TM
5-811-1/AFJMAN
32-1080
provided. The ratio in the entire clear zone outside
where accurate color rendition is required because
they have a monochromatic spectrum. A one-third
the perimeter fence will not exceed 10 to 1 and
mix of another light source mixed with LPS may
within a 30-foot inner area will not exceed 6 to 1.
be used when color rendition is a factor. Very near
Area lighting will not exceed a 6 to 1 ratio.
infrared (VNIR) lighting used together with infra-
e. Design considerations. During design, con-
red sensitive CCTV cameras has been used to
sider field conditions that could affect or degrade
detect an aggressor without the aggressor's knowl-
performance. These conditions include extreme
edge. VNIR is useful where visible light would be
temperatures, dust, corrosion, uneven terrain, ob-
a problem (such as a flight line). VNIR will be
structions, and irregular line voltages. Design
applied only when directed by the using agency.
illumination level should be set above the criteria
minimums and be increasingly conservative where
11-7. Electrical Power Sources.
one or more field conditions are uncontrolled.
a. Alternate electrical power requirement. In the
11-6. Light Sources.
event of an outage of normal electrical power, a
reliable alternate electric power source is neces-
When designing system for CCTV, coordinate the
sary to ensure continuous illumination. A standby
restart capability with the user. In some cases
generator will be used as the alternate source,
security regulations require instant restart. High
except where the electric power requirements of
intensity discharge (HID) lamps are more energy-
the lighting system are small enough to make
conserving than incandescent lamps, but they re-
battery backup more economical. Either automatic
quire several minutes to warm up and restart
or manual starting of the generator and load
after a power interruption. The warmup time to
transfer will be provided depending on the permis-
reach 80 percent of normal output will require a
sible electric power outage duration. In some
few minutes or more. Restriking takes a minute
cases, portable generators or portable battery-
for high-pressure sodium (HPS), but requires
operated lights are required in addition to station-
longer intervals for other HID sources. Specially
ary auxiliary electric power sources. Provision of
designed lamps and auxiliary equipment are avail-
portable units is not the designer's responsibility,
able where rapid start is required. Low-pressure
beyond providing a connection point when directed
sodium (LPS) lamps require 7 to 15 minutes to
by the using agency. The total design may require
start, but most lamps will restrike immediately
concrete pads adjacent to the connecting points for
after a power interruption. Fluorescent and the
placement of the portable units.
higher wattage LPS lamps cannot be provided
b. Backup electrical power requirement.
with the type of directional control needed for
(1) Additional outage (restrike) time for HID
protective lighting systems, but may be used
where such control is unnecessary, such as at
startup outage time is extended by the amount of
guardhouses. Either HPS lamps or incandescent
time required to restrike the arc in an HID lamp
lamps are acceptable, but the energy savings that
plus the time required for the lamp to reach full
HPS lamps provide make their installation prefer-
lumen output. The shortest restrike time applies
able. Incandescent lamps will be used only when a
to HPS lamps and is less than 1 minute from a
life cycle cost analysis indicates such a source is
hot-lamp state. A lamp is considered to be hot for
the most economical choice or when required by
3 minutes after loss of electric power. Cold-start
operational considerations. The instant-on charac-
time of 5 to 10 minutes for HPS lamps does not
teristic of incandescent lighting is a major factor
apply when auxiliary electric power is supplied.
in favor of its use. When lighting remains "off'
The total time lapse on loss of normal electric
during normal nighttime conditions, but is turned
power to full HPS lamp lumen output including
"on" during alerts, such as in the use of search-
allowance for engine-generator startup is 4 to 5
lights, the 5- to 10-minute warmup time for HPS
minutes (10 to 17 seconds for generator startup
units cannot be tolerated, which results in incan-
plus 55 to 60 seconds to restrike and 3 to 4
descent lighting being the only practical alterna-
minutes to full lamp lumen output).
tive. Tungsten-halogen incandescent lamps, also
(2) Tolerable outage time. Where the Using
known as quartz-iodine, with a longer lamp life
Agency has determined that the outage time or
than the conventional tungsten type, should be
reduced lighting levels must be less than 4 to 5
considered for incandescent lamp applications
minutes, lamps and auxiliary equipment with the
where appropriate. The LPS lamps may be consid-
desired output parameters for rapid startup and
ered if procurement and installation is in accord-
restrike will be specified. The lamp lumen output
ance with current Federal Acquisition Regulations
level at restrike of a hot restrike system is
(FAR). In addition, LPS lamps should be avoided
11-4
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