SATPC0042859 Tab 10 4 Questions.pdf
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- Attached to
- Dome Loaded Regulator
- Solicitation number
- 80NSSC27944860Q
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This is a Questions and Answers document clarifying requirements for a nitrogen gas (GN2) regulator procurement. NASA requires one custom-engineered regulator with one set of spare soft goods, featuring 4-inch Grayloc 4GR31 hubs on both ends. The regulator must meet a minimum flow coefficient (Cv) of 80 and deliver 80 lbm/sec GN2 flow, calculated at 4,000 PSIG inlet and 4,000 PSIG outlet pressure. Compliance is evaluated solely against the Statement of Work (SOW) requirements with no brand name or equal-to specifications. Clamps and seal rings may be quoted as optional line items but are not required.
The regulator must comply with ASME B31.3 standards for proof and burst testing, with test reports required for all pressure-containing parts. Performance requirements include external leakage testing at 6,000 PSI with zero leakage allowed over two minutes; internal leakage not exceeding 10 SCCM (67 bubbles per minute); functional testing demonstrating outlet pressure lockup within ±2% of set pressure at 1,000, 3,000, and 5,000 PSI outlet conditions; and pressure stability of less than 0.1 psig per 100 psig. Commercial-grade cleanliness is acceptable, though cleanliness to 400A per RPTSTD-8070-0001 may be quoted as an optional line item. Material test reports (MTRs) for all pressure-containing parts and ambient nitrogen as the test medium are required. NASA will provide a detailed acceptance test procedure post-award and will accept Cv compliance through certification, calculations, and supporting test data rather than requiring physical demonstration of the 80 lbm/sec flow rate.
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Other files
| File | Type | Posted |
|---|---|---|
| SATPC0042859 Tab 10 4 Questions.pdf | ||
| SATPC0042859 Tab 04 4 SOW.pdf | ||
| SATPC0042859 Tab 10 1 RFQ.pdf |
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Text version
We received some questions regarding this regulator. Please let me know how we should respond.
1.What quantity of regulators and spare soft-goods sets is required? 1 regulator, 1 set of spare soft goods.
2. The RFQ states “Brand Name or Equal To,” but no manufacturer or model is identified. Is there a reference model, or will compliance be evaluated solely against the SOW? No brand name or equal to, meeting the requirements of the SOW will suƯice.
3. Please confirm that Cv 80 minimum and 80 lbm/sec GN2 are correct. At what inlet pressure, outlet pressure, and temperature must the regulator achieve that flow? This is correct, the flow rates are referenced at 4,000 PSIG inlet, 4,000 PSIG outlet. (Note: the Cv is the controlling parameter, the flowrate number is a calculated quantity based on the Cv. NASA can potentially take some exceptions to the flowrate.)
4. Are 4-inch Grayloc 4GR31 hubs required on both ends, and must the regulator include the clamps and seal rings? Yes - 4GR31 hubs on both ends. You can quote with the clamps and seal rings as an optional CLIN but not required to per the SOW.
5. What ASME code, proof-test pressure, burst-test pressure, test medium, and acceptance criteria apply? Reference ASME B31.3 for proof and burst pressure, test reports for all pressure containing parts must be provided. NASA will provide an acceptance test procedure after contract award. It will entail flowing, at minimum, the three pressure test ranges listed in the SOW.
6. Please define the required pressure stability and leakage limits, operating-temperature and cleanliness requirements, and required certification/test documentation.
Commercial clean is acceptable, but a clean level to 400A per RPTSTD-8070-0001 (attached) can be quoted as an optional CLIN.
Pressure stability requirement is <0.1 psig per 100 psig.
Temperature and fluid media is ambient nitrogen (GN2).
Proof and burst test documentation per ASME B31.3.
MTR's for all pressure containing parts.
Documentation identifying test method, test fluid, pressures, temperature, duration, and any observed defects
External Leakage Test (Media: GN2)
Load inlet to 6000 PSI. With downstream shutoƯ valve in closed position slowly load dome to 6000 PSI.
Test: No external leakage allowed over a 2 minute period.
Internal Leakage Test (Media: GN2)
Load inlet port to 6000 PSI. Attach a ¼" tube to outlet port and submerge 1/8" to 1/4" underwater.
Test: Leakage not to exceed 10 SCCM (67 bubbles/minute) over a 2 minute period
Functional Test (Media: GN2)
Load inlet to 6000 PSI. With downstream shutoƯ valve in closed position apply pressure to dome port until outlet reaches 1000 PSI. Open downstream shutoƯ valve and allow moderate flow. Close downstream shutoƯ valve.
Test: Outlet to lockup at +/- 2% of set outlet pressure.
Repeat at 3000 PSI and 5000 PSI outlet pressure.
Please also confirm whether a custom-engineered regulator is acceptable. A custom engineered regulator is acceptable.
Q: Could you please confirm whether there is an existing regulator currently installed in the system?
If so, could you provide the manufacturer, model number, and/or part number of the existing unit for reference and compatibility purposes?
A: A regulator is not installed, this is a new system.
Thank you for the detailed clarification. We have two brief follow-up questions:
1. The stated flow condition lists both the inlet and outlet at 4,000 PSIG. What downstream pressure or minimum pressure differential should be used to verify the Cv 80 and 80 lbm/sec GN2 requirements?
The Cv should be calculated at 4,000 PSIG inlet and 4,000 PSIG outlet, the flowing Cv decreases significantly as the pressure delta increases, and that flow relationship should be understood, meaning if you can provide a flow conditions from the listed operating pressure ranges in the SOW that would appreciated but not required.
2. For acceptance, must the contractor physically demonstrate 80 lbm/sec flow, or may compliance be established through Cv certification, calculations, and supporting test data?
NASA will accept Cv certification though calculations and test data.
File details come from the government source that posted it. Updated .