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Essential Electrical System — Who is to say?

Posted By Ark Tsisserev, Sunday, July 01, 2012
Updated: Friday, September 07, 2012

No, really — who is to say? Where is such entity defined or described? The answer could be found in two following documents:

  1. In the CSA standard Z32, which is actually called Electrical safety and essential electrical systems in health care facilities; and
  2. In Section 24 of the Canadian Electrical Code which covers installation of electrical equipment in patient care areas.

Photo 1. An essential electrical system consists of loads and branches listed in Table 7, and such loads represent a combination of the electrical equipment comprising "life safety systems” defined and described in Section 46, CE Code, and electrical equipment essential for care of the patients for effective operations of the health care facility (i.e., electrical equipment that in addition to life safety systems is also supplied by vital, delayed-vital or conditional branches).

CSA standard Z32 offers the following definition of essential electrical system: "Essential electrical system — an electrical system that has the capability of restoring and sustaining a supply of electrical energy to specified loads if the normal supply of energy is lost.”

Clause 6 of Z32 is dedicated to all aspects of an essential electrical system including normal and emergency power supply arrangements and redundancy of power sources, requirements for transfer of power and for the maintenance and repair of transfer switches. Table 7 of Z32 lists types of the essential electrical system loads and branches and subdivides these branches for the purpose of life/public safety and patient care as vital, delayed vital and conditional branches.

Section 24 of the CE Code also offers almost identical definition of an essential electrical system and provides a clear description of the circuits comprising the essential electrical system and the requirements for wiring to these circuits.

However, let’s find out what these two documents are about. Scope of CSA standard Z32 states the following:

1.1.1 Application
This Standard deals with the following subjects:
(a) electrical safety associated with health care provision; and
(b) essential electrical systems for health care facilities.

Note: See Clause 3 for the definition of "health care facility”.

It is interesting to note that the reference to the definition of health care facility appears immediately at the outset of the scope of this standard, as a misapplication of this document is a very common occurrence. Clause 1.1.2.1 of the scope advises the users of this standard that the standard is not intended to be applied to veterinary facilities.

1.1.2.1 This Standard is not intended to apply to veterinary facilities, although its electrical safety principles could prove useful in the design, construction, and operation of such facilities.

The scope of this standard also describes the relationship with the applicable provisions of the Canadian Electrical Code as follows:

1.1.3 Provisions of this Standard are supplementary to the installation requirements specified in Sections 24 and 52 of the Canadian Electrical Code, Part I.

So far, so good. But how far is the scope of this standard intended to apply in a typical hospital? Would it cover such areas as a parking garage, offices, cafeterias, etc.?

The answer is provided in Clause 1.2.1 as follows:

1.2.1 This Standard applies to (a) patient care areas of Class A, Class B, and Class C health care facilities; and (b) areas outside health care facilities that are intended for patient diagnosis, treatment, or care involving intentional electrical contact of any kind between patients and medical electrical equipment.

Let’s take a look at the definition of health care facility and at the types of such facilities under the scope of this standard. This could help us in understanding whether a typical chiropractor’s office, dental hygiene office or a massage/physiotherapy office in a strip mall would fall under the scope of this standard.

Z32 offers the following definitions of health care facility and of specific classes of a health care facility:

Health care facility (HCF) — a set of physical infrastructure elements supporting the delivery of specific health-related services.

HCF, Class A — a facility, designated as a hospital by the government of Canada or the government of a Canadian province or territory, where patients are accommodated on the basis of medical need and are provided with continuing medical care and supporting diagnostic and therapeutic services. Note: Class A facilities include acute and complex care.

HCF, Class B — a facility whose residents cannot function independently because of a physical or mental disability and are accommodated because they require daily care by health care professionals.
 
Note: Class B facilities provide, e.g., extended, multi-level, hospice, psychiatric, or intermediate care. The definition includes rehabilitation facilities.

HCF, Class C — a facility where ambulatory patients are accommodated on the basis of medical need and are provided with supportive, diagnostic, and treatment services.

Note: Class C facilities include, e.g., outpatient and surgical clinics, dental offices, doctors’ clinics, private residences, and group homes.

These definitions clearly explain that both a huge hospital with the most comprehensive surgical, diagnostic and treatment infrastructure and a private residence where only a basic supportive medical care could be provided, would fall under the scope of this standard. This means that essential electrical systems (with all subsequent requirements for its installation and operation) would have to be arranged not only for the large hospital with dozens of operating rooms and variety of intensive care units, but also for a basic doctor’s office or even a group home.

The latter proposition sounds quite intimidating, as there are not too many (may be none) doctors’ offices or physiotherapy offices located in a typical retail mall or a typical office building that would be provided with all electrical infrastructure that comprise loads of a defined essential electrical system.

Perhaps, now a couple of other definitions of Z32 would be handy, as these definitions could help the readers to understand the extent of application of the essential electrical system described in Clause 6 of Z32 and in Rule 24-302 of the CE Code. These definitions deal with a very unique entity which is referenced by Clause 6 of Z32 and by Rule 24-302 in respect to essential electrical system. This entity is "administrator” or "administration” of a health care facility.

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.

Health care facility administration — the unit responsible, under the authority of a health care facility governing board, for planning, organizing, directing, and controlling the health care facility in accordance with the bylaws of the health care facility, the policies of the health care facility governing board, and government statutes, regulations, and directives.

So, why these two definitions are so critical for the purpose of the extent of essential electrical system for a particular class of a health care facility (or even for the applicability of essential electrical system for the health care facility)? The answer could be found in the scope of Clause 6 of Z32 as follows:

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, 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.

6.1.2 The requirements of Clause 6 shall also apply to those portions of an HCF in which the interruption of the normal supply of power to the essential electrical system loads described in Table 7 would produce unacceptable risk to the effective and safe care of patients.

Notes:
(1) Essential electrical systems should not be automatically deemed necessary for areas where the risk to patient safety is not dependent on the availability of the electrical supply. It is intended by Clause 6 that the administrator of an HCF may determine a need to comply with provisions of Clause 6 for the specific areas of the HCF.

First of all, let’s dissect the scope of Clause 6.
 
Clause 6.1.1 indicates that all its requirements apply to:
 
(a) the life safety systems that is mandated by the National Building Code of Canada (NBCC) to be provided with emergency power supply (i.e., to the life safety systems defined and described by Section 46 of the CE Code), and

(b) other electrical equipment that is essential for the effective operation of a health care facility during an interruption of the normal electrical supply.

The scope also states (Clause 6.1.2) that in addition to the life safety systems mandated by the NBCC, to the electrical equipment required to provide effective patient care in patient care areas proper, the components of an essential electrical system could be as well outside patient care areas, but in these locations loss of a normal power supply to the electrical equipment may also produce unacceptable risk to the effective and safe care of patients.

So, the scope of Clause 6 advises the users that essential electrical system consists of loads and branches listed in Table 7, and that such loads represent a combination of the electrical equipment comprising "life safety systems” defined and described in Section 46 of the CE Code and electrical equipment essential for care of the patients and for effective operations of the health care facility (i.e., electrical equipment that in addition to life safety systems is also supplied by vital, delayed-vital or conditional branches). Note: Vital, delayed-vital and conditional branches are defined in Z32 and in Section 24 of the CE Code.

Secondly, let’s carefully review Note (1) on the Scope of Clause 6 of Z32 "Essential Electrical Systems.” This Note is extremely important. It advises users of this standard that the essential electrical systems are not intended to be automatically invoked for design and installation of electrical equipment in health care facilities, and that it is up to an administrator of the specific type and class of a health care facility to elect applicability of Clause 6 of Z32 for that particular Class of a health care facility. This means that the extent of the components of essential electrical system in a major hospital would be drastically different from such extent in a typical rehabilitation clinic. Respectively, a health care facility administrator may decide to opt out from electing essential electrical system for a typical dental hygiene or physiotherapy office, etc.

Rule 24-302 of the Canadian Electrical Code re-enforces this fact.

This Rule states the following:

24-302 Circuits in essential electrical systems (see Appendix B)
(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.

(2) An essential electrical system shall comprise at the minimum a vital branch and may also include a delayed vital branch or a conditional branch, or both.

(3) The wiring of the essential electrical system shall be kept entirely independent of all other wiring and equipment and shall not enter a luminaire, raceway, box, or cabinet occupied by other wiring except where necessary
(a) in transfer switches; and
(b) in emergency lights supplied from two sources.

Subrule (1) clearly explains to the Code users that it is up to the health care facility administration to designate loads of the essential electrical system. There are numerous installations where a health care facility administrator chooses to select the loads of the facility entire distribution system as "essential electrical system.” In this case, an electrical designer may (in consultation with the administrator) elect to supply all loads of the health care facility from an emergency generator, and except for a fire pump, all these loads could be supplied via a single transfer switch. Some electrical safety regulators have a tendency to reject such design arrangements, stating that the electrical equipment comprising "life safety systems” described by Section 46 of the CE Code must be wired via a separate transfer switch. Some electrical safety regulators often mandate that conditional or delayed-vital loads must be connected via a transfer switch separate from the transfer switch dedicated to the vital loads. However, such decisions by the regulators who misinterpret codes and standards officially adopted for regulatory purpose could be legally challenged, unless the provisions of Z32 and Rule 24-302(2) are formally amended in their respective jurisdictions.

There are other situations where administrators of jails, colleges or airports would like to consider all loads of those facilities to be designated as essential electrical systems and being supplied with an emergency generator via a single transfer switch. In these cases, electrical designers and the proponents of such approach should communicate their intent with the electrical safety regulators and to demonstrate to the electrical safety authorities that the safety objectives by the relevant codes and standards are not compromised by such proposed distribution arrangements, as the CE Code intent to invoke application of essential electrical system is limited only to health care facilities in conjunction with application of the CSA standard Z32.

So, hopefully, the question raised in the title of this article has been answered.

Read more by Ark Tsisserev

Tags:  Canadian Perspective  July-August 2012 

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