Firefighters and other responders depend on portable radios, and the same building features that block cellular signals can cut them off from their command post. An emergency responder radio coverage system, usually a bi-directional amplifier feeding a distributed antenna system, carries the public safety radio signal throughout the building. Many fire authorities now require one, and their requirements vary, so the first step is always to find out what applies to your building.
Why it matters
During a fire, responders inside a building need to reach incident command outside, and each other, from stairwells, below-grade levels and the middle of large floor plates. Those are exactly the places where radio signals from outdoor sites are weakest. Losing communication during an interior attack or a search is a serious safety problem, and it has been identified as a factor in responder injuries and deaths.
The causes are the same as for poor cellular service: coated glass, concrete, steel and earth. The details are covered in what is a distributed antenna system? The difference is the consequence of failure, which is why public safety systems are held to stricter requirements for reliability, power and monitoring.
Who sets the requirements
There is no single national rule. Requirements come from the local fire authority, sometimes through a municipal bylaw, sometimes through provincial or local adoption of fire and building code provisions, and sometimes as a condition of a building permit or occupancy. Many local requirements draw on NFPA standards for emergency services communication systems, with local changes. The radio system's operator, often a municipal or regional agency, also has to authorise any equipment that retransmits its channels, and equipment must be certified for use in Canada.
Because of that variety, ask the fire authority early, in writing, which requirements apply, which frequencies the system must carry, what testing they expect and who must witness it. Check the current edition of anything they reference.
How a system is put together
A donor antenna on the roof is aimed at the public safety radio site. A bi-directional amplifier (BDA) in a protected room boosts the signal in both directions: down to radios inside, and up from radios back to the outdoor system. A riser and horizontal cabling distribute the signal to antennas on each floor, in stairwells and in other critical areas. The BDA reports faults to the building's fire alarm system or a dedicated annunciator, and a battery keeps it running if normal power fails.
Fire authorities commonly expect some or all of the following. The specifics, including durations and ratings, vary by jurisdiction:
- Backup power that keeps the system running for a set period after normal power fails.
- Monitoring of key conditions, such as amplifier failure, antenna faults, loss of normal power and low battery, reported to the fire alarm system or a dedicated annunciator.
- Protection of the equipment and riser cabling from fire, through rated rooms, rated pathways or survivable cable.
- Enclosures suited to the location, and equipment that will not oscillate or interfere with the outdoor radio system.
- Labelling, as-built drawings and a record of settings kept on site.
The fire alarm connection needs coordination with the fire alarm designer and the verification process; see fire alarm interfaces with HVAC, doors and elevators for how interfaces are typically handled.
Testing and acceptance
Coverage is usually proven with a grid test. Each floor is divided into a grid of roughly equal areas, and a technician measures signal strength and quality at the centre of each one, often both downlink and uplink. Critical areas, such as stairwells, fire command centres, fire pump rooms and exit passageways, are usually held to a higher standard than general floor areas. The fire authority sets the pass criteria and decides whether it wants to witness the test.
After acceptance, systems are commonly retested on a regular schedule, often annually, and after any change that could affect coverage, such as renovations, new partitions or changes to the outdoor radio system. Keep test reports, settings and drawings on site where the fire department can find them.
What the acceptance package usually contains
- The grid test results for every floor, with critical areas identified and any retests shown.
- Donor antenna details, including its location and the signal received from the radio site.
- Amplifier settings, such as gain and output levels, and confirmation that the system does not oscillate.
- Proof that monitoring signals reach the fire alarm system or annunciator, and a battery test.
- As-built drawings, equipment data, authorisation from the radio system operator and the maintenance plan.
A typical case
A new six-storey residential building with one level of underground parking is nearing completion when the fire authority asks for a coverage test. The benchmark survey shows good coverage on the upper floors near the windows, weak coverage in both stairwells and none in the parkade. Because the stairs and parkade were flagged early, the design is small: a donor antenna, a BDA and battery in a rated room, a riser in one stair shaft and a handful of antennas in the stairs and parking level. The grid test passes everywhere except one parkade corner behind a concrete ramp, which is fixed with an added antenna and retested before the results go to the fire authority.
Steps for owners
- Find out what applies. Ask the fire authority whether coverage is required, which requirements and frequencies apply, and what acceptance testing looks like.
- Test the existing coverage. A benchmark survey shows whether a system is needed at all, and where. Some buildings pass without one.
- Design. The design covers the donor link, BDA, riser, antenna layout, power, monitoring and protection, and is coordinated with the fire alarm and electrical design. Design drawings are sealed by a licensed professional engineer where required.
- Get authorisation. The radio system operator approves retransmission of its channels, and the fire authority reviews the design if it asks to.
- Build. Licensed electrical contractors and qualified installers install the system under permit.
- Accept and maintain. Commission, grid test, submit results and set up periodic testing and monitoring.
Common pitfalls
- Leaving the question until late in construction, when risers and rooms are already full.
- Designing to cellular practice and missing survivability, backup power or monitoring requirements.
- Amplifier settings that are too aggressive, causing oscillation or interference with the outdoor system.
- Not planning for the fire alarm interface, so trouble signals cannot be verified.
- No one responsible for the annual test after the building is handed over.
How ehZee can help
We benchmark existing coverage, design responder radio systems around the fire authority's requirements, coordinate with the radio system operator and the fire alarm design, and oversee installation and grid testing. Read more about our distributed antenna systems service, and see passive, active and hybrid DAS for how the distribution can be built.
Common questions
Does every new building need a responder radio system?
No. Where a requirement exists, it usually applies when the building fails a coverage test. Many buildings, especially smaller ones, pass without a system. The fire authority decides what applies.
Can the cellular DAS carry public safety radio too?
Sometimes, if the shared parts meet the public safety requirements for power, protection and monitoring. Many owners keep them separate to avoid compromises on either side.
Do existing buildings have to add one?
It depends on the jurisdiction. Some apply requirements only to new construction or major renovations; others can require existing buildings to comply. Ask the fire authority.