NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
16
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 C1 = 10' then C2
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 CALCULATIONSStep 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.
FTF8 Vertical Elevation Chart 11" to 380 1/2"
Inches Feet/Inches 12" 18" 36" 48"
11 0 11 1 0 0 0
17 1 5 0 1 0 0
21 ¹⁄₄ 19¹⁄₄ 2000
27 ¹⁄₄ 23¹⁄₄ 1100
35 2 11 0 0 1 0
47 3 11 0 0 0 1
51 ¹⁄₄ 43¹⁄₄ 0110
57 ¹⁄₄ 49¹⁄₄ 1001
63 ¹⁄₄ 53¹⁄₄ 0101
67 ¹⁄₄ 57¹⁄₄ 2001
73 ¹⁄₄ 61¹⁄₄ 1101
81 ¹⁄₄ 69¹⁄₄ 0011
93 ¹⁄₄ 79¹⁄₄ 0002
97 ¹⁄₄ 81¹⁄₄ 0111
102 ¹⁄₂ 86¹⁄₂ 1002
109 ¹⁄₄ 91¹⁄₄ 0102
113 ¹⁄₂ 95¹⁄₂ 2002
119 ¹⁄₂ 911¹⁄₂ 1102
127 ¹⁄₄ 10 7 ¹⁄₄ 0012
137 ¹⁄₂ 11 5 ¹⁄₂ 1012
139 ¹⁄₄ 11 7 ¹⁄₄ 0003
143 ¹⁄₂ 11 11 ¹⁄₂ 0112
149 ¹⁄₂ 12 5 ¹⁄₂ 1003
155 ¹⁄₂ 12 11 ¹⁄₂ 0103
159 ³⁄₄ 13 3 ³⁄₄ 2003
165 ³⁄₄ 13 9 ³⁄₄ 1103
173 ¹⁄₂ 14 5 ¹⁄₂ 0013
183 ³⁄₄ 15 3 ³⁄₄ 1013
185 ¹⁄₂ 15 5 ¹⁄₂ 0004
189 ³⁄₄ 15 9 ³⁄₄ 0113
195 ³⁄₄ 16 3 ³⁄₄ 1004
201 ³⁄₄ 16 9 ³⁄₄ 0104
206 17 2 2 0 0 4
212 17 8 1 1 0 4
219 ³⁄₄ 18 3 ³⁄₄ 0014
230 19 2 1 0 1 4
231 ³⁄₄ 19 3 ³⁄₄ 0005
236 19 8 0 1 1 4
242 20 2 1 0 0 5
248 20 8 0 1 0 5
252 21 0 2 0 0 5
258 21 6 1 1 0 5
266 22 2 0 0 1 5
276 23 0 1 0 1 5
278 23 2 0 0 0 6
282 23 6 0 1 1 5
288 24 0 1 0 0 6
294 ³⁄₄ 24 6 ³⁄₄ 0106
298 ¹⁄₄ 24 10 ¹⁄₄ 2006
304 ¹⁄₄ 25 4 ¹⁄₄ 1106
312 26 0 0 0 1 6
322 ¹⁄₄ 26 10 ¹⁄₄ 1016
324 27 0 0 0 0 7
328 ¹⁄₄ 27 4 ¹⁄₄ 0116
334 ¹⁄₄ 27 10 ¹⁄₄ 1007
340 ¹⁄₄ 28 4 ¹⁄₄ 0107
344 ¹⁄₂ 28 8 ¹⁄₂ 2007
350 ¹⁄₂ 29 2 ¹⁄₂ 1107
358 ¹⁄₄ 29 10 ¹⁄₄ 0017
368 ¹⁄₂ 30 8 ¹⁄₂ 1017
370 ¹⁄₄ 30 10 ¹⁄₄ 0008
374 ¹⁄₂ 31 2 ¹⁄₂ 0117
380 ¹⁄₂ 31 8 ¹⁄₂ 1008
Table 3aInches Feet/Inches 12" 18" 36" 48"
386 ¹⁄₂ 32 2 ¹⁄₂ 0108
390 ³⁄₄ 32 6 ³⁄₄ 2008
396 ³⁄₄ 33 0 ³⁄₄ 1108
404 ¹⁄₂ 33 8 ¹⁄₂ 0018
414 ³⁄₄ 34 6 ³⁄₄ 1018
416 ¹⁄₂ 34 8 ¹⁄₂ 0009
420 ³⁄₄ 35 0 ³⁄₄ 0118
426 ³⁄₄ 35 6 ³⁄₄ 1009
432 ³⁄₄ 36 0 ³⁄₄ 0109
437 36 5 2 0 0 9
443 36 11 1 1 0 9
450 ³⁄₄ 37 6 ³⁄₄ 0019
461 38 5 1 0 1 9
462 ³⁄₄ 38 6 ³⁄₄ 00010
466 ³⁄₄ 38 10 ³⁄₄ 0119
472 ³⁄₄ 39 4³⁄₄ 10010
478 ³⁄₄ 39 10 ³⁄₄ 01010
483 40 3 2 0 0 10
489 40 9 1 1 0 10
496 ³⁄₄ 41 4 ³⁄₄ 00110
507 42 3 1 0 1 10
508 ³⁄₄ 42 4 ³⁄₄ 00011
513 42 9 0 1 1 10
519 43 3 1 0 0 11
525 43 9 0 1 0 11
529 ¹⁄₄ 44 1 ¹⁄₄ 20011
535 ¹⁄₄ 44 7 ¹⁄₄ 11011
543 45 3 0 0 1 11
553 ¹⁄₄ 46 1 ¹⁄₄ 10111
555 46 3 0 0 0 12
559 ¹⁄₄ 46 7 ¹⁄₄ 01111
565 ¹⁄₄ 47 1 ¹⁄₄ 10012
571 ¹⁄₄ 47 5 ¹⁄₄ 01012
575 ¹⁄₂ 47 11 ¹⁄₂ 20012
581 ¹⁄₂ 48 5 ¹⁄₂ 11012
589 ¹⁄₄ 49 1 ¹⁄₄ 00112
599 ¹⁄₂ 49 11 ¹⁄₂ 10112
601 ¹⁄₄ 50 1 ¹⁄₄ 00013
605 ¹⁄₂ 50 5 ¹⁄₂ 01112
611 ¹⁄₂ 51 11 ¹⁄₂ 10013
617 ¹⁄₂ 51 5 ¹⁄₂ 01013
621 ¹⁄₂ 51 9 ¹⁄₂ 20013
627 ¹⁄₂ 52 3 ¹⁄₂ 11013
635 ¹⁄₂ 52 11 ¹⁄₂ 00113
645 ¹⁄₂ 53 9 ¹⁄₂ 10113
647 ¹⁄₂ 53 11 ¹⁄₂ 00014
651 ¹⁄₂ 54 3 ¹⁄₂ 01113
657 ¹⁄₂ 54 9 ¹⁄₂ 10014
663 ¹⁄₂ 55 3 ¹⁄₂ 01014
667 ³⁄₄ 55 7 ³⁄₄ 20014
673 ³⁄₄ 56 1 ³⁄₄ 11014
681 ¹⁄₂ 56 9 ¹⁄₂ 00114
691 ³⁄₄ 57 7 ³⁄₄ 10114
693 ¹⁄₂ 57 9 ¹⁄₂ 00015
697 ³⁄₄ 58 1 ³⁄₄ 01114
703 ³⁄₄ 58 7 ³⁄₄ 10015
709 ³⁄₄ 59 1 ³⁄₄ 01015
714 59 6 2 0 0 15
720 60 0 1 1 0 15
727 ³⁄₄ 60 7 ³⁄₄ 00115
738 61 6 1 0 1 15
739 ³⁄₄ 61 7 ³⁄₄ 00016
744 62 0 0 1 1 15
FTF8 Vertical Elevation Chart 386 1/2" to 744"
Table 3b