Whitfield Profile 20 FS Installation And Operation Manual page 5

PLANNING YOUR INSTALLATION
FLOOR PROTECTION - Profile    20 FS & Profile    30 FS
These appliances require
non-combustible floor pro-
tection. The floor protector
must be a 3/8" (minimum)
UL approved hearth pad or
equivalent. If the floor pro-
tection is to be stone, tile,
brick, etc., it must be mor-
tared or grouted to form a
continuous non-combust-
ible surface (see Using
Alternate Material as Floor
Protector on this page). If a
chimney connector extends horizontally over the floor, the
protection must cover the floor under the connector and
at least 2" to either side.
A non-combustible floor protector must fully cover
the area beneath the appliance and extend 6" to the
front, 6" to the sides, and 1" from the back (see il-
lustration bellow).
FLOOR PROTECTION / HEARTH EXTENSION USING AL-
TERNATE MATERIAL AS FLOOR PROTECTOR (also see
Floor Protection above for freestanding models and
Hearth Requirements, page 7 for an insert model)
The alternate material used as a floor protector or
hearth extension must be constructed of a durable non-
combustible material having an equal or better insulat-
ing value (lower k value) of k = 1.28 BTU / IN FT
or a thermal resistance that equals or exceeds r = 78
HR °F FT
2
IN / BTU. With these values, determine the
minimum thickness / material required using the formula
and the table shown here (see chart - Alternative Floor
Protection Materials).
Note: Any noncombustible material having a thickness
of 1" whose k value is less than 1.28 or whose r value is
more than .78 is acceptable. If the alternate material
used has a higher k value or lower r value will require a
greater thickness of the material used. In some cases, if
the k value is less or the r value higher, a thinner mate-
rial may be used.
Methods of determining floor protection equivalents
To determine the thickness required for any material
when either the k or r values are known:
T = Thickness of material in inches
M
K = K value of desired material
M
T = Minimum listed thickness
L
Example: Micore CV230 is to be used for the floor pro-
tection. How thick must this material be?
Top View
HR °F
2
PAGE 5
The following formulas give the means of determining
minimum thickness required of alternate materials.
Using the k formula:
Desired thickness k value of desire
of the alternate = material (per inch)
material k value of listed
material (per inch)
T (inches) = K x T
M
M L
1.28
T (inches) = 0.43* x 1"
M
1.28
Answer using k = 0.34 x 1" = 0.34 = 3/8"
3/8" thickness Micore will be required.
Using the r formula:
T (inches) = 0.78 x T
M
r
M
T (inches) = 0.78 x 1"
M
2.33*
Answer using r = 0.34 x 1" = .034 = 3/8"
3/8" thickness Micore will be required.
At times it is important to know what combination of
materials are acceptable for use as floor protection. The
"R values" are used to determine acceptable combina-
tions of materials because "R values" are additive where
r and k values are not.
"R value" = 1 = r x thickness of material used
k
ALTERNATIVE FLOOR PROTECTION MATERIALS
Listed
Material k
(per inch)
Millboard 1.28
Alternative
Materials k
(per inch)
Wonderboard 1.92
Common brick 5.00
Cement mortar 5.00
Ceramic tile 12.5
Marble 11.0
Micore CV230 0.43
(U.S. Gypsum)
Ceraform 126 0.27
(Johns-Manville)
Example: Given that the required "R value" for a suitable
floor protector used must be equal to or greater than:
"R" = r x T = 0.78 x 1" = 0.78.
L
Minimum thickness
x of listed
material
L
Values Min. Thick
r
(per inch)
0.78
Values Min. Thick
r
(per inch)
0.56 1 1/2"
0.20 3 7/8"
0.20 3 7/8"
0.08 9 3/4"
0.09 8 5/8"
2.33 3/8"
3.70 1/4"
T
L
1"
T
L