b) Air conditioned spaces, such as operating corridors and control
rooms, 80 +/- 5 degrees F (27 +/- 2 degrees C) and 50 +/- 10 percent relative
c) Heat exchange/air conditioned spaces, such as transmitter rooms
that are not partitioned into separate corridors and plenums, 70 degrees F (21
degrees C) minimum and 90 degrees F (32 degrees C) maximum with 60 percent
maximum relative humidity. Such facilities may have, but are not required to
have separately enclosed control rooms conditioned as in para. 220.127.116.11 b,
Uninterruptible Power Supply (UPS) Equipment Rooms. Depending on
the type of system utilized to remove waste heat from the room (refer to
Section 8), the following conditions apply:
a) Ventilated equipment rooms are controlled to the same
temperature conditions as in para. 18.104.22.168 a, above, for ventilated
b) Heat exchange/ventilation (similar to para. 22.214.171.124 c, above),
except using ventilation as the auxiliary heat removal means (in lieu of air
conditioning) can also be used, in which case the environmental limits should
be 70 degrees F (21 degrees C) minimum, 5 degrees F (2 degrees C) over ambient
maximum with relative humidity as naturally occurs with this system.
c) Air conditioning 80 +/- 5 degrees F (27 +/- 2 degrees C) and 50 +/-
10 percent relative humidity during normal operation with conditions rising
but not exceeding 120 degrees F (49 degrees C) and relative humidity as will
occur during a 15 minute power outage. Note that this will require a thermal
inertia system in most installations.
d) For the systems described in paras. 126.96.36.199 a, b, and c, if
other heating is not available, a unit heater shall be installed in the
equipment room to provide heating when the UPS is off for extended maintenance
periods (no waste heat available) and to prevent condensation damage. For
these occasions the heater shall maintain, and the controlling thermostat
shall be set for, a temperature of 85 degrees F (29 degrees C). Unit to be
energized only when the UPS is off to avoid cross control.
UPS and Microwave Equipment Battery Rooms. These rooms shall be
ventilated at all times. During cold weather, sufficient heat shall be
provided to remain within the following limits:
a) Temperature - 65 degrees F (18 degrees C) minimum, winter only
from waste heat, and a maximum as naturally occurs with ventilation.
b) Humidity - No minimum and 90 percent maximum. See para.
188.8.131.52 d) for method to limit.
c) A unit heater shall be installed in the battery room to provide
heat when waste heat is not available, to augment waste heat if inadequate and
to prevent condensation. The heater shall maintain, and the controlling
thermostat shall be set for 60 degrees F (16 degrees C). This heater shall be