Essential Electrical Systems and Life Safety Systems. Is there a difference between them?   

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The subject of essential electrical systems versus life safety systems is not consistently understood by the users of the Canadian Electrical Code (CE Code, Part I).

I will attempt to separate facts from misconceptions by means of a simple Question and Answer (Q&A) format and will cover answers to 8 questions (quite often,  8 is enough).

Q 1. What is the essential electrical system and where does it apply?

A 1.  Although all definitions of the CE Code are placed in Section 0, some sections provide special terminology that is applicable only under the scope of those specific sections. Essential electrical system applies only to a healthcare facility. CE Code Section 24 covers the installation of electrical wiring and equipment within patient care areas of healthcare facilities (HCFs) and the portions of their electrical systems designated as essential. Section 24 defines essential electrical system in Rule 24-002 as follows:

Essential electrical system: an electrical system that has the capability of restoring and sustaining a supply of electrical energy to specified loads in the event of a loss of the normal supply of energy”.

CSA Z32 “Applications of electricity in health care” (which covers electrical safety and essential electrical systems in HCFs) provides a similar definition.

Q 2.  What does essential electrical system comprise?

A 2.  CE Code Subrule 24-302(1) provides the following requirement on this subject 24-302(1). An essential electrical system shall comprise circuits that supply loads designated by the health care facility administration as being essential for the life, safety, and care of the patient and the effective operation of the health care facility. This requirement of Rule 24-302 states that a typical essential electrical system consists of circuits that supply loads designated by the HCF administrator as being essential for life safety, patient care and overall effective operation of the HCF. It should be noted that Clause 6.1.1 of Z32 offers the following description of an essential electrical system:

6.1.1 The requirements of Clause 6 shall apply to electrical systems that are considered essential for life and fire safety as specified in Article 3.2.7.9 of the National Building Code of Canada (NBCC), for effective and safe patient care, and for the effective operation of the HCF during an interruption of the normal electrical supply for any reason”.

Table 7 of Z32 lists and classifies loads and branches of the essential electrical system. Such classification clearly demonstrates that the first eight items on this list represent applicable components of a life safety system as mandated by the NBCC for any building required to be equipped with such systems, and that the remainder of the list covers specific loads intended to provide reliable patient care (e.g., loads in intensive care units, surgical suits, recovery rooms), and those loads of the entire HCF (outside the patient care area) that are deemed by the HCF administrator to be essential for the effective operation of the entire facility.

Thus, it becomes clear that “life safety systems” become an integral part of “essential electrical system” when such life safety systems are located in HCFs where the loads are designated by the administration “as being essential for the life, safety, and care of the patient and the effective operation of the health care facility”.

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Q 3.  Who is this mysterious entity, “HCF Administrator,” who possesses such sweeping powers to designate loads of essential electrical system?

A 3.  CE Code Section 24 is silent on this subject. However, Appendix B Note on the application of Section 24 (on Rule 24-000) provides reference to Z32, which offers the following definition in this regard:

Administrator: the person responsible for operating the health care facility (or his or her designee). Note: The term “administrator” is used in this standard to denote the authority representing the health care facility and charged with responsibilities specified in this standard. The administrator may (and usually does) delegate these responsibilities to appropriately qualified individuals”.

This fact demonstrates that users of CE Code Section 24 should understand the relevant provisions of Z32 to effectively apply the requirements of CE Code Section 24.

Q 4.  What are the life safety systems and where do they apply?

A 4.  Life safety systems are described and mandated by various NBCC provisions. Equipment comprising these electrically connected life safety systems includes (but is not limited to):

  • fire alarm systems, with or without voice communication capabilities;
  • emergency lighting, exit signs;
  • fire pumps, firefighter elevators;
  • smoke control and smoke venting equipment, including fans and dampers;
  • hold-open devices and electromagnetic locks

NBCC Subsection 3.2.7 requires that the emergency source of power be provided by generators or batteries to equipment such as fire alarm systems, emergency lighting and exit signs.

Article 3.2.7.9 of the NBCC specifically mandates the use of an emergency generator capable of operating under a full load for not less than two hours for life safety equipment such as electrically connected fire pumps, every elevator in a building that is more than 36-metres high, for every firefighter elevator, for smoke control and smoke venting equipment, for fans intended to limit passage of smoke in a vestibule located at an exit opening into interconnected space (e.g.,  atrium), in accordance with NBCC Article 3.2.8.5, and for the mechanical exhaust fans intended to remove air from the interconnected floor space, as specified in NBCC Article 3.2.8.8.

Special terminology provided in CE Code Rule 46-002 offers the following definition of life safety systems:

Life safety systems: emergency lighting and fire alarm systems that are required to be provided with an emergency power supply from batteries, generators, or a combination thereof, and electrical equipment for building services such as fire pumps, elevators, smoke venting fans, smoke control fans, and dampers that are required to be provided with an emergency power supply by an emergency generator in conformance with the National Building Code of Canada”.

Provisions of Rule 46-108 for wiring life safety systems apply to all buildings where they are mandated by the NBCC. Where such life safety systems are installed in an HCF, these life safety systems become part of the HCF essential electrical system, and additional separation of wiring connecting loads of life safety systems in an HCF from wiring to other loads of the HCF essential electrical system is unnecessary, as all wiring of the essential electrical system must be installed separately from all other wiring in accordance with Rule 24-302(3). It should be noted that, from the perspective of good engineering practice (and not from CE Code safety requirements), it is advantageous to separate circuits supplying vital, delayed vital, and conditional branches in an HCF so as to facilitate effective and reliable operation.

Q 5.  Is it permitted for a fire alarm system, emergency lighting and exit signs installed in an HCF to be provided with an emergency power supply source, such as battery (as indicated in Q4)?

A 5.  When a fire alarm system, emergency lighting and exit signs are installed in an HCF, and such life safety systems are part of the HCF’s essential electrical system, the emergency power supply source for the essential electrical system loads must be an emergency generator conforming to CSA C282 “Emergency electrical power supply for buildings” as stated in CE Code Rule 24-306. Of course, a typical central battery or UPS could be used as a temporary backup to the required emergency generator but these additional power supply sources should under no conditions be used as a substitution for the required emergency generator.

Q 6.  What are minimum required components of a typical fire alarm system?

A 6.  Clause 3.1.1 of ULC S524 “Installation of fire alarm systems” states that a fire alarm system must comprise at least the following interconnected devices:

  • control unit
  • manual station
  • audible signal device

Of course—depending on type of building occupancy classification—a fire alarm system would be required to be equipped with voice communication capabilities, visual signal devices, various fire detectors (including sprinkler waterflow-detecting devices), annunciators, and central alarm and control. NBCC Subsection 3.2.4 provides specific requirements in this regard.

Q 7.  What is electrical supervision of  fire alarm systems?

A 7.  Electrical supervision is a specific means of detecting abnormal conditions on a fire alarm system (e.g., open circuit, short circuit, ground fault, movement of a valve handle that controls the water supply in a standpipe or sprinkler system, loss of power to a fire pump). The definition of electrical supervision is provided by ULC S524. Clause 3.3 of ULC S524 lists all components of fire alarm system wiring that must be electrically supervised. In addition, NBCC Article 3.2.4.10 requires that electrical supervision must be provided for fire suppression systems (such as a standpipe or sprinkler system) and that such supervisory signals must be indicated on an annunciator of the building fire alarm system. It should be noted that the operation of all components of a fire alarm systems (including electrical supervision) must be verified in accordance with ULC S537 “Verification of fire alarm systems” upon completion of the installation. This requirement is mandated by Sentence 3.2.4.5.(2) of the NBCC.

Q 8.  Are hold-open devices, electromagnetic locks, smoke control and smoke venting equipment part of a fire alarm system?

A 8.  This equipment is considered by ULC S524 as “ancillary devices:  a device which has life safety application, and is activated by the fire alarm system, but is not part of the fire alarm system”.

Ancillary devices are not subject to the electrical supervision requirements, as they are not integral components of a fire alarm system. A verification procedure of a fire alarm system also includes a review as to whether a signal is sent to each ancillary device upon fire alarm system activation. However, evaluating the operation of these ancillary devices (equipment “which has life safety application” by the ULC S524 definition) is done—not via fire alarm verification—but by the field commissioning of these integrated life safety systems, as required by NBCC Article 3.2.4.6. Thus, wiring to these ancillary devices does not have to comply with CE Code Section 32, as such life safety equipment is not an integral part of a fire alarm system. Note that signals to the fire department cannot be electrically supervised by a fire alarm system. When a fire alarm system is activated, an output signal is sent via this system to a transmitter. The transmitter, communication channels between it and a monitoring station, and the facilities containing the monitoring station are components of the ULC listed “Fire signal receiving centres and systems,” conforming to ULC S561 “Standard for installation and services for fire signal receiving centres and systems” (see NBCC Sentence 3.2.4.8.[4]). Electrical supervision of communication channels is provided at the monitoring station.

Hopefully, these eight Q&As are enough to provide some clarity around essential electrical systems, life safety systems, and fire alarm systems. In each particular case, however, a relevant authority having jurisdiction (AHJ) should be consulted.