ASME B16.9 Pre-Shipment Inspection: Dimensional Checklist

Why the Pre-Shipment Inspection Is the Buyer's Last Cheap Chance to Reject

Once the container is on the water, rework = cost of new + freight + delay. A pre-shipment inspection at the supplier's plant typically costs $300-1,500 (depending on lot size and inspector). The cost of replacing a rejected lot from site can easily run 10x that, plus 6-8 weeks of project delay.

This article is the walk-down checklist your inspector (or your third-party agency: SGS, BV, TÜV, Lloyd's, DNV, Intertek) should follow at the supplier's plant before signing the release.

1. Tools the Inspector Should Bring

• Calibrated vernier or digital caliper (verify cal sticker date < 12 months)
• UT thickness gauge calibrated to a step block of the same material grade
• Bevel gauge / weld gauge (Cambridge or GAL type) for end prep
• Steel rule + tape (class II)
• PMI gun (XRF or OES) for alloy verification — mandatory on stainless / low-alloy
• Pit gauge + 10× magnifier
• Hardness tester (portable Brinell or UCI) for NACE / sour-service orders

2. Dimensional Checklist — Real ASME B16.9 Limits

Outside Diameter at Bevel End

Inside Diameter at End

Wall Thickness

Minimum 87.5 % of nominal unless purchaser specifies stricter (some EPCs require 90 % or "no minus tolerance").

Center-to-End

Off-Angle / Squareness of Ends

Typically ≤ 1° to 5° depending on NPS band. Check with a square against the end face.

End-Prep Bevel Angle

30° (+5° / −0°) with 1.6 mm root face per ASME B16.25 (which B16.9 references).

3. Visual Inspection — What to Walk Down per Fitting Type

Elbows

• Weld profile if welded construction
• Surface laminations
• Ovality at both ends
• End roundness within tolerance

Tees

• Branch alignment to run
• Squareness of branch to run
• Set-on / set-in transition smoothness

Reducers

• Concentricity (CR) vs eccentricity (ER) per drawing
• Taper smoothness, no flats
• Both ends round

Caps

• Dimple / wrinkle on crown
• End roundness
• No through-thickness wrinkle

Surface Defects (All Types)

• Scratches, dents, pits, laps, scab marks
• Depth must NOT push wall below 87.5 % of nominal
• Use UT to verify any suspect spot

4. NDT Spot-Check (Witness Sample, Not 100%)

For NACE / sour orders, also spot-check Brinell hardness with a portable tester — should read ≤ 187 HBW for A105 / A234 NACE-compliant.

5. Marking Verification (ASME B16.9 §3 / MSS SP-25)

Required hard-stamp / paint-stamp on each fitting:

• [ ] Manufacturer logo
• [ ] Material grade (e.g. WPB, WP304L, WP22-S)
• [ ] Size and schedule
• [ ] Heat number
• [ ] "WP" prefix for wrought
• [ ] Standard reference (B16.9)
• [ ] Inspector's mark

Cross-check: the heat number on the body must match the heat number on the MTC for that lot. Walk a random sample backward from "QC accepted" pile to incoming raw material to verify the chain.

6. Documentation Packet Before Sign-Off (the "No Doc, No Shipment" List)

• [ ] EN 10204 3.1 or 3.2 MTC for finished fitting AND mother material
• [ ] Heat treatment record (normalising / quench-temper / solution annealing chart with time-temperature curve)
• [ ] NDT reports (PT/MT/UT/RT) with technician's SNT-TC-1A Level II/III qualification
• [ ] Hydrostatic test report (if specified in PO)
• [ ] Dimensional inspection report signed by QC
• [ ] Packing list with heat-number-to-package mapping
• [ ] Certificate of Origin + Form A / Form E (if preferential tariff applies)
• [ ] Inspection release certificate if third-party witness was specified
• [ ] Photos of representative items (often part of inspection report)

7. Packing Checklist for Sea Freight to Overseas EPC Site

• [ ] Threaded ends / bevels protected with plastic caps
• [ ] Stainless segregated from carbon steel (no cross-contamination from rust)
• [ ] Wooden crates ISPM-15 fumigation stamped (mandatory for EU, US, AU, IN imports)
• [ ] Desiccant bags inside seal-wrapped pallets for monsoon-season ocean transit
• [ ] VCI (vapor-corrosion-inhibitor) paper wrap for stainless surfaces
• [ ] Container loading plan matches the packing list
• [ ] Shipping marks match the buyer's instructions exactly (port of discharge, project code, item code)

Final Sign-Off

After every checklist item passes, the inspector issues a Pre-Shipment Inspection Certificate that includes:

• Lot identity (heat numbers, item codes, quantities)
• Inspection methodology summary
• Findings (with photos)
• Disposition (accept / accept with deviation / reject)
• Inspector signature + date + agency stamp

Only then should the container be released for loading.

This article is provided as a procurement reference. Project specifications and the latest published ASME B16.9 edition take precedence for any commercial transaction.

Related Products

For physical supply of the specs discussed above, refer to the relevant Hebei Haihao product categories:

• seamless butt-welding pipe fittings
• induction pipe bends

Or browse the full product catalogue and filter by ASTM / ASME / EN / GB standards, material grades, and size ranges.

Further Reading

• NDT method selection (PT/MT/UT/RT) for pipe fittings
• EN 10204 3.1 vs 3.2 mill test certificates

Next Steps

• This article is a procurement reference; all standard numbers, chemistry limits, and process parameters defer to the latest published edition
• For project RFQs, submit your specs via the inquiry form; we respond within 4 business hours
• Factory certifications and inspection capability are listed on the certificates page