Radware VOYA-GRAND-PMH Lawn Mower User Manual


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September 25, 2012
7075-166
Page 33
VOYAGEUR GRAND Wood Insert
R
C. Calculating Alternate Floor Protection
Material
Thermal Conductivity: k value
Thekvalueindicatestheamountofheat(inBTU’s)that
willow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.
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