Special occupancies: high buildings, hospitals and residential suites

Most of what the crew installs follows the same general rules wherever it goes. But some buildings change the rules, because the people inside them can't simply walk out when the alarm sounds. In a high building, it takes too long to evacuate everyone at once, so occupants are moved in stages and firefighters need to control the system from one place. In a hospital, patients are protected where they are, or moved horizontally to another part of the floor. In an apartment building, people are asleep behind closed doors and each suite has its own alarms. Gerry's evening class on special occupancies starts with a question for Sasha: 'Which of our buildings fall into each group?' She works it out: Riverlight Tower is a high building with residential suites, Eastview is a hospital, and the north wing is both a hospital and, at six storeys with its penthouse, close to the high-building threshold. This lesson covers how the installation rules change in these buildings.

High buildings

The National Building Code, Subsection 3.2.6, applies extra requirements to high buildings: generally those more than 36 m from grade to the floor of the top storey, and some buildings with large assembly or care occupancies above a lower height. For the fire alarm, these requirements include a voice communication system so that occupants can be instructed floor by floor, a central alarm and control facility from which firefighters monitor and control the fire alarm, voice system, elevators, fans and other systems, firefighters' telephones or another two-way communication system, and fire protection for the conductors that link the control equipment, as FAT-130 covered. Evacuation in a high building is usually staged: the fire floor and the floors next to it are evacuated first, while other floors receive an alert.

For the installer, staged evacuation means the system is zoned and wired so that floors can be signalled separately, the voice system's speaker circuits are arranged by floor and by evacuation zone, and the risers that connect the floors survive a fire long enough to keep the other floors informed. A single speaker circuit serving two floors would make staged evacuation impossible, and a riser without the required protection could leave floors above the fire with no signal.

The central alarm and control facility at Riverlight Tower is a room off the main lobby, close to the firefighters' entrance, containing the fire alarm control unit, the voice system's controls and microphone, the firefighters' telephone panel, the elevator status panel and the smoke control panel. The building code and the authority set its location and contents; the installation standard sets how the fire alarm equipment in it is installed. Its layout is agreed with the fire department, because firefighters will use it under stress.

Voice systems and firefighters' communication

Voice systems are covered in detail in FAT-310. For the installer, their special feature is that speakers are arranged in circuits by evacuation zone, each circuit's amplifier power and wiring sized for its speakers' taps, and the speaker circuits supervised like notification circuits. Intelligibility, not just loudness, is what matters in a voice system, and it depends on speaker placement and the acoustics of each space, so the designer's speaker layout must be followed closely. Moving a speaker into a reverberant stairwell because it was easier to mount there can make messages unintelligible.

Firefighters' two-way communication can be a wired telephone system, with jacks or handsets at each floor's stair, or a radio system that ensures firefighters' radios work throughout the building. The building code and the authority decide which; many newer buildings rely on emergency responder radio coverage, which is a separate system tested to its own standard. Where wired telephones are used, their circuits are supervised and their jacks or handsets are installed at the locations the code specifies, usually in each exit stair.

Hospitals: protect in place

Hospitals and other care and treatment occupancies are designed so that patients can stay in place or be moved horizontally to another zone of the same floor, rather than evacuated down the stairs. The National Building Code requires patient floors to be divided into zones by fire separations so that patients can be moved across the separation, and it permits the fire alarm system to be two-stage, with alert signals to staff and a general alarm only if needed. CAN/ULC-S524's rules for two-stage systems govern how the alert and alarm signals and the acknowledge and silence functions are arranged. The fire alarm is zoned to match the building's fire separations and smoke compartments, so that the annunciator tells staff and firefighters which zone the fire is in, and doors in the separations close on alarm.

For the installer, zoning to match the compartments means checking that no zone, and no addressable device's description, spans a separation or smoke barrier, and that the doors in each barrier have door holders or closers controlled by the fire alarm. When the north wing's walls went up, one corridor smoke barrier moved two rooms west from where the early drawings showed it; three detectors that had been described as 'east compartment' were now in the west one, and their descriptions and zones had to be changed before programming was finished.

# Smoke compartment check for a hospital floor (limits: illustrative design limits; use the adopted code and the design)
max_area = 2000      # m2
max_travel = 60    # m to a door in the separation or smoke barrier
compartments = [("3N-west", 1650, 48), ("3N-east", 1980, 63), ("3N-surgery", 1200, 35)]
for name, area, travel in compartments:
    issues = []
    if area > max_area: issues.append(f"area {area} > {max_area}")
    if travel > max_travel: issues.append(f"travel {travel} > {max_travel}")
    print(f"{name:11s}", "OK" if not issues else "; ".join(issues))

3N-west     OK
3N-east     travel 63 > 60
3N-surgery  OK

The draft layout shows the east compartment's travel distance just over the limit, which is the architect's problem rather than the fire alarm's, but it matters to the crew: if the architect moves the barrier to fix it, the fire alarm zoning and device descriptions move with it. Sasha flags it to Ravi.

Hospitals also have areas that need special detection. Operating rooms and some laboratories have high air change rates that make spot smoke detectors unreliable, so detection may be in the return air ducts or use air-sampling systems. Patient rooms in psychiatric units need tamper-resistant devices. Medical gas and oxygen-enriched areas need equipment suitable for the location. The design addresses each, and the installer follows the specific devices and locations the design calls for.

Residential suites

In apartment buildings like Riverlight Tower, each suite has smoke alarms, which are separate from the building's fire alarm system: they sound only within the suite, so that a burnt dinner doesn't evacuate the building. The National Building Code requires them, and they are installed under their own standard. The building's fire alarm system provides the general alarm in the suites, through audible devices in each suite or in the corridor loud enough to reach the bedrooms with doors closed, and may include heat detectors in suites. The two systems must be installed so that the building's alarm is heard in each sleeping room, which is often why suites get their own sounder bases or speakers. Some suites' smoke alarms may be required to be connected to the fire alarm system to transmit a supervisory or alarm signal, depending on the building, and CAN/ULC-S524 sets how that is done.

For the installer, the main points are to keep the suite or unit smoke alarms and the building system distinct, to install the building's audible devices where the design shows them so that bedrooms get the required level, and to use the low-frequency signal and high-intensity strobes Lesson 5 described in sleeping rooms where required. Audibility is checked in the bedrooms with the doors closed, which in an occupied building means arranging access with the residents or the building manager well in advance.

Other special cases

Some buildings combine occupancies, such as Riverlight Tower's ground-floor shops below its apartments, and each part follows its own rules where they differ. Buildings with large assembly spaces, such as theatres and arenas, often need voice systems and special notification arrangements so that a crowd can be addressed calmly. Schools need visual signals in areas where hearing-impaired students may be, and attention to manual stations that students might misuse. Warehouses like Cartwright rely heavily on sprinkler waterflow for detection, with detection in offices and electrical rooms. In each case, the building code sets the requirement and the installation standard sets the method.

Existing buildings being converted, such as an office floor turned into a medical clinic, can suddenly fall into a special occupancy and need features the original system never had. Sasha learns to check the occupancy shown on the permit drawings before assuming the old system's arrangement still applies.

Assembly occupancies and crowds

Large assembly spaces, such as auditoriums, gymnasiums used for events and places of worship, raise their own notification problems. A sudden, loud alarm in a packed room can cause panic, and a crowd may not respond to a horn the way an office does. The building codes often require voice communication in large assembly occupancies, so that staff or recorded messages can give clear directions. Visual signals in large rooms are arranged so that they can be seen from every seat, which often means strobes on several walls rather than just at the exits.

Willowbank School's gymnasium is used for assemblies and community events in the evenings. When its summer addition was designed, Ravi checked whether its occupant load triggered a voice requirement; it didn't, but the design placed horn-strobes on three walls and confirmed audibility with the room's folding bleachers both open and closed, because the bleachers change the acoustics.

Child care and schools

Schools and child care facilities have young occupants who depend on staff to lead them out. The codes generally require manual stations, audible and visual signals throughout, and in some cases detection in specific rooms. Manual stations in schools are a frequent target of false alarms, so designs often use protective covers with local horns, which the installer mounts as the listing shows. Visual signals in classrooms are especially important for students with hearing loss, and the design places them so that they can be seen from desks, not only from the door.

Detention and secure areas

Areas where occupants are held under security, such as the psychiatric unit's secure rooms, have occupants who can't leave on their own and may try to damage devices. The codes allow staff-operated manual stations and tamper-resistant detectors in these areas, and require staff to be able to release locks, as Lesson 8 covered. Devices are mounted with security fasteners and placed out of reach where the design allows. The installation details are set by the design, often with input from the facility's security staff, and the installer follows them precisely: a standard device with a standard screw in a secure room is a ligature or tampering risk as well as a fire alarm deficiency.

The common thread through all these special cases is that the occupants' ability to respond determines the system's design. The installer's role is to make sure that what is installed matches that design exactly, because each special feature exists for a reason that may not be visible on the device itself.