The Vessel Is Legal Where It Sat, Not Where It Is Going

Buyers price used vessels on steel, volume, and MAWP. The expensive variable is paperwork, and it is settled at the destination. The same is true of the freezing equipment those vessels often come with.

The National Board’s NB-57 puts it plainly: vessels manufactured for use in the US or Canada must comply with the jurisdictional laws of their installation location. Jurisdictions are not only states. The National Board’s synopsis covers cities and counties as distinct jurisdictions, including Chicago, Buffalo, and Miami-Dade County.

Three states, three problems

Ohio Administrative Code Rule 4101:4-9-01, effective July 1, 2024, is the sharpest example. Paragraph (L) prohibits relocation within Ohio of a vessel that does not bear the appropriate ASME symbol, was not registered with the National Board, and has no Ohio boiler number. Paragraph (K) gives the route for a secondhand ASME-stamped vessel: apply for the installation, file the manufacturer’s data report with the state, and have an inspection performed before operation.

Rhode Island puts the gate earlier. Under 260-RICR-30-10-2 section 2.5.21, a used vessel must be inspected by a qualified or National Board commissioned inspector before it can be shipped for installation in the state. Nevada handles it through permitting: NAC 455C.142 cancels the operating permit for a vessel moved from the site at which it was inspected and requires a new inspection and permit on reinstallation.

One lesson, three mechanisms. Confirm the destination jurisdiction’s requirements in writing with its chief inspector before the vessel ships.

What the paperwork actually proves

The Manufacturer’s Data Report is a construction record, not a condition warranty. Form U-1A is the alternative form for single chamber shop or field fabricated vessels, which is what most receivers and accumulators carry. Form U-1 is more likely on a multi-chamber intercooler.

The fields to match against the nameplate are manufacturer serial number, National Board number, year built, MAWP at maximum temperature, minimum design metal temperature, and test pressure. The Authorized Inspector’s certification states the vessel was built to ASME Section VIII Division 1 and expressly disclaims any warranty about it. A mismatch signals an undocumented alteration or rerate.

The 45 dollar asymmetry

The National Board sells copies of registered Manufacturers’ Data Reports at a flat 45 dollars per National Board number. What it needs is the original manufacturer’s name and the National Board number, plus serial number and year built if available. IIAR’s own IIAR 9 checklist says the same thing.

Lose the file and you have a 45 dollar problem. Lose the nameplate and you have a different problem entirely.

Form NB-136 governs replacement of stamped data. It is completed with a true facsimile of the legible part of the nameplate, submitted to the jurisdiction where the equipment is installed, approved by that jurisdiction, and concurred in by the original manufacturer if it is still in business, with a commissioned inspector witnessing the re-stamping. That is why a nameplate rubbing belongs on the pre-shipment checklist. Where documentation is gone entirely, the remaining path is a state special application with general arrangement drawings, design calculations demonstrating equivalency to ASME construction, and an inspection addressing weld integrity and damage mechanisms.

Repair, alteration, and the form that goes with each

A repair is documented on Form R-1, Report of Repair. An alteration is documented on Form R-2, Report of Alteration. A rerate is treated as an alteration, so it travels on an R-2.

Both require an organization holding a National Board R Certificate of Authorization, which is held by organizations rather than individuals and requires an inspection agreement with an authorized inspection agency, a written quality system, and an onsite review. Verify any firm’s credentials in the National Board’s Manufacturer and Repair Directory.

Pressure relief valve repair is separate and requires a VR Certificate of Authorization. A valve rebuilt by anyone other than a VR holder is not a code acceptable repair, so ask who did it and for their VR number.

The trap specific to refrigeration: MDMT

A rerate qualifies equipment for operating conditions that exceed its original stamped pressure or temperature rating, or that fall below its minimum design metal temperature. Moving a vessel built for warmer duty into low temperature ammonia recirculation service is a downward MDMT change. That is a rerate, which makes it an alteration, which puts it in R-stamp and R-2 territory with code calculations and a new nameplate.

Check MDMT against the intended suction condition before you buy, not after the vessel is on the pad. Our guide to vessels and heat exchangers covers the spec side.

The overlays that attach once it is installed

ANSI/IIAR 2 governs safe design of closed-circuit ammonia systems and ANSI/IIAR 6 covers inspection, testing, and maintenance. ANSI/IIAR 9 is the one most relevant to a used vessel: it sets minimum safety requirements for existing systems and gives a methodology for evaluating compliance. OSHA notes these are consensus standards rather than regulations, though they function as recognized good engineering practice and are widely adopted into state and local codes.

On relief valves, the conventional five year replacement interval for valves discharging to atmosphere originated with IIAR and carried into ANSI/IIAR 6, which also recognizes a sample bench testing alternative. Valves relieving internally into the closed circuit are treated differently: IIAR Interpretation 2020-2 states they are maintained per the manufacturer’s recommendations. Confirm against the edition of IIAR 6 in force.

Finally, a threshold worth running before you buy. OSHA’s process safety management standard lists anhydrous ammonia at 10,000 pounds, and EPA’s Risk Management Program lists it at the same figure, with aqueous ammonia at 20 percent or greater at 20,000 pounds. Those are system charge tests, not per-vessel tests, so adding a relocated recirculator can push an entire facility across the line.

What to demand before it ships

• The ASME Manufacturer’s Data Report, U-1 or U-1A as applicable.
• Nameplate photographs and a physical rubbing.
• National Board number, manufacturer name, serial number, and year built.
• Confirmation that nameplate data matches the data report on MAWP, MDMT, year, serial, and test pressure.
• Repair and alteration history with R-1 and R-2 forms and the R Certificate holder’s number.
• Relief valve make, model, set pressure, capacity, date, and the VR number of anyone who repaired one.
• The most recent signed and dated inspection report, with deficiencies noted.
• Service history: refrigerant and oil held, operating pressures and temperatures, and years in service.

None of this is exotic. It is the file a well-run plant already has, alongside the refrigerant documentation. When a seller cannot produce it, that is the finding, and it belongs in the price.

Refrigeration Equipment Pros sells surplus industrial refrigeration vessels, heat exchangers, compressor packages, and complete plants, and we supply the documentation that travels with them. Browse inventory at refrigerationequipment.net/shop, list equipment you are removing on our Sell To Us page, or call or text 201-805-1441. Inspections, repairs, alterations, and re-stamping are performed by R and VR Certificate holders, National Board commissioned inspectors, or the jurisdiction, and we will point you to the right one.

About the Author

Michael Rosenberg writes on the industrial refrigeration equipment market for Refrigeration Equipment Pros, a surplus and used equipment dealer with more than 25 years in ammonia and halocarbon systems, plant decommissioning, and equipment valuation. The company operates warehouse locations in Newfield, New Jersey, Houston, Texas, and Patterson, California. This article is general information about code and jurisdictional requirements and is not engineering or legal advice.

Sources

1. National Board, NB-57 The National Board and ASME Guide: https://www.nationalboard.org/SiteDocuments/NB-57.pdf
2. National Board, Synopsis of Boiler and Pressure Vessel Laws, Rules and Regulations (NB-370): https://www.nationalboard.org/viewallsynopses.aspx
3. National Board, Manufacturers’ Data Report copies and ordering: https://www.nationalboard.org/index.aspx?pageID=113&ID=442
4. National Board, Registration of pressure retaining items: https://www.nationalboard.org/index.aspx?pageID=9
5. National Board, R Certificate of Authorization: https://www.nationalboard.org/index.aspx?pageID=115&ID=160
6. National Board, VR Certificate of Authorization: https://www.nationalboard.org/index.aspx?pageID=115&ID=161
7. National Board, Manufacturer and Repair Directory: https://buscenter.nationalboard.org/MfgRepDir.aspx
8. National Board, Form R-1 guide NB-66 and Form R-2 guide NB-229: https://www.nationalboard.org/SiteDocuments/Online%20Ordering/R-1Form_NB-66_Guide.pdf and https://www.nationalboard.org/SiteDocuments/Online%20Ordering/R-2Form_NB-229_guide.pdf
9. National Board, Form NB-136 Replacement of Stamped Data: https://www.nationalboard.org/SiteDocuments/Online%20Ordering/NB-136.pdf
10. ASME, Form U-1A Manufacturer’s Data Report for Pressure Vessels: https://www.asme.org/wwwasmeorg/media/resourcefiles/aboutasme/standards_certification/bpvc%20data%20forms/bpvc_viii-1_u-1a.pdf
11. Ohio Administrative Code Rule 4101:4-9-01, effective July 1, 2024: https://codes.ohio.gov/ohio-administrative-code/rule-4101:4-9-01
12. Rhode Island 260-RICR-30-10-2, Boiler and Pressure Vessel Rules: https://rules.sos.ri.gov/Regulations/part/260-30-10-2?reg_id=10729
13. Nevada Administrative Code Chapter 455C: https://www.leg.state.nv.us/nac/nac-455c.html
14. The Equity Engineering Group, Basics of Rerating Equipment, June 27, 2023: https://e2g.com/industry-insights-ar/basics-of-rerating-equipment/
15. Becht, State Approval of Used or Relocated Pressure Vessels, July 3, 2015: https://becht.com/becht-blog/entry/state-approval-of-used-or-relocated-pressure-vessels/
16. IIAR 9 Checklist, data report and relief valve provisions: https://www.iiar.org/common/Uploaded%20files/iiar_docs/iiar%20standards/Addendum/IIAR_9_Checklist.pdf
17. IIAR Standards Committee Interpretation 2020-2, internally relieving pressure relief valve replacement, August 24, 2020: https://www.iiar.org/common/Uploaded%20files/IIAR_Docs/Standards/Standards%20Interpretations/Interpretation%202020-2%20%20Internally%20Relieving%20Pressure-Relief%20Valve%20Replacement-%20Final.pdf
18. OSHA, 29 CFR 1910.119 Appendix A, list of highly hazardous chemicals and threshold quantities: https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.119AppA
19. EPA, List of Regulated Substances under the Risk Management Program, updated April 24, 2026: https://www.epa.gov/rmp/list-regulated-substances-under-risk-management-program

Michael Rosenberg

Refrigeration Equipment Professionals (REP) is a trusted supplier of industrial refrigeration systems and surplus/used equipment, offering compressors, chillers, condensers, evaporators, ice machines, freezers, coolers, pumps, motors, complete plants, and services like purchasing, refurbishing, shipping, export crating, and storage/consignment support. With 25+ years of experience and clients across North America, Latin America, the Middle East, and Asia, we deliver reliable, cost-effective refrigeration solutions worldwide.