Install Instructions

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IM-PR 566442 1114 (Design Manual)
Design Considerations
CSA B214 ASHRAE 90.1 ASHRAE 189.1 ASHRAE / ACCA 183 IMC IIECC ASHRAE 55 ACI 318 LEED
Loop balancing X X X X
System controls X X X X X
Credit for radiant energy savings X X X X
Distribution system installation or specification X X X
Insulation X X X X X
Load calculation X X X X X
Circulating pumps X X X
Radiant heating requirement for unenclosed spaces X X X
Snow melt X X X X X
Designing for comfort X X X X
Peak load reduction X
Table 3-1 Radiant design considerations as addressed by commercial national model codes, standards and
green building programs. Check with your local jurisdiction for applicability.
3.2 Insulation
Recommended minimum levels of slab insulation are given in Table 3-2 based on a location’s climate
zone, which can be found in Figure 1-8. If radiant floor delivery temperatures are limited by the equipment
type, higher levels of insulation can be specified to increase the heat transfer between the conditioned
space and the slab. In all cases, a vapor barrier should be provided under slabs with ground contact for all
indoor installations. Always provide full sub-slab insulation and adequate drainage where there is a high
water table.
Application
Slab with Ground Contact, Perimeter
Insulation by Climate Zone
Suspended Slab (e.g., between
floors), Horizontal Insulation
Heating Only
CZ 1-2: R-7.5, 12-inch depth
CZ 3: R-10, 24-inch depth
CZ 4-5: R-15, 24-inch depth
CZ 6-8: R-20, 48-inch depth
R-value that is 5 times the value of
the floor covering’s R-value. See
Table 3-3 for more detail on the back
loss as a function of insulation below
the suspended slab.
Cooling Only
R-5 where chilled slab abuts
unconditioned space
Same as heating
Heating and Cooling Same as heating Same as heating
Table 3-2 Minimum recommended R-values for slab insulation of conditioned slabs. Perimeter insulation
may be applied on the interior or exterior of the foundation. Perimeter insulation should be applied vertically
or a combination of vertically and horizontally, when it extends to at least the depth of the slab. Listed
depths are measured from the top of the slab.