30 November 1998
concept and continue throughout the design process. The control parameter criteria (temperature,
humidity, pressurization, occupancy schedules, etc.) must be defined for all systems. These criteria are
the starting point for the HVAC control system design. The controller setpoints are shown on the HVAC
control system contract drawings and are based on the HVAC system design criteria. The setpoints are
guidance for maintenance of the control system.
b. Reuse of existing control devices. Renovation and addition projects require extra engineering
work in the form of a detailed field survey of existing HVAC control systems to determine if existing
control devices can be reused for the project, and, if so, the extent to which they require modification.
Devices that use standard 4-20 milliampere or 21-103 kPa (3-15 psig) signals are among those which
possibly may be reused. Existing control system components which do not meet the current
specification requirements might be of questionable quality and/or reliability. The contract drawings must
show control devices that will be reused, replaced, modified, or removed.
c. Locations of control devices. The designer will show the locations of wall-mounted instruments,
HVAC control panels and outside air sensors, transmitters, and sunshields on HVAC floor plan drawings.
The designer must show the location of sensing elements and primary measuring devices on the HVAC
system drawings. The control system designer must coordinate with the mechanical designer to show
the sensing location of the duct static pressure sensor on the HVAC ductwork drawing for a VAV system.
This requirement is intended to insure that design consideration is given to these details so that the
sensing will be proper and accurate, and to provide for clearance and access for maintenance of the
control system. The locations of thermometers and pressure gauges should be selected for normal
visual access by personnel required to read them.
d. Control device clearance and access. Control system elements must not intrude upon the space
required for mechanical and electrical system maintenance access. The control system design must be
coordinated with the HVAC system design to provide ductwork access to install and service sensing
elements and transmitters including access doors for permanently mounted devices such as air flow
measurement stations and in-line fan inlet guide vanes.
e. Location of permanent instrumentation. The location of the permanent instrumentation
thermometers, spare wells, and valved outlets for gauges in piping systems must be coordinated with the
HVAC system design and must be shown on the HVAC system contract drawings. Sufficient access
space must be provided in the ductwork downstream of each air flow measurement sensor and array, to
allow for a traverse with a portable instrument for calibration purposes.
f. Coordination with electrical system design. The designer will coordinate the control system design
with the electrical system design to show power circuits for HVAC control panels, air compressor, and
10. DESIGN PACKAGE REQUIREMENTS FOR HVAC CONTROL SYSTEMS.
(1) The designer will include standard HVAC control panel drawings to describe control panel
construction and mounting arrangements as shown in chapter 4. These drawings are:
(a) Standard wall-mounted HVAC control panel arrangement.
(b) Standard HVAC control panel interior door.
(c) Standard HVAC control panel back panel layout.