October 2, 2013
In the wake of the deadly Navy Yard shootings comes a chilling report that the digital two-way radio system used by police, fire crews, and medical teams failed due to inadequate in-building coverage. Sadly, this isn’t the first time this has happened. If there’s a silver lining in this tragedy, it’s that members of Congress may now have the high-visibility incident they need to move forward with testing mandates.
The U.S. federal government mandates the use of digital radio technologies; specifically, APCO Project 25, or "P25" systems. While P25 offers many advantages, like any digital radio system it tends to perform in an "all or nothing" manner; there is no "soft failure" in digital radio. Digital offers increased performance in weak signal conditions, but when it fails it completely drops out. Because digital radios use a "codec" (encoder/decoder) to convert audio to digital data streams ambient noise can cause failures. This is due to the fact that the codec’s algorithms are designed to perform best with the human voice - not loud noises such as sirens, weapons fire, or heavy equipment.
The radio failures during the Navy Yard shooting initially have been attributed to both inadequate in-building coverage and codec failure caused by fire alarms. While further improvement of the radio codecs is a task the standards community will have to undertake, there's no reason why poor coverage can’t be addressed today. The National Fire Protection Association publishes a code document known as "NFPA 1" and this contains a section known as "Annex O" that gives guidelines for testing of in-building radio performance.
Modeled to some extent on the TIA’s TSB-88 outdoor coverage testing guidelines, NFPA 1 has been adopted by some local governments into their building codes. In these jurisdictions in-building testing for public safety radio is required both before final occupancy permits are issued and in most cases requires re-testing at regular annual or semi-annual intervals. Re-testing of coverage isn’t always easy because any building occupied will be full of furniture, equipment, and people. Coverage testing solutions need to be handheld and battery-powered - anything that requires a PC or a cart full of equipment and batteries isn’t going to work.
While the cost and complexity of indoor testing has generated consternation from building owners and radio system contractors, the reality is that citizens and building occupants should rightfully expect that radio systems paid for by taxpayers’ dollars will work during public safety response incidents. Nor is it reasonable to put police, fire, or EMS personnel in further danger because their radios fail after entering a building. Testing in-building is not an inexpensive proposition, but it's something which we MUST require via building codes. And if local governments are doing this, the federal government should not be immune to these same requirements. In some countries (Netherlands, for example) in-building testing for public safety radio is required by federal law prior to issuance of the station license.
Given the current economic slowdown it’s unlikely that changes will be coming soon on a nationwide level. Some areas, like the Silicon Valley, are experiencing a localized recovery and could support increased code requirements; the lessons learned from local implementation would serve as an example for the rest of the country when the economy does ultimately turn around. I remain hopeful that our local leaders will see the wisdom of this and take appropriate action.