scope:

This UFC describes the design of HVAC control systems and the associated building control network that can interface to a UMCS in an Open and non-proprietary manner. The guidance also provides a foundation for the design of other Open building systems.

PURPOSE

This UFC is intended to be used with UFGS 23 09 23 (LonWorks® Direct Digital Control for HVAC and Other Building Systems). The design concept described in this UFC provides definitive guidance intended to streamline DDC system design and installation leading to maintainable, interoperable, extensible, and non-proprietary control systems. The purpose of this UFC is two-fold;

• Commonality. Describe a definitive methodology for the design of buildinglevel control systems and strategies (primarily for HVAC) where the intent is to achieve at least a degree of commonality in systems designed and procured through different channels.

• Compatibility. Describe a definitive methodology to obtain multi-vendor systems that can communicate and interoperate with each other and with a supervisory monitoring and control system such as a basewide UMCS through the use of an Open communications protocol.

The Open systems approach described in this UFC is based on ANSI/CEA standard 709.1-C communications protocol (sometimes referred to as LonTalk^®) and on LONWORKS^® Network Services (LNS^®) network operating system. The standard protocol supports Open communications while LNS supports Open network management.

The design of an Open system is not simple. It requires attention to a great deal of detail. This UFC, the specifications, and accompanying drawings were developed to minimize the time and effort required on the part of the designer.

The level of detail contained in this UFC is necessary because of the variety of approaches that can be used to implement ANSI/CEA-709.1-C where, in the absence of this detail, would very likely result in incompatible systems.

'CEA-709.1' is used in this UFC as the shorthand reference to the ANSI/CEA standard 709.1-C communications protocol. In this UFC the term LONWORKS^® is used to loosely describe a collection of technologies (including hardware, and software), vendors and installers relating to or based on the CEA-709.1 communications protocol.

APPLICABILITY

This UFC and accompanying UFGS 25 10 10 'LonWorks Utility Monitoring and Control System' are for use on all USACE and AFCESA projects. The NAVFAC standard is to use BACnet® for its DDC communication protocol and NAVFAC systems should use UFGS 23 09 23.13 20 'BACnet Direct Digital Control Systems for HVAC'. NAVFAC allows the use of LonWorks for upgrades and additions to legacy systems.

At the discretion of and with approval from the assigning government agency (such as the responsible Corps of Engineers District) the control system designer may deviate from the approach defined in this UFC. When deviating from this guidance, systems based on an Open communications protocol are recommended and systems that lead to subsequent proprietary procurement or single-vendor systems are discouraged.