(A) General construction requirements.
(1) Before installing piping, the contractor shall carefully verify location, depth, type of joint needed and size of pipe to which connection is proposed. The contractor shall assure that the lines can be run as contemplated without interfering with footings, walls, other piping, fixtures and the like.
(2) All lengths of pipe shall be dimensioned accurately to measurements established at the site and shall be worked into place without springing or forcing. Cut sections of pipe shall be reamed to remove all burrs.
(3) Utmost care shall be exercised in transporting and handling all pipe, fittings, valves and the like, in order to avoid shock and damage to pipe and coatings. Lifting shall be by hoist or skids when hand lifting is not feasible. Droppings will not be permitted. Pipe handled on skidways must not be skidded or rolled against pipe already on the ground. Damaged or defective pipe and appurtenances shall be replaced.
(4) The pipe shall be thoroughly cleaned before being laid and kept clean during construction.
(5) The contractor shall cut all pipe and drill all holes that may be necessary.
(B) Pipe laying.
(1) The laying of pipe on the prepared bedding material shall commence from the lowest point, with the spigot ends pointing in the direction of flow. All pipes shall be laid true to line and grade. They shall be carefully centered so that when laid, they form a sewer with uniform invert.
(2) A pipe plug or bulkhead shall be used whenever pipe laying operations are not in progress as required to protect the pipe ends from foreign material.
(3) Before making pipe joints, all surfaces of the joints shall be clean and dry. Lubricants, primers and adhesives shall be used in accordance with the manufacturer’s recommendations. The pipe shall then be placed, fitted and adjoined so as to obtain a water-tight joint. In the event that previously laid pipe is disturbed, it shall be removed and relaid.
(4) The contractor shall assure proper alignment and grade by the proper use of lasers, batter boards, surveying instruments or other suitable means.
(C) Leakage tests.
(1) General. Prior to acceptance, all gravity sewers, including service laterals, shall be tested and pass a test for leakage. The contractor shall furnish all labor, materials and equipment required for making the tests and ground water level determinations with no extra compensation over and above the specified contract prices for the sewers. Testing shall not be performed until backfilling and compaction are completed. All gravity sewers shall pass a leakage test as further specified below.
(2) Low pressure air test.
(a) A “Low Pressure Air Test” conforming to the requirements of the latest revision of ASTM C828 and ASTM C924 shall be performed on all new sanitary sewer pipe, except as revised below. Low pressure air testing is used to determine the existence of pipe leaks; however, it does not indicate water leakage limits.
(b) Prior to the low pressure air testing, all wyes, tees or end of side sewer stubs shall be plugged with flexible-joint caps, or acceptable alternate, securely fastened to withstand the internal test pressures. Such plugs or caps shall be readily removable, and their removal shall provide a socket suitable for making a flexible-jointed lateral connection or extension.
(c) All plugs shall be securely braced to prevent possible blowout due to internal air pressure. One plug shall have an inlet tap, or other provision for connecting a hose to a portable air supply source. Air hose shall be connected to the inlet tap and a portable air supply source.
(d) Air equipment shall consist of all necessary valves and pressure gages to control rate of air flow into the test section and to enable monitoring of air pressure within the test section. Testing apparatus shall also be equipped with pressure relief device to prevent the possibility of loading test section with full capacity of compressor.
(e) Air shall be slowly added to test section until pressure inside pipe is raised to 4.0 psig. After a pressure of 4.0 psig is obtained, air supply shall be regulated such that pressure is maintained between 3.5 and 4.0 psig for a period of two minutes, to allow air temperature to stabilize in equilibrium with temperature of pipe walls. Pressure will normally drop slightly until equilibrium is obtained. During this period, all plugs shall be checked with soap solution to detect any plug leak.
(f) After this two-minute air stabilization period, air supply shall be disconnected and test pressure allowed to decrease. Time required for test pressure to drop from 3.5 psig to 2.5 psig is determined by means of stop watch, and this time interval is then compared with required time to determine if rate of air loss is within the allowable limit. Required time to arrive at the allowable air loss is calculated by means of following formula:
T = 0.0850 DK
Q
Where: T = time in seconds
K = .000419 DL, but not less than 1.0
Q = rate of loss (= 0.003 cfm/sq. ft. of internal surface)
D = diameter of pipe in inches
L = length of pipe tested in feet
(g) Upon completion of test, the bleeder valve shall be opened and all air allowed to escape. Plugs shall not be removed until all air pressure in test section has been released.
(h) If measured time interval for the pressure to drop from 3.5 psig to 2.5 psig is less than the required time as calculated, sewer section shall be deemed to have failed test. The contractor shall then proceed to repair pipe at his or her cost as necessary until the sewer section passes the test. All testing shall be conducted in presence of town or its representative.
(3) Infiltration test.
(a) An infiltration test shall be used only when approved by the town or when the starting pressure for the low pressure air test would be greater than 9.0 psig. For an infiltration test to be performed, the ground water elevation must be at least two feet above the crown of the upstream pipe. The test shall require cleaning of the line and then plugging the upstream pipe opening with a water-tight plug with length equal to or greater than the pipe diameter.
(b) A 90-degree V-Notch weir shall be placed in the downstairs manhole of the section of pipe being tested. When performing an infiltration test with a weir, sufficient time shall be allowed for the infiltration to crest the weir and stabilize. This time shall be determined by the town based on the allowable infiltration, the size of the sewer line, the slope of the line and other pertinent information. In no case shall the time be less than one hour. The contractor shall measure the head (H) of water flowing over the weir. The measurement must be accurate and taken a minimum distance of 18 inches or four times the height of H upstream of the weir, whichever is greater. The measured infiltration over the weir can be calculated as:
Q = 3240 H2.5
where: H is in inches and Q is in gallons per day
(c) In order for the section to pass the allowable leakage limits, the measured infiltration shall not exceed 200 gallons per day per inch of pipe diameter per mile (200 gpd/in./mile).
(D) Deflection testing.
(1) (a) Deflection testing shall be performed by the contractor in the presence of the town or his or her representative on all plastic pipes with nominal inside diameters of six inches or greater.
(b) Deflection testing shall be accomplished using one of the following devices: calibrated television or photography; or a properly sized “go, no go” mandrel or sewer ball.
(c) Deflections of no more than 5% based on the base inside diameters shown below will be allowed:
Table 1: Allowable Deflection | ||
Nominal Size (in.) | Base Inside Diameter (in.) | 5% Deflection Mandrel (in.) |
Table 1: Allowable Deflection | ||
Nominal Size (in.) | Base Inside Diameter (in.) | 5% Deflection Mandrel (in.) |
6 | 5.915 | 5.62 |
8 | 7.920 | 7.52 |
10 | 9.900 | 9.41 |
12 | 11.780 | 11.19 |
15 | 14.426 | 13.70 |
18 | 17.629 | 16.75 |
(2) The deflection test shall be performed no sooner than 30 days following installation of the pipe (including backfill). Prior to testing, the pipeline shall be thoroughly cleaned.
(3) Prior to acceptance, pipes having deflections greater than 5% shall be excavated, re-bedded and/or replaced and retested (successfully).
(4) (a) The contractor shall submit deflection test reports to the town within 30 days after performance of each said test.
(b) A separate report shall be submitted for each manhole to manhole sewer section.
(c) This report shall provide all pertinent data regarding the test including, but not limited to, the date of the test, details of the testing device used, diameter of the pipe, the date installation of the line was completed including backfill and whether the line passed or failed the test.
(2004 Code, Art. II, § A, part 3)