NIST tests help ensure reliable wireless alarm beacons for first responders

Aug 17, 2011 By Laura Ost
NIST engineer Kate Remley holds two Personal Alert Safety System (PASS) devices with wireless alarm capability. Credit: Paul Trantow/Altitude Arts

Wireless emergency safety equipment could save lives—if signals are transmitted reliably. But few performance standards exist. Now, tests at the National Institute of Standards and Technology (NIST) are helping to ensure that alarm beacons for firefighters and other emergency responders will operate reliably in the presence of other wireless devices.

NIST is providing technical support for industry consensus standards by developing test methods to evaluate how well these devices work under realistic conditions. The latest NIST study focused on interference between Personal Alert Safety Systems (PASS) with wireless alarm capability, and radio-frequency identification (RFID) systems. The methods developed in the study can test interference in other wireless devices such as radios, hands-free cell phone headsets, local area networks, and urban search and rescue robots.

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 research, to be presented at a conference this week, measured interference between “frequency hopping” PASS and RFID systems operating in similar frequency bands. Results show that, when signals are weak due to environmental or other conditions, a portable PASS unit’s receipt 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 only moderate RFID interference. Strong interference caused longer and variable delays that sometimes exceeded a minute, defined by the researchers as signal failure. NIST researchers 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 .

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.

Explore further: Tesla says decision on battery factory months away

More information: K. Remley, et al. Interference tests for 900 MHz frequency-hopping public-safety wireless devices. Presented at the 2011 IEEE Electromagnetic Compatibility Symposium, Long Beach, Calif., Aug. 17, 2011.

add to favorites email to friend print save as pdf

Related Stories

RFID might help track first responders

Mar 31, 2006

A National Institute of Standards and Technology team is studying the feasibility of using radio frequency identification technology during emergencies.

NIST Measures Challenges for Wireless in Factories

Aug 31, 2007

Factories have much to gain from wireless technology, such as robot control, RFID tag monitoring, and local-area network (LAN) communications. Wireless systems can cost less and offer more flexibility than cabled systems. ...

Conflicting signals can confuse rescue robots

Mar 02, 2007

Sensor-laden robots capable of vital search and rescue missions at disaster sites are no figment of a science fiction writer's imagination. Prototypes and commercial models of urban search and rescue (US&R) robots will soon ...

NIST Issues Guidelines for Ensuring RFID Security

Apr 27, 2007

Retailers, manufacturers, hospitals, federal agencies and other organizations planning to use radio frequency identification (RFID) technology to improve their operations should also systematically evaluate the possible security ...

Recommended for you

Tesla says decision on battery factory months away

Aug 01, 2014

(AP)—Electric car maker Tesla Motors said Thursday that it is preparing a site near Reno, Nevada, as a possible location for its new battery factory, but is still evaluating other sites.

Comfortable climate indoors with porous glass

Jul 31, 2014

Proper humidity and temperature play a key role in indoor climate. In the future, establishing a comfortable indoor environment may rely on porous glass incorporated into plaster, as this regulates moisture ...

Crash-testing rivets

Jul 31, 2014

Rivets have to reliably hold the chassis of an automobile together – even if there is a crash. Previously, it was difficult to predict with great precision how much load they could tolerate. A more advanced ...

Customized surface inspection

Jul 31, 2014

The quality control of component surfaces is a complex undertaking. Researchers have engineered a high-precision modular inspection system that can be adapted on a customer-specific basis and integrated into ...

User comments : 0