FIG. 16 – METHODS OF STRUCTURAL REINFORCEMENT
FOR ELBOWS
2-45° ELBOWS REINFORCED WITH PLATE SUPPORTS
2-45° ELBOWS REINFORCED WITH WALL SUPPORTS
CHIMNEY OFFSETS
Offsets should be avoided except when there is no other way to
route the chimney. When an offset must be used, good design
indicates that the angle used should be the minimum possible (See
FIG. 18
). If the appliance currently burns solid fuel or is capable
of being converted to burn solid fuel, the offset cannot exceed 30
degrees. No more than 2 offsets (4 elbows) may be used.
TABLE 8
indicates minimum center to center offset for two
elbows connected directly to each other.
FIG. 17 — MINIMUM ELBOW OFFSETS
(REFER TO TABLE 8)
TABLE 8 - MINIMUM OFFSETS
MINIMUM ELBOW OFFSETS PIC & IPIC-1
PIPE DIA.
“A” - 30° ELBOW
“A” - 45° ELBOW
6” thru 12”
14”
16” thru 24”
26” thru 36”
38” thru 48”
6” (152)
7 3/4” (197)
7 3/4” (197)
8 1/2” (216)
11” (279)
9 7/8” (251)
14 1/8” (359)
14 1/2” (368)
16 5/8” (422)
19 3/4” (503)
MINIMUM ELBOW OFFSETS IPIC-2
PIPE SIZE
“A” - 30° ELBOW
“A” - 45° ELBOW
6” thru 10”
12”
14” thru 22”
24” thru 34”
36” thru 46”
48”
6” (152)
7 3/4” (197)
7 3/4” (197)
8 1/2” (216)
11” (279)
12 3/4” (324)
9 7/8” (251)
14 1/8” (359)
14 1/2” (368)
16 5/8” (422)
19 3/4” (503)
23 3/4” (602)
MINIMUM ELBOW OFFSETS IPIC-4
PIPE SIZE
“A” - 30° ELBOW
“A” - 45° ELBOW
6”
8”
10” thru 18”
20” thru 30”
32” thru 42”
44” thru 48”
6” (152)
7 3/4” (197)
7 3/4” (197)
8 1/2” (216)
11” (279)
12 3/4” (324)
9 7/8” (251)
14 1/8” (359)
14 1/2” (368)
16 5/8” (422)
19 3/4” (503)
23 3/4” (602)
Bracing, above and below the elbows, is needed to avoid
subjecting them to bending moments. In order for bracing to
be effective, it must be rigidly attached to building members or
foundation. The design of the structure used to attach supports
must include the weight of the sloped section and whatever
additional pipe is carried by the support. Additionally, an
expansion joint or bellows joint is needed between the elbows to
relieve thermal expansion stresses.
ANGLE
45° FIXED ELBOW
PLATE SUPPORT
PLATE SUPPORT
ANGLE BRACING
PLATE SUPPORT
ANGLE BRACING
45° FIXED ELBOW
ANGLE
WALL SUPPORT
“A”
FIG. 18 – SUPPORT FOR CHIMNEY OFFSETS
HALF ANGLE
RING
45° FIXED ELBOW
EXPANSION JOINT
PLATE SUPPORT
MAX. 25 FT. (7620)
(OIL OR SOLID FUEL)
WALL SUPPORT ASSY.
OR PLATE SUPPORT
WALL SUPPORT ASSY.
OR PLATE SUPPORT
30° MAX. FOR OIL OR SOLID FUEL
EXPANSION JOINT
EXPANSION JOINT
30° FIXED ELBOW OR
45° FIXED ELBOW
30° FIXED ELBOW OR
45° FIXED ELBOW
VENTILATED THIMBLE ASSEMBLY
OR ROOF SUPPORT ASSEMBLY
9
used singly or in combination to provide turns of 30, 45, 60,
75, or 90 degrees. For engine or turbine exhaust systems, it
is recommended that 90º turns be accomplished by using two
(2) 45º elbows or a combination of one 45º elbow and one 45º
manifold tee to minimize flow resistance.