Hearth & Home Technologies 5100I-NL-B 用户手册

Page 10

September 1, 2008

R 

438-0380D

Thermal  protection  must  be  1/2  inch  (13mm)  minimum

thickness (“k” value = 0.8) or equivalent material.
All floor protection must be non-combustible (i.e., metals, 

brick, stone, mineral fiber boards, etc.).  Any organic materi-

als (i.e., plastics, wood paper products, etc.) are combustible

and must not be used.  The floor protection specified includes 

some form of thermal designation such as R-value (thermal

resistance) or k-factor (thermal conductivity).

If the hearth extension is lower than the fireplace opening, 

the portion of the insert extending onto the hearth must be

supported.    Manufacturer  designed  adjustable  support  kit 

can be ordered from your dealer.

The k value indicates the amount of heat (in BTU’s) that will flow 

in 1 hour through 1 square foot of a uniform material 1 inch thick 

for each degree (F) of temperature difference from one side of 

the material to the other.  The LOWER the k factor means less 

heat is being conducted through the non-combustible material to

the combustible material beneath it.  The k value of a material 

must be equal or smaller then the required k value to be accept-

able.

(BTU) (inch)

(foot

2

(hour) (

o

F)

Thermal Resistance: R value
The  R  value  is  a  measure  of  a  material’s  resisteance  to  heat

transfer. R value is convenient when more than one material is

used since you can add the R values together, whereas you can

not do this for k value.  The HIGHER the R factor means less 

heat is being conducted through the non-combustible material to

the combustible material beneath it. The R value of a material

must be equal or larger then the required R value to be accept-

able.
Converting k to R:
Divide 1 by k and multiply the results times the thickness in inch-

es of the material.
 

R = 1/k x inches of thickness

Converting R to k:
Divide the inches of thickness by R.
 

k = inches of thickness/R

Calculatons:
Example: Floor protection requires k value of 0.8 and / inch 

thick.
Alternative material has a k value of 0.6 and is / inch thick.
Divide 0.6 by .5 = k value of 0.80.  This k value is smaller than 

0.84 and therefore is acceptable.

Hearth & Home HX, HX

0.43

2.33

1/2 in.

USG Micore 00™

0.46

2.18

1/2 in.

USG Durock™ Cement Board

1.92

0.52

2-1/4 in.

Cement Mortar

5.0

0.20

5-7/8 in.

Common Brick

5.0

0.20

5-7/8 in.

Ceramic Tile

12.50

0.08

14-5/8 in.

Marble

14.3-

20.0

0.07-

0.05

16-5/8 in.

- 23-3/8 in.