HD110301-1 Rev2
Page 11 of 23
FIRE SUPPRESSION SYSTEM FREEZE PROTECTION DESIGN GUIDE
This section provides step-by-step instructions to design a fire suppression freeze protection
system. While the steps shown here allow for manual design, Drexan HeatTracer recommends the
use of the ProTrace Design Software to provide a compliant design complete with estimates of
power loads and detailed bills of material for the project.
STEP 1 – COLLECT THE REQUIRED INFORMATION FOR EACH LINE
Pipe diameter
Pipe length
Minimum ambient temperature
This is the minimum temperature expected (worst case) throughout the winter months
2
.
Maintain temperature
For freeze protection a typical maintain temperature of 4˚C/40˚F is sufficient.
Start-up temperature
This temperature will have a direct effect on the maximum circuit length and the breaker size
required. You should select the temperature at which the cable will normally become
energized, not necessarily the coldest temperature.
Metal or non-metallic Pipe
Some materials have superior heat transfer compared to others. For example, metal will
conduct heat better than a polymeric material. For this reason, we require the use of aluminum
foil tape (part# TAPE-AL) on polymeric pipes applied over the pipe under the cable.
Pipe hardware (valves, shoes, flanges etc.)
When measuring the total length of the pipe to be heat traced remember to allow extra cable
for the pipe hardware.
Thermal Insulation type & thickness
All pipes, equipment and pipe hardware must be thermally insulated as specified in the previous
section.
Measurement: Metric? Imperial? Temperature: Celsius? Fahrenheit?
Voltage: (include if 3 phase) _____________
APPLICATIONS
Pipe Tracing: Metal? Other? (specify) _______
Pipe Length:
Diameter:
Insulation Type:
Insulation Thickness:
Not Yet Determined
Low Ambient Temp:
Max. Pipe Temp:
Maintain Temp:
Number of Supports
Valves
Hangers
2
If in doubt, refer to historical data at: