Vermont Casting 647 BFC manual Chimney Requirements Offset Installations

BFC36 Balance Flue Heat-Circulating Fireplace

Chimney Requirements - Offset Installations

CHIMNEY FLUE EXIT

		Chimney
		Section
		Elbow		30°
				Return
A		B	G	Elbow
			30°	G
D			Offset
	E	Rise	Elbow
C	6 FT.			TCS8A
			30°
		H	Return	Support
	Offset		Elbow
				H
			30°
B
			Offset
			Elbow

	Hearth
	Floor
Example 1	Example 2	Example 3

Notes: G + H cannot exceed	20 feet.	FP269
Air Space Clearances:	= 2” Min. to Combustibles

OFFSET

RISE

						IWF282
	30˚ Elbow Offsets
1’	1¹⁄₂'	3’	4’	Chimney Support	Offset	Rise
0	0	0	0	0	3”	11”
1	0	0	0	0	8¹⁄₄"	20"
0	1	0	0	0	11¹⁄₄" 25¹⁄₄"
2	0	0	0	0	13¹⁄₂" 29¹⁄₄"
1	1	0	0	0	16¹⁄₂" 34¹⁄₄"
0	0	1	0	0	20¹⁄₄" 40³⁄₄"
2	1	0	0	0	21³⁄₄" 43¹⁄₂"
0	0	0	1	0	26¹⁄₄" 51¹⁄₄"
0	1	1	0	0	28¹⁄₂" 55¹⁄₄"
1	0	0	1	0	31¹⁄₂" 60¹⁄₄”
0	1	0	1	0	34¹⁄₂" 65¹⁄₂"
0	0	2	0	0	37¹⁄₂" 70³⁄₄"
1	1	0	1	1	41¹⁄₂" 77³⁄₄"
0	0	1	1	1	45" 83³⁄₄"
0	1	2	0	1	47¹⁄₄" 87¹⁄₂"
0	0	0	2	1	51"	94"
0	1	1	1	1	53¹⁄₄"	98"
0	0	3	0	1	56¹⁄₄" 103¹⁄₄"
0	1	0	2	1	59¹⁄₄"	108¹⁄₂"

Illustration Key

The following safety rules apply to offset installations (letters correspond with illustration above):

A. Height of the chimney is measured from the hearth to the chimney exit.

	BFC36
Maximum:	50’0”
Minimum:
Without Elbows	14’6”
With 2 Elbows*	14’6”
With 4 Elbows*	21’0”

B. Do not use more than 4 elbows per chimney.

Attach the straps of the return (top) elbow to a structural framing member.

The offset (first) elbow of any pair does not have straps.

C. The chimney cannot be more than 30˚ (45˚ in Canada) from the vertical plane in any installation*.

D. The maximum length of the angled run of the total chimney system is 20 feet. (G plus H cannot exceed 20 feet.)

E. A chimney support (Model TCS8A) is required every 6 feet of angled run of chimney. Chimney supports are required for every 30 feet and 60 feet of vertical chimney height above the hearth.

Determine the offset distance of your chimney arrangement from the centerline of the fireplace to the centerline of the chimney where it is to pass through the first ceiling.

NOTE: This offset distance may not be your full offset distance. See Examples 2 and 3.

0	0	2	1	1	62¹⁄₄" 113¹⁄₂"
0	1	3	0	1	64¹⁄₂" 117¹⁄₂"
0	0	1	2	1	68¹⁄₄"	124"
0	1	2	1	1	70¹⁄₂"	128"
0	0	0	3	1	74¹⁄₄" 134¹⁄₂"
0	1	1	2	2	78" 140³⁄₄"
0	0	3	1	2	81"	146"
0	1	0	3	2	84" 151¹⁄₄"
0	0	2	2	2	87" 156¹⁄₂"
0	1	3	1	2	89¹⁄₄" 160¹⁄₄"
0	0	1	3	2	93" 166³⁄₄"
0	1	2	2	2	95¹⁄₄" 170³⁄₄"
0	0	0	4	2	99¹⁄₄" 177³⁄₄"
0	1	1	3	2	101¹⁄₄" 181³⁄₄"
0	0	3	2	2	104¹⁄₄" 186¹⁄₄"
0	1	0	4	2	107¹⁄₄" 191¹⁄₂"
0	0	2	3	2	110¹⁄₄" 196³⁄₄"
0	1	3	2	3	114" 203¹⁄₄"
0	0	1	4	3	117³⁄₄" 209³⁄₄"
0	1	2	3	3	120" 213¹⁄₂"
0	0	0	5	3	123³⁄₄"	220"

Fig. 3 Chimney system requirements.

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