61-0036-17_--_Q&A_for_N00173-17-R-ST06.docx

Email 1

1. What size accumulators are required?

RESPONSE: Accumulator size is not specified but must be compliant with the requirements detailed in "Section 4 Hydraulic Power Unit" of the NRL-KW Hydraulic Structures/Material Test Systems Requirements:

· "The HPU shall be capable of providing a minimum of 60 GPM at a minimum of 3000 psi maximum working pressure. All aspects of the system shall be capable of an industry accepted safety factor above this maximum working pressure."

· "The HPU shall fit within 11 ft x 11 ft floor space. (The double doors allow 6' clearance into the Hydraulic Shed.)"

· "The HPU shall have built-in reservoir, accumulator(s), fill valve, filters, recirculating pump, heat exchanger, manifolds for connection of the 12 independent lines, and anything else that is necessary to provide for a safe and easily maintainable hydraulic test system."

2. What micron filters are required?

RESPONSE: The system shall be self-compatible and meet the requirements. The supplier shall design the system and select appropriate filter media.

3. Can you provide more information on the controller and software on your end so we can choose components that are compatible?

RESPONSE: As referenced in sections 1, 3, 7, 8 and 9 of the NRL-KW Hydraulic Structures/Material Test Systems Requirements, the software shall be vendor supplied and fully compliant with all relevant specifications.

· Section 1: Description of Need - "Software which run the Controller and Data Collection System and provide user interface with test parameters and control and allows for real-time viewing of data, post-processing, and export of data"

· Section 3: Overall System Requirements -" All physical equipment, control systems, data acquisition systems, firmware, and software shall be self-compatible and "turnkey" in operation. No NRL labor shall be required to integrate hardware, control systems, data acquisition systems, firmware or software."

4. In the "Support Equipment" section there is a variety of components that will be required and the description is quite basic. Can you exaggerate further to provide the size, length, pressure rating of the hoses and other components?

RESPONSE: A dimensional schematic of the test site is provided in Section 1 Figure 1 including location of control shed, hydraulic shed, chiller and load frames. The vendor shall provide support equipment sufficient to allow operation of the Test System within this footprint. Size of components and hosing will be in compliance with the operational requirements in Section 4.

"The HPU shall be capable of providing a minimum of 60 GPM at a minimum of 3000 psi maximum working pressure. All aspects of the system shall be capable of an industry accepted safety factor above this maximum working pressure."

5. Can you provide the details and specs of the software that the hydraulic power unit control system needs to interface with?

RESPONSE: As referenced in sections 1, 3, 7, 8 and 9 of the NRL-KW Hydraulic Structures/Material Test Systems Requirements the software shall be vendor supplied and fully compliant with all relevant specifications.

6. What are the detailed requirements of the controller and data recording system?

RESPONSE: As referenced in sections 1, 3, 7, 8 and 9 of the NRL-KW Hydraulic Structures/Material Test Systems Requirements the software shall be vendor supplied and fully compliant with all relevant specifications.

7. What control program will be used by NRL for this power unit?

RESPONSE: If this question is referring to software, the supplier shall supply software sufficient to meet requirements.

EMAIL 2

8. What is the NRL’s vision for onsite installation, specifically the plumbing & electric plan? Does the facility want Pressure, Tank & Drain lines (assuming no external pilot supply for the moment) for each of the twelve actuators? The specification implies the expectation is a single line (of each type) should be run to each actuator 75 feet from the hydraulics shed. Would the NRL consider one or two common P, T & D lines between the HPU and the load frame, whereby a header manifold would be placed at each load frame? Individual manually operated isolation valves would be at these header manifolds (outside at load frame).

RESPONSE: NRL prefers individual hoses due to the constant marine salt-spray environment and corrosion on these items (easier to replace hoses and store in controlled environment when not in use). Also, forklift access to the pad and configurability of the load frame system for future testing is easier to accomplish without permanently installed hard line.

9. Since installation is part of the scope, we need a better understand of the site. Is the expectation that there will be rigged stainless steel piping & electrical conduit coming from the hydraulic shed out to each load frame? If so, how are they routed (Are there bends? Are there plumbing & cable trenches, stanchions or support hangers?). If not, and you require flexibility, is the expectation that the 75 feet will be run with flex hoses? Need more requirements for field cabling: Does appropriate conduit already exist? Will the awardee be required to supply and install appropriate conduit, pull boxes, potted connectors & J-boxes? Are stainless steel (CRES) conduit & fittings required?

RESPONSE: NRL will provide for cableways, stations, or troughs at the site. Flexible conduit or marine compatible cable is preferred for cable runs. NRL will only expose equipment to the environment when required for testing, otherwise it is intended that the cables are coiled and stored in a controlled environment.

10. The specification requires closed loop pressure control (2nd paragraph in Section 7, “Controller”). The specification also advises that pressure instrumentation may be located in the hydraulic shed (4th to last paragraph in Section 6, “Hydraulic Cylinders, Servovalves, and Instrumentation”). These specs may conflict. Does the NRL require closed loop control of the supply pressure to the servo-valve actuators? If so, this effectively constitutes a 13th control axis. Does the NRL want the option of closed loop pressure control within each hydraulic actuator itself? If so, the pressure transducers must be installed between the cylinder and servo-valves. This means that the pressure instrumentation must be installed at the servo-valve actuator. If pressure control at the actuator is desired, only differential pressure control across the piston makes sense. This requires two pressure transducers at each actuator. So are we to supply one pressure transducer at the HPU or 24 transducers (with associated terminal blocks, field wiring and field cables)? This will have a significant impact on our costs.

RESPONSE: Closed loop control of the HPU pressure for 3 individual tests is required. It is intended that the hydraulic pressure be controlled at the manifold to allow 3 independent tests to be run simultaneously at 3 different HPU pressure settings. Individual closed-loop feedback of pressure at each servo-valve and actuator is not required. This is a retraction of “pressure” from Section 7, Paragraph 2 in discussion on control axes.

11. How many simultaneous tests will be performed? Does the “three (3) users running three (3) independent tests from independent workstations simultaneously” mean nine simultaneous tests? This will impact HPU and possibly field plumbing in addition to controls.

RESPONSE: The system shall be capable of running different test scenarios simultaneously. “3 users running 3 independent tests” is a statement of controller, software, and user interface requirements. The hydraulic system shall be capable of running 3 simultaneous independent tests at different supply pressures. The requirement for 3 independent tests at different supply pressures is intended to drive manifold requirements from the HPU.

12. The sizes of the actuators required to meet the force requirements are such that the required hydro-mechanical natural frequencies will preclude accurate control through the full specified bandwidth. This is also driving the need for larger & more expensive servo-valves. Can the NRL explain a bit more about what they are testing, under what conditions, given targets, position accuracy requirements, etc.? Also, our understanding for the graphic in Figure 2 is that the NRL has not yet determined what rod & cap end clevis attachments are appropriate. Should we make an allowance for this or can you confirm that these will be supplied by the NRL?

RESPONSE: Generally, the objective is material and structural testing. Of key importance is that an accurate and repeatable force-time history is generated by the system on the material/structure in test. The deflections given represent the anticipated deflections of materials and structures under test (understanding that the specifications as written are in a no-load configuration). Running at a higher frequency may be necessary to avoid a notch or resonance in the test. This would not be considered disqualifying condition for an offered test system. NRL is seeking a best value solution and any offer should consider balancing cost with capability.

NRL will supply end caps and clevis attachments. These items are not designed yet, as they need to interface with offeror specific equipment.

13. Are there any site environmental issues or regulations that would require or preclude any type of mineral oil, phosphate ester, or polyol-ester based hydraulic fluid? For now, we plan on quoting an Eco-friendly (Mobil Envirosyn) fluid compatible with servo-valves.

RESPONSE: Environmentally Acceptable Lubricant (EAL), is preferred. Synthetic Esters are preferred over petroleum based oils, such as Mineral Oil. This guidance comes from EPA 800-R-11-002, Publication U.S. Environmental Protection Agency, November 2011. The test site is in close proximity to open seawater, a spill is unlikely but risk of flood and hurricane should be considered. An environmentally preferable oil would help further reduce risk of environmental impact in case of disaster. Please comment in the proposal on the recommended oil, and any risks to premature wear or failure that the system may be exposed to from said oil.