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Vertical wet vent

alaskajoe

Registered User
Joined
May 22, 2019
Messages
53
Location
Alaska
A vertical 3" stack from the second floor has a washer, utility sink, and kitchen sink on it. Can that stack be used as a wet vent for a washer, utility sink, and lav on the first floor. If so would the 3x3x2 vent connection to the stack need to be a san tee turned down instead of up?
 
As I recall, a suds producing clothes washer can’t be on a wet vent. It’s been years since I’ve looked at the plumbing code for wet venting so you shouldn’t trust me.
 
Last edited:
908.1 Vertical Wet Venting. Wet venting is limited to vertical drainage piping receiving the discharge from the trap arm of one and two fixture unit fixtures that also serves as a vent not exceeding four fixtures. Wet-vented fixtures shall be within the same story; provided, further, that fixtures with a continuous vent discharging into a wet vent shall be within the same story as the wet-vented fixtures. No wet vent shall exceed 6 feet (1829 mm) in developed length.

908.1.1 Size. The vertical piping between two consecutive inlet levels shall be considered a wet-vented section. Each wet-vented section shall be not less than one pipe size of the upper fixture or shall be one pipe size exceeding the required minimum pipe size for the sum of the fixture units served by such wet-vented section, whichever is larger, but in no case less than 2 inches (50 mm).

908.1.2 Vent Connection. Common vent sizing shall be the sum of the fixture units served but, in no case, smaller than the minimum vent pipe size required for a fixture served, or by Section 904.0.


No mention of suds.
 
908.1 Vertical Wet Venting. Wet venting is limited to vertical drainage piping receiving the discharge from the trap arm of one and two fixture unit fixtures that also serves as a vent not exceeding four fixtures. Wet-vented fixtures shall be within the same story; provided, further, that fixtures with a continuous vent discharging into a wet vent shall be within the same story as the wet-vented fixtures. No wet vent shall exceed 6 feet (1829 mm) in developed length.

908.1.1 Size. The vertical piping between two consecutive inlet levels shall be considered a wet-vented section. Each wet-vented section shall be not less than one pipe size of the upper fixture or shall be one pipe size exceeding the required minimum pipe size for the sum of the fixture units served by such wet-vented section, whichever is larger, but in no case less than 2 inches (50 mm).

908.1.2 Vent Connection. Common vent sizing shall be the sum of the fixture units served but, in no case, smaller than the minimum vent pipe size required for a fixture served, or by Section 904.0.


No mention of suds.
ICE
Is that CPC or IPC?
 
❖ Vertical wet vents used to be referred to as “stack venting.”
The vertical wet vent extends from the connection
to the dry vent down to the lowest fixture drain connection.
A common example of vertical wet venting of a
single bathroom group is shown in Commentary Figure
912.1.1(1). The two most important requirements of
vertical wet venting are that all fixtures must connect
above or at the water closet connection elevation and
all fixtures must connect independently to the vertical
wet vent. Note that fixtures connected through a double
pattern fitting are considered to be independently
connected. If more than one water closet is to be connected,
both must connect at the same elevation [see
Commentary Figure 912.1.1(2)]. Note that in this figure,
a double sanitary tee is only acceptable where the
water closet drain connection to the sanitary tee is 18
inches (457 mm) or more in horizontal developed
length distance from the outlet of the water closet (see
Section 706.3 Exception). Otherwise, the water closets
must connect through double wye and eighth-bend fitting
(also known as a “double T-wye”) [see Commentary
Figure 912.1.1(3)].
zontal offsets. Commentary Figure 912.1.1(4)
illustrates various vertical wet vent arrangements.
Section 912.2.2 regulates how the dry vent connection
is made to the vertical wet vent and Section 912.3
regulates the size of the dry vent. Both are discussed
in this commentary section for continuity. The dry vent
is an extension of the vertical wet vent and is connected
to a vent stack, stack vent, air-admittance valve
or point of termination outside of the building. The dry
vent size must be at least one-half of the largest
required pipe size served by the wet vent. For example,
in Commentary Figure 912.1.1(2), the largest pipe
served by the vertical wet vent is 3 inches (76 mm),
requiring the dry vent to be a minimum of 11/2 inches
(38 mm). If the run of the dry vent from the start of the
dry vent fixture connection to the termination of the
vent (to a vent stack, stack vent, air admittance valve
or termination outdoors) exceeds 40-feet (12 192 mm)
developed length, Section 906.2 requires the dry vent
size to be increased by one nominal pipe size for its
entire length.
 
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