Section 117. Soil and Waste Pipes and Traps

Description

This section is from the book "The Building Code Of The City Of Boston", by City of Boston Building Department. Also available from Amazon: Building Code of the City of Boston.

Section 117. Soil and Waste Pipes and Traps

Par. 1. - The waste pipe of every independent sink, basin, bath-tub, water-closet, slop-hopper, urinal or other fixture shall be furnished with a separate trap which shall be placed as near as practicable to the fixture which it serves. A sink and set of three wash-trays may be connected to the house drain through one five inch round trap, when the outlet of the sink is not over three feet six inches from the nearest outlet from the wash-trays; and in such case the trap shall be above the floor. The outlet from each fixture shall enter the trap separately. Not more than four wash-bowls or sinks in a continuous line may be connected to the house drain through one five inch round trap. Two or more fixtures on the same level with not more than two feet of waste pipe and connecting into the soil or waste pipe not more than eighteen inches below the top water fine of the trap, shall not require other vent than the continuation of the soil or waste pipe full size for its whole length. Lateral branches of soil or waste pipe, if more than twenty feet in length, shall be extended through the roof undiminished in size. All connections on lead waste and back air pipes and of lead pipes to brass ferrule and soldering nipples shall be full size wiped soldered branch, round or flange joints. Soil and waste pipes shall have proper T-Y or Y branches for all fixture connections. No connection to lead bends for water-closets or slop sinks shall be permitted, except the required back air pipe where a continuous vent is not practicable.

Earthenware Traps

Par. 2. - Earthenware traps shall have heavy brass floor plates soldered to the lead bends and bolted to the trap flange, and the joint made gas tight with red or white lead. Rubber washers for floor connections shall not be used.

Back Air Pipes, Vents, Etc

Par. 3. - Traps shall be protected from siphonage or air pressure by special iron or brass air pipes of a size not less than the waste pipes they serve; back air pipes shall not be connected to the trap or branched into the waste pipe except where a continuous vent is not practicable, but a suitable non-siphon trap may be used without a back air pipe upon the approval of the commissioner. Back air pipes shall enter the waste pipe within eighteen inches from the trap and shall be a continuation of the waste pipe. Lead air pipes may be used only for short connections where they are exposed to view. Air pipes for water-closet traps shall be connected to the highest point of bend or trap, and may be of two inch bore if for not more than three fixtures and less than thirty feet in length; if for more than three fixtures or more than thirty feet in length they shall be of three inch bore. Air pipes shall be run as direct as practicable and if one and one half inches or less in diameter shall not exceed thirty feet in length. Two or more air pipes may be connected together or with a vent pipe; but in every such case the connection shall be above the top of the fixture. The trap for the upper fixture on a line of soil or waste pipe, within five feet of the stack in a horizontal line, shall not require a special air pipe, unless the outlet is branched into a stack more than eighteen inches below the top water line of the trap. Diameters of vent pipe shall be not less than two inches for main vents through less than seven stories; three inches for water-closets on more than three floors, and for other fixtures in more than seven stories. All vent pipes shall be increased one inch in diameter before passing through the roof. Vent lines shall be connected at the bottom with a soil or waste pipe or with the drain, in such a manner as to prevent accumulation of rust scale and properly to drip the water of condensation. Offsets shall be made at an angle of not less than forty-five degrees. Soil pipes or iron waste pipes, vents and back air pipes, shall be supported by clamps to the woodwork, iron drive hooks to brick walls, or bolted clamps to iron girders.

Non-Siphon Traps - Round Traps

Par. 4. - All traps, except for water-closets, not provided with special air pipes shall be suitable non-siphon traps and shall have at least a four-inch water seal. Round traps shall be not less than four inches in diameter and eight inches long, and made of eight-pound lead. All traps screws shall be water sealed.