User Guide

6
SnoTrace
™
RGS
™
Systems for Roof and Gutter Snow and Ice Melting
RGS Multipliers
Select a multiplier from the examples shown based
on the type of roofing material utilized. If gutters
and downspouts will also require protection, be sure
to add the cable requirements (see Table 3.3) to the
roof overhang footages.
Attention: Where conditions dictate
(heavy snow loads, steep roof slopes,
smooth roofing materials or long eave-
to-ridge distances), snow fences and/
or snow brakes should be considered to
prevent/reduce the potential for damage
to the cable and/or facility.
How far up the roof
the heating cable
should travel may
be determined
by measuring
the distance as
shown at right.
The heating cable
should loop past
the point where
an imaginary line
extending up from
the inside wall
would pass through the roof.
Metal/Tile Roofs
Metal roofing materials such as standing seam
or corrugated, as well as tile/concrete roofing
materials that have distinct ridges or grooves, must
be properly addressed when installing heat tracing.
Metal roofs in particular pose an avalanche potential
that could damage the heating cable if it were
installed in a serpentine pattern. To combat this, the
cable is installed parallel to the standing seams or
along the length of a corrugation. The partial sketch
below depicts RGS cable as it would be installed on
a corrugated metal roof. This method would also be
used on standing seam or tile roofs.
Any number of attachment methods may be used
for holding the heating cable in place. Whichever
method is used should take into consideration the
integrity of the roof and the heating cable.
To determine the layout pattern for RGS heating
cable on metal or tile roofs, use Table 3.1 in
conjunction with measurements of the spacing of
the seams, corrugations or ridges in the roofing
material. This spacing, combined with the desired
level of protection, will determine what multiplier
to use to determine the footage of cable required.
(Heating cable does not have to be installed on every
seam, corrugation, etc.) Be sure to add sufficient
extra cable to reach the power connection point for
each circuit.
Heavy Conditions Multipliers Moderate Conditions Multipliers
To establish the amount of cable required, select
the overhang distance that fits the application and
follow this row across to the ridge/seam spacing
column that corresponds to the roofing material.
The number where the row and column intersect
is the multiplier for that application. Multiply this
number by the number of linear meters (feet) of
roof eaves to be protected and add sufficient cable
to reach the power supply junction box plus any
additional cable to allow for on-site variations.
Table 3.1 Metal/Tile Roofs
Conditioned
Space
Overhang Distance
Section Detail
RGS Cable
Roof
RG-CMC
Gutter
Ridge/Seam Spacing
Section Detail
Overhang
Distance
Ridge/Seam Spacing
250 mm
(10")
300 mm
(12")
350 mm
(14")
400 mm
(16")
450 mm
(18")
500 mm
(20")
550 mm
(22")
600 mm
(24")
300 mm (12") 4.2 3.7 3.3 3.0 2.8 2.6 2.5 2.4
450 mm (18") 5.4 4.7 4.2 3.8 3.5 3.2 3.0 2.9
600 mm (24") 6.6 5.7 5.0 4.5 4.1 3.8 3.6 3.4
750 mm (30") 7.8 6.7 5.9 5.3 4.8 4.4 4.1 3.9
900 mm (36") 9.0 7.7 6.7 6.0 5.5 5.0 4.7 4.4