Isokern IBV-36, Установка, эксплуатация и обслуживание

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Venting Installation (cont.)
Mechanical Vent Systems:
It is acceptable to use mechanical draft systems, if the venting
companies do the engineering calculations and make the
necessary recommendations for fan size and flue vent diameter
following the guidelines of NFPA 211/2006, pg. 211-13.
Installation of such systems must also follow the mechanical
drafting company’s explicit installation and operation
instructions.
The B-Vent type chimney system must be enclosed within a
chase when installed in or passing through a living area where
combustibles or people may come in contact with it. This is
important to prevent possible personal injury or fire hazard.
Chimney Height Requirements:
Vent terminations must be located in accordance
with the height and proximity rules of ANSI Z223.1 / NFPA
54 or CANCGA B149. These rules apply to vents of twelve
inch (12”) diameter and less and require minimum height in
accordance with the roof pitch and a minimum of eight feet (8’)
distance from a vertical wall or other obstruction.
The location selected for the vent termination can
have significant influence on proper draft performance of the
appliance. On a windy day, obstructions such as nearby walls,
trees or topographical features can create high pressure zones.
The vent can become susceptible to windy conditions and tend
to back draft when it is located in such high pressure zones.
In situations where the vent must be installed in a
location that is less than eight feet (8’) from a wall, parapet or
other obstruction, the vent cap must be located at least two feet
(2’) above the obstruction.
For roofs from flat to 7/12 pitch the vent cap must be
positioned at least one foot (1’) above the roof surface.
As the roof pitch increases above 7/12 the roof begins
to act much as a wall with high pressure zones being created
by wind striking the roof itself. To compensate for this it is
necessary to increase the termination height of the vent. The
steeper the roof pitch the greater the vent height needed to
overcome the high pressure zone. See chart below for minimum
height requirements.
B-Type Vent Termination Chart (Figure 23)
(For 10 inch (10”) diameter and smaller B-Type Vent)
Roof Pitch Minimum Height (H)
Flat Roof up to 7/12 1 foot
over 7/12 up to 8/12 1.5 feet
over 8/12 up to 9/12 2 feet
over 9/12 up to 10/12 2.5 feet
over 10/12 up to 11/12 3.25 feet
over 11/12 up to 12/12 4 feet
over 12/12 up to 14/12 5 feet
over 14/12 up to 16/12 6 feet
over 16/12 up to 18/12 7 feet
over 18/12 up to 20/12 7.5 feet
over 20/12 up to 21/12 8 feet
8 ft. minimum
Listed vent cap
12
x
Roof pitch x/12
listed clearance
Listed gas vent
Lowest
discharge
opening
H (min.) Height from roof
Figure 22
Figure 23