the air handling system to ensure the original design intent of the control strategies are met.

Key Preparations and Cautions

Construction Verification Checklists and Start-up

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 issue is one reason for performing integrated testing.

Test Conditions, Considerations, and Cautions

Some tests will provide adequate results in response to forced stimulation. Examples include changeover, scheduled start-up and shut down, power-failure recovery, and fire-alarm response and recovery. Other tests are best accomplished via trend data analysis as each system responds to natural triggers because the thermal inertia typical of buildings and individual HVAC systems are virtually impossible to mimic using manual triggers in a real-world construction environment. Examples include the response of the system changes in weather and daily usage patterns.

Testing Issues

Passive testing is relatively safe because the systems are simply observed in the daily operating state and the results of the operations are analyzed. During passive testing, problems may occur that could have been actively tested and found. For example, the lack of a robust power-recovery routine following an actual power outage may be found through trend analysis, but after damage has been caused.

Active testing attempts to uncover problems by forcing or triggering pre-defined conditions. For example, removing and then restoring power at the primary switchgear simulates the response of a building to a power outage. While the outcome may have happened during an unforced power outage, this test can be a safer arrangement since potential problems can be anticipated in a test mode. These issues are discussed in greater detail in the Functional Testing Basics section.

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.

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.

Contractual Issues

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 so that the contract documents can be created to reflect the expectations and financial incentives deemed necessary to keep the contractors involved with the project.

The commissioning provider's contract with the owner and the owner's contract with the construction team should address how retesting will be handled. If 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.

Instrumentation Required

Instrumentation requirements typically will include the standard toolkit listed in Functional Testing Basics. Since integrated testing looks at the interactions of the system over time, having extensive trending capabilities in the building automation system is essential. Even with trending capability, supplemental data loggers can provide a means to gather data when rapid sample times are required or data is required that is not monitored.

In the absence of a building automation system, it may be necessary to augment the number of data loggers available in the commissioning provider's stock by renting additional loggers and input modules for the duration of the start-up process and perhaps a significant portion of the warranty year. This added cost should be considered when preparing budgets and bids.

Time Required to Test

Overview

The time required to test will vary with the testing technique used (active or passive), the specific test procedure employed, and the test preparation and follow-up time.

At a minimum, 8 to 16 hours should be planned for each time a set of data is retrieved and analyzed. For complex systems or systems that display numerous integration problems, this commitment can easily double, especially for the first analysis cycle. Reporting the findings can add more days to the process, depending on the formality of the report and the level of rigor.

Passive Testing

Passive testing relies on the actual system interactions in the operating environment to reveal problems through trend logging. This passive testing process can last for months or even through the first year of operation and is the foundation for an ongoing commissioning process. In this situation, the effort associated with the testing is concentrated at the following points in the process:

a Trend files must be set up and/or data loggers must be deployed at the beginning of the process.

b During trending, the trend data is downloaded and analyzed at a number of points in the process. Typically, these points will occur after an operational change or by season. Common points are at the end of the first week of scheduled operation, after a week of peak heating and cooling operation, and after a period of swing season (spring or fall).

c At the conclusion of the process, data loggers must be removed from the system and final reports must be written.

It is important to remember that the verification of corrections to problems that can only be detected by passive testing may require waiting for the triggering conditions to recur. For example, the corrections made to address a problem related to a peak cooling day may require analysis of data from another peak cooling day to verify resolution.

Active Testing

Active functional testing relies on the observation of the interactive system response as triggered by forced inputs simulating certain operational situations, such as a design heating load or a design cooling load. Active testing can require similar trending set-up efforts as passive testing, but the actual test, analysis, and reporting window is usually shorter than passive testing.

 

2.2. Testing Guidance and Sample Test Forms

Integrated Operation and Control Testing Guidance

This testing guidance describes the steps and potential issues that may arise during testing.  Since commissioning providers typically have their own style of forms, the Test Guidance is not provided in a field-ready form.  Commissioning providers may use the Test Guidance to expand and improve upon their existing forms.  Example tests based on the Test Guidance documents are provided where available.

Test ID

Testing Guidance

(View Appendix D for Test Descriptions)

Source

(View Appendix E for Source Details)

Example tests

TG16

Writing a Functional Test (general guidance)

STAC/PECI

Blank Test Form for Writing a Functional Test (Test ID 1015)

Example for Writing a Functional Test (Test ID 1020)

Whole Building-Level Integration

TG02

Relative Calibration

CEC/PECI

Relative Calibration Test (Test ID 1005)

TG07

System Recovery from Power Failure

DOE/PECI

 

TG12

Envelope Leakage

STAC/PECI

Envelope Leakage Test-High Rise (Test ID 1013)

Envelope Leakage Test-Low Rise (Test ID 1014)

TG14

Radiant Floor Heating

DOE Annex 47/PECI

 

System-Level Integration

TG09

Air Handling Unit Reset Strategies

STAC/PECI

 

TG13

Demand-controlled Ventilation

DOE Annex 47/PECI

 

TG15

Terminal Units - Variable Volume System Flow

STAC/PECI

Terminal Unit Reheat Test (Test ID 417)

Fire/Life-safety Integration

TG04

Fire and Smoke Control Systems

STAC/PECI

Combination Fire & Smoke Test (Test ID 1018)

TG05

Small Packaged Rooftop Units

STAC/PECI

 

TG06

Freezestat

STAC/PECI

Freezestat Example Test 1 (Test ID 1016)

Freezestat Example Test 2 (Test ID 1017)

TG11

Large Packaged Rooftop Units

STAC/PECI

 

Integrated Operation and Control Sample Test Forms

This table lists publicly-available sample tests from a variety of authors. Some of the tests are written for a specific building, while others are written for a general case.  This list of sample test forms also includes the Example Tests listed in the Testing Guidance table above.

Test ID

Test Forms

(View Appendix D for Test Descriptions)

Source

(View Appendix E for Source Details)

Building Automation System Prefunctional Checklists

278

Building Automation System Prefunctional Checklist

DOE/PECI

1005

Relative Calibration Test

CEC/PECI

1007

Verification Checks Checklist

CEC/PECI

Building Automation System Prefunctional Checklists and Functional Test Procedures

200

Standard Cx Procedure for EMCS

Seattle City Light/Kaplan

115

EMS Standard Cx Procedure

Multnomah/Kaplan

521

General Cx Acceptance Procedure for DDC Systems

PG&E/Gillespie

511

General Cx Acceptance Procedure for DDC Systems: Forms

PG&E/Gillespie

522

General Cx Acceptance Procedure for DDC Systems: Examples

PG&E/Gillespie

531

Verification and Functional Performance Test Plan for EMS

PG&E/Malek & Caluwe

Whole Building-level Integration Tests

1013

Envelope Leakage Test –High rise

PECI

1014

Envelope Leakage Test – Low rise

PECI

System-level Integration

417

VAV with Hot Water Reheat, Single Duct TU Functional Test

DOE/PECI

297

Emergency Power System (comprehensive form)

DOE/PECI

298

Emergency Power System (short form)

DOE/PECI

Fire/Life-safety Integration

1016

Freezestat Example Test 1

PECI

1017

Freezestat Example Test 2

PECI

1018

Combination Fire & Smoke Test

PECI