Lennox Hearth HCI-36-H, RDI-36-H Special Offset Instructions, Offset Calculations

12

4.Determine amount of chimney height re- quired by subtracting total combined height of all pre-selected components (fireplace and chimney components from total desired height.)

Reference Vertical Elevation Chart and deter- mine the number of chimney sections (quantity and length) required.

SPECIAL OFFSET INSTRUCTIONS

To clear any overhead obstructions, you may offset your chimney system using Security's 30° offset and return elbows. Use two elbows - an offset elbow to initiate the offset and a return elbow to terminate it. A 30° offset elbow, an- gling in any direction, may be the first compo- nent used off the top of the fireplace flue collar.

The offset and return elbows may be attached together, or a section or sections of chimney may be used between, but do not exceed 20' in total length between elbows. If sections of pipe exceed 10' between elbows, a chimney stabilizer must be used at the midpoint (Figure 37 ). The stabilizer support straps must be attached under tension (in shear) to structural framing mem- bers above. When two sets of elbows are used, the maximum combined length of chimney used between elbows cannot exceed 20' (Figure 38 ). Example: If C1 = 10' then C2 cannot exceed 10'.

If an offset exceeds 6' in length, each chimney joint beyond the first 6' of offset to the return elbow, must be secured by a No. 8 x 1/2" sheet metal screw located at the underside of the joint (Figure 39 ).

A 1/8" diameter hole must be drilled in the chimney joint using a 1/8" diameter drill. Hole should be drilled in center of joint overlap (Fig- ure 40 ). Be sure to drill only through the outer chimney casting. Do not puncture the inner flue.

Maximum offset of chimney system is 30° . Two offsets must not be assembled to form a 60° offset. However, two sets of offset and return elbows may be used on a single flue system, provided the total height of the system exceeds 25'.

Return elbow support straps must be securely attached under tension (in shear) to structural framing members above. Do not substitute a FTF8-30 offset elbow in place of a FTF8-E30 return elbow.

OFFSET CALCULATIONS

Step 1. Use Offset Chart to determine amount of horizontal offset (A) and height (B) for vari- ous chimney section assemblies.

Step 2. Use “Height of Chimney Only” column											Step 3. Use Elevation Chart as job estimator
in The Vertical Elevation Chart to determine											only. Add necessary firestop spacers and stabi-
combinations of chimney used above return											lizers as required. Firestop spacers must be
elbow to achieve desired heights. Reference											used as shown in Figures 23 and 24 and
Components Effective Height Chart in vertical											stabilizers as shown in Figure 29.
elevation chart section.
					FTF8 VERTICAL					ELEVATION CHART
		Height Of				Number Of FTF8						Height Of				Number Of FTF8
	Chimney Only					Chimney Lengths						Chimney Only				Chimney Lengths
	Inches		Feet/Inches			12"	18"	36"	48"		Inches		Feet/Inches			12"	18"	36"	48"
	11		0	11		1	0	0	0		386	¹⁄₂	32	2	¹⁄₂	0	1	0	8
	17		1	5		0	1	0	0		390	³⁄₄	32	6	³⁄₄	2	0	0	8
	21	¹⁄₄	1	9	¹⁄₄	2	0	0	0		396	³⁄₄	33	0	³⁄₄	1	1	0	8
	27	¹⁄₄	2	3	¹⁄₄	1	1	0	0		404	¹⁄₂	33	8	¹⁄₂	0	0	1	8
	35		2	11		0	0	1	0		414	³⁄₄	34	6	³⁄₄	1	0	1	8
	47		3	11		0	0	0	1		416	¹⁄₂	34	8	¹⁄₂	0	0	0	9
	51	¹⁄₄	4	3	¹⁄₄	0	1	1	0		420	³⁄₄	35	0	³⁄₄	0	1	1	8
	57	¹⁄₄	4	9	¹⁄₄	1	0	0	1		426	³⁄₄	35	6	³⁄₄	1	0	0	9
	63	¹⁄₄	5	3	¹⁄₄	0	1	0	1		432	³⁄₄	36	0	³⁄₄	0	1	0	9
	67	¹⁄₄	5	7	¹⁄₄	2	0	0	1		437		36	5		2	0	0	9
	73	¹⁄₄	6	1	¹⁄₄	1	1	0	1		443		36	11		1	1	0	9
	81	¹⁄₄	6	9	¹⁄₄	0	0	1	1		450	³⁄₄	37	6	³⁄₄	0	0	1	9
	93	¹⁄₄	7	9	¹⁄₄	0	0	0	2		461		38	5		1	0	1	9
	97	¹⁄₄	8	1	¹⁄₄	0	1	1	1		462	³⁄₄	38	6	³⁄₄	0	0	0	10
	102	¹⁄₂	8	6	¹⁄₂	1	0	0	2		466	³⁄₄	38	10	³⁄₄	0	1	1	9
	109	¹⁄₄	9	1	¹⁄₄	0	1	0	2		472		³⁄₄	39	4³⁄₄	1	0	0	10
	113	¹⁄₂	9	5	¹⁄₂	2	0	0	2		478	³⁄₄	39	10	³⁄₄	0	1	0	10
	119	¹⁄₂	9	11	¹⁄₂	1	1	0	2		483		40	3		2	0	0	10
	127	¹⁄₄	10	7	¹⁄₄	0	0	1	2		489		40	9		1	1	0	10
	137	¹⁄₂	11	5	¹⁄₂	1	0	1	2		496	³⁄₄	41	4	³⁄₄	0	0	1	10
	139	¹⁄₄	11	7	¹⁄₄	0	0	0	3		507		42	3		1	0	1	10
	143	¹⁄₂	11	11	¹⁄₂	0	1	1	2		508	³⁄₄	42	4	³⁄₄	0	0	0	11
	149	¹⁄₂	12	5	¹⁄₂	1	0	0	3		513		42	9		0	1	1	10
	155	¹⁄₂	12	11	¹⁄₂	0	1	0	3		519		43	3		1	0	0	11
	159	³⁄₄	13	3	³⁄₄	2	0	0	3		525		43	9		0	1	0	11
	165	³⁄₄	13	9	³⁄₄	1	1	0	3		529	¹⁄₄	44	1	¹⁄₄	2	0	0	11
	173	¹⁄₂	14	5	¹⁄₂	0	0	1	3		535	¹⁄₄	44	7	¹⁄₄	1	1	0	11
	183	³⁄₄	15	3	³⁄₄	1	0	1	3		543		45	3		0	0	1	11
	185	¹⁄₂	15	5	¹⁄₂	0	0	0	4		553	¹⁄₄	46	1	¹⁄₄	1	0	1	11
	189	³⁄₄	15	9	³⁄₄	0	1	1	3		555		46	3		0	0	0	12
	195	³⁄₄	16	3	³⁄₄	1	0	0	4		559	¹⁄₄	46	7	¹⁄₄	0	1	1	11
	201	³⁄₄	16	9	³⁄₄	0	1	0	4		565	¹⁄₄	47	1	¹⁄₄	1	0	0	12
	206		17	2		2	0	0	4		571	¹⁄₄	47	5	¹⁄₄	0	1	0	12
	212		17	8		1	1	0	4		575	¹⁄₂	47	11	¹⁄₂	2	0	0	12
	219	³⁄₄	18	3	³⁄₄	0	0	1	4		581	¹⁄₂	48	5	¹⁄₂	1	1	0	12
	230		19	2		1	0	1	4		589	¹⁄₄	49	1	¹⁄₄	0	0	1	12
	231	³⁄₄	19	3	³⁄₄	0	0	0	5		599	¹⁄₂	49	11	¹⁄₂	1	0	1	12
	236		19	8		0	1	1	4		601	¹⁄₄	50	1	¹⁄₄	0	0	0	13
	242		20	2		1	0	0	5		605	¹⁄₂	50	5	¹⁄₂	0	1	1	12
	248		20	8		0	1	0	5		611	¹⁄₂	51	11	¹⁄₂	1	0	0	13
	252		21	0		2	0	0	5		617	¹⁄₂	51	5	¹⁄₂	0	1	0	13
	258		21	6		1	1	0	5		621	¹⁄₂	51	9	¹⁄₂	2	0	0	13
	266		22	2		0	0	1	5		627	¹⁄₂	52	3	¹⁄₂	1	1	0	13
	276		23	0		1	0	1	5		635	¹⁄₂	52	11	¹⁄₂	0	0	1	13
	278		23	2		0	0	0	6		645	¹⁄₂	53	9	¹⁄₂	1	0	1	13
	282		23	6		0	1	1	5		647	¹⁄₂	53	11	¹⁄₂	0	0	0	14
	288		24	0		1	0	0	6		651	¹⁄₂	54	3	¹⁄₂	0	1	1	13
	294	³⁄₄	24	6	³⁄₄	0	1	0	6		657	¹⁄₂	54	9	¹⁄₂	1	0	0	14
	298	¹⁄₄	24	10	¹⁄₄	2	0	0	6		663	¹⁄₂	55	3	¹⁄₂	0	1	0	14
	304	¹⁄₄	25	4	¹⁄₄	1	1	0	6		667	³⁄₄	55	7	³⁄₄	2	0	0	14
	312		26	0		0	0	1	6		673	³⁄₄	56	1	³⁄₄	1	1	0	14
	322	¹⁄₄	26	10	¹⁄₄	1	0	1	6		681	¹⁄₂	56	9	¹⁄₂	0	0	1	14
	324		27	0		0	0	0	7		691	³⁄₄	57	7	³⁄₄	1	0	1	14
	328	¹⁄₄	27	4	¹⁄₄	0	1	1	6		693	¹⁄₂	57	9	¹⁄₂	0	0	0	15
	334	¹⁄₄	27	10	¹⁄₄	1	0	0	7		697	³⁄₄	58	1	³⁄₄	0	1	1	14
	340	¹⁄₄	28	4	¹⁄₄	0	1	0	7		703	³⁄₄	58	7	³⁄₄	1	0	0	15
	344	¹⁄₂	28	8	¹⁄₂	2	0	0	7		709	³⁄₄	59	1	³⁄₄	0	1	0	15
	350	¹⁄₂	29	2	¹⁄₂	1	1	0	7		714		59	6		2	0	0	15
	358	¹⁄₄	29	10	¹⁄₄	0	0	1	7		720		60	0		1	1	0	15
	368	¹⁄₂	30	8	¹⁄₂	1	0	1	7		727	³⁄₄	60	7	³⁄₄	0	0	1	15
	370	¹⁄₄	30	10	¹⁄₄	0	0	0	8		738		61	6		1	0	1	15
	374	¹⁄₂	31	2	¹⁄₂	0	1	1	7		739	³⁄₄	61	7	³⁄₄	0	0	0	16
	380	¹⁄₂	31	8	¹⁄₂	1	0	0	8		744		62	0		0	1	1	15