Clearances To Combustibles (Ul And Ulc); Alternate Floor Protection - Quadra-Fire 41I-ACC Owner's Manual

R
B. Clearances to Combustibles, United States
and Canada (UL and ULC) (cont.)
Thermal Protection
USA and CANADA
Floor height 0" to 1-3/4"
(0 to 44mm) below insert
base.
Floor height greater than
1-3/4" (44mm) below
insert base.
0" - 1-3/4"
Thermal protection
required (1/2 inch of
R=2.38)
1-3/4" or more, Ember protection
September 15, 2011
1/2 inch (13mm) of
R=2.38
Only ember protection
required.
only
7045-178
WARNING
Fire Risk.
• Comply with all minimum clearances to
combustibles as specified.
• Failure to comply may cause house fire.
NOTE: Clearances may only be reduced by
means approved by the regulatory authority
having jurisdiction
C. Alternate Floor Protection Calculation
Material
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 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 acceptable.
(BTU) (inch)
(foot 2 (hour) ( o F)
Thermal Resistance: R value
The R value is a measure of a material's resistance 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 acceptable.
Conversion Procedure
1. Convert specification to R-value
a. R-value given - no conversion needed
b. k-factor is given with a required thickness (T) in inches. [R = 1/k X
T]
c. K-factor is given with a required thickness (T) in inches. [R = (1/K X
12) X T]
d. r-factor is given with a required thickness (T) in inches. [R = r X T]
2. Determine the R-value of the proposed alternate floor protector
a. Use the formula in step 1 to convert values not expressed as "R".
b. For multiple layers, add R-values of each layer to determine overall
R-value.
3. If the overall R-value of the system is greater than the R-value of the specified
floor protector, the alternate is acceptable.
41I ACC Wood Insert
Page 33