Domestic Water Piping Questions Answered.docx

Domestic Water Piping Questions Answered

1. What is the required material for the pipe that's to be replaced (cast iron, ductile iron, etc) Response: PE pipe for Pipe Bursting, C900 or Ductile Iron for open cut.

2. Is there a preference between pneumatic and static systems for repair?

Response: Do not understand question? Is this regarding testing? If so, refer to SOW, 3.2 HYDROSTATIC TESTS NOTE: Test pressure for hydrostatic pressure and leakage tests will be the working pressure multiplied by 1.33. For a working pressure of 150 psi, the test pressure will be 200 psi. For other working pressures the test pressure will be adjusted accordingly. Where any section of a water line is provided with concrete thrust blocking for fittings or hydrants, the hydrostatic tests shall not be made until at least 5 days after installation of the concrete thrust blocking, unless otherwise approved.

3. Are there any confined spaces anticipated?

Response: Yes. There may be Manholes that require access. Per Specification, CONFINED SPACES: Contractors who enter confined spaces during construction operations shall do so in strict accordance with Air Force Occupational Safety and Health (AFOSH) Standard 12725. The contractor shall request the proper permits for access from the COTR, in writing a minimum of 10 work days prior to confined space entry. The 87th Air Base Wing Safety Office shall issue all permits. Contractor will price accordingly.

4. In the requirement for a CCTV pipe inspection of all pipes to be pipe bursted, from our experience, it is not possible to video 4" or smaller pipe in runs longer than 200'.

Response: A Close Cable Television CCTV (i.e. boroscope) internal pipe inspection is necessary for the pipe to be burst. A log must be kept noting: any sections of existing pipe that is crushed, and numbering and identifying the position of all lateral connections.

5. Is it necessary to video piping of 4" or less?

Response: A Close Cable Television CCTV (i.e. boroscope) internal pipe inspection is necessary for the pipe to be burst. A log must be kept noting: any sections of existing pipe that is crushed, and numbering and identifying the position of all lateral connections.

6. The specs state that ”All gas lines must be at least twelve inches away from the pipe to be burst in question. If a gas line is closer than twelve inches it must be excavated to relieve the ground around the gas line to minimize damage." We would appreciate clarification on how that is measured.

Response : A digging permit must be obtained for the pipe to be burst. Even though the majority of the pipe will not be excavated the permit is used to identify all utilities in the area. All gas lines must be at least twelve inches away from the pipe to be burst in question. If a gas line is closer than twelve inches it must be excavated to relieve the ground around the gas line to minimize damage. Ground sonar can be used for utilities in question

7. The USACE specs caution about the effect on "deteriorated" utilities present within 2-3 diameters of pipe being replaced - and if using pneumatic pipe bursting any utility within 2.5 feet should be excavated. Our own in-house risk management rules call for any utility crossing the pipe bursted pipe to be potholed. Do you agree?

RESPONSE: Contractor will utilize current Spec sheet

8. Are rollers needed for piping 4" or smaller if piping is kept off of any abrasive surface?

RESPONSE : Yes, Rollers will be used regardless of pipe size. Per Specification, Locate above ground area (corridor & slit trench to slope pipe into main) used for initial layout of polyethylene pipe to be fused and use rollers every fifteen feet to support polyethylene pipe that is fused (refer to ASTM D-2657) and going to be pulled into the entrance excavation.

9. The specs call for removing the inside and outside fuse bead. Is it necessary to remove the internal bead on all sizes of piping? And is it necessary to remove the outside bead?

RESPONSE : No. The external and internal beads will not be require removal.

10. The specs stat that "After new main pipe has been pulled into place the section must stay isolated and pressure checked for leaks." Assuming that this pressure test is performed with air and not hydrostatic; is this test performed just long enough to verify the pipe will hold pressure?

RESPONSE: Leakage test shall be conducted after the pressure tests have been satisfactorily completed. The duration of each leakage test shall be at least 2 hours, and during the test the water line shall be subjected to not less than 200 psi pressure.

11. Open Excavation pipe type? C-900 PIC or Class 52 DIP*** DIP Pipe & fittings do not come smaller than 3", what should be used?

RESPONSE: C-900 or DIP

12. Polyethylene Pipe wall thickness SDR-17 w/ C-900 PVC O.D.?

RESPONSE: TABLE I

This table shows the sizes of polyethylene pipe for use with Pipe Bursting Methods (all dimensions are in inches)

IPS Average Wall Thickness Nominal OD Actual OD DR26 DR21 DR17 (Outside Diameter) (Dimensional Radius) 6 06.625 0.270 0.335 0.443 8 0.8625 0.352 0.436 0.538 10 10.750 0.439 0.543 0.671 12 12.75 0.520 0.644 0.795 16 16.000 0.652 0.808 0.999

The dimensional ratio's (DR's) are: 26, 21 and 17. These are referred to as DR 26, DR 21 and DR 17. Dimension Ratio is calculated by dividing the specified outside diameter by the minimum wall thickness.

13. Pipe Bursting/Lining: If an unknown repair clamp and/or service saddle are encountered and pipe bursting/lining operations are delayed or stopped, how will we be compensated?

Response: It’s incumbent upon the contractor to bid accordingly. No additional line item will be added.

14. Section “L” II Past Performance Information: It states that there’s a page limitation. Is there a limitation?

Response: No. There is no page limitation

15. Section “L” III Document Certification: What type of certification is required?

Response: Please provide proof from SBA that your company is a Certified HUBZone.