30 November 1998
1. PURPOSE. This document provides criteria and guidance for the design of heating, ventilating and
air conditioning (HVAC) control systems, and designates the standard control loops to be used.
2. SCOPE. These instructions describe frequently encountered control system loops, provide examples
of how these loops are used, and provide guidance and criteria for the design of standard HVAC control
systems and standard control panels. This document does not provide guidance on selecting HVAC
systems and does not prohibit selection of system types not included herein.
3. REFERENCES. The following documents form a part of this technical instruction to the extent
a. Government Publications TM-5-785 Engineering Weather Data.
b. Government Publications TM-815-2 Energy Monitoring and Control Systems.
a. Adherence to the standards. The design of the HVAC control systems will not deviate from the
standards established in these instructions, except where the design agency has an approved waiver
b. Control system designer responsibilities. The HVAC control system designer will be responsible
for designing each control system required for the project HVAC systems, and will incorporate the control
loops, control system sequences of operation, and HVAC control panel layouts (except when designing a
Direct Digital Control (DDC) HVAC control system), using the symbols, abbreviations, and acronyms
designated in these instructions. This design responsibility requires producing a design package that
includes a specification, a set of drawings, and commissioning procedures for each HVAC control
system. The designer will not depend on any HVAC control system vendor for the design of the HVAC
c. Control system vendor compliance. The HVAC control system vendor will be required by the
contract documents to make the system product specific. The specification will require the HVAC control
system vendor to produce shop drawings, schedules, instructions, test plans, test procedures,
commissioning procedures, and other documents showing the application of products to implement the
control system design. The specification will require that the HVAC control system vendor test the
control system and document the test to show that the control system functions as designed, and to
commission the control system.
5. CONTROL SYSTEM DESIGNER GUIDANCE.
a. Control system loops and control logic. These instructions include descriptions of loops for
controlling temperature, humidification, airflow, and duct system static pressure. In addition, these
instructions contain control logic for the following:
(1) Scheduling and initiating system operation.
(2) Changes in control modes of operation.
(3) Normal interlocks.