CHAPTER 11

1 Where Required. Roofs, paved areas, yards,courts, courtyards, vent shafts, light wells, or similar areashaving rainwater, shall be drained into a separate storm sewersystem, or into a combined sewer system where a separatestorm sewer system is not available, or to some other place ofdisposal satisfactory to the building Storm Water Drainage to Sanitary Sewer water shall not be drained into sewersintended for sanitary drainage Traps Required for Combined water from an exterior area drain, catch basin, orfrom a roof and discharging to a combined sewer shall betrapped. The trap shall be of approved design and locatedin the storm drain line between the sanitary sewer con-nection and the inlet opening into which storm is than one roof drain or other storm receptordrain shall be served by a single trap where the trap islocated so as to receive, through its inlet side, drainagefrom roof drains and water drainage traps shall be below the frostline or within the building.

2 An accessibly locatedcleanout not smaller than the size of the trap, shall beextended to grade from the inlet side of each such trapwith approved piping and fittings. Where the cleanout isinstalled on the exterior of the building, it shall extend atleast 6 inches (152 mm) above grade and be within 24inches (610 mm) of the foundation unless otherwiseapproved by the building : Where a roof drain is located not less than10 feet (3048 mm) from, or at least 3 feet (914 mm)above an openable window, door, opening, air intake, orvent shaft, or not less than 3 feet (914 mm) in everydirection from a lot line, road, ally and street linesexcepted, no trap is , trap primers and vents for exterior area drainsand catch basins where located less than 10 feet (3048mm) from a building, shall be the same as for floor drainsand catch basins located within a building where suchdrains are connected to a combined sewer as required bythis Material Uses.

3 Rainwater piping placed within theinterior of a building or run within a vent or shaft shall be ofcast-iron, galvanized steel, wrought iron, brass, copper, lead,Schedule 40 ABS DWV, Schedule 40 PVC DWV, stainlesssteel 304 or 316L (stainless steel 304 pipe and fittings shallnot be installed underground and shall be kept not less than 6inches (152 mm) aboveground), or other approved shall be the same as that specified for sanitarydrainage pipe, except that 90 degree ( rad) sanitary teebranch fittings shall be used in lieu of combination wye and1 8bends. Short-turn 90 degree ( rad) bends shall be sub-stituted for long-turn 90 degree ( rad) bends. Fittingsinstalled in a storm drain between a trap and a connection toa combined sewer shall be the same as those for sanitarydrainage work. Inside conductors shall connect to anapproved roof or deck, or overflow drain. ABS and PVCDWV piping installations shall be installed in accordancewith CHAPTER 15 Firestop Protection.

4 Except for individualsingle-family dwelling units, materials exposed within ductsor plenums shall have a flame-spread index of a maximum of25 and a smoke-developed index of a maximum of 50, wheretested in accordance with ASTM E84 and UL storm drainage piping and fittings shall be CPEas listed in Table The installation of building storm sewers shallbe in accordance with the requirements applicable underthis storm sewers located 2 feet (610 mm)or more away from a building or property line, exceptroads, streets or alleys, shall be of cast iron, vitrified clay,concrete, asbestos cement, ABS, PVC, CPE, or otherpipe meeting standards approved by the building shall be the same as specified for san-itary sewers in Section of this :Approved taps shall be installed in accor-dance with the manufacturer s listing where firstapproved by the building shall be required and shall beinstalled in accordance with Section of this and connections shall be as prescribed inSection of this or other products or appurtenances inci-dental to the installation of building storm sewers shall bein accordance with the requirements for approval ofChapter 3 of this code and shall be identified in a man-ner satisfactory to the building Expansion Joints Required.

5 Expansion joints orsleeves shall be provided where warranted by temperaturevariations or physical between insideconductors and roof, deck and overflow drains shall bemade with approved adapter fittings as required by thiscode. Such connectors shall be provided with an expan-sion or approved swing joint. Rain or storm water pipingwithin a building shall be watertight and shall be testedpursuant to Section of this Storm and Groundwater conductor pipe shall beused as a sanitary drain or vent; nor shall any sanitary832014 OREGON PLUMBING SPECIALTY CODE CHAPTER 11 STORM DRAINAGE drain or vent pipe be used as a conductor. Subsoil drainsunder and around buildings shall be used to collect anddrain Subsoil, Foundation and AbsorptionTile Drains. Groundwater collected or drained fromunder or around buildings shall be disposed of throughapproved pipe material, as follows:(1)Disposal. Where practical, such groundwater shallbe drained by gravity to a natural surface drainagecourse or other approved disposal site.

6 (2)Sump. Where groundwater is drained by gravity toa combination sewer or storm sewer system, thegroundwater shall be drained into an accessibletrapped sump or catch : Subsoil drain lines covered with anapproved filter fabric shall connect to a combinationsewer trapped as per Section Subsoil drainlines covered with an approve filter material shalldirectly connect to the storm pipe on the discharge side of such sump,trap or catch basin shall be tested as per (3)Backwater , foundation, and absorp-tion drains that are subject to reverse flow shall beequipped with approved, accessible backwatervalves as required by the building official.(4)Ejectors. Subsoil drains which cannot removegroundwater by gravity shall have the storm waterlifted by means of an approved ejector. The dis-charge shall be drained into the building stormsewer, or an open drainage course, or other suitabledisposal facility at least 10 feet (3048 mm) beyondthe exterior of the building.

7 (5)Valves and discharge pipe from apump or ejector used to lift groundwater shall beequipped with a swing check or backwater valve anda gate valve. Where the gravity drainage line to whichsuch discharge line connects is horizontal, the methodof connection shall be from the top through wyebranch fitting. The gate valve shall be located on thedischarge side of the backwater or check valve.(6) and watertight receiving tanks orsumps shall be vented by means of an approved pipenot less than 2 inches (51 mm) in size. Such ventsshall be properly terminated in accordance with theapplicable section of this code.(7)Tracer piping for yard, groundor storm water for building sewers shall have anelectrically conductive tracer wire (18-gauge, insu-lated copper, or heavier, green in color or otherapproved materials) installed in the trench for locat-ing the pipe in the future. The tracer wire shall runthe full length of the installed pipe, with one end leftabove the finished grade at t the building end of thepipe, or at a cleanout next to the building wall, andshall be clearly marked.

8 The other end of the tracerwire shall be spliced into the serving utilities tracerwire, when present.(8) drainage, groundwater drainage,rainwater piping systems, exterior building drains,subsurface, foundation, footing, under-slab andabsorption drains shall be of materials approved byand specified in Section of this code, exceptfor corrugated metal storm sewers installed as perOregon IS Dry Wells; Construction, Use permitted bythe building official, dry well shall be used. Thebuilding officialshall require soil percolation authorized, dry wells shall be of reinforcedconcrete rings with an inside diameter of not lessthan 28 inches (700 mm) with a minimum depth of5 feet (1524 mm), measured from the bottom to thetop of the reinforced concrete cover and set onundisturbed soil. Dry wells shall be covered with atleast 2 feet (610 mm) of compacted earth wheremeasured from the top of the lid to the finishedgrade. Where first approved by the building official,dry wells shall be constructed of brick or otherapproved material in of not less than 4 inches (102mm) thickness.

9 Brick or block shall be assembledwith or without openings, provided the openings onthe outside of the dry well are not greater than 3inches (76 mm). This type of dry well shall have abrick arched top or an arched top of other dry well shall be locatedcloser than 5 feet (1524 mm) of a property line norcloser than 10 feet (3048 mm) to a building unlessapproved by the building official. Each drainageconnection to a dry well shall be made at the topcenter of the lid by the use of an approved 90 degree( rad) waste fitting. Support of piping shall be asrequired by CHAPTER 3 of this code. Special permis-sion shall be granted to enter the side of the dry wellwhere grade and structural conditions make topentrance particle size of the back-fill surrounding a dry well shall be of sufficient sizeto prevent its incursion into the interior of the drywell. The backfill shall form a continuous layeraround the dry well not less than 6 inches (152 mm)in thickness and shall extend to the full height of thedry :Where the dry well is installed in sandy-type soil an approved filter material shall be placedaround the exterior of the liner to prevent infiltra-tion of sand.

10 The backfill shall be of native soil prop-erly Abandonment. Where required bythe building official, every drywell which has beenabandoned or has been otherwise discontinued fromfurther use shall be completely filled with earth,sand, gravel, concrete, or other approved OREGON PLUMBING SPECIALTY CODE STORM Building subdrains locatedbelow the public sewer level shall discharge into a sump orreceiving tank, the contents of which shall be automaticallylifted and discharged into the drainage system as required forbuilding Areaway Drains. Open subsurface space adjacent toa building, serving as an entrance to the basement or cellar of abuilding, shall be provided with a drain or drains. Such areawaydrains shall be not less than 2 inches (50 mm) in diameter forareaways at a maximum of 100 square feet ( m2) in area,and shall be discharged in the manner provided for subsoildrains. Areaways in excess of 100 square feet ( m2) shallnot drain into subsoil drains.