Researchers Studying PASS Alarm Interference

Tests developed by researchers at the National Institute of Standards and Technology may make Personal Alert Safety Systems more useful and reliable. PASS devices are worn by firefighters; the systems detect motion and activate an alarm if the wearer has been motionless for too long. But there is interference between PASS systems with wireless alarm capability and radio-frequency identification (RFID) systems, so NIST developed test methods to evaluate how well the PASS technology works under realistic conditions. The methods can test interference in other wireless devices, such as radios, local area networks, and urban search and rescue robots, according to the agency.
 
PASS devices sense movement and activate an alarm if a firefighter remains motionless for too long. Newer PASS systems also have a wireless link connecting incident command base stations and portable units, allowing emergency recall signals to be sent to firefighters or “firefighter down” alarms to be sent to the base. Because firefighters also may carry RFID tags for location tracking, or may be in warehouses or other buildings using RFID inventory systems, there is potential for significant interference.
 
“Every wireless device will fail given strong enough interference,” says NIST project leader Kate Remley. “The question is the level at which the device fails. Our goal is to develop lab-based test methods to quantify the level of interference at which PASS units fail so we can help ensure they operate reliably.” The NIST researchers shared their findings at the 2011 IEEE Electromagnetic Compatibility Symposium in Long Beach, Calif., on Aug. 17. They measured the interference between “frequency hopping” PASS and RFID systems operating in similar frequency bands and found that, when signals are weak due to environmental or other conditions, a portable PASS unit’s reception of an alarm from its base station can be delayed or fail, even without interference, and becomes more likely to fail in the presence of moderate RFID interference. Strong interference caused longer, variable delays that sometimes lasted longer than one minute, which the researchers defined as signal failure. They also found that an RFID system can be less reliable when the PASS unit is nearby.
 
The NIST tests involved measuring the total output power of each system in a test chamber and then isolating the systems in different labs for the interference tests. The portable PASS device and RFID tag and reader were placed in a test chamber, while the PASS base station was in a separate room. Researchers evaluated performance at various levels of signal strength and interference.
 
NIST is working with the National Fire Protection Association, which will consider adopting the NIST tests as part of revised PASS performance standards. An NFPA technical committee on electronic safety equipment will soon consider the wording of a draft standard, and after a public comment period, the standards could be approved by 2013. At that point, manufacturers would need to show that their PASS devices pass the tests.
 
The research is supported by the Department of Homeland Security.

Featured

New Products

  • Camden CV-7600 High Security Card Readers

    Camden CV-7600 High Security Card Readers

    Camden Door Controls has relaunched its CV-7600 card readers in response to growing market demand for a more secure alternative to standard proximity credentials that can be easily cloned. CV-7600 readers support MIFARE DESFire EV1 & EV2 encryption technology credentials, making them virtually clone-proof and highly secure.

  • PE80 Series

    PE80 Series by SARGENT / ED4000/PED5000 Series by Corbin Russwin

    ASSA ABLOY, a global leader in access solutions, has announced the launch of two next generation exit devices from long-standing leaders in the premium exit device market: the PE80 Series by SARGENT and the PED4000/PED5000 Series by Corbin Russwin. These new exit devices boast industry-first features that are specifically designed to provide enhanced safety, security and convenience, setting new standards for exit solutions. The SARGENT PE80 and Corbin Russwin PED4000/PED5000 Series exit devices are engineered to meet the ever-evolving needs of modern buildings. Featuring the high strength, security and durability that ASSA ABLOY is known for, the new exit devices deliver several innovative, industry-first features in addition to elegant design finishes for every opening.

  • Mobile Safe Shield

    Mobile Safe Shield

    SafeWood Designs, Inc., a manufacturer of patented bullet resistant products, is excited to announce the launch of the Mobile Safe Shield. The Mobile Safe Shield is a moveable bullet resistant shield that provides protection in the event of an assailant and supplies cover in the event of an active shooter. With a heavy-duty steel frame, quality castor wheels, and bullet resistant core, the Mobile Safe Shield is a perfect addition to any guard station, security desks, courthouses, police stations, schools, office spaces and more. The Mobile Safe Shield is incredibly customizable. Bullet resistant materials are available in UL 752 Levels 1 through 8 and include glass, white board, tack board, veneer, and plastic laminate. Flexibility in bullet resistant materials allows for the Mobile Safe Shield to blend more with current interior décor for a seamless design aesthetic. Optional custom paint colors are also available for the steel frame.