Questions_and_Answers_0003.pdf

Attachment No. 1 Solicitation No. 140R2026R0018

Bradbury Dam Outlet Valve Replacement

Offeror Questions and Answers

1. Question: SF 1442 specifies that an offer guarantee is required. What is the Offer Guarantee Amount?

Response: The offer guarantee indicator on SF 1442 was selected inadvertently. An offer guarantee is not required for this Request for Proposal.

2. Question: Will the 365 day period of performance include the full outage from September 1 - March 31? At a minimum we would request that the period of performance include September 1, 2027 - December 31, 2027.

Response: See revised period of performance in Section H.

3. Question: How is the penstock unwatered and who is responsible for unwatering and sealing the penstock?

Response: The Government will be responsible for placing the clearances for the penstock interruption of service and closing the high pressure gate as shown on informational drawing number 368-D-99. The Government will attempt to achieve a full seal, however leakage of approximately 1 cubic foot per second (cfs) should be expected. See specification Section 35 22 25, paragraph 1.04.G.

4. Question: What is the amount leakage that the contractor should expect to have to manage in the penstock pipes?

Response: See response to Question 3.

5. Question: What is the reason for the December 15, 2027 date that mandates that the facility shall be able to control and release water through the new fixed cone valves?

Response: Reclamation has commitments with downstream partners and fisheries to fulfill.

6. Question: For a job of this size having 3 full time and 1 part time supervisors onsite seems excessive, please confirm that the Contractor supervision can dual or triple hat. i.e. Can the Contractor Site Superintendent also serve as the Onsite Safety Representative and/or Quality Control? Can the Onsite Safety Representative and Safety Professional roles be filled by the same individual?

Response: See revised Specification Section 01 35 30. The specifications do not prohibit the Safety Professional, Onsite Safety Representative, or Quality Control personnel from having collateral duties, such as Site Superintendent, provided they have the required qualifications for the duties being performed.

7. Question: Section 01 78 30, 1.02.A.3 states that there is 10% retainage from progress payments (exclusive of mobilization and preparatory work), can you please confirm that all other work will have 10% retainage held from the Contractor until final acceptance? If the above is true, would the Government reconsider and change retainage to 5%?

Response: Please refer to revised specification Section 01 78 30.

8. Question: 35 22 25, 2.01.A.1 - What is the valve body material requirement for the Butterfly Valves?

Response: Material shall be selected to meet operating requirements. See response to Question 15 for further discussion of operating requirements of butterfly valves.

9. Question: 35 22 25, 2.07.A - Please confirm that there is coating required on the stainless steel cone valves.

Response: Specification Section 09 60 20 – Coatings describes requirements for coating of the fixed-cone valves. Exterior surfaces of the fixed-cone valves that are not stainless steel shall be coated. Stainless steel parts shall not be coated.

10. Question: 35 22 25 2.03 Reducer - What is the expected Face to Face dimension for the reducing spool?

Response: Both AWWA C208 and ASME B16.9 have a standard face-to-face dimension of 24 inches for reducing from 30 inches to 24 inches.

11. Question: 35 22 25 2.03 Reducer - What is the pipe schedule or wall thickness for the reducer spool?

Response: Pipe schedule to meet requirements of AWWA C208 or ASME B16.9 per Specification Section 35 22 25, paragraph 2.03 A. Working pressure to meet or exceed the maximum operating head of the fixed-cone valve in paragraph 2.04 A.2.

12. Question: 35 22 25 2.03 Reducer - Is the Reducer Spool to be Stainless Steel?

Response: The reducer is to be carbon steel and coated per Specification Section 09 96 20 – Coatings, Tabulation No. 1.

13. Question: Is the area where the existing valves are located and new valves will be installed considered a permit restricted confined space that will require a standby confined space rescue team?

Response: The space where the existing valves are located is a confined space. If the contractor introduces hazards that cause the space to meet the criteria for a permit-required confined space, the applicable permit-space entry and rescue requirements would apply.

14. Question: Based on initial feedback received about the fixed cone valve lead times, it is not possible to complete this project within the 365 day period of performance stated in the solicitation documents. Is the Government willing to adjust the period of performance to 2 years to allow for procurement of the fixed cone valves?

Response: See revised Specification Section 01 14 30, Interruption of Service from Amendment 001, and revised Section H.

15. Question: The proposed design includes a 30-inch butterfly valve upstream of a 30-inch × 24-inch reducer and 24-inch fixed cone valve at each outlet. Based on the available hydraulic information, operation of the fixed cone valve at 100% open under the maximum water head of approximately 206 feet is expected to produce a flow of approximately 275 cfs. This corresponds to a velocity of approximately 56 ft/sec through the 30-inch butterfly valve. Please confirm that the specified 30-inch butterfly valves are designed and rated for continuous operation at the anticipated maximum flow velocity of approximately 56 ft/sec, including the associated hydrodynamic forces, vibration, pressure differential, and potential cavitation effects. Please provide the valve manufacturer's allowable velocity and cavitation limits, or other engineering basis demonstrating that the proposed butterfly valves are suitable for these operating conditions.

Response: There are significant existing line losses in the system, see drawing 368-D-98 that shows the extend length of 38-inch diameter pipe upstream of the Outlet Works. The maximum flow through each butterfly valve will be 150 cfs per revised Specification Section 35 22 25 – Valves, included in Amendment 001. Additionally, the specified valve brand or equal was removed, allowing for open selection of valve manufacturers.

16. Question: Has a hydraulic/cavitation analysis been performed for the complete valve arrangement—30-inch butterfly valve, 30-inch × 24-inch reducer, and 24-inch fixed cone valve— at the full anticipated range of reservoir heads, flow rates, and valve positions? If so, please provide or identify the analysis confirming that the upstream butterfly valve and downstream fixed cone valve can operate throughout the required range without unacceptable cavitation, vibration, flow instability, or damage.

Response: No, an analysis has not been performed.

17. Question: Given that typical allowable velocities for the proposed butterfly valve application may be substantially below the approximately 56 ft/sec calculated at maximum discharge, would Reclamation consider revising the design to eliminate the butterfly valves and utilize an isolation valve better suited to the anticipated high-velocity service, such as an appropriately designed bonneted knife gate-type isolation valve upstream of each fixed cone valve?

Response: The design will not be changed.

18. Question: Please also consider whether relocating the 30-inch-to-24-inch transition and/or revising the isolation-valve arrangement would provide improved hydraulic conditions at the inlet to the fixed cone valve and reduce the potential for cavitation, turbulence, vibration, and premature valve wear.

Response: The existing facility layout limits the ability to increase spacing between the fixed-cone valves and other components.

19. Question: As a potential alternative to the proposed butterfly-valve arrangement, our design engineers have evaluated the use of appropriately designed bonneted knife gate isolation valves upstream of the fixed cone valves and have confirmed that the alternative arrangement can be accommodated within the available width and height constraints. The proposed arrangement provides several potential operational advantages that we request Reclamation consider:

A. Emergency Isolation Capability.

Our engineers have determined that a properly selected and actuated knife gate valve can provide emergency isolation in the event a downstream fixed cone valve becomes stuck or otherwise remains in the open position. This capability has been evaluated at the maximum identified operating condition, including approximately 206 feet of head and 100% fixed cone valve opening. By comparison, the proposed butterfly valve may be subject to significant hydrodynamic forces at the calculated flow velocity of approximately 56 ft/sec, which may limit its ability to reliably close under flowing conditions.

B. Improved Hydraulic Conditions Upstream of the Fixed Cone Valve.

When fully open, the bonneted knife gate is withdrawn from the primary flow path, resulting in a substantially unobstructed flow passage. This configuration minimizes upstream head loss and flow disturbance and reduces the potential for turbulence, cavitation, vibration, and other adverse hydraulic effects at the inlet to the downstream fixed cone valve.

Given these considerations, would Reclamation consider replacing the proposed butterfly valves with properly designed bonneted knife gate isolation valves suitable for emergency closure under the maximum anticipated dynamic-flow condition?

Response: See responses to Questions 15 and 17.

20. Question: Does the Government anticipate that the Outlet Works outage will occur during the December 1, 2027 through March 31, 2028 window? If so, please let us know that the period of performance will be 16 months long from NTP and not 365 days.

Response: See revised Specification Section 01 14 30, Interruption of Service from Amendment 001, and revised section H.