Fireplace Liner Sizing Guide
The standard 10-1 ratio has been used in the chart below. To be safe, we recommend a 10-1 ratio for chimneys less than 25 feet in height and a 12-1 ration for chimneys greater than 25 feet in height.Please contact us for other sizes or with any further questions.
Fireplace OpeningUp to 600 sq. in |
Liner Size9" |
| 601 - 760 sq. in. | 10" |
| 761 - 942 sq. in. | 11" |
| 943 - 1140 sq. in. | 12" |
| 1141 - 1356 sq. in. | 14" |
| 1357 - 1846 sq. in. | 16" |
Liner Sizing Charts
Calculate the area needed for fireplace liners of various shapes:| Rectangle |
1.
Figure the opening for the fireplace (length x width) 2. Divide this number by 12 |
| Circle |
Area = pi r2 Circumference = pi d pi = 3.14 r = radius (half of diameter) r2 = radius squared d = diameter Look at the charts below for round or ovalized liners. |
| Oval |
1. Divide the shape into a rectangle and two half circles (1/2 circle on each end
of the rectangle) 2. Figure the area for the rectangle 3. Then figure the area for the circle 4. Add the two amounts together. This gives you the approximate area of the oval Look at the charts below for round or ovalized liners. |
| Square | Area = length (L) x width (W) |
| Triangle | Area = length (L) x width (W) x 1/2 |
Use a liner size where the square inches for the liner is larger than the number you came up with. This is the appropriate liner for this fireplace opening.
Area in Square Inches of ROUND Liners
| 3" | 4" | 5" | 6" | 7" | 8" | 9" | 10" | 11" | 12" |
| 7.07 | 12.56 | 19.63 | 28.26 | 38.46 | 50.25 | 63.58 | 78.5 | 94.99 | 113.14 |
Area in Square Inches of OVALIZED M-Flex Liners
Original
|
12" | 63 | 72 | 79 | 86 | 93 | 99 | 102 | 106 | 113 |
| 11" | 57 | 65 | 72 | 78 | 83 | 87 | 92 | 95 | * | |
| 10" | 50 | 57 | 63 | 68 | 72 | 76 | 79 | * | * | |
| 9" | 43 | 50 | 53 | 56 | 61 | 63 | * | * | * | |
| 8" | 36 | 42 | 45 | 48 | 50 | * | * | * | * | |
| 7" | 32 | 34 | 36 | 38 | * | * | * | * | * | |
| 6" | 24 | 25 | 28 | * | * | * | * | * | * | |
| 5" | 18 | 19 | * | * | * | * | * | * | * | |
| 4" | 5" | 6" | 7" | 8" | 9" | 10" | 11" | 12" | ||
The Size of the Liner Ovalized To |
||||||||||
Calculating the Dimension of the LARGER SIDE of an M-Flex OVALIZED Liner
Original
|
12" | 16.5" | 16.2" | 15.7" | 15.4" | 15.0" | 14.5" | 14.0" | 13.0" | * |
| 11" | 15.3" | 14.8" | 14.3" | 13.6" | 12.8" | 12.0" | 11.5" | * | * | |
| 10" | 13.8" | 13.3" | 13.0" | 12.5" | 12.0" | 11.3" | * | * | * | |
| 9" | 12.5" | 12.0" | 11.8" | 10.8" | 10.0" | * | * | * | * | |
| 8" | 10.5" | 10.3" | 9.5" | 9.0" | * | * | * | * | * | |
| 7" | 9.3" | 8.8" | 8.3" | * | * | * | * | * | * | |
| 6" | 7.7" | 7.0" | * | * | * | * | * | * | * | |
| 5" | 5.7" | * | * | * | * | * | * | * | * | |
| 4" | 5" | 6" | 7" | 8" | 9" | 10" | 11" | 12" | ||
The Smaller Side of the M-Flex Ovalized Liner
|
||||||||||