12 May 2003
Including change 1, 19 January 2007
Where Required. Provide freeze protection for saltwater, fresh-water,
sanitary-waste (sewage), and oily-waste (bilge) pipes exposed on piers and wharves
and in drydocks when located in freezing climates.
Regional Weather Differences. See Figure C-1 and Table C-1. For
design purposes, coastlines within the United States can be divided into the five regions
listed below. Table C-1 lists average historical weather data for the five regions. For
freeze protection systems at locations outside of the United States, match weather data
(insofar as possible) to one of the regions in Table C-1 and design accordingly. The five
weather regions are defined as follows:
"Severe": Alaska, Maine, New Hampshire, Great Lakes and inland
"Cold": Connecticut, Massachusetts, Rhode Island, and New York.
"Moderate": Pennsylvania, New Jersey, Delaware, Maryland, and
"Mild": Washington, Oregon, Virginia, and North Carolina.
"Very Mild": California, South Carolina, Georgia, Texas,
Mississippi, Louisiana, Alabama, and Florida.
Methods. The methods described below vary with climate. Use the
methods recommended below when the relative costs of electricity, sewage disposal,
and freshwater are not abnormally high. Where the cost of electricity, sewage disposal,
or water is abnormally high, then modify the freeze protection system and use an
approved method that minimizes operating cost. Use approved life cycle cost
procedures and submit analysis.
Protection in Regions I and II
Water Lines. For water lines, provide freeze protection by using a
combination of electric heat tape and pipe insulation. The suggested combinations of
insulation thickness and heating (watt density) for various pipe sizes are shown in Table
C-2. Heat tape should be controlled by remote thermostats having sensors taped to the
surface of pipes and under the insulation. Consult with the Activity and the cognizant
NAVFAC EFD/EFA OR USACE DISTRICT regarding preferred heat tape systems and
methods. Several sections of heat tape may be required due to overall pipe length.
Provide each section of heat tape with a dedicated thermostat. Thermostats must be in
a protected location that is also accessible. The heating requirement given in Table C-2