Control Theory and Application
ASHRAE Technical Committee 1.4

Scope of TC 1.4

TC 1.4 is concerned with control theory, systems, and components (excluding refrigerant flow controls), for heating, ventilating, air conditioning and refrigeration uses.


The ASHRAE Handbook is published in a series of four volumes, one of which is revised each year, ensuring that no volume is older than four years. TC 1.4 is responsible for developing and maintaining the following chapters in the ASHRAE Handbook.

Fundamentals Handbook, “Fundamentals of Control”


This chapter focuses on the fundamental concepts and devices used by a control system designer. It covers (1) control fundamentals including terminology; (2) types of control components; (3) methods of connecting components to form various individual control loops, subsystems, or networks; and (4) commissioning and operation.

HVAC Applications Handbook, “Design and Application of Controls”
This chapter addresses control of typical HVAC systems, design of controls for system coordination and for energy conservation, and control system commissioning.

ASHRAE Handbooks may be purchased in the ASHRAE On-Line Bookstore through the following links:

Comment on the Handbook: ASHRAE welcomes your comments on the Handbook or a specific Handbook chapter.  To submit a comment about any aspect or part of the Handbook series, you can use the Handbook Comment Form.

Review a Handbook Chapter: To provide your feedback about a specific Handbook chapter, you can answer the brief survey questions on the Handbook Chapter Review Form.


Technical committees develop and sponsor technical sessions at the winter and annual conferences. Information about their future technical program is discussed at each TC meeting and at the TC’s Program Subcommittee meeting.


ASHRAE publishes papers and transactions from presentations at its conference events. In addition, ASHRAE records most of the seminar sessions from its conferences on DVD. These DVDs are ideal for use at chapter meetings, in university courses, or company lunch and learns. Products available from the most recent conference may be found here.


Technical Committees are responsible for identifying research topics, proposing research projects, selecting bidders, and monitoring research projects funded by ASHRAE. TC 1.4 has an active research program with several topics in various stages of development. Information about their specific research program is discussed at each TC meeting and at the TC’s Research Subcommittee meeting.  TC 1.4 has developed the following research strategy:

Research Strategy
Controls are fundamental to the building environment. As such, past research sponsored by TC 1.4 has dealt with basic issues related to the operation and control of HVAC systems, excluding refrigeration equipment. The research strategy of TC 1.4 is concerned with improving the capability of HVAC systems to manage energy use in buildings and to maintain quality indoor environments. These goals are being addressed through research aimed at,
 1) obtaining equipment characteristics necessary for the design of HVAC systems and their controls,
 2) the development of local loop control strategies;
 3) comparing alternative strategies for local loop control to recommend preferred strategies; and
 4) verifying that control strategies work properly in field installations.



 ASHRAE writes standards for the purpose of establishing consensus for: 1) methods of test for use in commerce and 2) performance criteria for use as facilitators with which to guide the industry. ASHRAE publishes the following three types of voluntary consensus standards: Method of Measurement or Test, Standard Design and Standard Practice. ASHRAE does not write rating standards unless a suitable rating standard will not otherwise be available. ASHRAE is accredited by the American National Standards Institute (ANSI) and follows ANSI's requirements for due process and standards development.  Standards may be purchased at the ASHRAE On-line Bookstore.


TC 1.4 is the cognizant committee for the following guidelines and standards.
GDL-13P:  Guideline for Specifying DDC Systems
The purpose of this guideline is to provide recommendations for developing specifications for direct digital control (DDC) systems in heating, ventilating, and air-conditioning (HVAC) control applications.
STD-135:  BACnet - A Data Communication Protocol for Building Automation and Control Networks
The purpose of this standard is to define data communication services and protocols for computer equipment used for monitoring and control of HVAC&R and other building systems and to define an abstract, object-oriented representation of information communicated between such equipment, thereby facilitating the application and use of digital control technology in buildings.
STD-135.1: Method of Test for Conformance to BACnet
STD-195: Method of Test for Rating Air Terminal Unit Controls

BACnet is now an American national standard, a European pre-standard, and a potential global standard.
BACnet information and files for download are available at the BACnet web site.


ASHRAE Technical FAQs are provided as a service to ASHRAE members, users of ASHRAE publications, and the general public. While every effort has been made to ensure their accuracy and reliability, they are advisory and provided for informational purposes only, and in many cases represent only one person’s view. They are not intended and should not be relied on as an official statement of ASHRAE.

Technical questions not addressed may be submitted to the ASHRAE Technical Services department at

Presently TC 1.4 is responsible for the following FAQs:
What is BACnet?
How do I know if a control system is BACnet compatible?
Does BACnet apply to residential and simple control systems?

Other Activities

Multi-Disciplinary Task Groups (MTGs) are formed when the Society has determined a need for activity in a field of interest that encompasses the expertise of TCs from two or more sections and/or from non-TC groups such as SSPCs or outside organizations.  Presently TC 1.04 does not participate on any MTGs.