Understanding the FT Guide

Functional Testing Basics. 2

System Modules. 2

Air Handling System Reference Guide. 3

Integrated Operation and Control4

Appendices. 5

 

The Functional Testing Guide: from Fundamentals to the Field provides both a practical understanding of the fundamentals, as well as field tips for functional testing.  The Functional Testing Guide (FT Guide) also reviews the energy and performance implications of common problems and provides links to test procedures.

Figure 1: Functional Testing Guide Structure

The Functional Testing Guide presents information at three different levels.   Two “cross-cutting” sections, Functional Testing Basics and Testing for Integrated Operation and Control, are applicable to the five system modules: air handling, chillers, condensers, boilers, and pumping.  For testing details at a more detailed component level, a reference guide was developed – at this time only for air handling systems.  This reference level is the original FT Guide for Air Handling Systems, which was released in May 2003.

The Functional Testing Guide allows easy access to the many functional tests collected in the Commissioning Test Protocol Library (CTPL).  The CTPL is the largest existing collection of functional test procedures, including many non-copyrighted test procedures that can be customized to suit individual system configurations. 

Since the test procedures in the CTPL include forms rather than detailed explanations, the Functional Testing Guide explains the “how” and “why” behind the functional tests in the CTPL.  Understanding the reasoning behind test procedures and how to interpret and act upon the results is essential for successful testing.  For more information about the CTPL, see Appendix A

Commissioning providers and building engineers are the primary audience for the Functional Testing Guide.  They should already be familiar with the commissioning process, HVAC fundamentals, and the building construction industry. 

The information in the Functional Testing Guide will help commissioning providers to:

·       Understand how to test from a systems perspective

·       Identify common problems and the root causes of these problems

·       Customize test procedures to meet the needs of their specific projects

·       Understand why a specific test sequence is being executed

·       Understand the possible outcomes and necessary precautions during testing

·       Qualitatively understand the costs and benefits of testing

The next sections provide additional description of the components of the FT Guide.

Functional Testing Basics

The first section of the Functional Testing Guide, Functional Testing Basics, covers the general functional testing concepts that underlie all subsequent modules.  Basic concepts that are given only minor treatment during later modules are covered in detail here.  This section includes an introduction to the system approach – a fundamental way of looking at the components of a system as a whole.  Other topics include the testing hierarchy, training, verification checks, useful tools, elements of a functional test procedure, precautions, and test preparations.

System Modules

Test Guidance for Specific Systems

The system modules provide test guidance at an individual system integration level (as opposed to whole building integrated operation), as well as example test documents. 

The following systems are included, each as separate modules:

·       Air Handlers

·       Chillers

·       Condensers

·       Boilers

·       Pumping

Although each module covers a different component or system, they all follow the same format containg the following sections:

·       Functional Testing Field Tips This section provides practical, field-tested functional testing information organized into the following areas:

1   Key Commissioning Test Requirements: Practical considerations for functional testing.

2   Key Preparations and Cautions: Potential problems that may occur during functional testing and ways to prevent them.

3   Time Required to Test: The amount of time necessary to execute functional tests.

·       Testing Guidance and Sample Test Forms Each module contains a table of relevant test procedures for easy access to all publicly available tests. The tests available in each module can be downloaded and edited to serve a specific project or used as the basis for development of a new test procedure. The test documents include functional testing guidance documents, verification checks and functional tests, and cover system integration testing as well as testing of individual components. The tests were developed by a variety of sources, including:

·       USDOE/FEMP/PECI Version 2.05 Commissioning Tests

·       CoolTools Chilled Water Plant Design and Performance Specification Guide

·       Multnomah County, Oregon Document Review

·       PG&E A General Commissioning Acceptance Procedure for DDC Systems

·       PG&E Comprehensive Commissioning Services Guideline.

·       Seattle City Light: Building Commissioning Assistance Handbook

Air Handling System Reference Guide

The Air Handling System Reference Guide is located within the Air Handlers module – the only module with such a resource at this time.  This reference guide is the “Original” Functional Testing Guide for Air Handling Systems, released in May 2003 as a California Energy Commission, Public Interest Energy Research project.  This content was developed for air handling systems to provide necessary details in understanding the theory behind air handling processes and typical problems found.  The chapters within the reference guide cover the functional testing of each component of an air handler, from the outdoor air intake section to the exhaust air discharge point.  Regardless of the system configuration, the functional testing associated with a component is similar.  For example, a preheat coil in a variable volume system performs the same function as it would in a constant volume system.  The following components are included, each with a separate chapter:

·       Outdoor air intake

·       Fan casing

·       Economizer and mixed air

·       Filtration

·       Preheat

·       Cooling

·       Humidification

·       Reheat

·       Warm-up

·       Fans and drives

·       Distribution

·       Terminal equipment

·       Return, relief and exhaust

·       Scrubbers

·       Management and control of smoke and fire

The component chapters in the Air Handling System Reference Guide each include Functional Testing Field Tips tables similar to the system module tables. These chapters also include information useful in understanding the systems to be tested, as well as in designing and implementing tests. These sections include:

·       Theory and Applications: This sectionprovides general insight and theory regarding the typical applications of the component or system. 

·       Design Issues Overview: This look at how the design parameters affect the outcome of functional testing also supports the design review process.  Currently, this overview has been completed for the following components: Cooling (Chapter 6), Humidification (Chapter 7), Reheat (Chapter 8), Warm-up (Chapter 9), Fans and Drives (Chapter 10), Distribution (Chapter 11).

·       Typical Problems: Important problems normally uncovered during testing or design review are highlighted.  Currently, this section has been completed for the following components: Preheat (Chapter 5), Cooling (Chapter 6), Reheat (Chapter 8), Warm-up (Chapter 9), Fans and Drives (Chapter 10).

·       Supplemental Information: Supplemental information describes the fundamental concepts behind specific components.  The extent to which this information has been developed will vary from chapter to chapter.  Chapter 3: Economizer and Mixed Air and Chapter 11: Distribution include an extensive presentation of supplemental information. 

Integrated Operation and Control

Functional Testing for Integrated Operation and Control

The Integrated Operation and Control chapter cross-cuts other modules, as the title implies. The chapter offers broad and deep coverage of the many details and challenges that await commissioning providers when the taking steps to commission a building while considering the simultaneous influences of the building envelope, building systems, ambient (outside) environment, occupant activities, and other factors. Not only do these factors need to be considered at the time of test, but in future and hypothetical contexts, as well, because commissioning and tuning a building for only current conditions can mean lead the building to perform erratically in other conditions.

The chapter discusses the fundamental principles of integrated, interoperable building systems and instructs on how to commission and fine-tune building systems under diverse operating conditions. A practical case study is provided as Appendix 1 so readers can more easily apply what they are reading to what they may experience in the field. Major sections include:

·       Hypothetical Case Study: A brief discussion of the project and its supporting documents in Appendix 1, which are often referred to for practical examples of the fundamentals and fine points presented in subsequent sections.  

·       Theory and Applications: An illustrated explanation of different interactions occurring in buildings among construction elements, systems, weather, and occupant activities. Controls and control loops involving air-handling units are explicitly covered.  

·       Commissioning for Integrated Control and Operation: Two tables comprise this section. The first, Functional Testing Benefits, justifies why this level of commissioning needs to occur. The second table, Functional Testing Tips, provides detailed information for how to conducts integration tests and the resources required.

·       Testing Guidance and Sample Test Forms: This table of test guidance and example tests covers general control system testing. Two more focused example integration tests are also provided – a relative calibration test and a recovery from power failure test.

·       Relationship Between Integrated Control, Commissioning, and Operation: This section illuminates how everything from time to the position of economizer dampers affects how buildings operate and interact with people and the environment. How to consider future conditions and events with seasonal tests and other methods is covered.

·       Planning and Preparing for System-Integration Testing: How to plan in detail for integrated tests that are safe, reliable, efficient, and repeatable for different seasons and operating conditions. Manually activated tests and trending day-to-day operations are covered.

·       Component-Level Control Integration:  How to test individual components and subassemblies of HVAC equipment and systems. Pre-heat coils, fire/smoke dampers, humidifiers, and other equipment are specifically covered.

·       System-Level Integration: Building upon the previous section, this section covers in detail the interactions that occur among building systems, with particular focus on controls and control loops. Concepts such as thermal inertia, cascading instability, Murphy’s Law are covered.

·       Integrating Multiple Systems with the Building and Environment:  Using a scheduled start-up from a shut-down condition as a basis for discussion, this section runs through integration issues of building systems, and how complex and sometimes unplanned interactions, need to be considered by commissioning providers. Also covered are integration issues involving end-user equipment with central plants and utility services.

Appendices

The Functional Testing Guide features several Appendices: 

·       Appendix A Overview of the Commissioning Test Protocol Library provides a description of the CTPL.

·       Appendix B Resources provides a list of resources that can be useful for further reference.

·       Appendix C Calculations is the main component of the cost-benefit analysis for the Functional Testing Guide.  Currently, the calculations for fan energy savings associated with static pressure reduction have been fully developed and serve as a model for additional calculations.  Spreadsheets associated with these calculations are provided to help streamline their use. 

·       Appendix D Test Descriptions provides a more detailed description of the Functional Test Protocol Examples referred to in the individual modules.

·       Appendix E Test Sources presents the sources of the Functional Test Protocol Examples that are referred to in the individual modules.