Install Instructions
125
IM-PR 566442 1114 (Design Manual)
5.12 Planning and installation
5.12.1 Creating a material list
Use this worksheet to make an initial material list
for the amount of tubing and fasteners needed.
Then select one worksheet below to create a piping
and control material list. These charts are intended
for conceptual purposes; there may be variations in
each job.
Equation: Snow melt area x multiplier =
estimated amount
Example: For a snow melt area of 500 ft
2
with
tubing at 9" spacing, the estimated amount is
500 x 1.5 = 750 ft. The fasteners required for the
same area at 9" spacing are found as 500 x 0.75 =
375 pieces.
The number of circuits in the area will be covered
in the following section. Installer’s preference
determines the choice of fasteners. (Use plastic zip
ties for 3/4" tubing.)
Tubing
(½" ⅝" ¾")
Snow Melt
Area (ft³)
Multiplier
Estimated
Amount
6" Spacing 2.2
9" Spacing 1.5
12" Spacing 1.1
Fasteners
Snow Melt
Area (ft³)
Multiplier
Estimated
Amount
6" Spacing 1.1
9" Spacing .75
12" Spacing .55
Table 5-19 Snow melt material list worksheet.
Plastic fasteners that are supplied by Viega include
zip ties, foam staples and U-channels.
5.12.2 Layout planning
To avoid waste and to have equal circuit lengths,
a carefully planned layout should be done. First,
determine where the manifold should be installed.
Remember the manifold must be accessible. When
calculating the number of circuits, always round
up. Keep the length of each circuit the same in the
snow melt area.
Tubing Size Max. Circuit Length (ft)
⅝" 200
¾" 300
Table 5-20 Maximum circuit lengths
Size
mm (in)
Average active
loop, m (ft)
Total loop
m (ft)
PEX tubing
16 (
⅝)
68.6 (225) 76.2 (250)
19 (¾) 91.4 (300) 99.1 (325)
25 (1) 137.2 (450) 144.8 (475)
Table 5-21 Loop lengths for snow melt systems
(See Clause 17.4.3.2)
NOTES:
1. 13 mm (½") tube should not be used. The total
PEX loop lengths consist of two separate sections,
the active loop and the leader length. The active
loop is installed within the heated slab. The
leader length is the total distance to and from the
manifold and heated slab, including any vertical
distances.
2. The manifolds should be installed as close to the
snow melt area as possible.
(CSA B214, Clause 17.4.3.2)
The maximum length of continuous tubing from a
supply-and-return manifold arrangement shall not
exceed the lengths specied by the manufacturer or,
in the absence of manufacturer’s specications, the
lengths specied in Table 3. Actual loop lengths shall
be determined by spacing, ow rate, temperature and
pressure drop, as specied in the system design.
38
38. ©CSA Group, B214-12. 2012. “Installation Code for Hydronic Heating Systems” Table 3, Clause 17.4.3.2
Maximum loop lengths
(CSA B214 Table 3)