TSC_High_Head_Test_Facility_Equipment_Site_Visit_Questions_and_Answer_Session_0003.pdf

TSC High Head Test Facility Equipment Site Visit Questions and Answer Session

High Head Lab Pump:

Q.1 Measurement from centerline of motor to discharge flange face.

A:13 inches. See photo below.

Q.2 Any funding constraints (BABA, etc.?)

A: (See Clauses)

Q.3 There seems to be active growth on the existing unit. Is there something in the water that is causing this?

A: We are not sure what that growth is. The pump has been in the water for at least 40 years, and our sump water is tap water that is treated with an ozonation system to disinfect the water and prevent organic growth.

Q.4 Is that line that is routed to the suction bearing part of a remote greasing system? If not, is it a pressurized flush for rifle-drilled shaft? It seems that there is an existing grease line to the bottom bearing. Do you want to duplicate that?

A: We are not sure what the line is but appears to be a greasing system with a zerk on top for access and feeds the bottom impeller bearing. We do not need to duplicate this.

Q.5 2.01. B.1 and 2.03.3.k- Guarantee point - Recommend selecting a point in the center of the curve, not one on either extreme. The pump will likely operate more often in the middle of the curve, and test results will be more accurate. In addition, the high flow point is met at reduced speed, making that less meaningful as a guarantee point. Bureau may want to consider increasing the impeller diameter to maximize use of the 250 hp motor and reach both points at reduced speeds. This would provide a little more performance than the existing pump.

A: Pump operation will be different for every lab test configuration. Operation over the full range is critical. If anything, the pump will likely operate more often at the left of the curve with low flow and high head. Thank you for the recommendation. When submitting a quote, please note any deviations to the specifications and explain why you recommend changes.

Q.6 2.01.5. a, b, and c- Minimum Continuous Stable Flow, runout (right end of curve) and allowable operating range are undefined opinions. Different manufacturers may use different values for identical pumps.

A: Yes, correct.

Q.7 2.01. C.2.A and 2.01.C.2.g- "Design bowl assembly for easy removal of impeller and bearings" is subjective. Please specify either colletted impellers (more common and less expensive, but some may consider them more difficult to remove) or keyed impellers with split ring keys for axial thrust (more engineered for things like power plants, more expensive, some consider them easier to remove)

A: Either colletted or keyed impellors are acceptable. Please describe the reason for your selection and any deviations from the provided specifications in your quote.

Q.8 2.01. C.4.c - " ... allowable deflection of mechanical seal manufacturer". Recommend using packing in lieu of mechanical seal. Mechanical seal is not reliable in applications where the pump is operated all the way across the pump curve.

A: Thank you for the recommendation. Packing instead of mechanical seal is acceptable.

Q.9 2.01. C.4.d - Vibration analysis can be calculated but are invalid if pump is mounted to steel frame. Recommend eliminating this requirement.

A: Dynamic analyses will not be required but requirements will hold for field testing per HI 9.6.4 and HI 9.6.8.

Q.10 2.01. C.4.h - Please confirm that you want to maintain existing two-piece discharge head/riser configuration with cast iron head.

A: We have no strong preference on a single piece or two-piece configuration.

Q.11 2.01. C.4.j - Plastic tubing or stainless-steel tubing?

A: Plastic tubing is acceptable.

Q.12 2.01. C.4.k - Is this 3/4" tap required? I don't see one on the existing pump. The discharge head is cast iron and custom taps like this cannot be added easily.

A: We will not require a pressure tap in the discharge head. The existing ½ inch threaded tap on the top of the discharge flange is shown in the photos below.

Q.13 2.01. C.8.c - Rigid coupling for a vertical turbine pump is not a gear coupling. Rigid coupling with space for seal removal will make the unit significantly taller, with higher risk of vibrations. Suggest modifying specifications to hollow shaft motor with WP-1 enclosure and packing. Less expensive, more reliable, easier to service.

A: Yes, correct. We don’t want to make the unit taller than it needs to be. Hollow shaft motor would be acceptable.

Q.14 2.01. C.9 - Recommend using high quality graphite impregnated packing in lieu of mechanical seal. Seals are more prone to failure when operating far off BEP. More expensive to buy, more expensive to repair, and more difficult to service.

A: Thank you for the recommendation. Packing would be acceptable.

Q.15 2.01. D.2.d - Asking for a TEFC motor. With rigid spacer coupling and mechanical seal, pump will be taller, more prone to vibrations, and less reliable. TEFC is not required indoors.

Recommend WP-1 hollow shaft motor instead.

A: A WP-1 hollow shaft motor would be acceptable.

Q.16 2.01. D.2.p - Indication and protective devices - Are we correct in assuming there are only two RTDs located one each at the upper and lower motor bearings? No RTDs in the motor windings? Also clarifying no vibration monitoring on the motor bearings.

A: It would be best if the motor also includes winding temperature and vibration RTDs as well to ensure the best protection. If that is something that is not available or difficult to obtain then at least the bearing RTDs would be acceptable.

Q.17 2.01. E.2.f - VFD Panel is described as NEMA 4, suitable for control cabinet". A NEMA 4 enclosure would be stand alone, not mounted in a separate cabinet.

A: That is acceptable. Losing the enclosure with the VFD being NEMA 4 is fine.

Q.18 2.01. E.4 - Describes a full NEMA 1 control cabinet for the VFD and associated control equipment. Previous line-item requests NEMA 4 cabinet. Please clarify. We assume you want the VFD packaged in a stand-alone NEMA 1 or NEMA 4 enclosure and not the VFD enclosure repackaged into another control panel. Also, do you want the disconnect switch to be separate from or integral to the VFD enclosure? (E-stop will be independent device)

A: NEMA 4 and NEMA are both acceptable. Please describe the reason for your selection.

Please see response above.

There will be a disconnect switch for the 480V incoming line to deenergize the VFD/motor for maintenance or safety. The disconnect switch will be provided by a separate contract. The VFD will be standalone and not repackaged into another control panel

Q.19.2.02 Dynamic Analysis - We can provide a critical speed analysis as requested in the spec, but the results are invalid for pumps mounted to steel structures rather than concrete foundations.

Recommend eliminating these entirely and finding possible natural frequencies during on-site testing.

A: Dynamic analyses will not be required but requirements will hold for field testing per HI 9.6.4 and HI 9.6.8.

Q.20 3.03.C - All pressure and flow instruments to be provided by the Government in the existing system.

A: Yes, that is correct.

Q.21 3.04. B.1 - Contractor to supply alignment verification tools and vibration tools. Pressure and flow to be measured with existing meters.

A: Yes, that is correct.

Q.22 3.04. B.5 - Recommend modifying test procedure. Operating for 4 hours at one speed at both service points is not recommended. Seals are not likely to survive such long durations so far from a reasonable operating range. Rather, we suggest running the pump at its lowest projected speed from runout to shutoff, selecting 5 data points to record flow, head, speed, total vibration level (in/sec), motor bearing temperatures, voltage, and amperage. The repeat the test at 5 more speed increments, finishing at full speed. This should provide a reasonable map of the entire operating range and identify regimes where vibration issues were observed for avoidance in the future.

A: Thank you for the recommendation please include your deviation and explanation in your quote.

Q.23 3.04. B.5.d - Suggest replacing full spectrum vibration analysis with total vibration levels as described above. We will be taking exception to the modification of the motor and pump to meet HI vibration limits, as the range of operation is too large and the foundation not sufficiently rigid.

A: Thank you for the suggestion. Please include your deviation and explanation in your quote/proposal.

Q.24 Equipment they bring in does is it required to strictly use electrical? Deisel not allowed because indoors?

A: It is strongly preferred that equipment used for installation, removal, and transport inside the building is electric or propane powered. Diesel is the least preferred option and would require a safety and monitoring plan.

Q.25 How much of the electrical conduit needs to be removed?

A: GSA contractor will disconnect electrical connection to existing pump/motor and remove existing 4” diameter conduit between motor and column L21. Please see photo below. There will be a new rack to mount the VFD with a disconnect adjacent to column L21.

Q.26 What is the vertical distance from the floor to the pipe centerline?

A: 31 inches

Q.27 What is the reach distance for installation machinery (horizontal distance from concrete floor at edge of metal grating to centerline of pump/motor installation location)?

A: Reach distance is 8 ft 2 inches.

Q.28 What is the footprint of the current pump mount?

A: Photos and drawings are shown in Figures 8-14 of the original Statement Work and a two photos from the vendor site visit are shown below.