By Anne Cosgrove
Published in the November 2006 issue of Today’s Facility Manager
Many facility managers have discovered how wireless technology canboost the performance of their buildings, both publicly and behind thescenes. Access to a cell phone signal and the ability to log on to theInternet using a laptop are expected by occupants in most buildingstoday. Facilitating such activities in their buildings has requiredmany facility managers to install equipment and implement strategies tomaximize signal strength.
Additionally, wireless technology is being used more and more to control building automation systems. The continued development of wireless sensor networks for building controls is beginning to make the technology more visible to potential end users. Learning more about wireless building controls systems can help a facility manager to determine if the cost and benefits of the technology are a good fit for a particular building.
Problem Solving With Wireless Controls
When Russell Hussey, building manager at the Newburyport Masonic Temple in Massachusetts, needed to lower energy costs and gain greater control of the indoor environment of the facility, he did not initially expect wireless technology would provide a solution. However, he eventually learned that such an approach to an HVAC upgrade would not only solve his problems, but it would also address two related concerns—budget constraints and preservation of the building’s historic structure.
Built in the early 1800s and upgraded in 1929, the 24,000 square foot building Hussey manages relied on an aging control system for heating operations in 10 zones. These zones were unable to communicate with each other, and only two were able to control the boiler. The facility’s inconsistent operating hours also contributed to unnecessary energy consumption, since Hussey was not always present to turn the system off when it was not needed.
These control and monitoring issues could be addressed by installing an automated system, but there were issues of cost along with concerns over penetrating walls to install wiring and related infrastructure.
In the end, a wireless building controls system solved Hussey’s problem. Existing thermostats were replaced with wireless controllers and digital sensors; each zone in the building was linked to a master controller; and Hussey can now view and control all the system elements from his computer. Since the required wiring was minimal, this solution saved on installation costs and eliminated the need to alter the structure.
Wireless Coming Of Age?
The story of the Newburyport Masonic Temple illustrates several points about the potential for wireless technology in the realm of facility management. While some in the profession have adopted building automation controls based on wireless technologies, the application is not widespread.
Facility managers are generally concerned with the cost, reliability, and security of wireless building automation controls. With this in mind, some take the leap from freestanding, independent building controls to a completely integrated, wireless automation approach. Others already have facilities with building automation systems and consider weaving wireless technologies into the existing infrastructure.
As president and founder of Building Intelligence Group, a consulting firm in St. Paul, MN, Paul Ehrlich, P.E., works with facility professionals who are implementing building automation systems, both wired and wireless.
“Regarding building controls,” he says, “we see managers and owners looking for two things. The first is the ability to make their staff more productive by being mobile with the ability to receive a work order or troubleshoot a problem without having to be in an office.”
In terms of a wireless solution, Ehrlich says, “Wireless building controls provide a benefit in the form of dramatically reduced costs as well as the flexibility to relocate or add sensors to the network easily.”
Ankit Shukla, a research analyst with Frost & Sullivan, a growth consulting company based in Palo Alto, CA, who has researched the issue of wireless building automation, says, “With wireless technology finding greater adoption in building automation, the number of addressable applications is large. Seen in both a supportive and/or disruptive role with existing wired infrastructure, wireless technology has opened many new fronts.
“As part of a wireless sensor network, sensors provide information about the physical world around us,” continues Shukla. “And their mass deployment in building areas that are difficult or very costly to wire can be addressed via the use of wireless technologies.”
Shukla notes that the first wave of wireless sensor products for building management has consisted largely of sensors used to measure carbon dioxide, temperature, and pressure. He terms these “under the ceiling” applications, as opposed to wider building management systems such as HVAC, lighting, and security.
Accommodating The Facility
The use of wireless sensor networks can present cost benefits on the installation end. In many cases, implementing a wireless system will be less costly than a comparable wired system, due to less wiring and the fact that the installation process may not be as labor intensive.
Jon Williamson, product marketing manager at TAC in North Andover, MA, says, “The power of wireless is in its ability to solve installation problems. This includes when a project is considered too costly due to the installation of wires; when the installation is too difficult because of building materials and wall penetrations; or when the installation is too damaging to a historic building. In any of these situations, wireless provides an excellent and cost effective solution.” TAC performed the installation at the Newburyport Masonic Temple, where all of these issues were present.
Williamson adds that wireless can also be appropriate when maximum flexibility is required, such as in modular office spaces that are frequently changed.
Says Linda McDaid, senior install market manager at Honeywell Building Solutions in Minneapolis, MN, “As [the cost per point] comes down, wireless will be used more and more in the new construction arena to lower total install costs. Applied in the right building type, there will definitely be a benefit of reduced costs.”
However, this is not always the case, and each facility has specific conditions and requirements that may or may not make wireless the best choice. Structural issues should be a key concern,” advises McDaid. “If an existing building has severe limitations with regards to existing wireless technology—for example, if cell phone reception is poor—it may not be a good candidate, because the expense to implement wireless may far outweigh the benefit.”
Regardless of whether the system is going to be installed in a new or existing building the proper design and implementation of the wireless infrastructure is critical, according to McDaid. Much depends on the expertise of the engineering team.
Standards Helping To Reduce Costs And Increase Reliability
Over the past few years, the costs of the devices used to create a wireless sensor network in a building have decreased. The emergence of standardization for the technology is one reason for this evolution.
In 2003, the Institute for Electrical and Electronic Engineers, Inc. (IEEE) introduced the 802.15.4 Standard for Low-Rate Wireless Personal Area Networks (WPANS). A general definition of a WPAN is “a network for interconnecting devices centered around an individual workspace,” with the objective of facilitating seamless operation among devices and systems.
The applications addressed by IEEE’s Standard 802.15.4 are characterized by low data rate, low power consumption, and low complexity. This focus aligns with the function of wireless sensor networks used for building management applications.
Unlike cell phone and Internet use, which require a constant signal in order to be powered, building automation control systems do not need to access the wireless signal constantly. They are able to “power down” between active use. Additionally, when data is transmitted through the network, the information for a building management system is significantly less than the data volume for cell phone and Internet use.
Says Shukla, “Cost associated with the current state of wireless technology, which is based on ratified protocols, is going down tremendously. The key is whether wireless technology is a ‘nice to have’ or a ‘have to have.’ The cost reductions will eventually turn most of the ‘nice to have’ scenarios into ‘have to have’ scenarios. This will also take place once wireless products and solutions have proved their performance and reliability compared to traditional wired technology.”
Working in concert with the specifications contained in IEEE Standard 802.15.4, the ZigBee Alliance began developing communication protocols that would build on IEEE’s low data rate and low power consumption goals. The ZigBee Standard, which was ratified in 2004, adds a significant building block to a uniform wireless infrastructure, since it was designed and optimized specifically for sensor network applications.
Bob Heile, chairman of the ZigBee Alliance, notes two advantages of the organization’s standard that are also making it cost-effective for manufacturers to use—complexity is low, and the technology is mature.
“ZigBee chose a radio technology and modulation scheme which is the same as [IEEE] 802.11b [existing Wi-Fi], so there is a lot of fabrication experience,” explains Heile. “The technology is well understood and inexpensive. Yet, because ZigBee is a low data-rate solution, tolerances on both the transmitter and receiver are a lot more relaxed than they need to be for 802.11b, thereby increasing yields and further reducing costs.”
Mesh Networks: The Next Step?
What the ZigBee Alliance brings to the table for wireless building controls is its focus on being able to use IEEE’s standard not only within a hub (point-to-point) network, but also in a mesh network. In a mesh network, each device (or point) in the wireless network can communicate with each other, as opposed to a hub network, where each point can only communicate with the “master” device. Therefore, if a point within the network fails, the signal can continue to move toward its destination by finding another point in the network through which to travel.
Mesh networking, which has its origins in the military, is being considered as a solution to a problem that faces all types of wireless technology applications—interference. When the numerous radio signals traveling throughout a wireless network vie for airspace, they can collide, and as a result, none make it to their destination. Structural elements of a building and items inside can also stop signals in their tracks.
“For control applications, mesh networking is the best choice,” says Ehrlich. “It offers a solution that is much more robust, has a lower cost, and has longer battery life than a hub based system.”
Shukla sees mesh technology as a way for wireless to succeed in the controls market. “There is no doubt that mesh network architecture has been predominantly adopted in a number of application scenarios compared to hub networks,” he says. “This is owing to benefits such as the self-forming and self-healing capabilities of mesh. With wireless networks, reliability is probably one of the biggest issues to be addressed to gain widespread acceptance, and wireless mesh networks have been able to provide this reliability.”
Ehrlich says, “I expect mesh technology to follow the curve of most new technologies. For the next few years, it will be used on a small percentage of projects. As it proves out, and the standards are completed, it will be used more often.”
But Will It Work… Securely?
In terms of reliability, Ehrlich says that for the facility managers he consults with about wireless control systems, this is a top concern. “The first worry is if the technology really works,” he says. “Many have a wait and see attitude. There is no question it will work. The question is how long it will take for facility professionals to be comfortable with it.”
Early adopters of the technology are key to demonstrating proven operating efficiencies, no matter what the application. “Currently, about 3% of facilities are using wireless clock systems,” says Michael Garven, director of sales for BRG Precision Products based in Derby, KS. “So, there are [facility managers in] the other 97% who need to be educated about wireless systems.” BRG manufactures and installs synchronized, wireless clock systems for commercial and industrial facilities.
Garven adds, “Wireless systems can not only save money up front when building a facility, but will also reduce long-term maintenance as compared to a hard wired system.”
As with wired systems that transport information, data security is of paramount importance. Many facility managers are concerned about system vulnerabilities that may enable hackers to disrupt operations or acquire information about the organization.
Lester LaPierre, marketing manager at Schlage/Ingersoll Rand Security Technologies in West Chicago, IL, notes that spread spectrum technology addresses the issue of hackers. Developed by the U.S. military for secure communications, this technology was declassified in 1985 for commercial use.
“There are two kinds of spread spectrum technology—frequency hopping and direct sequence,” says LaPierre. “We use direct sequence. In this scenario, there is a center frequency, and the system transmits on dozens of frequencies above and below the center frequency.”
LaPierre explains how the spread spectrum technology combats unauthorized access data transmitted through the system. “Say, for example, you have a 26-bit Wiegand prox card, and you present that to a lock. The system takes that card data in binary form (adding ones and zeros), and the data is spread around dozens of frequencies. That spreading algorithm is how the signal is encoded. If someone were trying to intercept with high-tech equipment, like a spectrum analyzer, perhaps they could discover what the center frequency is. However, the ones and zeros that are added, along with the bits that the system adds, makes it more difficult. All the information is also buried in a noise field, so someone cannot make out the hard edges that represent a one or a zero. Even if they could, they wouldn’t know what the spreading algorithm is.”
Facility managers should be sure to find out from potential vendors what security safety nets are built into their respective systems.
A Practical Approach
Along with the increasing flexibility of wireless building management systems come more choices to consider. It can be confusing for a facility professional who wants to glean the best fit for his or her situation. And certainly, one size does not fit all.
Says Williamson, “It comes down to how practical the wireless solution is for a given application (i.e. HVAC, security, or lighting). If a wireless solution effectively solves whatever challenges a building owner is facing in a given situation, then that is the approach to use. ”
Whether a facility manager is looking to jump on the fast track from no automation to wireless, or wants to add wireless into an existing wired infrastructure, the advances being made in the industry provide numerous options. What is required is careful consideration of what the goals are and if the technology will help to meet them.
This article was based on interviews with Ehrlich, Garven, Heile, LaPierre, McDaid, Shukla, and Williamson.