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2009 Edition of the Design AND CONSTRUCTION STANDARDS FOR WASTEWATER C OLLECTION SYSTEMS. Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS. General Information Design Standards Highlights Construction Standards Highlights
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2009 Edition of the Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • General Information • Design Standards Highlights • Construction Standards Highlights • Control of Materials Highlights • Standard Drawings • Tables
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS Section 1 General Information Question / Comments
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS Section 2 Design Highlights Changes from the 1997 Edition Not a comprehensive list
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • PRIVATE SEWERS • LATERALS • FLOW CALCULATIONS • ALLOWABLE SLOPES • FORCE MAINS • EASEMENTS • EASEMENTS continued • SEWER MAINS – DEPTH • EXISTING CONDITIONS • HORIZONTAL CLEARANCES • DROP MANHOLES • MASTER UTILITY SHEET • LATERALS • STUBS • MANHOLES • MANHOLES continued • ODOR CONTROL REQUIRED FOR • SIPHONS • FULL FRONTAGE SEWER MAINS
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • PRIVATE SEWERS • Private sewer mains will not be allowed for single family residence (SFR) subdivisions. Public sewer mains will be required even if the streets are private. • Easements must be granted to the sewer agency at main locations.
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • LATERALS • All 4-inch and 6-inch laterals connected to sewer mains 15-inch and larger will require a new T-Lock manhole, due to on-site odor issues.
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • FLOW CALCULATIONS • All projects, including parcel improvements, will require peak wet weather flow estimates. • Flow capacity of a pipe is calculated at peak wet weather flow with the pipe 75% full.
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • ALLOWABLE SLOPES • Minimum slope based on 2 feet per second at project’s estimated peak flow. • Maximum slope based on 10 feet per second with pipe 75% full. • Terminal sewers in cul-de-sacs shall have 2.0 percent minimum slope.
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • FORCE MAINS • All lift stations will require dual force mains, with a minimum of 4-inch diameter. • Force mains must maintain continuous upward slope from the pump discharge flange to the discharge manhole. No dips or high points allowed. • Force mains shall discharge into a T-Lock lined manhole, with invert of force main 0.2 ft higher than the invert of the gravity pipe outlet.
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • EASEMENTS • Easements are a last resort design, and will not be allowed if it is feasible to route sewer within the roadways. • Easement width will be 20 feet minimum, with additional space for deep sewer or other utilities. • Easements shall be bounded by 4-foot minimum screen walls with locking gates or locking, removable bollards at each end. • Easements shall provide permanent drivable access, designed for H20 traffic loading, 2 percent maximum side slope, 5 percent lengthwise slope, and free from landscaping, trees, utility poles, or other structures.
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • EASEMENTS Continued • Overhead obstructions are not permitted. • Sewer must be centered in the easement. • For each easement, the plans shall show surfaces, grading slopes, all utilities, drainage, removable locking bollards, gates, and screen walls in the following views: • Plan view and elevation view • Cross sections at 1:1 vertical / horizontal scale, at both ends of easement minimum.
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • SEWER MAINS – DEPTH • Minimum depths have been increased and clarified.
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • EXISTING CONDITIONS • Existing utilities are to be verified by potholing wherever possible. • Unexpected underground conflicts will not result in any exceptions to the design standards being allowed.
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • HORIZONTAL CLEARANCES • Sewer to water clearance is pipe OD to OD, not centerline to centerline, so nominal separation must account for pipe diameter. • Minimum manhole to curb separation shall be 8 feet from back of curb to center of manhole.
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • DROP MANHOLES • Drop manholes are prohibited unless special permission is granted per agency. Never allowed in CCWRD service area.
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • MASTER UTILITY SHEET • Master utility sheet is required for projects with two or more utility sheets. • Include: • manhole number • street names • pipe size • and signature block.
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • LATERALS • A minimum of two 3M marker balls shall be placed for each lateral as shown in SD-22 and SD-23
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • STUBS • Length of stub shall be limited to 50 feet. • Each stub shall have a minimum one yard concrete thrust block place to secure cap in place.
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • MANHOLES • All manholes bases on new sewer lines shall be the precast type. • 15-inch pipe requires a 60-inch manhole. • In general, manhole size will increased where branch inlets are present, to allow proper sweeps in base. • All manhole lids shall be the concentric or eccentric (by agency) 24inch inner/36-inch outer type, for worker safety.
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • MANHOLES continued • On 12-inch and larger sewer mains, horizontal change of direction is limited to 45 degrees maximum. • Vertical dimension from top of manhole lid to shoulder or manhole cone shall be 18 inches maximum. • Shallow manholes will be used as a last resort. • Special monitoring or debris screening manholes required for certain types of projects.
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • ODOR CONTROL (liquid & gas phase) REQUIRED FOR • Large projects . • Siphon inlets & outlets. • Lift station/pump station wet wells. • Force main discharge manholes. • Manholes with velocity of 5FPS or greater.
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • SIPHONS • Siphons are a last-resort design. • All new siphons require a self-draining air jumper, which may require a pipe bridge.
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • FULL FRONTAGE SEWER MAINS • Full frontage sewer main installation may be required on all street frontages of a parcel. • Applies to unpaved streets only.
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • Questions / Comments
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS Section 3 Construction Highlights Changes from the 1997 Edition Not a comprehensive list
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • JOB START CHECKLIST • MANUFACTURER CERTIFICATION OF INSTALLATION PROCEDURES • BYPASS PUMPING • BLASTING • PIPE INSTALLATION • MANHOLE INSTALLATION • LATERAL INSTALLATION • SANITARY SYSTEM TESTING
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • JOB START CHECKLIST (partial list) • Approved Construction Documents • Schedule • All shop drawings approved • Blasting and Bypass Pumping approved • All permits and bonds • All easements granted to Agency • All materials approved.
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • MANUFACTURER CERTIFICATION OF PIPE INSTALLATION PROCEDURES • Pipe manufacturer shall provide certification that contractor’s superintendent, on-site foreman and lead pipe layer have been trained in manufacturer’s recommended pipe installation procedures • Pipe manufacturer shall observe actual pipe installation at specified intervals and certify that installation conforms to manufacturer’s recommendations
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • BYPASS PUMPING • Plan submitted at least 30 days prior to start of pumping operation – Notify Agency prior to start-up of pumping • Pump Capacity 1.25 times capacity of incoming sewer – fully on-line 100% redundant pump capacity required • Noise attenuation required for all pumps, generators and air compressors • On-site operator required 24/7 when pumping is in operation
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • BLASTING • Contractor solely responsible for blasting • Plan submitted at least 30 days prior to start of blasting operation – Notify Agency prior to start of blasting – Agency Representative on site for all blasting • Nearby existing sanitary and storm sewers televised before and after blasting • Blaster qualified and licensed • Agency may employ independent blasting consultant – cost to be borne by contractor
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • PIPE INSTALLATION • Installation must conform to and all permitting Agency requirements; ASCE and UNI-BELL technical standards; and pipe manufacturer recommendations • Jetting of trench backfill prohibited – mechanical compaction only • Greater clearances from other utilities and site objects now required • Expanded requirements for construction in easements • Locator ribbon required for main sewers and marker balls required for laterals
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • MANHOLE INSTALLATION • Manholes on new sewers must have pre-cast bases • New manholes on existing sewers may have pre-cast or cast-in-place bases at contractor’s option • All pipe connections shall meet ASTM C923 – connections to manholes on new sewers must be factory-installed • Pipe connections to existing manholes must be cored – no break-in connections allowed • Interior corrosion protection and exterior waterproof coatings required by Agency in locations specified • Maximum of 18-inches of adjustment including grout
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • LATERAL INSTALLATION • Wyes required for connections to new sewers • Cored connections with tapping saddles required for connections to existing sewers • No curves or horizontal bends in laterals • Mark ball required at wye and property line over lateral – 3-feet min to 5-feet max below finish grade • No direct lateral connections to sewers 15-inches and larger – laterals may be connected at manholes only or a parallel sewer provided per SD-24 • Caps at ends of laterals for low-pressure air test
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • SANITARY SYSTEM TESTING • Low-pressure air test for all new sewers • Visual inspection and corrosion protection holiday testing for all manholes • Deflection test for all new flexible pipe sewers • Televising for all new sewers and for those existing sewers where new mainline or lateral connections have been installed • Pressure test for all new forcemains • Operational tests for all new pump stations
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • Questions / Comments
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS Section 4 Materials Highlights Changes from the 1997 Edition Not a comprehensive list
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • Sewer Pipe • Forcemain • Manhole Components
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • PIPE FOR NEW MAIN SEWERS & LATERALS • Generally limited to PVC – DIP may be used for special situations upon Agency approval – Engineer should contact Agency having jurisdiction for additional requirements for pipe larger than 15-inch diameter and regarding the use of DIP or other pipe materials
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • PIPE FOR FORCEMAINS • PVC permitted by all County Agencies – DIP also permitted by select Agencies – Engineer should contact Agency having jurisdiction for pipe material requirements
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • MANHOLE COMPONENTS • Pre-cast concrete - conform to ASTM C478 • Pipe connections - conform to ASTM C923 • Frame & Cover – dual 36/24–inch opening - grey iron Class 35B minimum – contact Agency having jurisdiction for specific casting numbers required • Internal corrosion protection & exterior waterproofing – contact Agency having jurisdiction for requirements
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS • Questions / Comments
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS Section 5 Standard Drawings Question / Comments
Design AND CONSTRUCTION STANDARDS FOR WASTEWATER COLLECTION SYSTEMS Section 6 Tables Question / Comments