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New Standard Has Teeth

Even though it will have a profound effect on the structured cabling industry, not many appear to realize the importance of ANSI/TIA/EIA 862.


November 1, 2002  


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Earlier this year, TIA published the Building Automation System (BAS) Cabling Standard for commercial buildings, ANSI/TIA/EIA 862. Not too many people are aware of the existence of this standard and its importance to the industry.

We can draw on the analogy of the human body that has many different functions that are essential to sustain life.

COMMAND CENTER

As Cabling is like the nervous system in our body. It conveys information to and from the command center, which processes this information and regulates the many different systems in a commercial building. The standard defines a standard topology and the types of cabling that are required to support these systems.

Building automation systems are used for controlling building systems such as fire alarm, security and access control (e.g., closed circuit television and electronic door control), and energy management systems (e. g., heating, ventilation, air conditioning (HVAC), lighting and power control.

The BAS Cabling Standard enables the planning and installation of a structured cabling system for building automation system applications used in new or renovated construction of commercial buildings.

The proper implementation of a BAS needs to be formulated in the early phases of building design and construction. It is critical that the layout and selection of the cabling components is done to ensure the greatest design flexibility for the deployment of building automation system (BAS) services.

HORIZONTAL CABLING LINK

Early planning and a structured BAS horizontal cabling design will minimize disruptions to building occupants.

The BAS standard extends the structured cabling concepts that are found in the ANSI/TIA/EIA 568-B and 569-A standards for voice and data communications to BAS services.

It defines a modified star topology for horizontal and backbone cabling that can be easily configured to support known BAS application requirements.

Elements of the horizontal cabling link include the horizontal cross-connect (HC), horizontal cable, horizontal connection point (HCP), and an optional BAS outlet/connector.

A minimum of one dedicated horizontal cabling link is provided for each distinct building automation service (e.g. fire alarm safety system, HVAC, etc.). The maximum distance for a horizontal cabling link is 90 meters. Horizontal cabling link performance verification is recommended using permanent link requirements between the HC and BAS outlet/connector or between the HC and HCP. When permanent links are tested, the test shall be performed without bridge or bus connections

The coverage area (CA) for BAS is similar to the Work Area (WA) for voice/data cabling. The coverage area refers to the space served by one BAS device. The size of a coverage area is typically about 25 square meters, based on average values from a study of floor lighting systems, security and HVAC applications.

Depending on their function, BAS devices may have overlapping coverage areas. Coverage areas may be served by a) centralized equipment located in an equipment room (ER) or mechanical room (MR), typically through the backbone cabling) distributed equipment located in a telecommunications room (TR), typically through the horizontal cabling or c) local equipment located in the coverage area itself.

Although it is recommended that horizontal cabling be configured in a star topology, the BAS standard can accommodate different coverage area topologies for different BAS applications.

For example, the coverage area topologies include a star, bridge connection, chain, multipoint bus or multipoint ring/fault tolerant circuit.

This is a brief overview of the key elements of the standard, which will be a valuable reference for end users, architects and system integrators who are planning new and renovated building constructions. It is important to get involved early in the construction project to consider the total cabling needs of the building.

Planning ahead using an integrated, structured cabling approach can save money and will be better able to serve the functional requirements of the building and for the building occupants.

Paul Kish is Director, IBDN Systems & Standards at NORDX/CDT. He is also vice chair of the TR-42 engineering committee.

Disclaimer: The information presented is the author’s view and is not official TIA correspondence.