First responders can now render aid more quickly in an emergency, thanks to a communication system called Public Safety DAS. The market for DAS systems is growing rapidly and offers huge opportunities for installation contractors and technicians. In this article, WaveLengths interviews Chief Alan Perdue and Eric Toenjes, two leading advocates of Public Safety In-Building Communications, including DAS; they explain what DAS is, and offer advice for network contractors who wish to become involved in this growing market.
Thank you Chief Perdue and Mr. Toenjes for this opportunity to learn about Public Safety DAS, and its implications for public safety. What, exactly, is Public Safety DAS?
Chief Perdue – First, let me explain DAS in
general as a solution to public safety in-building
communications. DAS stands for Distributed
Antenna System. A DAS uses multiple antennas
installed in strategic locations to extend the
operating range of RF for communication devices
such as cell phones, two-way radios and other
portable communication devices. DAS can be
installed anywhere, including university and office
buildings, hospitals, sports stadiums and so forth.
One of the most important types of DAS is one that improves public safety in-building communications. The purpose of a Public Safety DAS is to enable firefighters and other first responders to use their portable radios to communicate from any location inside a building where radio signals could otherwise be blocked by windows, building walls and partitions. This is accomplished by installing DAS antennas throughout the interior of the building in places such as offices, exit corridors, stairwells, basements and so forth.
There is another type of DAS called Cellular DAS which we can discuss as well. Both types of DAS support the mission of the Safer Buildings Coalition (SBC), which is to ensure that the public can call for help when they need to, that critical information can be pushed to building occupants about an emergency incident and that public safety personnel can communicate when they get there. A DAS enhances the ability for first responders to communicate which can help save lives.
WaveLengths – A large portion of our readership consists of network contractors and technicians. Does Public Safety DAS provide business opportunities for network installers?
Mr. Toenjes – Yes, and the potential
market is enormous. It is generally
accepted that less than 5% of
the commercial real estate in this
country has any kind of coverage
solution in it. So you’re talking
about a massive market, which
analysts say will provide 19 billion
dollars in business opportunities
over the next 5 years.
There are many market factors that are driving Public Safety DAS. Building owners are beginning to see DAS as a way to make their buildings safer, which could help them avoid liability in certain situations. Also, the public increasingly relies on their mobile devices and DAS can enable them to communicate from wherever they are, which is important in emergency situations. Like fire sprinkler systems, people will come to expect DAS in the workplace, hotels, shopping malls and so forth.
The biggest market driver is the fact that building codes are beginning to require Public Safety DAS. Although Public Safety DAS is still relatively new, it will soon become part of the plan for every new building.
Chief Alan W. Perdue, Executive Director, Sfafer Buildings CoalitionChief Perdue has firsthand knowledge of issues relating to public safety, having gained front line experience as a firefighter and eventually becoming Emergency Services Director for Guildford County Department of Emergency Services. His career spans 34 years in public safety, working in both the state and national arenas. After retiring from the fire department he continued his work to promote public safety as Executive Director of Safer Buildings Coalition (SBC).
Eric Toenjes, Mobility Business, Development Manager, GraybarMr. Toenjes has many years of experience in the wireless market, providing solutions to end users and carriers alike. He works with organizations like HetNet Forum and Safer Buildings Coalition to help resolve issues facing building owners, influence public safety codes and to understand the business motivations that are driving solutions. Graybar is a distributor for SOLiD, a company that manufactures radio equipment, including components for Public Safety DAS.
WaveLengths – What do present building codes require in terms of Public Safety DAS?
Chief Perdue – There are two organizations that develop model codes relating to public safety. One is the International Codes Council (ICC), which produces the International Fire Code. The other is the National Fire Protection Association (NFPA), which produces NFPA 1. Both of these codes provide model language that is available for local adoption either on the state or local jurisdiction level, or a
combination of both.
Model codes state that in-building coverage shall be provided in all new buildings where signal strength doesn’t exist as it does on the street. For example, if I’m at the front door of a building I may have adequate public safety signal strength on my mobile device. If I lose that signal when I walk through the front door into any part of that building, then an in-building solution must be provided. That solution doesn’t necessarily have to be a DAS, but a DAS is a solution that is often utilized.
The requirements of the Authority Having Jurisdiction (AHJ), are based on the adopted code language. It is important to know what code language is adopted for that area that a DAS is being provided to ensure that that final system design and installation is in compliance so a certificate of occupancy can be obtained.
WaveLengths – What types of buildings require a Public Safety DAS?
Mr. Toenjes – The requirement typically applies to new buildings and older buildings that are undergoing major renovations.
Chief Perdue – There are some jurisdictions that have, or are looking at, retroactive requirements for older buildings due to the sensitive nature of the public safety issue.
WaveLengths – Do you think these codes will continue to evolve?
Mr. Toenjes – Public Safety DAS codes are only a few years old and the codes are still evolving. The finer details of the code provisions aren’t really the big issue. The bigger challenge is the variety of ways that they are enforced.
The AHJ is allowed to interpret and enforce the code at the local level, which can be vastly different than what the national model codes recommend. In other words, the AHJ doesn’t have to adopt all of the provisions of the NFPA code that apply to public safety radio systems; the jurisdiction can just decide which elements of code they want to adopt.
So there is definitely a difference between what a building owner has to do and what they should do, and that’s why the topic of “moral responsibility” comes up so often in these discussions.
When Seconds Count
Cellular DASYour heart is pounding in your ears. Something is seriously wrong. You are barely aware of the emergency medical technicians hovering over you. Your mind is preoccupied with thoughts of your family. How will they manage without you?
Fortunately, you never had to find out. Someone used their cell phone to call 911, saving precious seconds. Thanks to Cellular DAS installed in the building, emergency medical assistance arrived in time to save your life.
Public Safety DASYour two-way radio beeps as a call comes in through the building’s Public Safety DAS network. A fellow firefighter outside the building informs you that someone is still missing and was last seen in the Accounting Department. Despite the dense smoke, you manage to locate the individual lying motionless on the floor. You carry the victim outside where oxygen is administered by EMTs. A life was saved, thanks to Public Safety DAS
Mass Notification SystemYou hear an odd “pop, pop, pop” sound, repeated at irregular intervals. You look into the hallway as a student of yours rounds the corner and runs into your room. “There’s a crazy guy with a gun” he says frantically. “People are trying to hide; they don’t know what to do!” Then your cell phone dings and a text message appears. “Gunman in east wing, moving west through main hallway. Exit though science wing if you can.” Other building occupants receive the same message. Many lives are saved thanks to the Mass Notification sent over the school’s Cellular DAS network.
WaveLengths – Are their special requirements for hi-rise vs. low-rise buildings?
Chief Perdue – No, the requirements in the model codes are the same for any type of structure. If the building prevents radio signals from penetrating throughout the building, a solution must be found. It’s important to remember this is an RF issue not a building size issue.
WaveLengths – Is Allied Fiber competing against local telecoms?
Hunter – Absolutely not! That’s the single most important thing I want people to understand. Allied Fiber is not a local access provider. We’re in the real estate business, that’s all that we do. We simply negotiate land rights to bring high capacity fiber to, through, and near cities and towns. Who chooses to use that fiber, for whatever purpose, is entirely up to them. If incumbent carriers want to use our dark fiber we are happy to provide it to them. If their potential competitors want to lease our fiber, that is OK too.
The world is changing. Telecoms can’t expect to remain the sole service provider forever. Look at what happened to Bell Telephone.
WaveLengths – Who pays to have a Public Safety DAS installed in a building?
Chief Perdue – The majority of public safety equipment is the responsibility of the building owner, much like other life safety systems in a building such as exit lighting, exit panic hardware on doors, fire alarms, fire sprinklers, etc.
WaveLengths – Are there alternative solutions for emergency communications? What about COWs?
Chief Perdue – Cell On Wheels, or
COWs, are mobile systems that
are sometimes used to temporarily
improve cellular coverage for large
numbers of people attending
outdoor events. They’re not much
use for providing emergency
coverage inside of a building.
For one thing, in an emergency you don’t want to depend on somebody showing up at the right moment and setting up communications equipment. All of that takes time and we can’t predict where the next emergency incident will occur. BDA’s Small Cells are another solution that continues to be discussed. However, a DAS seems to be utilized more often.
WaveLengths – Don’t firefighters shut off power before entering a building to fight a fire? Wouldn’t that shut down power to the building’s Public Safety DAS?
Mr. Toenjes – The NFPA model code requires 12 hours battery backup for Public Safety DAS. Whether a community chooses to adopt that portion of the code depends, again, on the AHJ.
Training OpportunitiesAccording to Mr. Toenjes, because Public Safety DAS is relatively new, there are no universally recognized certification programs specifically designed for this type of network. However, there are ways that installers get some DAS credentials under their belt. For example:
Equipment Certifications Original Equipment Manufacturers such as SOLiD, ComScope and Corning have training and certification classes related to the installation, maintenance and repair of their specific DAS equipment.
Software Training and Certification Various computer design programs and certifications are available from software companies that serve the wireless industry. Most notable among them is iBwave, which is design software for Cellular DAS, Public Safety DAS, WiFi applications and more. For more information visit www.ibwave.com.
Editor’s Note: DASpedia offers an excellent program for installers and technicians wishing to learn about Cellular DAS. While they don’t cover Public Safety DAS in detail, their coverage of Cellular DAS provides a solid foundation for learning about other types of DAS.
See the information about upcoming DASpedia Training to be held at the NFOC Communications Conference in September.
WaveLengths – I understand that the government agency FirstNet is working toward building an emergency public safety broadband network that spans the entire U.S. What is FirstNet and will their system be compatible with local Public Safety DAS installations?
Chief Perdue – We are certainly
having those discussion and
continue to evaluate what is
necessary to carry the data piece
of public safety band 14 on the
in-building solution. FirstNet,
which stands for First Responder
Network Authority, was created when the Middle Class Tax
Relief and Job Creation Act
passed in 2012.
Mr. Toenjes – There are a few things that need to be worked out before FirstNet and Public Safety DAS can be integrated completely. FirstNet is designed to be a broadband data network not a voice communications system like local first responder radio systems. It’s an LTE or 4G network similar to existing cellular networks. The design requirements for radio voice could be quite different than a data network on the Public Safety DAS.
I believe that eventually you are going to see voice over IP on FirstNet, which will have a very positive impact on interoperability. That probably won’t happen anytime soon though.
WaveLengths – I get the sense that Public Safety DAS installations are relatively simple to install. Is that correct?
Mr. Toenjes – Yes, they can be easier to design, install and optimize than a cellular DAS. System installation, including running cable, hanging antennas and racking and stacking equipment is pretty straightforward for an installation contractor. However, there can be interaction among all the different wireless frequencies within the operating environment. This means that you have to have the knowledge required to pull signal data in advance as well as commissioning and optimizing the system. You never want your network interfering with, or being interfered by, other networks in your area.
WaveLengths – Is installing one of the systems within the capability of the average network installer?
Chief Perdue – There are
requirements in the code that
address the capabilities of network
designers as well as the installers
who are actually putting these
Mr. Toenjes – For example, the codes may require that both the system designer and lead installation person have an FCC radio license, certification of in-building system training by an approved organization or school or demonstrate capability in installing public safety in-building communications solutions.
You need to do RF engineering, know how to use design software, and have access to expensive wireless test equipment. All these requirements may be beyond the capabilities of the average installer to turn-key these projects all by themselves.
Fortunately, systems integrators are very often looking to partner with local contractors who have access to potential customers and can do the physical installation. A systems integrator would likely have the FCC licenses and other credentials required to work with these wireless systems. Forming these partnerships enable installation contractors and system integrators to go into this market more effectively.
WaveLengths – What are the typical components that comprise a Public Safety DAS installation?
Mr. Toenjes – First I’ll describe a
“passive” DAS system. The vast
majority of Public Safety DAS is
passive today because the VHF
and UHF frequencies used by
many agencies travel well through
cable and walls.
In a passive system, you would have an antenna on the roof that is pointed at a nearby tower. This so-called donor antenna brings the donated signals from the cell tower into the building. Once inside, the signals are transported, via a coaxial cable, to a bi-directional amplifier (BDA), also called a repeater. The BDA amplifies the signal and also filters out noise that can be caused by signals from nearby frequency bands. A second coaxial cable transports signals from the BDA to splitters that distribute the signals, again via coax, to multiple antennas mounted throughout the building. Finally, the antennas wirelessly broadcast the signals to the portable handsets used by firefighters and other first responders. Of course, signals travel in both directions, which enables two-way communications.
So that describes a passive Public Safety DAS system. There are also active systems, which are used in larger buildings or a campus environment. They are increasingly common, especially as we move toward newer trunked radio systems operating in higher frequencies like 700 or 800 MHz, but also for data networks like FirstNet. These systems use fiber optic cable and coax. The fiber reduces signal loss caused by the longer distances and the many cable splitters typical of a large system. Calling this an active system can be confusing in that optical fiber itself is passive and is often associated with Passive Optical Networks. However, the electronic signal converters used in fiber optic DAS systems have active components.
There isn’t a hard and fast rule but typically at around 100,000 square feet I’m going to have to move to an active-fiber based DAS system. For areas smaller than that, I can probably use passive equipment.
That same building may also have a Cellular DAS installed, probably as a separate system. Both a Cellular DAS and a Public Safety DAS are very similar, but cellular services operate in higher frequencies that don’t penetrate buildings as well so they require more antennas from the DAS.
WaveLengths – How can property owners determine if Public Safety DAS is required in their buildings?
Chief Perdue – They can talk with their local fire marshal or fire inspector to see what is mandated in their jurisdiction. If a Public Safety DAS isn’t yet required in their community, they should give serious consideration to installing it anyway. Just like fire sprinklers, DAS saves lives. Building owners have a moral responsibility to make their buildings safe.
Public Safety DAS vs. Cellular DAS
Chief Perdue and Mr. Toenjes feel that both Cellular DAS and Public Safety DAS are vital for public safety.
WaveLengths – Conceptually, what’s the difference between Cellular DAS and Public Safety DAS?
Chief Perdue – With Cellular DAS, the system has to
have the capacity to serve hundreds or thousands
the cell phone customers that carriers serve in a
specific area. This could be a sports stadium, the
interior of a large office building and so forth. In
contrast, with Public Safety DAS you don’t have to
reach hundreds of people. You just need to ensure
that the signal gets to first responders who are inside
the building, wherever they may be.
Mr. Toenjes – Another difference is that because you need permission from cell carriers to repeat their signals, there is a lot of carrier oversight at every step of the installation process. Also, a Cellular DAS is more complex from a technology standpoint because they are more likely to be active systems, have more frequencies involved, and have to handle both voice and data. In contrast, most Public Safety DAS are simple passive systems and only require approval from the local AHJ.
WaveLengths – Why do you consider both Public Safety DAS and Cellular DAS to be vital to public safety?
Mr. Toenjes – We know that 70% of 911 calls are made
from cell phones. We also know that many people
use their cell phones to call 911 even when they are
standing next to a desk phone. If their cell phone
can’t connect, they’ve just lost a bunch of time. In
an emergency, things get worse with every tick of
the clock. So if a building can’t provide a good cell
signal, it’s an unsafe situation.
I should mention that first responders also rely on Cellular DAS, in addition to Public Safety DAS. For example, a firefighter can use an iPad to download building layouts. Or, when someone suffers a heart attack, an EMT can use a cellular network to transmit EKG data to a doctor at the hospital.
Although not required by code, Cellular DAS is often part of the public safety plan for a building. Cellular DAS and Public Safety DAS complement one another when installed in the same building.
WaveLengths: I’ve read that many public safety experts advocate installing Cellular DAS and Public Safety DAS as separate systems. Do you agree?
Chief Perdue – Yes, in most cases. However, we
should look into that further. At Safer Buildings
Coalition, we are asking manufacturers to begin
exploring whether any system components can be
shared without compromising either system. These
might include antennas, cabling, certain system
components and so forth.
Mr. Toenjes – Local municipalities have a big say on whether or not the two systems can be joined together. For example, in the city of Denver proper, local codes require that these be installed as separate systems. However, in most of the suburbs surrounding Denver you are allowed to put them on the same system.
WaveLengths – Thank you Chief Perdue and Mr. Toenjes, for your insights. I’d like to provide our readers with an update from time to time as Public Safety DAS moves forward.
Chief Perdue – Thank you Charlie. Just contact us for any information you may need. Also, I invite
your readers to learn more by visiting the Safer Buildings Coalition website at
Mr. Toenjes – Yes, and people can contact me directly at firstname.lastname@example.org.