New Buck Corporation 81 User Manual

MINIMUM CLEARANCES

Floor Protection:

When installing freestanding heater, a floor protector must be use. Floor protection must be
3/8” minimum thickness non-combustible material or equivalent.

How to use alternate materials and how to calculate equivalent thickness

An easy means of determining if a proposed alternate floor protector meets requirements listed
in the appliance manual is to follow this procedure:

1. Convert specification to R-value:

R-value is given—no conversion is needed.

K-factor is given with a required thickness (T) in inches:

C-factor is given: R=1/C

2. Determine the R-value of the proposed alternate floor protector.

Use the formula in step (1) to convert values not expressed as “R”

For multiple layers, add R-values of each layer to determine the overall R-value.

3. If the overall R-value of the system is grater than the R-value of the specified floor protec-

tor, the alternate is acceptable.

Example:
The specified floor protector should be 3/4” thick material with a K-factor of 0.84.
The proposed alternate is 4” brick with a C-factor of 1.25 over 1/8” mineral board with a
K-factor of 0.29.
Step (a): Use formula above to convert specification to R-value. R= 1/K x T = 1/0.84 x .75 =

0.893

Step (b): Calculate R of proposed system. 4” brick of C=1.25, therefore Rbrick = 1/C = 1/1.25

=0.80 1/8” mineral board of K = 0.29, therefore Rmin.bd. =1/029 x0.125 = 0.431

Step (c): Compare proposed system R of 1.231 to specified R of 0.893. Since proposed

system R is greater than required , the system is acceptable.

Definitions:

Install in accordance with 24 CFR, Part 3280 (HUD).

Thermal conductance

= C =

Btu

(hr)(ft²)(°F)

(m²)(°K)

Thermal conductance

= K =

(Btu)(inch)

(Btu)

(hr)(ft²)(°F)

(m)(°K)

(hr)(ft)(°F)

Thermal conductance

= R =

(ft²)(hr)(°F)

(m²)(°K)

Btu

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