What Should Be Checked at the Lining and Branch Connections of a Steel-Lined Tee?

When inspecting a steel-lined tee, check that the liner is continuous, correctly positioned, and free from visible damage, and that it meets the approved material and thickness requirements. At the branch connection, verify the opening, liner transition, branch angle, and internal flow path against the drawing. Also inspect the steel body, connection ends, and any specified test or inspection records. Acceptance limits should come from the project specification and approved drawings—not from assumptions about what is standard.

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Quick Inspection Summary

• Confirm the liner material, thickness, and configuration against the purchase documents.
• Inspect the full accessible lining surface for cracks, cuts, blisters, loose areas, or contamination.
• Check the branch opening and lining transition for obstruction, exposed steel, and uneven edges.
• Verify the tee geometry, end dimensions, and connection orientation against the approved drawing.
• Review required inspection and test records, and clarify any acceptance criteria that are not stated.

1. Confirm the Product and Inspection Requirements

Match the tee to the approved documents

Start by checking the product identification and purchase order against the drawing, data sheet, and inspection plan. Confirm the main-run and branch sizes, pressure class or design conditions where specified, end connections, and material description. For a steel-lined UHMWPE tee, verify that the specified lining is UHMWPE rather than relying on the product name alone. Record any difference before accepting the component or proceeding with installation.

Agree on measurable acceptance criteria

Ask the supplier to identify the required liner thickness, dimensional tolerances, inspection methods, and test requirements in writing. Requirements can vary with the design, service conditions, and contract, so a generic checklist cannot replace project documents. If the documents do not state how to evaluate a defect or measure a dimension, resolve that point before inspection. This helps prevent disagreements over whether a visual mark or dimensional variation is acceptable.

2. Inspect the Lining Surface

Check continuity and visible condition

Inspect all accessible liner areas under adequate lighting, including the main bore, branch bore, and transitions between them. Look for cracks, cuts, gouges, bubbles, blisters, folds, contamination, or areas that appear lifted or loose. Pay particular attention to edges and changes in direction, where a defect may be harder to see. A visual inspection can identify visible problems, but it does not by itself confirm liner thickness or bonding performance.

Verify thickness, position, and exposed steel

Compare the liner thickness and coverage with the approved drawing or specification, using the measurement method agreed for the product. Check that the liner is positioned consistently and does not leave unintended steel exposed on a wetted surface. If thickness measurements are required, record their locations as well as the readings so that results can be reviewed and repeated. Do not apply a universal minimum thickness unless the project documents specify one.

3. Examine the Branch Connection and Internal Transition

Inspect the branch opening

Look into the branch and confirm that the liner reaches the opening as designed, with no gap, sharp obstruction, loose edge, or visible damage. Check whether the branch connection creates a smooth and unobstructed passage into the main run. A poorly aligned transition can affect flow and may create a place where solids collect, depending on the service. Confirm that the actual configuration matches the drawing rather than judging it only by appearance.

Check alignment and branch geometry

Verify the branch angle, orientation, and centerline position against the approved dimensional drawing. A 90° branch is a common configuration, but other angles and orientations may be specified; never assume the intended geometry from the word “tee.” Check the branch-end dimensions and mating face or connection details using the method and tolerances agreed for the order. Photograph or record any apparent mismatch before the tee is installed.

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Review the junction for damage or weak-looking transitions

The junction between the branch liner and the main liner deserves a close visual review because it combines a change in direction with a change in geometry. Look for abrupt steps, exposed substrate, cracks, or a liner edge that could catch material or be damaged during handling. If the internal junction is difficult to see, ask whether the supplier can provide an agreed inspection view or supporting manufacturing documentation. Do not infer hidden construction quality from a smooth external surface alone.

4. Inspect the Steel Body and End Connections

Although the lining and branch junction are the focus, the steel body must also be checked for transport damage, dents, corrosion, and visible weld or surface issues relevant to the specification. Confirm that the ends are clean and that their dimensions and facing details match the mating piping. Check that the liner has not been damaged or displaced near the ends during storage, lifting, or handling. Keep protective covers in place until inspection or installation requires their removal.

5. Check Inspection Records and Required Tests

Review the documents required by the purchase order, such as material identification, dimensional inspection records, and any specified lining or pressure-test records. Confirm that the records identify the inspected item and correspond to its drawing or order details. A pressure test, when required, should follow the project’s stated medium, pressure, duration, and acceptance criteria. For example, a test pressure expressed in MPa is meaningful only when the applicable value and procedure are defined for that specific design.

Use numerical examples only to clarify what should be recorded, not as default acceptance limits. A drawing might specify a 90° branch, and a hypothetical liner detail might call for 5 mm thickness; both values must be verified against the actual approved documents. Measurement results should be recorded in appropriate units, such as millimetres for dimensions and MPa for pressure. These examples are illustrative and do not establish requirements for every steel-lined tee.

Common Inspection Mistakes to Avoid

• Checking only the outside: External appearance cannot confirm the internal liner condition or branch transition.
• Assuming all tees have the same geometry: Verify angle, orientation, and dimensions against the project drawing.
• Accepting vague thickness statements: Request a specified value, measurement method, and record when thickness verification is required.
• Using an unspecified test pressure: Apply only the pressure and procedure stated in the approved test requirements.
• Ignoring handling damage: Reinspect the liner and ends after transport or movement if damage may have occurred.

Buyer Checklist for Supplier Discussion

Before placing an order or approving inspection, send the supplier the service conditions, connection details, branch geometry, and relevant drawings. Ask which liner characteristics will be documented and how the branch junction can be inspected. Confirm which checks are visual, which require measurement, and which records will be supplied with the product. If your service involves abrasive solids, corrosive media, or demanding operating conditions, state those requirements clearly so the design and inspection plan can be reviewed in context.

Conclusion: What Should You Check?

Check liner continuity, visible condition, thickness and coverage against the specification, then examine the branch opening and internal transition for alignment, obstruction, damage, or exposed steel. Verify branch geometry, end dimensions, steel-body condition, and any inspection or test records required by the order. The next step is to compare these findings with the approved drawing and document any unresolved acceptance criteria before installation. At Shandong Haohua Pipe Industry Co., Ltd., we encourage buyers to share drawings and inspection requirements early so the steel-lined tee configuration and verification points can be clarified before production and delivery.