General. All mechanical criteria that apply to naval facilities in
general also apply to electronic facilities. Only items specifically
applicable to electronic facilities are covered in this section.
Heating, Ventilating, and Air Conditioning (HVAC) Systems
Outside Design Conditions
220.127.116.11 Permanent and Transportable/Nonrelocatable Facilities. NAVFAC P-
89, Engineering Weather Data, shall be used to determine winter and summer
outdoor design conditions. HVAC systems for spaces designated as critical by
the BESEP shall be designed on the basis of the 99 percent column for heating
and the 1 percent dry-bulb and mean coincident wet-bulb columns for
ventilating and air conditioning. Design of systems for other spaces shall be
based on the 97.5 percent and 2.5 percent columns, respectively.
Transportable/Tactical and Transportable/Relocatable Facilities.
If the location of the installation is known and it is probable that the
location will not change, the outdoor design conditions defined above shall be
used. If the location is not known, or if it is probable that the container
will be relocated, HVAC equipment shall be designed for the "worst case"
likely to be encountered. Temperature and humidity extremes are defined in
MIL-STD-210, Climatic Extremes for Military Equipment.
Inside Design Conditions. Spaces not containing electronic
equipment but meeting the programming priority requirements of MIL-HDBK-1190
shall be air conditioned. Inside design conditions shall be in accordance
with NAVFAC DM-3.03, Heating, Ventilating, Air Conditioning and
Dehumidification Systems. Spaces not meeting the priority requirements shall
be heated and ventilated only, also in accordance with NAVFAC DM-3.03.
Requirements for electronic equipment spaces are discussed below. In all
cases, the BESEP should be consulted for specific guidance.
Computer Rooms. These areas generally should be maintained at
2 degrees Fahrenheit (F) (22
1 degrees Celsius (C)), 45
relative humidity (RH) year-round. If a wider range in space conditions can
be tolerated by the equipment, the less restrictive values should be used.
Receiver Buildings and Similar Areas. Electronic equipment in
receiver buildings, telephone and switchgear rooms, radio direction-finder
facilities, and similar areas generally require a year-round environment of 75
5 degrees F (24
2 degrees C), 50
5 percent RH.
Transmitter Buildings. Depending on the type of system utilized to
remove waste heat from the facility (see Section 8), the following conditions
a) Ventilated spaces, such as plenums, 90 degrees F (32 degrees C)
minimum, 5 degrees F (3 degrees C) over ambient maximum and relative humidity
as naturally occurs with the related ventilation.