Справочник Пользователя для Radware VOYA-GRAND-PMH

September 25, 2012

7075-166

Page  33

R

Thermal Conductivity: k value
The k value indicates the amount of heat (in BTU’s) that

will flow in 1 hour through 1 square foot of a uniform mate-

rial 1 inch thick for each degree (F) of temperature differ-

ence from one side of the material to the other.  

The LOWER the k factor means less heat is being con-

ducted through the non-combustible material to the com-

bustible material beneath it.  

The k value of a material must be equal or smaller then the

required k value to be acceptable.

  (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, where-

as 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 acceptable.
Converting k to R:
Divide 1 by k and multiply the results times the thickness

in inches 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 0.84 and 3/4

inch thick.
Alternative material has a k value of 0.6 and is 3/4 inch

thick.
Divide 0.6 by .75 = k value of 0.80. This k value is smaller

than 0.84 and therefore is acceptable.