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All roofs exceeding 300 square feet, all paved areas exceeding 5000 square feet, all paved courts and all paved open shafts shall be drained to an approved point of disposal, except that for oneand two-family dwellings, and where approved, storm water is permitted to discharge onto flat areas such as lawns, provided that the storm water flows away from the building. All paved areas in excess of 5000 square feet and all open shafts shall be drained into a public storm-sewer system, an approved storm water management system or a public combined sewer system, to a point of disposal approved by the Department so as to:
  1. Protect the foundation of buildings from water damage;
  2. Prevent water accumulation on streets, sidewalks and other areas used for pedestrian or vehicular travel;
  3. Prevent water accumulation which may cause odors, the breeding of insects, or other health hazards;
  4. Prevent contamination of water supply systems.
Area drains may be required by the Department in order to comply with Section P-1001.1.
Each lot shall be provided with area drains as required in Section P-715.
Rainwater conductors connected with the storm water upright of an area drain shall be permitted, provided that the area drain does not receive the discharge from waste pipes.
Leaders, yard drains, and other storm drains connected to a combined sewer shall be effectively trapped, except that inside leaders connected to roof outlets are permitted without traps if they are not located directly below a door or window or other ventilating opening of the same or an adjacent building nor within 12 feet of such an opening.
Where an owner is required to abandon an individual sewage disposal system and connect to an available public sewer, the rain leaders of detached accessory buildings exceeding 300 square feet located on the same lot shall be permitted to discharge to a point of disposal other than the public sewer upon request by the property owner. In such case, there shall be an inspection and approval by the Department to determine that no nuisance or unsanitary conditions will be created.
Construction of storm water catch basins shall be one of the following:
  1. Reinforced concrete with the base and walls not less than 6 inches in thickness; or
  2. 8-inch sewer brick, parged to a smooth finish on the interior wall; or
  3. 8-inch 75% solid concrete block, parged to a smooth finish on the interior walls; or
  4. Other materials as approved by the Department.
Figure P-1001.7


Expansion joints or sleeves shall be necessary because of temperature variation or physical condition.
Subsoil drains connected to street sewers or house drains shall discharge into and through a properly trapped sand interceptor.
Where subsoil drains are located below the sewer level, they shall be in accordance with Section P-1003.1. The storm water shall be raised and discharged in the house drain by an automatically operated sump pump.
In a single-family dwelling, the subsurface water shall drain directly into an open sump or be raised by means of an automatically operated sump pump, which discharges into an area drain, floor drain, or laundry tray.
Subsoil drains shall be open-jointed, horizontally split or perforated pipe conforming to one of the standards listed in Table 1003.4.

TABLE P-1003.4
SUBSOIL DRAIN PIPE MATERIALS
MATERIAL STANDARD
Asbestos-cement pipe ASTM C 508
Cast-iron pipe ASTM A 74; ASTM A 888; CISPI 301
Polyethylene (PE) plastic pipe ASTM F 405; CAN/CSA B182.1; CSA B182.6; CSA
B182.8
Polyvinyl chloride (PVC) Plastic pipe (type sewer pipe, PS25, PS50 or PS100) ASTM D 2729; ASTM F 891; CSA B182.2; CAN/CSA B182.4
Stainless steel drainage systems, Type 316L ASME A 112.3.1
Vitrified clay pipe ASTM C 4; ASTM C 700
Storm water shall not be drained into sewers that are intended only for sanitary sewage. Sanitary waste shall not be drained into sewers that are intended only for storm water.
No soil stack, or vent stack shall also serve as a leader. No leader shall also serve as a soil stack, waste stack, or vent stack.
Inside storm drainage conductors installed above ground shall conform to one of the standards listed in Table P-902.1.
Outside leaders and downspouts shall be connected to the house drain which shall be cast iron pipe extending vertically at least 18 inches above the grade level with tight connection between leader and soil pipe.
Underground building storm drain pipe within a building and beyond the building wall to the street, including site work shall conform to one of the materials and standards listed in Table P902.2. These materials shall be installed with approved fittings in compliance with Section P-305.
House storm drains underground beyond the building wall shall be installed in accordance with Section P-902.3. These materials shall be installed with appropriate fittings in compliance with standards in Section P-305.
When installed in filled or unstable ground, the house storm drain shall be of cast iron or hard temper copper of a weight not less than type "L".
ABS plastic and PVC plastic pipe and fittings authorized by Sections P-1005.1 and P-1005.3 shall be installed in accordance with Section P-305.0 and shall be limited to use only in connection with the following buildings:
  1. Residential buildings containing no more than four families and not exceeding three stories in height. For the purpose of this section, basements are not considered a story.
All underground storm water piping installed parallel to a foundation wall shall be at least 3 feet from the building foundation wall when the depth does not exceed 4 feet. One-foot of additional distance from the foundation wall shall be required for each addition one-foot depth below 4 feet.
The minimum size of a vertical leader, including the horizontal offset at the top of the vertical leader draining a roof, shall be based on the horizontal roof area served by such leader, as provided in Table P-1006.1.

TABLE P-1006.1
MAXIMUM HORIZONTAL PROJECTED ROOF AREA IN SQUARE FEET FOR BUILDING STORM DRAINS AT VARIOUS SLOPES
Diameter (Inches) Fall Per Foot Vertical Leaders
1/8" 1/4" 1/2"
3 930 1,300 1,750
4 1,585 2,100 3,300 3,650
5 2,875 3,800 5,300 6,000
6 4,300 6,000 9,000 10,800
8 9,200 13,000 18,000 23,000
10 16,500 25,000 35,000 40,000
12 26,600 40,000 60,000 65,000
15 47,500 75,000 100,000 115,000
16 57,250 92,500 131,000
18 67,000 110,000 162,000
20 85,500 135,000 196,000
24 155,000 225,000
30 295,000 416,000

Note: Seeded areas shall be calculated as 55% of the actual measured area.
Where there is a continuous or semi-continuous discharge into the house storm drain, as from a bilge pump, ejector, air conditioning equipment, or similar device, each gallon per minute of such discharge shall be assumed to be equivalent to 14 square feet of roof area.
The minimum size of the house storm drain or any of its branches that drain a roof or area drain shall be determined according to Table P-1006.1. The main drain shall be graded at a fall of not less than 1/8 inch per foot, except by approval of the Department.
Canopies, marquees, and similar extended roof surfaces shall be drained by minimum two-inch leaders where construction does not permit the installation of larger pipe with approval of the Department. A three-inch trap and underground drain shall be provided.
Where a combined main sewer is utilized, the house drain and house storm drain shall be connected to a combined house drain or combined sewer.

Figure P-1006.4

PARKING GARAGE DRAINAGE ONE-PIPE SYSTEM
The size of the combined house drain shall be obtained from Table P-1006.1, by adding to the square feet of storm water drainage area an allowance for each fixture unit on the house drain. This allowance shall be in square feet, as determined in accordance with Table P-1006.4.

TABLE P-1006.4
ALLOWANCE IN SQUARE FEET OF PITCHED ROOFS FOR FIXTURE UNITS
Square Feet        Fixture Units       
7 for each of the first 1,500
5 for each of the next 1,500
4 for each of the next 2,000
3 for each unit thereafter
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