|
• (1) The wet vent and its extension to the vent stack is
<br />2" in diameter.
<br />(2) Each water closet below the top floor is individually
<br />back vented.
<br />(3) The vent stack is sized as given in Table 5.
<br />22.1-113. Table 5—Size of Vent Stacks, Wet Vented Fixtures.
<br />Number of Wet -Vented Fixtures Diameter of Vent Stacks
<br />Inches
<br />1 or 2 bathtubs or showers 2
<br />3 to 5 bathtubs or showers 21/2
<br />6 to 9 bathtubs or showers 3
<br />10 to 16 bathtubs or showers 4
<br />Exception—In multistory bathroom groups, wet vented in
<br />accordance with paragraph 3 of the water closets below the
<br />top floor need not be individually vented if the 2" waste con-
<br />nects directly into the water closet bend.
<br />22.1-114. Stack Venting.
<br />(c) Vent Connections.
<br />• When the circuit, loop, or relief vent connections are taken
<br />off the horizontal branch, the vent branch connection shall
<br />be taken off at a Vial angle or from the top of the hori-
<br />zontal branch.
<br />(d) Fixtures Back=to_Ba cit 4n Battery.
<br />b9�
<br />When fixtures are conn f -ted to one horizontal branch
<br />through a double wye or a double sanitary tee in a vertical
<br />position, a common vent for each two fixtures back-to-back
<br />or double connection shall be provided. The common vent shall
<br />be installed in a vertical position as a continuation of the
<br />double connection.
<br />I
<br />22.1-116. Relief Vent.
<br />(a) Stacks of More than 10 Branch Intervals.
<br />Soil and waste stacks in buildings having more than 10
<br />branch intervals shall be provided with a relief at each tenth
<br />interval installed, beginning with the top floor. The size of
<br />the relief vent shall be equal to the size of the vent stack to
<br />which it connects. The lower end of each relief vent shall
<br />•
<br />connect to the soil or waste stack through a wye below the
<br />horizontal branch serving the floor and the upper end shall
<br />connect to the vent stack through a wye not less than 3 feet
<br />above the floor level.
<br />(b) Offsets at an Angle Less than 45 Degrees from the
<br />Horizontal in Buildings of Five or More Stories.
<br />Offsets less than 45 degrees from the horizontal, in a soil
<br />or waste stack, shall comply with paragraphs on Separate
<br />Venting and Offset Reliefs.
<br />(c) Separate Venting.
<br />Such offsets may be vented as two separate soil or waste
<br />stacks, namely, the stack section below the offset and the
<br />stack section above the offset.
<br />(d) Offset Reliefs.
<br />Such offsets may be vented by installing a relief vent as a
<br />vertical continuation of the lower section of the stack or as a
<br />side vent connected to the lower section between the offset and
<br />the next lower fixture or horizontal branch. The upper section
<br />of the offset shall be provided with a yoke vent. The diameter
<br />of the vents shall not be less than the diameter of the main
<br />vent, or of the soil or waste stack, whichever is the smaller.
<br />22.1-117. Main Vent to Connect at Base.
<br />All main vents or vent stacks shall connect full size at their
<br />base to the building drain or to the main soil or waste pipe,
<br />at or below the lowest fixture branch. All vent pipes shall
<br />extend undiminished in size above the roof, or shall be re-
<br />connected with the main soil or waste vent.
<br />22.1-118. Vent Headers.
<br />Stack vents and vent stacks may be connected into a com-
<br />mon vent header at the top of the stacks and then extend to
<br />the open air at one point. This header shall be sized in accord-
<br />ance with the requirements of Table 6, the number of units
<br />being the sum of all units on all stacks connected thereto and
<br />the developed length being the longest vent length from the
<br />intersection at the base of the most distant stack to the vent
<br />terminal in the open air as the direct extension of one stack.
<br />22.1-119. Size and Length of Vents.
<br />(a) Length of Vent Stacks.
<br />The length of the vent stack or main vent shall be its de-
<br />veloped length from the lowest connection of the vent system
<br />with the soil stack, waste stack, or building drain to the vent
<br />stack terminal, if it terminates separately in the open air, or to
<br />the connection of the vent stack with the stack vent, plus the
<br />developed length of the stack vent from the connection to
<br />the terminal in the open air, if the two vents are connected
<br />together with a single extension to the open air.
<br />(b) Size of Individual Vents.
<br />The diameter of an individual vent shall be not less than
<br />11/2 inches nor less than one-half the diameter of the drain to
<br />which it is connected.
<br />(c) Size of Relief Vent.
<br />The diameter of a relief vent shall be not less than one-half
<br />the diameter of the soil or waste branch to which it is con-
<br />nected.
<br />(d) Size of Circuit or Loop Vent.
<br />The diameter of a circuit or loop vent shall be not less than
<br />one-half the size of the diameter of the horizontal soil or
<br />waste branch or the diameter of the vent stack, whichever is
<br />smaller.
<br />(e) Size of Vent Piping.
<br />The nominal size of vent piping shall be determined from its
<br />length and the total of fixture units connected thereto, as
<br />provided in Table 6. Twenty per cent of the maximum length
<br />may be installed in a horizontal position.
<br />(a) One Bathroom Group.
<br />A group of fixtures, consisting of one bathroom group and
<br />•
<br />a kitchen sink or combination fixture, may be installed with-
<br />out individual fixture vent, in a one story building on the
<br />top floor of a building, provided each fixture drain connects
<br />independently to the stack, and the bathtub or shower stall
<br />drain enters the stack at the same level or into the water closet
<br />bend.
<br />All fixtures discharging downstream from a water closet
<br />shall be vented.
<br />(b) Limits of Fixture Units Above Bathtubs and Water
<br />Closets.
<br />A fixture or combination of fixtures whose total discharge
<br />rating is not more than 3 fixture units, may discharge into a
<br />Cb
<br />stack not less than 3 inches in diameter without reventing,
<br />provided such fixture connections are made above the con-
<br />nection to the highest water closet or bathtub tee-wye, and
<br />the fixture -unit rating of the stack is not otherwise exceeded.
<br />22.1-115. Circuit and Loop Venting.
<br />(a) Battery Venting.
<br />A branch soil or waste pipe to which two but not more
<br />than eight water closets, pedestal urinals, shower stalls, or
<br />floor drains are connected in battery, shall be vented by a
<br />circuit or loop vent which shall take off in front of the last
<br />fixture connection. In addition, lower floor branches serving
<br />more than three water closets shall be provided with a relief
<br />vent taken off in front of the first fixture connection. When
<br />lavatories or similar fixtures discharge above ,such branches,
<br />each vertical branch shall be provided with a continuous vent.
<br />(b) Dual Branches.
<br />When parallel horizontal branches serve a total of eight
<br />water closets (four on each branch), each branch shall be
<br />provided with a relief vent at a point between the two most
<br />distant water closets. When other fixtures (than water clos-
<br />ets) discharge above the horizontal branch, each such fixture
<br />shall be vented.
<br />(c) Vent Connections.
<br />• When the circuit, loop, or relief vent connections are taken
<br />off the horizontal branch, the vent branch connection shall
<br />be taken off at a Vial angle or from the top of the hori-
<br />zontal branch.
<br />(d) Fixtures Back=to_Ba cit 4n Battery.
<br />b9�
<br />When fixtures are conn f -ted to one horizontal branch
<br />through a double wye or a double sanitary tee in a vertical
<br />position, a common vent for each two fixtures back-to-back
<br />or double connection shall be provided. The common vent shall
<br />be installed in a vertical position as a continuation of the
<br />double connection.
<br />I
<br />22.1-116. Relief Vent.
<br />(a) Stacks of More than 10 Branch Intervals.
<br />Soil and waste stacks in buildings having more than 10
<br />branch intervals shall be provided with a relief at each tenth
<br />interval installed, beginning with the top floor. The size of
<br />the relief vent shall be equal to the size of the vent stack to
<br />which it connects. The lower end of each relief vent shall
<br />•
<br />connect to the soil or waste stack through a wye below the
<br />horizontal branch serving the floor and the upper end shall
<br />connect to the vent stack through a wye not less than 3 feet
<br />above the floor level.
<br />(b) Offsets at an Angle Less than 45 Degrees from the
<br />Horizontal in Buildings of Five or More Stories.
<br />Offsets less than 45 degrees from the horizontal, in a soil
<br />or waste stack, shall comply with paragraphs on Separate
<br />Venting and Offset Reliefs.
<br />(c) Separate Venting.
<br />Such offsets may be vented as two separate soil or waste
<br />stacks, namely, the stack section below the offset and the
<br />stack section above the offset.
<br />(d) Offset Reliefs.
<br />Such offsets may be vented by installing a relief vent as a
<br />vertical continuation of the lower section of the stack or as a
<br />side vent connected to the lower section between the offset and
<br />the next lower fixture or horizontal branch. The upper section
<br />of the offset shall be provided with a yoke vent. The diameter
<br />of the vents shall not be less than the diameter of the main
<br />vent, or of the soil or waste stack, whichever is the smaller.
<br />22.1-117. Main Vent to Connect at Base.
<br />All main vents or vent stacks shall connect full size at their
<br />base to the building drain or to the main soil or waste pipe,
<br />at or below the lowest fixture branch. All vent pipes shall
<br />extend undiminished in size above the roof, or shall be re-
<br />connected with the main soil or waste vent.
<br />22.1-118. Vent Headers.
<br />Stack vents and vent stacks may be connected into a com-
<br />mon vent header at the top of the stacks and then extend to
<br />the open air at one point. This header shall be sized in accord-
<br />ance with the requirements of Table 6, the number of units
<br />being the sum of all units on all stacks connected thereto and
<br />the developed length being the longest vent length from the
<br />intersection at the base of the most distant stack to the vent
<br />terminal in the open air as the direct extension of one stack.
<br />22.1-119. Size and Length of Vents.
<br />(a) Length of Vent Stacks.
<br />The length of the vent stack or main vent shall be its de-
<br />veloped length from the lowest connection of the vent system
<br />with the soil stack, waste stack, or building drain to the vent
<br />stack terminal, if it terminates separately in the open air, or to
<br />the connection of the vent stack with the stack vent, plus the
<br />developed length of the stack vent from the connection to
<br />the terminal in the open air, if the two vents are connected
<br />together with a single extension to the open air.
<br />(b) Size of Individual Vents.
<br />The diameter of an individual vent shall be not less than
<br />11/2 inches nor less than one-half the diameter of the drain to
<br />which it is connected.
<br />(c) Size of Relief Vent.
<br />The diameter of a relief vent shall be not less than one-half
<br />the diameter of the soil or waste branch to which it is con-
<br />nected.
<br />(d) Size of Circuit or Loop Vent.
<br />The diameter of a circuit or loop vent shall be not less than
<br />one-half the size of the diameter of the horizontal soil or
<br />waste branch or the diameter of the vent stack, whichever is
<br />smaller.
<br />(e) Size of Vent Piping.
<br />The nominal size of vent piping shall be determined from its
<br />length and the total of fixture units connected thereto, as
<br />provided in Table 6. Twenty per cent of the maximum length
<br />may be installed in a horizontal position.
<br />
|