When a team is repeatedly getting beat by a powerful player, an adaptive defense will often switch to a double team or even collapse into a triple team at times. It is a useful concept as there is strength in numbers. False alarms are an exasperating adversary in fire detection. According to “False Alarm Activity in the U.S. in 2009,” by Michael J. Karter Jr., National Fire Protection Association, Fire Analysis and Research Division, Quincy, Mass., false alarms consistently represent one out of every 10 calls in the United States. It is a problem requiring a new kind of defense, or, in this case, detector. Why go head-to-head with fire and false alarms with one technology, when you can use multiple technologies?

False alarms are a problem everyone involved in fire protection wants to beat. In fact, on May 3, 2011 the United States Fire Administration (USFA), International Association of Fire Chiefs (IAFC), and the National Fire Protection Association (NFPA) co-hosted a first-ever summit to begin the discussion on how to reduce the number of unnecessary fire alarm responses.

“Stakeholders with responsibility for this issue attended to have a meaningful discussion about the issues and to map out the next-step strategies to continue the dialog. In addition to maintenance and testing issues [system malfunction causes 32 percent of false alarms] new technology, such as multi-criteria detection, was recognized as a potential device that could help minimize the problem of false alarms,” says Wayne D. Moore, P.E.,CFPS, SET, principal, Hughes Associates Inc., Warwick, R.I.

Todd Alford, marketing manager, Commercial Business Unit, System Sensor, St. Charles, Ill., agrees with multi-criteria detectors’ potential. “False alarms continue to be a real issue and carry costs in both dollars and lives. We need to solve this issue without sacrificing performance/response to real fires. How do we do that? One growing approach is multi-criteria sensors,” Alford says.

Multi-criteria detectors combine multiple sensing elements to help validate signals that would lead to alarm. Each manufacturer in the industry offers a unique combination of sensing elements. One example, the IntelliQuad detector from Notifier, combines four separate sensing elements:

  • Photoelectric Detector: Photoelectric chamber senses airborne particulates for smoke detection.
  • Carbon Monoxide Detector (CO): Electrochemical cell technology monitors carbon monoxide gas produced by incomplete combustion.
  • Infrared Detector: Measures ambient light levels across 360° as a background value and compares the background levels to the presence of light generated by a burning fire.
  • Thermal Detector: Heat sensor technology with a software compensated, linear temperature response to monitor rate-of-rise or a fixed temperature (135°F) threshold.

If the photoelectric sensor detects airborne particulates as smoke, the on-board microprocessor will verify the fire condition by looking for a second signature from one of the other three sensors; the infrared, thermal or CO detector. As soon as the second fire signature is confirmed by IntelliQuad’s internal algorithms, then the detector sends an alarm signal to the fire alarm control panel.

Using more than one form of detection helps detect fires of all kinds more rapidly than single element detectors, plus it leads to far fewer nuisance alarms — especially in problem applications where using only one sensor frequently leads to false alarms.

Before multi-criteria devices entered the defensive game plan for detecting fire, a debate had long raged over choosing one of two technologies: photoelectric or ionization detection.

The debate has recently swung toward photoelectric technology in specific circumstances, as earlier this year, the International Association of Fire Fighters (IAFF), Washington, D.C., announced that it now urges households to change to a photoelectric smoke alarm, while NFPA 72 also added language that requires smoke detectors installed within 20 feet of cooking equipment be the photoelectric type (to reduce the amount of alarms caused by cooking fumes, a top source of false alarms in homes).

“Let’s end the debate and stop just talking about ionization versus photoelectric detection,” advises Alford. “Let’s simply talk about what is the best way to detect a fire without false alarms. There are new technologies that are being worked on now that make a very responsive detector without the drawbacks of either photoelectric or ion detectors. There are municipalities who want both put in — ion and photoelectric — or are requiring one over the other, but legislating certain technologies is a mistake. Minimizing false alarms is important, but let us in the industry find the technology that is going to best do that. Mandating technology on an industry gets passed along to the consumer in cost.”

Cost is a critical area as multi-criteria detection is facing a double team of its own — cost and anonymity.

“The use of multi-criteria detectors is growing, but slowly. The reasons for this slow growth seem to be attributable to higher cost and a lack of knowledge by many specifying engineers and authorities having jurisdiction (AHJs) as to the real benefits gained from using the detectors,” explains Moore.

“In my opinion, the specifying community is not fully aware of the advantages of multi-criteria detectors and even when they do know the advantages they are concerned with the cost differential between the multi-criteria and the ‘one-sensor’ types. That said, they may not realize the benefit of using the multi-criteria detectors in known environments that will obviously be false-alarm prone for standard ionization or photoelectric smoke detectors. As an example of the cost issue, a recent design using primarily photoelectric smoke detectors in a large hotel fire alarm system design was modified to accommodate working fireplaces used in the building. The client and the AHJ wanted to avoid false alarms and the only way to ensure that goal was to replace the standard photoelectric smoke detector with multi-criteria detectors. However, the detector cost prevented the client from a total replacement of all the photoelectric type devices. Instead only ‘key area’ detector replacements were made.”

Competition makes cost impossible to ignore.

“The biggest thing that is going to influence whether multi-criteria detection will become a standard in the industry is the cost of the detectors because with everyone being so competitive to win bids, trying to price multi-criteria detectors into a job that doesn’t require them is hard. There really isn’t room in most jobs to do that. Once the cost comes down on par with regular smoke detectors you’ll see it more,” says Corey Messing, E.T., design manager, F.E. Moran Inc. Alarm, Fraser, Mich.

The cost issue is there, but it is offset by the benefit, says Andy Johannsen, director of sales, VES Fire Detection Systems, King of Prussia, Pa.

“Multi-criteria sensors typically cost 25 to 40 percent more than stand-alone addressable heat or smoke sensors, but they provide a wider range of adjustability and false activation immunity once installed.”

Brad Tolliver, vice president of electronic security, Per Mar Security Services, Davenport, Iowa emphasizes protection over cost.

“Ultimately, the focus has to be protection for the customers. The last thing we want is to not educate the customer on potential risk or solutions and then only after there is a loss say, ‘Oh there is this or that technology available.’ It is key to try to sell the appropriate devices up front. Sometimes people are cautious up front and don’t want to spend money, but after the fact, people always understand how worth it it is to spend the money. Our goal is to help prevent a situation like that from happening and offer the full complement of service and devices.”

Don’t count out the problem-solving quality of multi-criteria detectors, especially in areas where false alarms have high consequences and occupant evacuation carries a significant health, security or financial consequence.

“Think about projects you have specified and ones you’ve dealt with in the past where the owner or occupants have been plagued with the costs and frustrations of false alarms. Think about the areas of those facilities that are prone to false alarms. Finally, be prepared to offer the best technology available to discriminating customers. Meeting code is a good start, but in some cases is not sufficient to fully serve your customers,” Alford says.

Multi-criteria detectors shine at solving false alarm problems in many problematic applications. It’s the double-team effect. There’s always power in numbers — and in using more than one source of detection.

  CO Detection: Fire vs. Life Safety

Changes in multi-criteria detectors are frequently including a carbon monoxide (CO) cell that is specifically used for smoke detection. Fires that are slow to develop or fires that smolder release large quantities of CO before traditional detectable smoke aerosols and particulates escape from the fire. In these situations, using carbon monoxide detection of fires can occur hours before ion chamber or photoelectric smoke detectors operate. It is a promising advancement, but don’t be confused. Many multi-criteria devices are not applicable for applications where UL268 3230-3250 standalone CO detection is required for life safety. 

CO detection for life safety remains its own critical area and continues to be a fast-growing area of detection with many of its own changes, as described by Leon Langlais, director of product management, Tyco Security Products, for Kantech, DSC, Sur-Gard and Bentel security brands.

“Smoke and heat detectors have traditionally been required by law by many U.S. states and Canadian provinces. As a result, the demand for smoke and heat detectors has remained steady but stagnant for quite a long time. However, a significant change is happening within the CO detector market, as CO detectors are becoming mandatory in North America. As of January 2011, 24 U.S. states have laws on the books requiring the installation of CO detectors in either new or existing homes, with California representing the latest state to implement such a law. California’s law is scheduled to go into effect in July of this year. In Canada, Ontario is the first province to adopt CO detector laws for homes, and other provinces are expected to follow suit,” Langlais says.

“Legislation is driving the demand for CO detector, but it’s not the type of detector typically found at the local big-box hardware store that plugs into an outlet and emits an audible alarm. Instead, the market is installing CO detectors that connect to a security system, enabling a central station to monitor the device much like an intrusion alarm system. Should the CO detector produce an alarm, the central station would be able to quickly dispatch emergency personnel. In addition, professional CO detectors available in the market emit both a loud sound and flashing lights to alert occupants that the device has detected dangerous levels of CO.

“Another trend in the market is the introduction of wireless CO detectors, which is unique in the wireless intrusion market. Homeowners don’t want their houses wired over and over again, but wireless devices enable CO detectors to be added to virtually any room in a house, such as a bedroom, without worrying about wiring.  In addition, homeowners demand aesthetically pleasing devices, and as a result, CO detectors are being designed in compact sizes to blend in with the surroundings,” Langlais explains.