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Heatilator • Birmingham BIR50-B Installation Manual • 4059-701 • Rev G • 06/29/15
• Field-fabricated spacing clips (1/2 in./13 mm tall, 24
ga/.024 in. galvanized steel) must be used to support
the chase top flashing or chase pan, in order to provide
air flow.
• 14 in. (345 mm) DuraChimney II pipe must extend at
least 6 in. (152 mm) above the chase pan/flashing.
• A DuraChimney II cap must be used inside the shroud.
• The shroud must not be in direct contact with any of the
DuraChimney II components (other than the chase top
flashing).
• All open areas of the shroud must be covered with 1/2
in. (13 mm) stainless or galvanized steel mesh screen
to prevent debris from entering the shroud.
• Shrouds must follow the dimensional requirements
specified in Tables 5.1, 5.2 or 5.3, depending on the
style of shroud used. The three basic shroud styles are
1) House, 2) Arch or Mailbox, and 3) Pyramid. Most
factory-fabricated shrouds will fall under one of these
basic style categories.
B. House Style Shroud
The house-style shroud is roughly square or rectangular
with a closed top and exhaust openings on four sides
(Figure 5.2). Table 5.1 lists the minimum shroud dimen-
sions, the minimum open area per side, and the minimum
total open area for the shroud.
H
W
L
Shaded area represents screened open area. Actual
shape of shroud may vary as long as minimum dimen-
sions and minimum open area requirements are met.
H: Minimum height of shroud
L: Minimum length of shroud
W: Minimum width of shroud
Figure 5.2 House-Style Shroud Minimum Dimensions
House Style Shroud Minimum Dimensions
Chimney
Diameter
Chimney Area Min Height H Min Length L Min Width W
Min Open Area
per side
Min Total Open
Area
in
mm
in
mm
in
mm
in
mm
in
mm
sq in
sq in
14
355.6
154
3911.6
24
609.6
32
812.8
32
812.8
260
1040
Table 5.1
