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Building Operating Management

Wireless BAS Networks Benefit from Mature Standards and Security Improvements





By Josh Thompson   Building Automation

OTHER PARTS OF THIS ARTICLEPt. 1: This PagePt. 2: Wireless Devices Go Batteryless
The benefits of a building automation system are well-documented: energy efficiency, cost management, accessibility and flexibility. But if cabling is required, even the latest IP-based BAS can be difficult to deploy and integrate in an existing building.

In addition to the obvious physical barriers, with horizontal and vertical wireways either stuffed to the gills or inaccessible, there are other complications that can be far worse. The costs associated with cabling an existing building can be formidable and extend beyond the cost of the wire and the labor to pull it. Occupancy interruptions can occur as a result of demolition and repair, which also adds cost. Punching holes, modifying assemblies, running conduits, and transiting partitions and spaces are all a part of a cabling job and it can be expensive, disruptive and dirty work.

The obvious solution is to “cut the cord” and go wireless. Today’s meshed wireless technologies offer the best solution for secure, reliable and cost-effective building automation — no matter what your IT department may tell you.

Wireless solutions offer competitive advantages. Requiring no cabling, conduits or other infrastructures, a wireless deployment affords a level of flexibility in both design and operation that a wired system cannot. Throughout the life of a building, changing occupancy, migratory cubicles and moving walls can wreck hardwired integration. Further, surfaces, structures and assemblies that are architecturally important are left undamaged while sensors and devices are strategically placed where they are needed, not just where the wire has been pulled. Thanks in large part to the work of manufacturers, the IEEE and several technology alliances, the market is awash with new wireless products. These systems and devices are highly integrated, self-configuring, self-healing and readily available.

For the various devices in a wireless sensor network (WSN) to work, they all have to speak the same language. Several manufacturers have jumped into the market with their own proprietary systems, all with their own protocols. Selecting one of these systems may make sense if, for example, you have an existing BAS or mechanical system from a given vendor and integration of new wireless components would be greatly simplified by keeping everything on the same platform. Also, it may be advantageous for facility executives to partner with one of these larger companies to deploy a system across a campus or enterprise, leveraging the economies of scale.

Regardless of the manufacturer, proprietary systems all tend to be robust, high-performance and reliable. These manufacturers build good products and they stand behind them with support that may not be available from a system that is assembled from various parts and pieces. That said, a system based on a proprietary communications platform is not likely to play well with others. If you have committed your facility to the Brand X wireless network, integrating devices from another vendor may be difficult.

Alternatives to proprietary networks have arisen as a result. Standards-based wireless networks are nothing new. WiFi — the standard for wireless computers — goes by 802.11a/b/g. Similarly, 802.15.4 describes a wireless-controls language called ZigBee. Far from being alone, ZigBee is now being joined by a host of other platforms, or “languages,” complete with their own names and acronyms.

What these protocols have in common is that they enable connected devices to talk across their respective networks using a common language without regard to who made each of the devices. This works in much the same way as a laptop — a WiFi card will make a connection with any wireless access point, provided it has permission to do so. As a result of these open communication platforms, many new and innovative manufacturers have brought countless new devices and applications to the market.

So what’s the catch? Frankly, there aren’t many. Battery life is often presented as the largest single negative when considering a wireless BAS integration. In truth, the systems are engineered specifically to provide years of service off of a single battery. Some manufacturers claim that drain is so low that the only limiter is the shelf life of the battery, which can be up to seven years. Other new systems eliminate batteries altogether. (See “Going Batteryless” on page 31 .)

Further, the data being gathered and transmitted by these devices is incredibly small, which also means long battery life. When the sensors are strategically placed (for operation and maintenance), it should, by design, be a simple operation to swap a battery out when the system tells you that one is getting low.

Getting on IT

Perhaps the biggest barrier to cross in the design of any BAS comes from the possessive and occasionally paranoid folks in the IT camp. Despite being at the core of the movement to provide “unified communications” and truly “integrated systems,” most are being dragged kicking and screaming into the prospect of allowing any system, let alone a building control system, access to their network.

A wireless BAS helps facility executives overcome most, if not all, of these challenges. Even so, a system made up of all wireless sensors will likely have to cross paths with IT at some point or another. One of the biggest advantages afforded by a modern BAS is the ability to monitor and control the building remotely. Allowing access to the network in this regard is rarely met with opposition because it’s easy to accomplish using a virtual private network (VPN) or remote desktop sharing. The real concerns come about when you must hop on the existing network to jump between floors or between buildings in a larger integration.

In fairness, IT professionals have plenty of valid reasons to be protective of their electronic turf. The networks they are responsible for carry information that is vital to the activities the building was constructed to support. They are constantly under attack from threats as simple as a mass download of the latest Internet craze or as complex as a multi-port viral attack from an overseas ne’er-do-well.

In the design stage, it is possible to overcome a good deal of this anxiety by providing the network engineer with as much information as possible about the protocol chosen. Ask the system vendor to provide additional information about the type and volume of traffic the network is likely to encounter, as well as any specific engineering requirements that may need to be addressed such as port requirements and security concerns. Most importantly, communicate that the BAS is a very low traffic system that is inherently stable and poses no security threat to the network.

Security of BAS

In some circles, the perception exists that wireless networks are subject to being hacked or taken down by interference from other radio sources. For building systems, security is the highest priority. Thankfully, meshed networks are inherently secure — each device on the network must be “trusted” before connection is established. Any packet or bit of data that enters the network from a non-trusted sender is simply ignored.

For additional security, most protocols add 128-bit Advanced Encryption Standard (AES) encryption with protection on both the application and transport layers. When those measures are combined, the risk of a malevolent device being introduced to the network and feeding erroneous data to the system without being detected and disabled is extremely small. The likelihood of such a device entering and compromising the corporate network through such a window is even smaller, particularly if the BAS is properly firewalled and segmented on its own VLAN (virtual network).

All of this security is meaningless if the system can be disrupted by a CB radio, however. Fortunately, another component of the current communications technologies is that they operate in a known and regulated frequency band and are almost universally frequency agile. If a rogue radio “keys up” on a frequency being used by the BAS, the system instantly changes channels. Further, most systems are “spread spectrum” in operation, which means that they are constantly “changing channels” to remain in clear air and loss free. This method of radio traffic further enhances security because the BAS cannot be “tuned in” and monitored.

Whether an existing building facing challenges in BAS integration or a new project hoping to leverage a reduction in infrastructure costs and long-term flexibility, wireless systems are worthy of serious consideration. Armed with careful engineering, forethought and IT consideration, its integration and deployment will be simple, reliable and cost effective.

Josh Thompson is vice president at Polysonics Corp., a technology consulting firm. He has more than 20 years experience working on wireless and audio/visual deployments in buildings ranging from Caesar’s Palace in Las Vegas to the Washington, D.C., Public Library.


Continue Reading: Wireless BAS Systems Grow Up

Wireless BAS Networks Benefit from Mature Standards and Security Improvements

Wireless Devices Go Batteryless

posted on 8/12/2009

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