Consulting-Specifying Engineer - January 2008 - (Page 23) Codes & Standards Still ‘Bullish on BACnet’ Since CSE’s 2005 article, BACnet is growing bigger and faster. BY BILL SWAN lmost three years ago, ConsultingSpecifying Engineer published “Bullish on BACnet,” an article by then editor Jim Crockett, to update its readers on advances in ANSI/ASHRAE Standard 135-2004, “BACnet—A Data Communication Protocol for Building Automation and Control Networks.” Those were exciting times for BACnet, with its adoption around the globe, and its commitment to evolving with building and information technologies. A Because the original security mechanisms in BACnet have been rendered insecure by advances in computer technology, the BACnet Network Security Working Group has developed replacement mechanisms. Since then, BACnet has not only made good on that commitment, but the scope and pace at which it is doing so are increasing. Since 2005, BACnet has extended into more areas of building automation, added new features and capabilities, and expanded into international markets. Going into 2008, BACnet is poised to make substantial additions to its extensions through the next round of proposed addenda to the standard. This article provides a look at these addenda, and a synopsis of BACnet’s direction beyond 2008. The addenda agenda At the 2008 ASHRAE Winter Meeting in January, the BACnet Committee will vote on key addenda that will submit for public review shortly afterward. Some of these addenda were in public review in the spring and fall of 2007, and comments from those reviews are being incorporated for this next round of public reviews. In addition, several new addenda are being prepared for their first public review. All told, the Committee is readying 13 addenda for public review starting on March 21, most for 45-day reviews. Among the proposed addenda to BACnet are the following: • Addendum g: Secure communications on all BACnet networks AT A GLANCE The Web site for the BACnet committee is www.bacnet.org. Readers can comment on the proposed addenda from there during the public review period beginning March 21. BACnet International members include companies involved in the design, manufacturing, installation, commissioning, and maintenance of control equipment that uses BACnet for communication, as well as other interested persons. Its Web site address is www.bacnetassociation. org. • Addendum i: Extensions to support lighting controls • Addendum j: Extensions to support physical access control • Addendum l: Specify different kinds of BACnet workstations • Addendum o: BACnet/IP and NAT firewalls • Addendum p: New capability needed by the Japanese market • Addendum q: BACnet/ZigBee wireless Of these, Addenda, g, i, j, l, o and q are of particular interest to the engineering community, so more information about them is provided below. The goal of Addendum g is to secure network communications on all BACnet networks, using encryption and authentication. Because the original security mechanisms in BACnet, based on the old Data Encryption Standard (DES), have been rendered insecure by advances in computer technology, the BACnet Network Security Working Group has developed replacement mechanisms based on the newer Advanced Encryption Standard (AES) adopted by the U.S. government. An added benefit of AES is that it is simple enough that all BACnet networks can be secured, which would have been difficult and expensive with the computation-heavy DES. Addendum i presents extensions to support lighting control in BACnet directly, as well as to support gateways to DALI lighting systems. The BACnet Lighting Applications Working Group is working with IESNA (the Illumination Engineering Society of North America) to develop these extensions, which will provide direct support for lighting controllers from simple on/off controllers up to complex controllers with continuous analog-lighting level control, ramping at fixed rates of change, fading over a fixed period of time, and incrementally stepping values up and down. Addendum j will complete BACnet’s support of physical access control, building on the Access Door object published in 2007. Representatives of several access control manufacturers are participating in the BACnet Life Safety and Security Working Group, as 23 Consulting-Specifying Engineer • JANUARY 2008 http://www.bacnet.org http://www.bacnetassociation.org http://www.bacnetassociation.org
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