Hearth Extension Dimensions

 

 

 

A

16"

 

 

 

B

38"

 

 

 

C

8"

 

 

 

D

54"

 

 

 

Note: To convert

inches to millimeters

C

B

C

 

 

A

divide by 0.03937

 

 

D

 

 

 

 

 

Figure 47

Methods of Determining Hearth Extension and Wall Shield

Equivalents - To determine the thickness required for the alternate material when either the “k” value or “r” value is known, use either the k formula or r formula.

Example: If Micore 160 is to be used for the hearth extension fireplace, how thick must this material be?

kM = k value per inch of alternate material rM = r value per inch of alternate material

TM = minimum thickness required for alternate material TS = standard thickness of the alternate material

kL = k value per inch of listed material rL = r value per inch of listed material

TL = minimum thickness of listed material

Note: An asterix “*” indicates, it is a value taken from Table 1.

Using the k formula:

Minimum

 

k-value (per Inch) of

 

Specified min.

thickness of

=

alternate material (kM) x

thickness

alternate

 

k-value (per inch)

 

of listed

material (TM)

 

of listed material (kM)

 

material (TL)

TM (inches)

=

kM

x

TL

 

 

*.43

 

 

TM (inches)

=

*.35

x

1"

 

 

*.43

 

 

.875 (inches) =

.875

x

1"

Answer - The minimum required thickness of the Micore 160 is .875”, therefore round up to 7/8” and use the nearest standard thickness available which is 1”.

Using the r formula:

Minimum

 

r-value (per Inch)

 

Specified min.

thickness of

=

of listed material

x

thickness

alternate

 

r-value (per inch)

 

of listed

material

 

of alternate material

 

material

TM (inches)

=

rL

x

TL

 

 

rM

 

 

TM (inches)

=

*2.33

x

1"

 

 

*2.86

 

 

.875 (inches) =

.875

x

1"

Answer - The minimum required thickness of the Micore 160 is .875”, therefore round up to 7/8” and use the nearest standard thickness available which is 1”.

Listed Material

 

k (per inch)

r (per inch)

Listed Min.Thickness

Listed Material

0.43

2.33

1"

 

KL

rL

TL

** Approved Alternate Materials for Floor/Hearth Protection

AlternativeMaterials

Thermal Values

MinimumThickness

 

 

 

(rounded to nearest 1/8 inch)

 

k (per inch)

r (per inch)

Min. Thickness

 

KM

rM

TM

Kaowool M Board

.47

2.13

1.09" (1-1/8")

Micore 160™

.35

2.86

.81" (7/8")

U.S. Gypsum

 

 

 

Micore 300™

.46

2.17

1.07" (1-1/8")

U.S. Gypsum

 

 

 

Durock™ Cement Board

1.92

.52

4.47" (4-1/2")

U.S. Gypsum

 

 

 

Hardibacker™

1.95

.513

4.53" (4-1/2")

Hardibacker 500™

2.30

.435

5.35" (5-3/8")

Cultered Stone Hearth-

2.82

.355

6.56" (6-1/2")

stone™

 

 

 

Wonderboard

3.23

.31

7.51" (7-1/2")

Super Firetemp M

.61

1.64

1.42" (1-3/8")

Johns-Manville

 

 

 

Super Firetemp L

.54

1.85

1.26" (1-1/4")

Johns-Manville

 

 

 

Face brick

9.00

.111

20.93" (20-7/8")

Common brick

5.00

.20

11.63" (11-5/8")

Cement mortar

5.00

.20

11.63" (11-5/8")

Ceramic tile

12.5

.08

29.07" (29-1/8")

Marble

11.0

.09

25.58" (25-5/8")

Table 1

**If the hearth extension material(s) that is intended to be used is NOT listed on Table 1, the material can still be used if the material(s) is noncombustible. However, the manufacturer of the material must provide either the listed k- value per inch or r-value per inch with listed thickness so that the minimum thickness required for the hearth can be calculated (per instructions on this Page and/or as specified in the NFI Certification manuals).

Note: Also see NFI (National Fireplace Institute) Certification Manuals showing other acceptable calculation methods and acceptable alternate materials which can be used.

NOTE: DIAGRAMS & ILLUSTRATIONS NOT TO SCALE.

17

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Image 17
Lennox Hearth RDI-42-H Hearth Extension Dimensions, Methods of Determining Hearth Extension and Wall Shield, Inches =

RDI-42-H, HCI-42-H, RDI-42, HCI-42 specifications

The Lennox Hearth series includes some of the most impressive gas fireplaces available, such as the HCI-42, RDI-42-H, HCI-42-H, and RDI-42. These models are designed to blend efficiency, style, and comfort, making them ideal for modern homes.

One of the standout features of these fireplaces is their versatile design. They come in various sizes to fit a range of spaces while offering customization options that allow homeowners to tailor their aesthetic, including various trim finishes and decorative options. The HCI-42 and RDI-42-H models are particularly noted for their seamless integration into both traditional and contemporary home decor.

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Safety features are integral to Lennox Hearth products. These include sealed combustion systems that prevent outdoor air from entering the home and built-in safety shut-off systems to ensure peace of mind. The HCI-42 and its counterparts have been rigorously tested for safety and performance, adhering to strict industry standards.

In summary, the Lennox Hearth HCI-42, RDI-42-H, HCI-42-H, and RDI-42 bring together cutting-edge technology, beautiful design, and ease of use to offer homeowners a top-tier fireplace experience. With their efficient heating capabilities, customizable aesthetics, and emphasis on safety, these models stand out as exceptional choices for modern living spaces. Whether you are looking to enhance your home’s ambiance or increase energy efficiency, Lennox Hearth fireplaces are a smart investment for any homeowner.