Table 1.8.15F: CIRCULAR EQUIVALENTS OF RECTANGULAR BREECHINGS & STACKS
WIDTH
(INCHES)
HEIGHT (INCHES)
6 8 10 12
14 16 18 20 22 24 26 28 30 36 42 48 54 60
6
7 8 8 9 10 10 11 11 12 12 13 13 14 15 16 17 17 18
8
8 9 10 11
11 12 13 13 14 15 15 16 16 15 19 20 21 21
10
8 10
11 12
13 14 15 15 16 17 17 18 18 17 21 22 23 24
12
9 11
12 13
14 15 16 17 18 18 19 20 20 20 23 25 26 27
14
10 11
13 14
15 16 17 18 19 20 21 21 22 22 26 27 29 30
16
10 12
14 15
16 17 19 20 20 21 22 23 24 24 28 29 31 32
18
11 13
15 16
17 19 20 21 23 23 24 24 25 26 29 31 33 34
20
11 13
15 17
18 20 21 22 24 24 25 26 27 27 31 33 35 37
22
12 14
16 18
19 20 22 23 25 25 26 27 28 29 33 35 37 39
24
12 15
17 18
20 21 23 24 26 26 27 28 29 31 34 37 39 40
26
13 15
17 19
21 22 24 25 27 27 28 29 31 32 36 38 40 42
28
13 16
18 20
21 23 24 26 28 28 29 31 32 35 37 40 42 44
30
14 16
18 20
22 24 25 27 31 29 31 32 33 36 39 41 44 46
36
15 17
20 22
24 26 27 29 33 32 33 35 36 39 42 45 48 50
42
16 19
21 23
26 28 29 31 35 34 36 37 39 42 46 49 52 55
48
17 20
22 25
27 29 31 33 37 37 38 40 41 45 49 52 56 59
54
17 21
23 26
29 31 33 35 39 39 40 42 44 48 52 56 59 62
60
18 21
24 27
30 32 34 37 39 40 42 44 46 50 55 59 62 66
1.8.16 SPECIAL APPLICATIONS
FLUE GAS ECONOMIZERS
When applying flue gas economizers, care must
be taken to assure that:
1. Proper draft must be maintained. This requires
that the gas side pressure drop be considered
and that the economizer exchanger must be
designed so as to allow cleaning.
2. The vent system materials must be considered,
regarding resistance from corrosion, which might
result from the lower flue gas temperature.
3. In general, it is recommended that the boiler
manufacturer be consulted when a flue gas
economizer is to be added.
HIGH EFFICIENCY APPLIANCES
High efficiency appliances require special
consideration in vent design because of the
reduced stack gas temperatures. Under no
circumstances can a condensing type appliance
be vented into the same vent system with other
appliances. The vent system for such appliances
must be provided by or specified specifically by
the manufacturer of the condensing appliance.
High efficiency non-condensing appliances
should generally be installed only on vent
systems that are resistant to corrosion from flue
gas condensate. This generally requires stainless
steel vent construction.
Summary of Contents for Forced Draft Steam Boilers
Page 34: ......
