PART 1 - GENERAL
1.01 SECTION INCLUDES
A. Testing and inspection of sanitary sewers.
B. Testing and inspection of storm sewers.
1.02 DESCRIPTION OF WORK
A. Test and inspect sanitary sewers, sanitary sewer force mains and building sanitary sewers.
B. Test and inspect storm sewers, culverts, footing drain sewers and building storm sewers.
C. Test and inspect lined pipe.
D. Reference is made to the Iowa Department of Transportation Standard Specifications for Highway and Bridge Construction, Series 2001, and all General Supplemental Specifications and Materials Instructional Memorandum by the term “Iowa DOT Specifications” and/or “Iowa DOT I.M.”
A. Notify Jurisdictional Engineer when installation is complete and ready for testing.
B. Notify Jurisdictional Engineer at least 24 hours prior to performing testing.
C. Representative of Jurisdictional Engineer must be present to review testing procedures and to record results.
1.04 MEASUREMENT FOR PAYMENT
All measurements for payments will be made by the Jurisdictional Engineer or authorized representative.
A. Video Inspection: Video Inspection of sewer lines shall be measured and paid for on a lump sum basis or measured in linear feet of sewer actually video inspected as specified in the contract document. payment shall be at the contract price bid. Either method of payment shall be full compensation for all labors, tools, equipment, and materials necessary to complete the work. The contractor shall provide the Jurisdictional Engineer with a copy of all sewer video inspections. Any re-testing required for clarification by the Jurisdictional Engineer shall be done at the Contractor's expense.
B. Testing and inspection of sanitary sewers, storm sewers and pipe rehabilitation is incidental to construction.
C. Include costs for testing and inspection in the bid prices for sewer construction and pipe rehabilitation.
PART 2 - PRODUCTS
2.01 TESTING EQUIPMENT
A. Conform with applicable sections of ASTM.
B. Conform to other applicable industry standards and codes.
C. Video Inspection
1. The video camera will be high-resolution color with adjustable iris focus.
2. The camera shall have pan and tilt capabilities.
3. Lighting will be suitable to allow proper illumination and a clear video image of the entire periphery of the pipe.
4. The video camera will be operative in 100% humidity conditions.
5. The video camera and other video components of the video system will produce a high quality video image.
6. The video inspection equipment shall be capable of displaying on-screen footage distance measured. The distance measured shall be accurate within 1%.
7. The inspection shall be recorded in color on a standard VHS videotape and/or on compact disc if requested by the Jurisdiction.
PART 3 - EXECUTION
A. Clean all sanitary sewers and storm sewers by flushing with water and by removing sheeting, bracing, shoring, forms, soil sediment, concrete, or other debris as directed by Jurisdictional Engineer prior to final acceptance.
B. Do not discharge soil sediment or debris to drainage channels or existing storm sewer or sanitary sewer systems.
3.02 VISUAL INSPECTION
A. Check each section of sanitary sewer or storm sewer by lamping.
B. Light should be visible through section of pipe lamped.
C. Visually inspect each section of pipe.
D. Repair or replace defective pipe or joints or remove and relay pipe not meeting alignment tolerances as directed by Jurisdictional Engineer.
3.03 VIDEO INSPECTION
A. Video inspection of all new and rehabilitated sanitary sewers shall be conducted after all backfill and compaction operations are completed, but prior to paving.
B. Notify Jurisdiction the day prior so that a representative of the Jurisdiction may be present during the inspection.
C. Inspection Procedure:
1. Prior to video inspection, the sewer will be cleaned to remove all debris and sediment. Sufficient water shall be run through the pipe so as to saturate any potential low spots so that they may be detected during inspection.
2. The inspection will be performed with closed circuit video equipment.
3. The inspection will begin at one end of the project and will continue in the same direction until the inspection is complete.
4. All lateral connections and other observations shall be inspected at right angles utilizing the pan and tilt capabilities of the camera.
5. The video camera will be centered in the pipe during the inspection.
6. The video inspection shall not exceed a rate of 30 feet per minute.
D. Inspection Reporting:
1. Provide a copy of the video inspection, recorded in standard play speed, in color, on a 1/2” VHS videotape. Upon request from the Jurisdiction, provide a copy of the video inspection on compact disc in addition to, or in lieu of a VHS tape. The video recording shall include on screen continuous footages, pipe diameter, direction of viewing, and manhole and street location references. The tape or CD shall have labels affixed that include the name of the project, the date, and the location of the inspection.
2. A written report of the inspection shall also be provided. The report shall include true to scale drawings of all sewer defects and observation locations. Each line item entry on the written report will reference the VCR counter number.
E. Low spots (bellies) in excess of 1" for pipe diameters 18" or less and 5% of the pipe diameter for pipes 24" and larger shall be considered unacceptable. If unacceptable low spots exist, as indicated by standing water during video inspection, remove and replace sewer as necessary and re-inspect.
3.04 SANITARY SEWER LEAKAGE
A. Maximum allowable infiltration or exfiltration for new sanitary sewer section including manholes is 200 gallons per inch of diameter per mile of pipe per day.
B. Test for sanitary sewer for infiltration or exfiltration as specified.
C. Test sanitary sewer manholes separately as specified in Section 6040 - Testing.
3.05 SANITARY SEWER INFILTRATION TESTING
A. Use only where ground water is more than 2 feet above top of pipe at highest point in section being tested.
B. Provide documented verification of ground water elevations for not less than 24 hours before measurement of infiltration.
C. Measure infiltration in sanitary sewer with V-notch weir in downstream manhole.
3.06 SANITARY SEWER EXFILTRATION TESTING
A. Use exfiltration test when ground water level is less than 2 feet above top of pipe at highest point in section being tested.
B. Sectionalize test section so that internal pressure in pipe does not exceed 5 feet of water.
C. Test Procedures:
1. Install watertight plug in inlet of upstream and downstream manhole of sewer section being tested.
2. Fill sewer and upstream manhole with water until water elevation in upstream manhole is 2 feet higher than outside top of pipe in section being tested or 2 feet above existing ground water level, whichever is highest elevation.
3. Allow water level to stabilize for 1/2 hour, then refill upstream manhole with water to original level and begin test.
4. Measure amount of water lost in upstream manhole in one hour. Use amount to determine exfiltration in 24 hour period.
D. Exfiltration Rate: The following table may be used to determine exfiltration in gallons per 24 hours by measuring loss that occurs in 1 hour. The table is applicable only for 48 inch diameter manholes.
|Loss in Gallons Per
24 Hours for
Drop in Water Level Per Hour in 48" Dia. Manhole
For manholes larger than 48" diameter use the following formula.
G = 0.0816(H)(D2)
G = gallons drop in 24 hours in inches.
D = diameter of manhole in inches.
H = drop in manhole in inches.
3.07 SANITARY SEWER LOW PRESSURE AIR TESTING
A. Low pressure air test may be used in lieu of exfiltration test except as noted.
B. Air test not recommended when ground water elevation is 2 feet or greater above top of pipe and cannot be used when ground water is greater than 6 feet above top of pipe.
C. Use extreme care and follow safety precautions during testing operations. No one allowed in manholes during testing.
D. Test Procedures:
1. Clean entire line of all debris. Flush or wet line to produce consistent results.
2. Plug all inlets and outlets to resist the test pressure. Special attention must be given to stoppers and laterals.
3. Test duration. Determine test duration for section being tested from table. This table ignores pipe length and uses the factor 0.472d, with d being in inches. Pressure holding time based on average holding pressure of 3 psi gage or drop from 3.5 psi to 2.5 psi gage.
|Size Pipe||Test Period
4. Add air to line segment being tested until internal air pressure of sewer line is raised to approximately 4.0 psi gage greater than average back pressure of any ground water that may be over top of the pipe. Pressure in sewer should not exceed 5 psi. Allow at least 2 minutes for air pressure to stabilize.
5. When pressure has stabilized and is at or above starting test pressure of 3.5 psi gage, commence test. Record drop in pressure for test period. The test may be discontinued when prescribed test time has been completed, even though 1.0 psi gage drop has not occurred.
6. If groundwater level at time of testing is above pipe invert, add 0.43 psig air per foot of water above invert to test air pressure range of 2.5 psig to 3.5 psig stated above.
7. If pressure drop exceeds 1.0 psi gage during the test period, the test shall be considered to have failed. Repair and retest line.
3.08 SANITARY SEWER VACUUM TESTING
A. Vacuum testing may be used in lieu of other specified test methods.
B. Use extreme care and follow safety precautions during testing operations. Keep personnel out of and away from manholes during testing.
C. Where practical, clean pipe prior to testing and wet the pipe surface. Isolate test segment as necessary, including closing service connections.
D. Test Procedures:
1. Determine test time for size of pipe being tested using following Minimum Test Time Table.
2. Test time is time required for vacuum to drop from 7 to 5 inches of mercury.
3. Minimum Test Time Table
4. Use a vacuum pump with capacity to evacuate sewer test section in time equal or less than that shown in Minimum Test Time Table for size of pipe being tested.
5. Evacuate air until internal air pressure of the sewer line is lowered by approximately 8 inches of mercury. Allow the air pressure to stabilize.
6. When air pressure is stabilized near the starting test vacuum of 7 inches of mercury, commence test by allowing gage pressure to drop to 7 inches of mercury, then commence time recording. Record drop in vacuum for test period.
7. If drop in vacuum is 2 inches of mercury or less during test period, test will be considered successfully passed.
8. If drop in vacuum is greater than 2 inches of mercury during test period, inspect, evaluate, repair and retest.
3.09 DEFLECTION TESTING
A. Perform deflection tests on all sanitary sewer flexible pipes, including PVC and PVC truss, and all HDPE storm sewer pipe 12" diameter or greater.
B. Perform deflection tests after backfill has been in place at least 30 days and before paving activity takes place or as per appropriate sections of these specifications.
C. Pipe deflection shall not exceed 5% of average inside diameter as established by ASTM Standards.
D. Pull approved 9-arm deflection mandrel through sewer by hand.
E. Approved mandrel must conform to applicable ASTM Standards.
F. Remove and replace pipe exceeding deflection limits.
G. Handle and divert existing flows during deflection testing.
3.10 FORCE MAIN TESTING
A. Clean force main as specified prior to testing.
B. Provide test pumps, test plugs, pipe and gages, and make necessary piping connections.
C. Fill force main with potable water and flush before test to remove entrapped air. Other water source may be used if approved by Jurisdictional Engineer.
D. Insert taps as required to remove air. Plug taps after completion of tests.
E. Test pressure: 1.5 times the working pressure at lowest point along test section but not less than 50 psi.
F. Pressurize test section and allow to stabilize prior to beginning leakage test.
G. Pressurize test section to specified test pressure and maintain pressure to within 5 psi of test pressure by pumping in potable water as required.
H. Leakage is quantity of water that must be supplied into test section to maintain pressure within 5 psi of specified test pressure during 2 hour test period.
I. Maximum allowable leakage as determined by formula:
L = (S)(D)(P)0.5
L = allowable leakage in gallons per hour
S = length of pipe tested in feet
D = nominal pipe diameter in inches
P = average test pressure in pounds per square inch (gage)
|Maximum Allowable Leakage Rate
(P = 50 psi, S = 1,000 feet)
(Gallons per Hour)
J. Examine exposed pipe and fittings during test. Repair all visible leaks.
K. If test indicates leakage greater than allowed, locate, repair or replace damaged or defective pipe and repeat tests until requirements are met.
END OF SECTION