Which areas of a health care facility electrical system must be tested for voltage difference between ground points, for ground return path voltage rise — in grounded systems or for test of impedance to ground — in isolated systems? Which loads of an electrical system in a health care facility are considered to be essential system loads and what kind of the power supply must be provided to these loads?
These questions are often asked by the electrical designers and contractors. The answer may be found in a combination of the following documents: the National Building Code of Canada (NBCC), the Canadian Electrical Code (CEC) and the CSA Standard Z32 "Electrical Safety and Essential Electrical Systems in Health Care Facilities”.
Article 22.214.171.124. of the NBCC states that an emergency electrical power supply system for emergency equipment required by the Building Code (for elevators, smoke control and smoke venting fans, fire pumps) must be installed in conformance with CAN/CSA-Z32.
Z32 defines emergency electrical power supply system as "one or more in-house electrical generator sets intended to be available if all other supplies fail, and capable of supplying all of the essential loads”.
Essential electrical system is also defined by this standard. It means "an electrical system that has the capacity of restoring and sustaining a supply of electrical energy to special loads if the normal supply of energy is lost.”
Section 6 of Z32 provides requirements for essential electrical systems and explains that the essential system consists of the emergency equipment required by the NBCC (elevators, smoke control and smoke venting fans, fire pumps) and of special loads that are intended to provide effective and safe patient care in a health care facility.
Table 8 of Z32 classifies essential system loads and branches and their intended performance (vital, delayed vital or conditional) for a specific type of patient care.
So, now some of our questions posed at the outset — appear to be answered. But what about a difference in electrical installations between hospitals and, let’s say, doctors’ offices? Section 24 of the CEC helps to clarify this issue. Until the 2002 edition of the CEC had been developed, Section 24 was limited only to electrical installation requirements in patient care areas of hospitals.
However, Scope of Section 24 in the 19th edition of the CEC, Part I (2002 edition) had been expanded to cover installations within patient care areas of "health care facilities”. Respectively, definition of hospital has been deleted from Rule 24-002 "Special Terminology” and a new definition health care facility has been added.
This change from hospital(s) to health care facility(ies) had been made throughout Section 24 and Appendix B, to harmonize Section 24 with the CAN/CSA-Z32. CSA standard Z32 further subdivides health care facilities into three separate classes as follows:
Health care facility, Class A – a hospital, so designated by Canada or one of its Provinces or Territories, where patients are accommodated on the basis of medical need and are provided with continuing medical care and supporting diagnostic and therapeutic services;
Health care facility, Class B – a facility where residents, as a result of physical or mental disabilities, are unable to function independently and are accommodated due to a need for daily care by health care professionals;
Health care facility, Class C – a facility where ambulatory patients are accommodated on the basis of medical need and are provided with supportive, diagnostic, and treatment services.
Z32 provides a variety of examples of such health care facilities, and in addition to hospitals these examples include surgical, outpatient and doctor’s clinics, dentist offices, psychiatric and rehabilitation facilities.
The impact on installations is that facilities that were previously not included by Section 24 rules now have to follow the Patient Care Areas requirements (Rules 24-100 to 24-114) which have very specific criteria for circuits, bonding, receptacles and other equipment.
Thus, in our example above, electrical installations in a patient care are of a large teaching hospital have be similar to the installations in a typical doctor’s office that is located in a unit of an office building. Of course, such installation requirements for a patient care area occupied by a psychiatrist or a massage therapist may appear to be very drastic, as offices of such health care practitioners may be established in a typical unit of a commercial building where the previous tenant was a travel agent or an alteration shop and where special needs for receptacles, bonding, etc., have not previously existed.
It should be understood that relevant Rules of Section 24 are intended to apply to the installation of electrical wiring and equipment within patient care areas of those types of health care facilities where permanently or cord connected electro-medical equipment is used for the purpose of intentional contact at a patient’s skin surface or internally during the patient’s treatment, diagnostics or monitoring.
The inspection authority may require involvement of the professional electrical engineer at the permit and installation stages in order to ascertain a specific class of a health care facility and conditions of use of the electro-medical equipment and to supervise tests referenced in Appendix B Note on rules 24-104(1) and 24-112 of the Code.
Some jurisdictions provide additional clarifications to the electrical contractors on application of the requirements of Section 24 of the CEC.
City of Vancouver, for example, has developed a special declaration form for completion by a professional electrical engineer, where a statement is made that permanently or cord connected electro-medical equipment is not used for the purpose of intentional contact at a patient’s skin surface or internally during the patient’s treatment, diagnostics or monitoring; or that there will clearly be no danger from use of the electro-medical equipment when a typical commercial unit is intended to be occupied as a doctor’s office, etc., where a patient care area as defined by Section 24 of the CEC will exist.
However, where the installation of electrical wiring and equipment is done in patient areas of those types of health care facilities where permanently or cord connected electro-medical equipment is used for the purpose of intentional contact at a patient’s skin surface or internally during the patient’s treatment, diagnostics or monitoring, then all applicable provisions of Section 24 of the CE Code must be met, and all test requirements for voltage drop test, voltage difference between ground points test, impedance to ground test, etc., as mandated by Section 5 of Z32 must be met.
And as usual, authorities having jurisdiction must be consulted by designers and contractors contemplating electrical installations in patient care areas of health care facilities.
Read more by Ark Tsisserev