All traps must be protected from syphonage, and the waste pipes leading from them ventilated by special vent pipes of sizes as follows:
Size of trap
(inches)
Size of vent pipe
(inches)
4
2
3
2
2
1 1/2
1 1/2
1 1/4
1 1/4
1 1/4
A. 
The seal of any trap to a plumbing fixture shall not be less than two inches.
B. 
Vent pipes must not extend less than eight inches nor more than two feet above the roof of any building, and shall be increased one size for all sizes under four inches before passing through the roof. It will, however, be permissible to connect these vent pipes together and branch them into main vent above the top of the highest fixtures. These vent pipes must always have a continuous slope to avoid collecting water by condensation; minimum horizontal runs 1 1/2 inches. The bowing of vent pipes must be avoided.
C. 
All main vents or vent stacks shall connect full size at their base to the main soil or waste pipe at or below the lowest fixture branch and shall extend undiminished in size and shall be reconnected with the main soil or waste vent at least 3 1/2 feet above the highest fixture branch.
D. 
All vent pipes and fittings must be of galvanized wrought iron, galvanized steel pipe, cast-iron hub-and-spigot pipe, known in commerce as extra-heavy, or cast-iron screw pipe and fittings approved, may be used. Also, copper may be used.
E. 
The horizontal vent pipes leaving the vent T in the stack to relieve the closet must be two inches in size. Where but one fixture enters the closet bend, the waste and vent pipe shall be 1 1/2 inches.
F. 
Washdown and syphon water closets, when above the cellar or basement, need not be back vented where the bend or ferrule of the closet is ventilated by any other fixture.
G. 
A single closet on an upper floor need not be back vented when within five feet of main soil line. All plumbing fixtures in cellar or basement shall be back vented separately, except where a waste from another fixture connects to a closet bend, then the waste and vent from said fixture must be not less than two inches. Toilet rooms consisting of a group of closets, urinals and showers may be vented by a loop or shaft vent.
A. 
The number of fixtures connected to a back-vent pipe shall not be more than as set forth in the following table:
Fixture Unit Equivalents
Fixture
Fixture units
1 closet counts as
6
1 floor urinal counts as
3
1 slop sink counts as
3
B. 
Back vents for water closets and other fixtures with traps over two inches:
Size of vent
(inches)
Number of closets
Number of fixture units
2
2
12
2 1/2
7
42
3
12
72
4
54
324
5
75
450
6
96
756
8
244
1,464
C. 
Back vents for fixtures with traps two inches and smaller:
Size of vents
(inches)
Number of 1 1/2 inch traps
1 1/4
1
1 1/2
3
2
12
2 1/2
42
3
72
4
324
5
450
6
576
8
1,464
A. 
In new and existing buildings where a closet is placed on the first floor and a washstand is required in connection with the same, the said fixtures may be vented by a two-inch vent; provided, however, there is a three inch or four-inch stack or stacks extending full size through the roof.
B. 
All vent couplings must be either ground joint or brass soldering nipples, right and left couplings with running thread and locknut or Tucker connection.
C. 
Trap back-vent pipes shall be continuous. Where the vent pipes are continuous and traps are ventilated through the waste fitting, the center of the outlet of such fitting shall not be set below the water seal of the trap and the trap shall not be more than three feet from the waste fitting. No crown venting will be permitted.
D. 
All roof extensions of soil and waste stacks shall be run full size at least eight inches above the roof and, when the roof is used for other purposes than weather protection, such extension shall be not less than 10 feet above the roof and be protected.
E. 
Where two fixtures discharge into a double T-Y branch and there are no other fixtures discharging above them, said fixtures may be back vented through a common vent pipe, provided that waste and vent pipe be of full size.
F. 
A branch or waste pipe to which three and not more than eight water closets, urinal stalls and trap for shower stalls are connected in a series may be ventilated by a circuit or loop vent, which shall be taken off in front of the last fixture connection, and in no case shall the loop vent be less than full size, as may be approved by the Examining Board of Plumbers.
G. 
Double hubs, common offsets, shortneck bends, saddles or tapping soil pipe to receive the waste pipe from fixtures and T's are prohibited. Offsets of a forty-five-degree angle, double hubs and T's for vent connections may be used above all waste openings.
H. 
A combination lead bend and ferrule will not be allowed.
I. 
Soil, waste or vent pipes shall not be used as rain leaders.
J. 
Slip joints on waste pipes on sewer side of trap to fixture or fixtures allowed.
K. 
In no case shall the waste pipe from any plumbing fixture be connected to a water-closet trap.
L. 
No form of trap will be permitted that has an interior chamber or plates, nor one that depends upon interior partitions for a seal.
A. 
No trap plumbing fixtures shall be located in any room or apartment which does not contain a window placed in an external wall of the building or is not provided with a system of ventilation.
B. 
Compartments containing not more than four water closets or their equivalent shall be located in an apartment containing windows of sufficient area to ventilate properly the compartment, placed in the external walls of the building, or shall be provided with a mechanical means of ventilation which will change the air at a normal temperature at least six times per hour.
C. 
Compartments containing more than four water closets or their equivalent shall be located either in an apartment containing windows and provided with a gravity or mechanical system of ventilation which will change the air at normal temperature not less than six times per hour; or may be placed in a compartment without windows in the external wall of the building, provided a mechanical system of ventilation is installed which will change the air at normal temperature not less than six times per hour.
D. 
Alternate for B and C. Every toilet room and every water closet or urinal compartment, unless provided with a suitable system of exhaust ventilation, shall be ventilated directly to the outer air by movable windows or by skylights with fixed or pivoted louvers. Every such toilet room or compartment shall have a window or glass skylight not less than one-foot wide, and an area of not less than two square feet for one water closet or urinal, and the area of the window or skylight shall be increased by at least one square foot for every additional water closet or urinal.
E. 
If a mechanical system of ventilation is used, such system shall consist of metal or smooth masonry ducts extending from the individual toilet rooms or compartments to a fan or fans of sufficient capacity to exhaust a volume of not less than 30 cubic feet of air per minute for each water closet or urinal, and in no case shall less than six changes of air in the toilet room or compartment be allowed per hour. The exhaust duct shall discharge into the outside air above the room and in such a manner as not to create objectionable odors or a nuisance on the premises or adjacent premises.
F. 
Ventilation from toilet rooms shall be separate and distinct and have no connection whatever with the other ventilating ducts in the building.
A. 
Plunger, pan, prison or long-hopper closets are not allowed. Flush-rim hoppers may be used in compartments that have no direct connection with a building used for human habitation. The hopper must be flushed with a tank protected from frost and the trap for said hopper must be placed just below the floor and properly protected from frost by the use of mineral wool packing. It shall be ventilated with a three-inch stack, and increased to four inches before passing through the roof.
B. 
Wooden laundry trays or sinks are prohibited.
A. 
All urinals having either intermitten or automatic flushing devices shall be flushed at regular intervals not to exceed 10 minutes each during the hours that such fixtures are in use.
B. 
All urinals, troughs or gutters other than those heretofore prescribed shall be constructed of materials impervious to moisture and that will not corrode under the action of urine. When the floor gutters are used as urinals, the gutters shall be made with portland cement or other impervious material, and the floors and walls within five feet of such gutter shall be made equally watertight and impervious.
C. 
The lip of all stall urinals must be set below the top of the floor so that all water or urine will drain from the floor to the urinal waste outlet, or a separate floor drain shall be provided for the toilet room.
D. 
No closet trough or urinal trough shall be allowed in any house or building.
No privy vault or cesspool will be allowed on any premises where there is a sewer and the town water is in said street.
Local or vapor vent pieces from hospital sterilizers or any plumbing fixture or fixtures must be carried through the roof separately.
Any local vent or duct pipes installed to ventilate the interior of a room where any plumbing fixture or fixtures are installed shall have no connection whatever with other ventilating pipes or ducts in building. Such local vents shall be extended through the roof, or they may be connected into an available heated flue.
A. 
Where a lavatory, bath and shower are wasted into the same waste line, which waste line is taken off from a closet bend, said waste line must be at least two inches in size. The tub in such case may be vented through the lavatory, if the waste pipe and the vent are run 1 1/2 inches in size. The shower must have a waste pipe of at least two inches in size and may be vented by a one-and-one-quarter-inch size vent to the roof, and through such vent, shall be increased to 1 1/2 inches or may be vented by a one-and-one-quarter-inch size pipe back into the tub vent three or more feet above the floor.
B. 
Where a one-and-one-half-inch bath waste is run from a closet bend, it must be vented by a one-and-one-quarter-inch vent pipe, but the portion running horizontally from the one-and-one-quarter-inch vent pipe to the stack must be at least 1 1/2 inches in size. If said bath waste is vented through the roof, it must be increased to 1 1/2 inches in size or more, through the roof.
C. 
Where a lavatory or bath is wasted into a two-inch pipe from a closet bend and the bath trap is not more than three feet from the lavatory waste Y, the bath trap need not be vented. When a bath trap is vented through the lavatory waste pipe, the waste pipe and the vent pipe must be 1 1/2 inches in size to the soil stack, or increased to at least two inches before passing through the roof.
D. 
Where a bath waste pipe is taken off the soil stack and not off the closet bend, and the stack, being three inches or four inches in size, is continued through the roof or back to the main vent pipe, the toilet need not be back vented if the toilet opening is not more than five feet from the main soil pipe and the top waste inlet not more than 1 1/2 inches higher than the crown of the soil pipe. One lavatory or one sink may be wasted into the stack above the toilet as a high fixture.