Tuesday, March 20, 2012

Transfer Switch Location Battery Lighting

QUESTION:  Where is the requirement for battery lights at transfer switch locations?  When did that requirement first appear?


RESPONSE:


This requirement could not be found in the 1999 editions of either NFPA 99 or NFPA 70.  There was however a requirement for battery lighting at the generator set locations in those 1999 editions.

From the 1999 edition of the NEC®, NFPA 70-1999 (www.nfpa.org/70) :
517-32. Life Safety Branch
(f) Generator Set Location. Task illumination and selected receptacles in the generator set location.

From the 1999 edition of NFPA 99, NFPA 99-1999: (www.nfpa.org/99) : 
3-4.2.2.2 Emergency System.
5. Task illumination, battery charger for emergency battery- powered lighting unit(s), and selected receptacles at the generator set location


This language first appeared in NFPA 99-2002: [see paragraph (5) below:

4.4.2.2.2.2 Life Safety Branch. The life safety branch of the
emergency system shall supply power for the following lighting,
receptacles, and equipment:
(1) Illumination of means of egress as required in NFPA 101,
Life Safety Code
(2) Exit signs and exit direction signs required in NFPA 101,
Life Safety Code
(3) Alarm and alerting systems including the following:
(a) Fire alarms
(b) Alarms required for systems used for the piping of nonflammable
medical gases as specified in Chapter 5, Gas
and Vacuum Systems
(4)*Hospital communication systems, where used for issuing
instruction during emergency conditions
(5) Generator Set Location: Task illumination, battery
charger for emergency battery-powered lighting unit(s),
and selected receptacles at the generator set location and
essential electrical system transfer switch locations
(6) Elevator cab lighting, control, communication, and signal
systems
(7) Automatically operated doors used for building egress
(8) The auxiliary functions of fire alarm combination systems
complying with NFPA 72National Fire Alarm Code®
No function other than those listed in items (1) through (8)
shall be connected to the life safety branch.

It has been repeated in later editions of NFPA 99 since then, and the NEC® (NFPA 70) also picked up the requirement in 2005. I included an excerpt from a more recent NEC® edition for further reference.

From the National Electrical Code® (NEC®), NFPA 70-2008:
517.32 Life Safety Branch. No function other than those
listed in 517.32(A) through (H) shall be connected to the
life safety branch. The life safety branch of the emergency
system shall supply power for the following lighting, receptacles,
and equipment.
(A) Illumination of Means of Egress. Illumination of
means of egress, such as lighting required for corridors,
passageways, stairways, and landings at exit doors, and all
necessary ways of approach to exits. Switching arrangements
to transfer patient corridor lighting in hospitals from
general illumination circuits to night illumination circuits
shall be permitted, provided only one of two circuits can be
selected and both circuits cannot be extinguished at the
same time.
FPN: See NFPA 101-2006, Life Safety Code, Sections 7.8 and 7.9.
(B) Exit Signs. Exit signs and exit directional signs.
FPN: See NFPA 101-2006, Life Safety Code, Section 7.10.
(C) Alarm and Alerting Systems. Alarm and alerting systems
including the following:
(1) Fire alarms
FPN: See NFPA 101-2006, Life Safety Code, Section 9.6 and 18.3.4.
(2) Alarms required for systems used for the piping of
nonflammable medical gases
FPN: See NFPA 99-2005, Standard for Health Care Facilities,
4.4.2.2.2.2(3).
(3) Mechanical, control, and other accessories required for
effective life safety systems operation shall be permitted
to be connected to the life safety branch.
(D) Communications Systems. Hospital communications
systems, where used for issuing instructions during emergency
conditions.
(E) Generator Set and Transfer Switch Locations. Task
illumination battery charger for battery-powered lighting
unit(s) and selected receptacles at the generator set and
essential transfer switch locations. [99:4.4.2.2.2.2(5)]
(F) Generator Set Accessories. Generator set accessories
as required for generator performance.

It has never been in NFPA 110 (www.nfpa.org/110), even now.

From NFPA 110-2010: [Note that the “EPS equipment” as used in NFPA 110 is the generator and its systems, NOT the ATS’s.
7.3 Lighting.
7.3.1 The Level 1 or Level 2 EPS equipment location(s) shall
be provided with battery-powered emergency lighting. This
requirement shall not apply to units located outdoors in enclosures
that do not include walk-in access.
7.3.2 The emergency lighting charging system and the normal
service room lighting shall be supplied from the load side
of the transfer switch.
7.3.3* The intensity of illumination in the separate building or
room housing the EPS equipment for Level 1 shall be 32.3 lux
(3.0 ft-candles), unless otherwise specified by a requirement
recognized by the authority having jurisdiction.

And from the Annex:
A.7.3.3 Where units housed outdoors are used, it is recommended
that a flashlight or battery-powered light with a flexible
cord be maintained in the housing.

NFPA Disclaimer: Although the author is Chair of the NFPA Technical Committee on Emergency Power Supplies, which is responsible for NFPA 110 and 111, the views and opinions expressed in this message are purely those of the author and shall not be considered the official position of NFPA or any of its Technical Committees and shall not be considered to be, nor be relied upon as, a Formal Interpretation. Readers are encouraged to refer to the entire text of all referenced documents.  NFPA members can obtain NFPA staff interpretations at www.nfpa.org.

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