W9127826A0005 Government Response to Questions.pdf

W9127826A0005 Air Compressors and One Air Dryer

1. Question: Please advise on the basis of design and intended industry or application. Also, could you confirm whether a Class 0 (oil-free) air compressor is required?

Government Response: The intended use is to supply station air for our hydropower powerhouse. The station air needs to be a steady supply ready for brakes applied to the generator and station uses. Oil Free air compressors are not required.

2. Question: Please let me know the clarifications on the following.

Section 2.2.6 Flow Controller specifically states the flow controller must have ModBus RTU communication capability between the two compressors and come with electronic control.

Obviously, this can be obtained, but it’s going to add significant cost to the project as a master system controller will need to be added as well, the flow controller will not communicate with the compressors directly without a master system controller.

An alternative is a manual flow controller that is adjusted by hand, far less expensive option.

Reading through the entire spec, there are no mention of receiver tanks, not wet or dry. There must be a wet tank between the air compressors and the dryer for proper operation. The wet tank can be stand alone or the compressors can be tank mounted to achieve the appropriate wet tank capacity.

A dry tank will also be required if a flow controller is required, flow controller will not operate properly without a sufficient amount of dry storage.

Government Response: The KRT’s suggestion of a manual flow controller is acceptable.

We do not want new tanks. We are reusing tanks on site.

3. Question: The desiccant dryer is rated for a maximum inlet flow of 260 scfm at 100 psi.

However, please note that after accounting for the purge air required for regeneration, the actual available outlet flow for your plant will be approximately 215 to 223 scfm. Is this outlet flow sufficient for your requirements?

Government Response: No 215 to 223 will not be accepted, the requirement is for 250 CFM at

100 PSI.

4. Question: Can you please review and confirm that the following products meet your requirements as the products are originating from China. Once confirmed I will proceed with pricing.

#1 air compressor based on your requirements pls see the model SLT-22V

• Type: Rotary Screw--support

• Power: 30 HP, 480V, 3-Phase electric motor with VFD controls--support

• Performance: Must deliver at least 130 SCFM at 125 PSI--support

• Features: Must include Air-Cooled Heat Exchangers and a top-opening enclosure.--support pls see the detailed specification in the attachment.

about top open enclosure

Below is an exploded view of our product; you can see the ventilation window at the top.

#2 air dryer based on your requirements as below.

Pls see the air dryer specification in the attachment.

Type: Continuous-duty, dual tower, regenerative heated desiccant dryer--support

• Performance: Rated for 250 CFM, maintaining a dew point of -40 degrees F at 100 PSIG.--support

• Features: Must include a three-valve bypass system.--we can add for you

• Power: 480V, 3-Phase electrical source--220V 1phase currently but we can modify for you

#3 Certification

Could I please understand the product certification requirements?

Exporting to the US requires compliance with ASME and UL certifications, while some customers only require ASME compliance.

May I know your specific certification requirements?

USACE: The Buy American Act is in effect with this contract. Purchases originating from out of the US will not be accepted.

5. Question: Refer to Notice ID - W9127826A0005 - 2 Air Compressors and one Air Dryer, could you please clarify whether compressors are required to be tank-mounted or base-mounted, and whether an air receiver tank is required as part of this procurement. If required, please specify receiver capacity and ASME code requirements.

Government Response: Base Mounted is the desired mounting method. The intent is to use our existing receiver tank.

6. Question: We are currently working on the quote for the St. Stephen Air Compressor and Dryer requirement and need clarification on one technical point.

For Item 001, the specifications identify rotary screw compressors, 30 HP, 480V, 3 phase, but do not state whether the units must be oil flooded or oil free. There is a significant price difference between these two configurations, which materially impacts overall project pricing.

To ensure accurate and compliant submission, could you please confirm whether oil flooded rotary screw compressors are acceptable, or if oil free units are required?

Government Response: Oil Free vs Oil Filled is not specified. Either will be accepted. Please note there are requirements listed for oil filed.

7. Question: The SFC22 zone 2 adder is assuming the compressor is indoors - this would need to be confirmed.

Please note that the stated temperature is from -15°F to 110°F but the compressor with zone 2 adder would be rated down to +14°F and the standard no adder is rated to +40°F.

No site conditions were given to convert ACFM to SCFM for compressor sizing.

SFC 22

SFC 22, price adder for Indoor Zone 2 SFC 22 mounting feet adder

KED 300

purge booster adder Desiccant Vessel Insulation adder filter package B adder

Please confirm the above is what is required by this job?

Government Response: Compressor will be indoors in a climate-controlled facility. The temperatures will be well within the -15 F to 110 F range.

8. Question: Contract is requesting 2 variable speed drive compressors - is 1 of them going to be strictly a backup machine? Would they be open to 2 fixed speed machines? Reason why I am asking this is if both of the machines are going to be running and are variable speed they will be battling each other to run and there could be pressure drop across the system. Two fixed speed 30HP machines may be best here. See attached literature on our AS30 model and SFC22S variable speed machine model as both of these supply the same 141 cfm @ 125 psi.

For the dryer, any particular reason why they are requested a heated model. I've attached literature on our desiccant dryers and see which model they would prefer. KAD Heatless may be the best option if they can use heatless. The KED is a heated purge dryer and the KBD is a blower purge dryer.

Government Response: The intent is to use one compressor at a time in a lead lag scenario.

With the heated vs non heated dryer either option will be accepted. The spec doesn’t specify.