The rapid growth and development of advanced technology has been of significant benefit to the built environment. Advances in buildings system technology have led to the widespread development of Intelligent Buildings. An Intelligent Building is one that uses technology to automate the operation of building systems to enhance the safety, efficiency, and comfort of occupants. Intelligent Buildings utilize technology to monitor facility systems and make any necessary adjustments. The goal of an Intelligent Building is to use computers and software to control lighting, alarm systems, HVAC (heating, ventilation, air-conditioning), and other systems through a single computer interface.
While there is no universal standard of an Intelligent Building, there are some common characteristics that most Intelligent Buildings share. Typically, Intelligent Buildings offer:
- The ability to control major building systems. The most basic functionality required for an Intelligent Building is to control the major building systems that impact safety, efficiency, and occupant comfort. Those systems include HVAC, fire and life safety systems, alarms, access control, or any other system recognized as critical for facility operation.
- The ability to perform complex management tasks. An Intelligent Building is able to proactively manage systems according to both preset and variable schedules, environmental conditions, and emergency events.
- The ability to coordinate actions between and among multiple systems. An Intelligent Building must be able to control multiple systems in concert to achieve a single, coordinated action.
- The ability to communicate and report. Intelligent Building systems are able to generate customized, detailed information and reports using modern connectivity practices (such as xml over IP). This information is used by the facility manager to monitor the facility. Intelligent building systems can generate comprehensive reports, send automated e-mail alerts, and produce other customized reports required by the facility manager. As well, Intelligent Building systems communicate with outside systems, facilities, stakeholders, remote or headquarters offices, or any other entity the facility manager identifies.
Network Design
Modern facility systems use sensors and control devices that are linked to a central control system. These sensors and control devices are installed throughout the facility. In the past, each individual system would have its own set of cables that would allow it to communicate with the central control system. This is still the case in many facilities, but newer buildings are implementing converged networks that act as a single communications backbone for multiple systems.
Internet Protocol (IP)-based network systems are becoming increasingly common as a communications backbone for facility systems. Many facilities are now starting to deploy multiple Intelligent Building systems as well as administrative Local Area Networks on a single IP-based network. Most manufacturers of BAS and related sensors and controls are designing their products to operate on an IP network.
Some of the major benefits of using a single network include:
- Cost efficiency. Multiple systems, such as the BAS, the corporate LAN (local area network), VoIP (Voice over Internet Protocol), and even video signals can be run on a single network. Instead of multiple cable sets, only one is required. POE (Power-Over-Ethernet) can power low voltage devices through the network cable with no separate electrical supply. This eliminates yet another cabling system. Some access control and video surveillance systems now utilize only a single CAT6 cable for each device, eliminating separate power supplies.
- Higher data capacity. IP systems can communicate at speeds of 10 MB/sec on older cabling systems; 100 MB/sec is common on most systems. This is often hundreds or even thousands of times faster than previous communications on non-IP cabling. This extra capacity allows you to operate multiple systems on a single network.
- Greater flexibility. Newer, IP-based networks can be easily upgraded for faster speed, often without replacing cabling. As well, new systems can easily be added to the existing network.
- Many vendor options. IP is vendor-independent, so facility managers can choose from a wide variety of different manufacturers’ products to build the network.
Estimating Network Loads
Network systems are very complex and often nonintuitive. Estimating the load that systems will put on the network is a very complex task, and will have a huge impact on the success of the system. Is it recommended that you hire a network designer (preferably with a CCNA certification) to design and implement the network. It is also important to note that surveillance video can stress an IP network far more than access control systems or BASs.
Using video on an IP network can use hundreds, and possibly even thousands, more bandwidth than an access control system. Be sure to thoroughly understand your network capacity before adding video to networks that operate critical building systems.
Proper Network Cabling
One of the biggest impediments to a single, converged IP network is often the type of cabling installed in the facility. Many facilities still use CAT5 cabling, which is not sufficient to run some of the newer, high bandwidth systems such as video and VoIP. Even CAT5E, which offers a higher bandwidth than CAT5, is quickly becoming obsolete in the shadow of newly developed, highly advanced systems and their large data capacity requirements. CAT7 is highly recommended for today’s systems and can accommodate future systems in development. If you are upgrading to new cabling or installing cabling in a new facility, the added cost of CAT7 is minimal compared to the long-term advantages. Fiber optic cable offers the highest capacity, currently up to 10 GB/sec, but it is cost prohibitive compared to CAT7, and is typically not used extensively in facilities.
It can be a risk to run all Intelligent Building systems on a single data network. However, you can mitigate this risk by investing in equipment that can safely handle your needs and ensuring that redundant systems are in place. Like all technology, it is possible that the IP network will fail one day, so it is important to have a network service provider available for emergencies.
Wireless Communication
Some BAS device manufacturers are making equipment that communicate via wireless radio connections using standard 802.11 communications wireless LAN communications. The advantage of these systems is that they do not require network cabling, which can be difficult to install in some mechanical areas, on roofs, and other places where BAS systems may be located.
The challenges posed by wireless communication come from several areas:
- Interference from physical materials. Steel, wood, concrete, or almost any material will absorb or reflect some of the signals from wireless equipment. This can reduce the signal to the point where it is not useable.
- Interference from electromagnetic sources. Radio sources, fluorescent lights, and electrical equipment and cabling can interfere with wireless signals.
- Too few (or too many) wireless access points. In order for wireless to work, it requires the correct number and location of access points to connect the wireless signal to the wired network.
If any of these factors exist, slow communication will result because of low quality signal or interference. As a result, the wireless devices may not work. To determine if these factors exist in the areas where you wish to use wireless BAS sensors and devices, it is recommended that you have a wireless survey conducted prior to installation. The survey will tell you what interference, if any, is present, and what your resulting connection speed will be. If the connection speed is not fast enough, you may need to install wireless repeaters to improve the signal strength and quality and increase the speed of the connection.
Device Communication in Intelligent Buildings
Intelligent Buildings communicate with their devices by sending signals in communications protocols through data networks. Think of the protocol as the ‘language’ the system speaks, and the network is the ‘phone line’ that carries the conversation (although networks are far more complex than phone lines).
Intelligent Building systems communicate by sending signals through networks to and from sensors, actuators, and the control software. The information is sent in small segments, known as packets. It is helpful to think of a packet as a fax, going through the fax machine one page at a time, with a confirmation message returned after each page has been sent. Of course, this all happens much faster than a fax machine operates. Packets are sent and confirmed in fractions of seconds. Each packet contains information written in a protocol, a language that both sender and receiver understand.
Protocols
In the early days of BAS, each vendor had a proprietary protocol that they alone used. As a result, it was impossible to use any products except for those supplied by the BAS manufacturer. With the popularity of open source, however, BAS manufacturers have made their products more generic. This has allowed customers to choose different products from different manufacturers and still have the components work together. Two of the most popular open source protocols are BACnet and LonWorks.
BACnet
BACnet is a vendor-independent, open source communications protocol designed specifically for HVAC and BASs. BACnet is a flexible and comprehensive control language, and can also be used to control lighting, security, access control, fire alarm, and many other systems. It is supported by most of the major BAS makers, as well as manufacturers of other facility systems. BACnet has been ratified and endorsed by ASHRAE (the American Society of Heating, Refrigeration and Air-Conditioning Engineers) and ANSI (the American National Standards Institute).
LonWorks
The LonWorks device networking platform was created by the Echelon Corporation, and is widely used thoughout the world. It is part of the BACnet control standard for buildings, and has been included in EIA-709.1, the EIA (Electronic Industries Alliance) Control Network Protocol Specification. Similar in concept to the BACnet standard, it uses a different communications protocol that is not compatible with devices that use BACnet to communicate. The LonWorks communication protocol is freely distributed, although chips manufactured by the Echelon corporation are required in all devices that use LonWorks.
Choosing a Protocol
There is some debate among facility owners and managers, engineers, and architects, as to whether BACnet or LonWorks is the superior protocol. There is still some debate as to the definition of ‘open source’ and what makes a system truly open. BACNet is completely vendor-independent and does not require proprietary chips in its devices. LonWorks systems, however, are widely used and are have found industry-wide acceptance. Many BAS manufacturers have compromised between the two protocols by designing their systems to communicate with either BACnet or LonWorks devices and operate on multiple types of networks.
There are also a number of other protocols in existence, although BACnet and LonWorks are becoming the industry standards. However, it is still common to have some equipment operating using older protocols such as RS232 or Modbus in part or all of a facility. COBA (Connected Open Building Automation), is a Linux-based operating system that has had limited success. Many BAS manufacturers provide the ability to talk to devices using these protocols.
This article is adapted from BOMI International’s Technologies for Facilities Management. More information regarding this is available by calling 1-800-235-2664, or by visiting www.bomi.org.
