required for generator performance.
(G) Elevators. Elevator cab lighting, control, communica
tions, and signal systems.
(H) Automatic Doors. Automatically operated doors used for building egress. [99:4.4.2.2.2.2(7)]
517.33 Critical Branch.
(A) Task Illumination and Selected Receptacles. The critical branch of the emergency system shall supply
power for task illumination, fixed equipment, selected
receptacles, and special power circuits serving the
following areas and functions related to patient care:
(1) Critical care areas that utilize anesthetizing gases
— task illumination, selected receptacles, and
fixed equipment
(2) The isolated power systems in special environments
(3) Patient care areas — task illumination and selected receptacles in the following:
a. Infant nurseries
b. Medication preparation areas c. Pharmacy dispensing areas
d. Selected acute nursing areas
e. Psychiatric bed areas (omit receptacles)
f. Ward treatment rooms
g. Nurses' stations (unless adequately lighted by corri
dor luminaires)
(4) Additional specialized patient care task illumination and receptacles, where needed
(5) Nurse call systems
(6) Blood, bone, and tissue banks
(7) Telephone equipment rooms and closets
(8) Task illumination, selected receptacles, and selected power circuits for the following:
a. General care beds (at least one duplex receptacle
per patient bedroom)
b. Angiographic labs
c. Cardiac catheterization labs d. Coronary care units
e. Hemodialysis rooms or areas
f. Emergency room treatment areas (selected)
g. Human physiology labs h. Intensive care units
i. Postoperative recovery rooms (selected) (9) Additional task illumination, receptacles, and selected power circuits needed for effective hospital operation. Single-phase fractional horsepower motors shall be permitted to be connected to the critical branch. [99:4.4.2.2.2.3(9)]
(B) Subdivision of the Critical Branch. It shall be per- mitted to subdivide the critical branch into two or more branches.
FPN: It is important to analyze the consequences of supplying an area with only critical care branch power when failure occurs between the area and the transfer switch. Some proportion of normal and critical power or critical power from separate transfer switches may be appropriate.
517.34 Equipment System Connection to Alternate Power Source. The equipment system shall be installed and connected to the alternate power source such that the equipment described in
517.34(A) is automatically restored to operation at appropriate time-lag intervals following the energizing of the emergency system. Its arrangement shall also provide for the subsequent connection of equipment described in 517.34(B). [99:4.4.2.2.3.2]
Exception: For essential electrical systems under 150 kVA, deletion of the time-lag intervals feature for delayed automatic connection to the equipment system shall be permitted.
(A) Equipment for Delayed Automatic Connection. The following equipment shall be permitted to be arranged for delayed automatic connection to the alternate power source:
(1) Central suction systems serving medical and surgical functions, including controls. Such suction systems shall be permitted on the critical branch.
(2) Sump pumps and other equipment required to operate for the safety of major apparatus, including associated control systems and alarms.
(3) Compressed air systems serving medical and surgical functions, including controls. Such air systems shall be permitted on the critical branch.
(4) Smoke control and stair pressurization systems, or both.
(5) Kitchen hood supply or exhaust systems, or both, if required to