Fire Alarm System (FAS): Extent Of Electrical Supervision & FAS Application In A Building
Ark Tsisserev, Principal
Apparently, the subject of this article is of interest to quite a few readers as I have received several questions in this regard. In this article, I’ll try to answer the following questions received on this subject:
1. Is a pre-action system conforming to NFPA 13, required to be electrically supervised by a FAS?
2. Is a stand-alone dry type fire suppression system required to be electrically supervised by a FAS?
3. Is a heat tracing system installed on a wet sprinkler system piping required to be electrically supervised by a FAS?
4. Is an emergency generator required to be electrically supervised by a fire alarm system?
5. Are positions of smoke dampers required to be electrically supervised by a FAS?
6. is activation of smoke control and smoke venting equipment required to be electrically supervised by a fire alarm system?
7. Are electromagnetic locks, hold open devices and elevator homing required to be electrically supervised by a FAS?
8. Is a single fire alarm system allowed to serve only a portion of the building?
9. Is more than one FAS allowed to serve a single building?
10. Is a single fire alarm system allowed to serve more than one building?
Before we discuss the posted questions, let’s review the provisions of the ULC S524 “STANDARD FOR INSTALLATION OF FIRE ALARM SYSTEMS” and review the requirements of the National Building Code of Canada (NBC) regarding electrical supervision.
ULC S524 defines “fire alarm system” and “electrical supervision” as follows:
3.41 FIRE ALARM SYSTEM – A combination of interconnected devices consisting of at least a control unit, a manual station and an audible signal device, designed to warn the building occupants of an emergency fire condition.
ELECTRICAL SUPERVISION – A means whereby a fault condition which would interfere with the operation of a circuit in a fire alarm system is detected.
Clause 4.3 of ULC S524 mandates the following requirements for electrical supervision:
4.3 ELECTRICAL SUPERVISION
4.3.1 General
4.3.1.1 Electrical supervision of the wiring shall be provided to the following:
A Manual stations;
B Fire detectors;
C Water flow devices;
D National Building Code of Canada required supervisory devices for water based fire protection systems;
E Audible signal devices;
F Visible signal devices;
G Voice communication equipment;
H Emergency telephone handsets;
I Primary power supplies and emergency power supplies;
J Power supplied to field devices;
K Annunciators;
L Display and control centres; and
M Common fault indication from the engine driven generator, as required by Clause 4.2.4.2.
It is clear from the ULC S524 requirement indicated above, that all wiring for devices comprising a fire alarm system proper (i.e., fire alarm initiating devices, control units, transponders, equipment operating as Central Alarm and Control Facility, fire alarm audible and visual signal devices and fire alarm voice communication devices, such as emergency telephones and voice communication speakers), is subjected to the electrical supervision.
The NBC offers additional requirements for electrical supervision in Article 3.2.4.9. (particularly in respect to supervisory devices for water-based fire protection systems), as follows:
3.2.4.9. Electrical Supervision
(1) Electrical supervision shall be provided for a fire alarm system.
(2) If a fire alarm system in a building is required to have an annunciator by Sentence 3.2.4.8.(1), except for hose valves, all valves controlling water supplies in a standpipe system shall be equipped with an electrically supervised switch for transmitting a trouble signal to the annunciator in the event of movement of the valve handle.
(3) An automatic sprinkler system shall be electrically supervised to indicate a supervisory signal on the building fire alarm system annunciator for each of the following:
(a) movement of a valve handle that controls the supply of water to sprinklers,
(b) loss of excess water pressure required to prevent false alarms in a wet pipe system,
(c) loss of air pressure in a dry pipe system,
(d) loss of air pressure in a pressure tank,
(e) a significant change in water level in any water storage container used for firefighting purposes,
(f) loss of power to any automatically starting fire pump (see Note A-3.2.4.9.(3)(f)), and
(g) a temperature approaching the freezing point in any dry pipe valve enclosure or water storage container used for firefighting purposes.
(4) A fire pump shall be electrically supervised as stipulated in NFPA 20, “Installation of Stationary Pumps for Fire Protection.”
(5) Indication of a supervisory signal in accordance with Sentence (3) shall be transmitted to the fire department in conformance with Sentence 3.2.4.7.(4).
So, it could be seen from the provisions above, that wiring to all devices which represent a fire alarm system, must be electrically supervised.
These devices (in addition to manual stations, smoke/heat detectors, audible, visual signal devices and voice communication devices and in addition to control units, annunciators and transponders) also represent water flow detecting devices, which detect a water flow in a sprinkler system, as such water flow detecting devices are integral components of a fire alarm system.
Therefore, all components of a fire alarm system, which are subjected to a verification to ULC standard ULC S537 “Verification of Fire Alarm Systems”, must be electrically supervised, and therefore, all supervisory conditions, shown in Sentences 3.2.4.9.(3) and (4) of the NBCC above, and all abnormal conditions (such as faults or open circuits), must be indicated on a fire alarm system annunciator by trouble or supervisory signals.
Thus, all components of a FAS in the upper portion (shown inside the dotted line) in the figure above, are subjected to an electrical supervision, as each such component is an intrinsic part of a fire alarm system.
Now is the appropriate time to answer the posted questions regarding electrical supervision.
1. Is a pre-action system conforming to NFPA 13, required to be electrically supervised by a FAS?
Standard NFPA 13, “Installation of Sprinkler Systems” recognizes that a sprinkler system may be provided with a pre-action component. This “pre-action” component or pre-action system keeps a designated portion of sprinkler system dry (usually in the area where a sensitive communication equipment is installed), and it will allow for automatic opening of a valve controlling water supply to this portion of the sprinkler piping, if dedicated smoke detectors in the controlled area, are activated. As this pre-action system is an integral part of a sprinkler system, which is required to be electrically supervised by Sentence 3.2.4.9.(3) of the NBC, then the pre-action system also must be electrically supervised. Therefore, upon actuation of a pre-action system, a supervisory (but not an alarm) signal must be provided at the fire alarm system annunciator. If, however, a flow switch is activated in this portion of the sprinkler piping (i.e., if the water flow is detected), then a fire alarm signal will have to be initiated, and actuation of the particular flow switch will be indicated on the fire alarm annunciator by a dedicated fire alarm initiating zone, as required by Articles 3.2.4.8. and 3.2.4.15. of the NBC.
2. Is a stand-alone dry type fire suppression system required to be electrically supervised by a FAS?
A typical dry type fire suppression system is not required to be electrically supervised by a FAS in accordance with the NBC, as such dry fire suppression system is not a part of a sprinkler system, and its operation has nothing to do with operation of a building FAS. If a proponent wants to incorporate electrical supervision of a dry type fire suppression into operation of a building FAS, this approach should be discussed with local AHJ for each particular project.
3. Is a heat tracing system installed on a wet sprinkler system piping, required to be electrically supervised? When portions of wet sprinkler supply mains are subject to freezing, the pipe must be protected against freezing by reliable heat-generating systems capable of maintaining a minimum temperature of plus 4.4 Deg. C.
NFPA13 recognizes that heat tracing cables approved for application on fire protection piping, could be used – to maintain the required temperature level. As such, heat tracing cable system becomes a component of a sprinkler system, (and as we already know that the latter is required by the NBC to be electrically supervised). Therefore, operation of the heat tracing cable system installed on sprinkler piping, also must be electrically supervised similarly to the conditions listed in Sentence 3.2.4.9.(3) of the NBC.
4. Is an emergency generator required to be electrically supervised by a fire alarm system?
When an emergency generator is selected as an emergency power supply source for a building FAS, then electrical supervision of this emergency generator is required by Clause 4.3.1.1 (I) of ULC S524 (see above). Clause 4.2.4.2 of ULC S524 clarifies that a single common supervisory signal must be provided at the FAS annunciator as follows:
4.2.4.2 Where the emergency power supply is an engine-driven generator, a warning condition from the generator safety control panel shall provide a supervisory signal on the fire alarm system indicating a common generator fault condition.
5. Are positions of smoke dampers required to be electrically supervised by a FAS?
Smoke dampers, similarly to other life safety equipment, automatically activated by a fire alarm system, are no part of a FAS proper. These ancillary devices are outside of fire alarm system supervisory circuits, and their operation cannot be electrically supervised by a fire alarm system, but it could be validated only by functional testing required by Articles 3.2.6.9. or 3.2.9.1. of the NBC. Bottom portion of Figure shown above, describes this type of equipment as “ancillary devices”. This description is consistent with definition of “ancillary devices” provided by ULC S524 as follows:
ANCILLARY DEVICE – A device which has a life-safety application, and is activated by the fire alarm system, but is not part of the fire alarm system.
6. Is activation of smoke control and smoke venting equipment required to be electrically supervised by a fire alarm system?
No, activation of smoke control and smoke venting equipment is not required to be electrically supervised by a fire alarm system (see explanation in the answer to question 5 above).
7. Are electromagnetic locks, hold open devices and elevator homing required to be electrically supervised by a FAS?
No, release of electromagnetic locks and hold open devices, and elevator homing is not required to be electrically supervised by a FAS (see explanation in the answer to question 5 above).
8. Is a single FAS allowed to serve only a portion of the building?
Sentence 3.2.4.2.(4) of the NBC allows installation of a fire alarm system – to serve only a specific portion of a building (and not the entire building) under the following conditions:
(4) Except as required by Sentence (5), the requirements in this Subsection are permitted to be applied to each portion of a building not more than 3 storeys in building height, in which a vertical fire separation having a fire-resistance rating not less than 1 h separates the portion from the remainder of the building as if it were a separate building, provided there are no openings through the fire separation, other than those for piping, tubing, wiring and totally enclosed noncombustible raceways.
9. Is more than one FAS allowed to serve a single building?
No. Except as indicated in the answer to question 8 above, the NBC mandates installation of a single fire alarm system in a building – to serve all occupancies of the building, see Sentences 3.2.4.2.(2) and (3) as follows:
3.2.4.2.(2) Except as permitted by Sentence (4), if a building contains more than one major occupancy and a fire alarm system is required, a single system shall serve all occupancies.
3.2.4.2.(3) Except as permitted by Sentence (4), if a fire alarm system is required in any portion of a building, it shall be installed throughout the building.
10. Is a single FAS allowed to serve more than one building? The NBC recognizes that in accordance with the fire safety plan accepted by the AHJ, there may be situations when a campus consisting of numerous buildings under a single ownership and single control, may have a single dedicated fire department response point at a specific location, where a common annunciator could be installed for use by the fire respondents. Examples of such situations could be campuses for schools, hospitals, colleges, and similar occupancies. As such, the NBC does not specifically restrict installation of a single FAS to a single building, see Sentence 3.2.4.1.(1) below:
3.2.4.1. Determination of Requirement for a Fire Alarm System (1) Except as permitted in Sentences (2) and (3), a fire alarm system shall be installed in buildings in which an automatic sprinkler system is installed.
Hopefully, answers provided to the posted questions, clarifies this subject. However, local AHJs administering legally adopted building code, should be consulted regarding each specific project as necessary.
This article was originally featured in Electrical Line Magazine.