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Important: For the nVent warranty to be valid, you must comply
with all the requirements outlined in these guidelines.
All thermal and design information provided here is based upon a
“standard” installation with heating cable fastened to an insulated
pipe. For any other application or method of installation, consult
nVent at (800) 545-6258.
HEATING CABLE SELECTION AND DESIGN
Make sure that the heating cable being used is suitable for your
application. Refer to the Commercial and Residential Application and
Design Guide (H53585) for heating cable application information.
1. Determine the heating cable type
Use Table 1 to select heating cables for insulated metal pipes.
Use Table 2 to select heating cables for insulated plastic pipes.
Read across the table to find your pipe size, then drop down to the
line corresponding to the lowest air temperature for that application
and the correct insulation thickness. The cell at that intersection has
a particular shading and may have a number. The shading indicates
which heating cable to use (key to the shading appears above the
table headings). A number represents the spiraling ratio
(feet of heating cable per foot of pipe).
If no number appears in the cell, straight trace the pipe. If a number
does appear in the cell, spiral trace the pipe.
If your spiraling ratio is 2.0, multiple trace the pipe using two straight
traces at the 4 o’clock and 8 o’clock positions.
If your spiraling ratio is 3.0, multiple trace the pipe using three
straight traces at the 11 o’clock or 1 o’clock position, and at the
4 o’clock and 8 o’clock positions.
Example 1:
Pipe size:
1 in
Lowest air temp.:
0°F
Insulation thickness:
1/2 in
Metal pipe:
WinterGard H311
Plastic pipe:
WinterGard Plus H611, H621
WinterGard Wet H612, H622
Example 2:
Pipe size:
2 1/2 in
Lowest air temp.:
–20°F
Insulation thickness:
1/2 in
Metal pipe:
1.3
WinterGard Plus H611 or
WinterGard Wet H612
(Use 1.3 feet of heating cable per foot of pipe.)
Plastic pipe:
2.0
WinterGard Plus H611 or
WinterGard Wet H612
(Use two straight traces at the 4 o’clock and 8 o’clock positions.)
Table 1. For METAL pipes with fiberglass insulation or equivalent (based on 40°F maintain temperature)
Table 2. For PLASTIC pipes with fiberglass insulation or equivalent (based on 40°F maintain temperature)
Lowest air
temp. (°F)
Insulation
thickness
Nominal pipe size
1/2 in
6 in
4 in
3 in
2 1/2 in
2 in
1 1/2 in
1 1/4 in
1 in
3/4 in
1/2 in
1 in
1 1/2 in
1/2 in
1 in
1 1/2 in
2 in
1/2 in
1 in
1 1/2 in
2 in
0
–20
–40
1.8
1.3
3.0
1.8
1.5
1.3
1.1
1.5
1.1
1.1
3.0
2.0
1.7
1.4
1.2
1.1
1.9
1.4
1.1
1.4
1.1
Key to Table 1:
= H311
= H611, H612, H621, H622
= Use a thicker insulation
3.0
2.0
1.7
3.0
1.8
1.5
1.3
1.1
3.0
1.8
1.4
1.7
3.0
3.0
2.0
1.8
1.5
1.1
3.0
1.6
1.4
1.2
3.0
1.8
1.4
1.2
1.6
1.2
1.2
2.0
1.2
1.1
1.3
1.1
1.4
1.1
1.1
1.9
1.7
1.4
1.2
1.1
1.3
1.1
Lowest air
temp. (°F)
Insulation
thickness
Nominal pipe size
1/2 in
6 in
4 in
3 in
2 1/2 in
2 in
1 1/2 in
1 1/4 in
1 in
3/4 in
1/2 in
1 in
1 1/2 in
1/2 in
1 in
1 1/2 in
2 in
1/2 in
1 in
1 1/2 in
2 in
0
–20
–40
Key to Table 2:
= H311
= H611, H612 H621, H622
= Use a thicker insulation
H908 DESIGN AND INSTALLATION INFORMATION FOR HEATING CABLE ON PIPES ONLY
(WINTERGARD H311, WINTERGARD PLUS H611, AND WINTERGARD WET H612 HEATING CABLES)
