N.Y.C. Admin. Code § PC 1101: Section PC 1101: General

1101.1 Scope.

The provisions of this chapter shall govern the materials, design, construction and installation of storm drainage. Storm water discharge shall be in accordance with Department of Environmental Protection requirements. Extension requirements from the public storm or combined sewer to the building sewer shall be determined by the Department of Environmental Protection.

1101.2 Where required.

All roofs, paved areas, yards, courts and courtyards shall drain into a separate storm sewer system, or a combined sewer system, or to a place of disposal approved by the commissioner and in accordance with the requirements of the Department of Environmental Protection. An approved system for beneficial collection and use of storm water may be installed, in which case overflow from such a system shall be discharged to a safe location subject to the approval of the commissioner and the Department of Environmental Protection. See Section 107.6.2 of this code for required construction documents relating to provisions for discharge for stormwater runoff.

1101.2.1 Increases in existing impervious surfaces.

Whenever impervious surfaces on the lot are increased, such impervious surfaces shall drain into a storm sewer system, or a combined sewer system, or to an approved place of disposal.

Exception:

An existing one- or two-family dwelling where the area of a proposed horizontal building enlargement plus any proposed increase in impervious surfaces in total is less than or equal to 200 square feet (19 m

2

). In such cases, the storm water discharge may be accommodated by existing facilities. For the purposes of this exception, the 200 square feet (19 m

2

) shall include all enlargements and increases cumulatively after July 1, 2008.

1101.2.2 Availability of public storm or combined sewer.

The determination as to whether a public storm sewer or public combined sewer is available to a building shall be made in accordance with applicable requirements of the Department of Environmental Protection.

1101.2.3 Feasibility of connecting to an available public storm or combined sewer.

The determination as to whether connection to an available public storm sewer or combined public sewer is feasible shall be made in accordance with applicable requirements of the Department of Environmental Protection.

1101.2.4 Extensions of public storm or combined sewers.

Extensions of public storm or combined sewers shall be made in accordance with the rules of the Department of Environmental Protection.

Storm water shall not be drained into sewers intended for sewage only.

1101.4 Tests.

The conductors and the building storm drain

shall be tested in accordance with Section

312

.

1101.5 Change in size.

The size of a drainage pipe shall not be reduced in the direction of flow.

Exception:

Drainage pipe that is part of an approved detention or retention system.

1101.5.1 Detention systems.

Where a detention system is provided, the pipe leaving the detention tank shall be permitted to be reduced to the flow allowed by the Department of Environmental Protection, provided, however, that an emergency overflow shall be provided to protect the building from internal flooding.

1101.5.2 Detention and retention tanks.

Detention and retention tanks located within buildings in flood hazard areas shall be located above the design flood elevation or shall be designed and constructed to withstand the static pressure conditions the system will experience in the event of a flood condition.

1101.5.2.1 Emergency overflow.

Emergency overflow piping shall equal the full size of the incoming storm water flow. Emergency overflows and vent terminations for buildings located in flood hazard areas shall be located above the design flood elevation. Such emergency overflow shall discharge the overflow outside of the building into either of the following locations:

1. The tax lot; or

2. The public sewer, provided that the overflow piping is provided with a vent, of the same diameter as the overflow piping, that terminates on the front wall of the building facing the street and no more than 2 feet (610 mm) above the sidewalk See

Figures 1101.5.2.1(1)

,

1101.5.2.1(2)

and

1101.5.2.1(3)

.

Figure 1101.5.2.1(1) Detention Volume & Tank Above Grade (Within Building)

Figure 1101.5.2.1(2) Detention Volume Above Sewer, Tank Below Grade (Within Building)

Figure 1101.5.2.1(3) Detention Volume & Tank Below Grade (Within Building)

1101.6 Fittings and connections.

All connections and changes in direction of the storm drainage system shall be made with approved drainage-type fittings in accordance with

Table 706.3

. The fittings shall not obstruct or retard flow in the system.

1101.7 Roof design.

Roofs shall be designed for the maximum possible depth of water that will pond thereon as determined by the relative levels of roof deck and overflow weirs, scuppers, edges or serviceable drains in combination with the deflected structural elements. In determining the maximum possible depth of water, all primary roof drainage means shall be assumed to be blocked. The maximum possible depth of water on the roof shall include the height of the water required above the inlet of the secondary roof drainage means to achieve the required flow rate of the secondary drainage means to accommodate the design rainfall rate as required by Section

1106

.

1101.8 Cleanouts required.

Cleanouts shall be installed in the storm drainage system and shall comply with the provisions of this code for sanitary drainage pipe cleanouts.

Exception:

Subsurface drainage system.

1101.9 Backwater valves.

Storm drainage systems shall be provided with backwater valves as required for sanitary drainage systems in accordance with Section

715

.

1101.9.1 Backwater valves in flood hazard areas.

Backwater valves for all buildings located in flood hazard areas shall be installed in storm drainage systems in accordance with the requirements of this code and the additional requirements of Section 7.3.4 of ASCE 24 as modified by

Appendix G

of the

New York City Building Code

.

1101.10 Plastic pipe.

Plastic piping and fittings shall not be used.

Exceptions:

1. Plastic piping and fittings may be used in residential buildings five stories or less in height.

2. Corrugated polyethylene and corrugated polypropylene piping and fittings, with a diameter of 12 inches (305 mm) or more may be used in connection with any type of building for underground yard drainage and storm water piping when used outside of the foundation wall of the building and not connecting to any piping system from the interior of the building.

1101.11 Cured-in-place pipe.

Cured-in-place pipe (CIPP) and epoxy spray pipe lining systems shall not be used.

1101.12 Site grading.

Except as otherwise permitted by this code, no person shall perform site grading or land contour work, as defined in Section

19-137

of the

Administrative Code

, that would cause storm water to flow across sidewalks or onto an adjacent property. Site grading or land contour work performed on the site of a covered development project shall comply with the rules of the Department of Environmental Protection and this code.