Hearth and Home Technologies BIR50-B - Manual (Page 33)

33
Roof radiation
shields
Allow a 1 in. (25 mm) air gap between
storm collar and chase top flashing
1/2 in. (13 mm) air space
established by spacers
1/2 in.
overhang
14 in. (345 mm)
diameter chimney
must extend at least
6 in. (152 mm) above
chase top flashing.
DuraChimney II
Pipe
1/2 in.
(13 mm)
Spacers for chase
top flashing
Chase Top
Flashing
Storm Collar
20 in. diameter
opening
Chimney Cap
Maintain 2 in. (51 mm)
clearance between
DuraChimney II and
chase enclosure
• Chase top shrouds may be field constructed where
permitted by regional building codes.
WARNING! Risk of Fire! Shrouds must be constructed as
specified. Improper construction may overheat chase top.
NOTICE: Some regional codes require an agency-Listed
shroud. Consult your local building officials.
10
Shrouds
• Hearth & Home Technologies Inc. supplies UL listed
shrouds. See your dealer for details.
A. Shroud Requirements
Figure 10.1 Shroud Requirements
Shrouds can either be field-fabricated or factory-fabricated,
but they must meet the requirements as specified in these
instructions. Shrouds must be constructed of a minimum
24 ga (.024 in.) stainless steel, aluminized steel, galva-
nized steel, or copper. Other materials may also be used,
such as brick, mortar, stucco, stone, etc. provided they are
completely non-combustible. Check with your local building
code authroities for any additional shroud requirements.
Shrouds must be able to be removed to allow chimney ac-
cess to properly clean the chimney. DuraChimney II instal-
lations which include the use of a shroud must comply with
the following requirements (Figure 10.1)
• DuraChimney II must maintain at least 2 in. (51 mm)
clearance from combustible materials.
• The chase enclosure must be ventilated.
• The chase top flashing or field-fabricated chase pan must
be used. Field-fabricated chase pans are acceptable if
they meet these requirements:
- Material must be 24 ga (.024 in) galvanized steel or
equivalent.
- Chase pan must have opening 3 in. (76 mm) larger
than outside diameter of chimney pipe with at least a
1/2 in. (13 mm) upturned flange/collar.
- Chase pan must overhang chase by 1/2 in. (13 mm)
per side for proper air flow.
- Chase pan must have a 1 in. (25 mm) down turned
outside edge (weather protection).
Heatilator • Birmingham BIR50-B • 4059-682D• 9/12