Offset Calculations; Vertical Elevation Charts - Lennox Hearth Products MP-36OD Installation Instructions Manual

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 45). The
stabilizer support straps must be attached
under tension (in shear) to structural framing
members above. When two sets of elbows
are used, the maximum combined length of
chimney used between elbows cannot exceed
20' (Figure 46). Example: If C
cannot exceed 10'.
If an offset exceeds 6' in length, each chimney
joint beyond the fi rst 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 47).
A 1/8" diameter hole must be drilled in the
chimney joint using a 1/8 " diameter drill. The
hole should be drilled in center of joint overlap
(Figure 48). Be sure to drill only through the
outer chimney casting. Do not puncture the
inner fl ue.
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 fl ue
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 the Offset Chart (Table 4) to deter-
mine amount of horizontal offset (A) and height
(B) for various chimney section assemblies.
Step 2. Use "Height of Chimney Only" column
in The Vertical Elevation Chart to determine
combinations of chimney used above return
elbow to achieve desired heights. Reference
Components Effective Height Chart in vertical
elevation chart section.
Step 3. Use Elevation Chart as job estimator only.
Add necessary fi restop spacers and stabilizers
as required. Firestop spacers must be used as
shown in Figures 31 & 32 and stabilizers as
shown in Figure 37.
16
FTF8 Vertical Elevation Chart
Inches
11
17
21
27
35
47
51
= 10' then C
57
1 2
63
67
73
81
93
97
102
109
113
119
127
137
139
143
149
155
159
165
173
183
185
189
195
201
206
212
219
230
231
236
242
248
252
258
266
276
278
282
288
294
298
304
312
322
324
328
334
340
344
350
358
368
370
374
380
Table 3a
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
11" to 380 1/2"
Feet/Inches 12" 18" 36" 48"
0 11 1 0 0
1 5 0 1 0
1 9 2 0 0
2 3 1 1 0
2 11 0 0 1
3 11 0 0 0
4 3 0 1 1
4 9 1 0 0
5 3 0 1 0
5 7 2 0 0
6 1 1 1 0
6 9 0 0 1
7 9 0 0 0
8 1 0 1 1
8 6 1 0 0
9 1 0 1 0
9 5 2 0 0
9 11 1 1 0
10 7 0 0 1
11 5 1 0 1
11 7 0 0 0
11 11 0 1 1
12 5 1 0 0
12 11 0 1 0
13 3 2 0 0
13 9 1 1 0
14 5 0 0 1
15 3 1 0 1
15 5 0 0 0
15 9 0 1 1
16 3 1 0 0
16 9 0 1 0
17 2 2 0 0
17 8 1 1 0
18 3 0 0 1
19 2 1 0 1
19 3 0 0 0
19 8 0 1 1
20 2 1 0 0
20 8 0 1 0
21 0 2 0 0
21 6 1 1 0
22 2 0 0 1
23 0 1 0 1
23 2 0 0 0
23 6 0 1 1
24 0 1 0 0
24 6 0 1 0
24 10 2 0 0
25 4 1 1 0
26 0 0 0 1
26 10 1 0 1
27 0 0 0 0
27 4 0 1 1
27 10 1 0 0
28 4 0 1 0
28 8 2 0 0
29 2 1 1 0
29 10 0 0 1
30 8 1 0 1
30 10 0 0 0
31 2 0 1 1
31 8 1 0 0
FTF8 Vertical Elevation Chart
386 1/2" to 744"
Inches Feet/Inches 12" 18" 36" 48"
386 32 2
0
390 32 6
0
396 33 0
0
404 33 8
0
414 34 6
0
416 34 8
1
420 35 0
0
426 35 6
1
432 36 0
1
437 36 5
1
443 36 11
1
450 37 6
1
461 38 5
2
462 38 6
1
466 38 10
2
472 39 4
2
478 39 10
2
483 40 3
2
489 40 9
2
496 41 4
2
507 42 3
3
508 42 4
2
513 42 9
3
519 43 3
3
525 43 9
3
529 44 1
3
535 44 7
3
543 45 3
3
553 46 1
4
555 46 3
3
559 46 7
4
565 47 1
4
571 47 5
4
575 47 11
4
581 48 5
4
589 49 1
4
599 49 11
5
601 50 1
4
605 50 5
5
611 51 11
5
617 51 5
5
621 51 9
5
627 52 3
5
635 52 11
5
645 53 9
6
647 53 11
5
651 54 3
6
657 54 9
6
663 55 3
6
667 55 7
6
673 56 1
6
681 56 9
6
691 57 7
7
693 57 9
6
697 58 1
7
703 58 7
7
709 59 1
7
714 59 6
7
720 60 0
7
727 60 7
7
738 61 6
8
739 61 7
7
744 62 0
8
Table 3b
0 1 0 8
2 0 0 8
1 1 0 8
0 0 1 8
1 0 1 8
0 0 0 9
0 1 1 8
1 0 0 9
0 1 0 9
2 0 0 9
1 1 0 9
0 0 1 9
1 0 1 9
0 0 0 10
0 1 1 9
1 0 0 10
0 1 0 10
2 0 0 10
1 1 0 10
0 0 1 10
1 0 1 10
0 0 0 11
0 1 1 10
1 0 0 11
0 1 0 11
2 0 0 11
1 1 0 11
0 0 1 11
1 0 1 11
0 0 0 12
0 1 1 11
1 0 0 12
0 1 0 12
2 0 0 12
1 1 0 12
0 0 1 12
1 0 1 12
0 0 0 13
0 1 1 12
1 0 0 13
0 1 0 13
2 0 0 13
1 1 0 13
0 0 1 13
1 0 1 13
0 0 0 14
0 1 1 13
1 0 0 14
0 1 0 14
2 0 0 14
1 1 0 14
0 0 1 14
1 0 1 14
0 0 0 15
0 1 1 14
1 0 0 15
0 1 0 15
2 0 0 15
1 1 0 15
0 0 1 15
1 0 1 15
0 0 0 16
0 1 1 15