ServicesTechnologyLife Safety – First Responder Radio CoverageAnswers to Frequently Asked First Responder Radio Questions

Answers to Frequently Asked First Responder Radio Questions

What happens when a building fails?

At this point in the project a distributed antenna system (DAS) incorporating bi-directional amplifiers (BDAs) to boost, enhance, and increase the coverage must be designed and installed. The code has specific requirements for certification to design and install these systems as well as requirements for fire alarm monitoring of the system components. This solution cannot be met by one entity. Drawings must be submitted for permit and fire code official approval with a PE seal. JDRM has aligned with a number of strategic partners to form a design/build team to implement and execute a code compliant system and get competitive pricing for your project.

How do I plan during design for the cost and construction impact a FRR/DAS system will have on my building when I do not know if I need one due to not being able to test until the structure is up?

This question comes up often and is extremely important. There are several options the JDRM FRR Testing team suggests:

  1. Allocate construction dollars and retain them throughout construction to install an enhanced system. We recommend $1.00-$1.50 per square foot. Also, obtain a quotation for testing the building during the design phase and procure a contract to test as early as possible.
  2. Contact the fire code official to see if they will waive the requirement. There are provisions in the code and conditions that may warrant a waiver.
  3. Consider pre-testing of existing buildings or pre-testing of greenfield sites to ascertain signal strength prior to building. This information may help determine ahead of time the probability of a system requirement. Another method would be to do a predictive analysis via IBWAVE software program that will predict how well the RF signal may penetrate the building.
  4. Allocate space requirements in the building and construct proper infrastructure to house the BDA’s. Code requires BDAs to be located in a 2-hour rated room and depending on the number of frequencies and quantity of BDAs, substantial wall space may be required to house the equipment.
  5. Consider creating and/or installing raceways, chases, etc. for the roof-mounted donor antennas, horizontal cabling, and other components. Waiting until the building is completed can prove costly or difficult to get raceways in later.
  6.  Test as early as possible for code required signal strength. We suggest that the building envelope be complete, all interior partitions erected with unfinished drywall, ductwork, piping and other components installed. Ceilings need not be installed and in fact, is better if they are not. This will allow routing of DAS cabling if it is determined that a system needs to be installed.
  7. Include in your design specifications, for new and remodeled buildings, FRR testing and include this cost as part of the construction bid.
  8. Require independent third-party testing. Do not let the firm selling and installing the DAS system perform the testing (don’t let the fox watch the hen house). Obtain and retain a professional, PE-sealed test report. Do not accept hand-written test results scribbled on a scratch pad because the code requires these records be kept and maintained, just like other building system inspection reports.

Should I just design a system for complete building coverage while I’m designing the rest of the building?

Unlike other code requirements, emergency communications systems for first responder radio should not be designed up front without testing results. We see a number of specifications requiring a bid for a system without any testing being conducted or test results provided. Though this will get you a price, it is not necessarily an accurate price. There are a number of issues with this approach:

  1. The code only requires enhancement of failed areas, not the entire building. We have seen many buildings fail only on one floor or on one side and not the entire floor. Pricing and designing a system for the entire building may prove to be unnecessary, resulting in elevated costs.
  2. Accurate designs are not necessarily obtainable if the signal strength values and deficiencies are not known. The designer needs to know how much amplification of the signal is required. Without these values upfront, one may over-design or under-design a system.

My building has a DAS/BDA system for FRR, what do I need to know about the maintenance and testing of this system?

  • The new 2017 OFC requires that DAS/BDA systems and their components be inspected and tested annually just like a fire alarm system, sprinkler system, or emergency lighting systems. The fire code official can enforce this and issue citations if required.
  • Budget for inspection and re-testing like you do for any other building system.
  • Keep your records. Just like fire alarm and emergency lighting testing, the test results for DAS/BDA systems need to be kept, logged and maintained.

Why or when do I need to re-test?

The Code requires systems to be inspected and re-tested annually. This includes testing the hardware and the batteries under load to be sure the BDE (bi-directional amplifier) is in conformance to the original specifications.

Several reasons besides the code required annual test may occur and require you to re-test.

  • The FRR frequencies may change. Fire departments or other first responders may change their radio system and/or frequencies. Many departments change from analog to digital or from one frequency to another like the Ohio MARCS system. This will require retesting and perhaps re-design of your DAS/BDA system.
  • You may get a new neighbor who builds a building that blocks your signal coming into your building. (In Seattle, WA, code requirements state that your neighbor pays for required changes to your system.)
  • Other environmental elements may impact coverage. Surprisingly, we’ve found pine trees absorb RF signals. Your evergreen trees may have grown and this can impact your signal levels.
  • Window replacement/upgrades have significant effects on RF signals. Low E glass will block RF signals from – 35dB to as much as -56dB. Replacing windows or adding a new atrium will have a major impact on your signal level.

Can I put cellular coverage on this system and use it for my maintenance radios?

There is no easy “yes” or “no” answer to this. It depends on the frequencies, your carriers, certain signals are not recommended to be mixed together on the same system — and there are more factors to consider. Please call us, we’ll be happy to guide you through that process.

When has your team been surprised?

By LOTS of Windows:  Generally, when the first floor of a building passes FRR testing, the higher levels do as well. We have experienced a testing situation where this was NOT true. The first floor passed our tests, but the higher floors did not, due to an abundance of windows in the upper stories. Low E- Energy saving glass windows can block RF by -35 to -56Db. Adding a BDA DAS enabled the facility to meet code by bringing the signal strength to the proper levels inside the building.

We Can’t Amplify What isn’t Available: Initial signal tests failed when low failing signal was identified while testing outside of a facility in an industrial park. Our work turned from testing the facility to coordinating with state and local authorities to coordinate enhancing the state radio system to enable our client to meet code requirements.