Infloor Infloorboard - Manual (Page 9)

Infloorboard™ Application & Installation Manual
9
DESIGN & PERFORMANCE
ESTIMATING THE REQUIRED NUMBER OF BOARDS:
For simple and fast installation, it is highly recommended that a full
Infloorboard™ layout be used, indicating the precise panel and tubing layout.
This can be provided by the National Radiant Design Center (See Design servic-
es). A full plan is recommended for the first few jobs. Contact your
Infloorboard™ distributor about getting a layout and a design. The following
calculations can be used for estimating the required number of boards. For expe-
rienced installers, calculate the net square footage of each room and multiply by
the following factors: Straight – 0.133 Utility – 0.028 Combo End – 0.028
Example: For a 600 Sq. ft. room, multiplying 600 by 0.133 gives approximately
80 straight boards. Multiplying 600 by 0.028 gives 17 Utility pieces.
Multiplying 600 by 0.028 gives 17 Combo end pieces. It is always recommend-
ed that an additional 10% material excess be added to the estimation.
TUBING: AND LOOP LENGTHS:
Infloorboard™ is designed for use with 3/8” nominal ASTM
F-876 PEX (cross-linked polyethylene), with an average
outer diameter measuring 0.5 inch. Loops shall never be
over 250 feet including the leaders to the manifolds. For
areas with heat loss greater than 25 BTU/Sq.Ft., loops shall
never be over 200 ft. This is due to high pressure drops and
water velocity, as shown in the following chart C-2* (grayed
area over 25 BTU/Sq. Ft). Friction losses in the chart are
approximate; actual friction losses depend on fluid viscosity
and temperature.
*The shaded area in the 250’ loop chart C-2 on the follow-
ing page indicates a high pressure drop. It is recommended
to use the shorter 200’ loop length in this case, as shown in
the second chart. Once the room square footage is determined, multiply the total
by 1.5. Example: For a 600 Sq.Ft. room, multiplying 600 by 1.5 gives 900 line-
al feet of 3/8” PEX tubing. This room would require 4 loops at 225 ft. each.
Alternatively, three 250 foot loops and one 150 foot loop could be used, provid-
ed that the flow to the different loops is balanced by using, and adjusting
correctly, balancing valves on each loop.
Notice Loop Lengths
• Notice that loop
lengths should never
be over 250’ , for heat
loss areas over 25
BTU/Sq.Ft., loop
lengths should not be
over 200’
• Since the tubing is 8”
on center, a 250’ loop
will cover a maximum
of 166 Sq.Ft. A 200’
loop will cover a max-
imum of 133 Sq.Ft.
Remember to allow
for the length to the
manifolds.