1. Describe the geometry
The catalogue includes elbows, equal and reducing tees, caps, and concentric and eccentric reducers.
- Elbow: 45°, 90° or 180°, plus long or short radius.
- Tee: main-run diameter and branch diameter.
- Reducer: large-end diameter, small-end diameter and concentric/eccentric form.
2. Separate size from wall thickness
A nominal pipe size and a wall schedule describe different aspects of the product. Include both when the specification uses schedule designations.
- Give DN/NPS and SCH or the wall thickness in millimetres.
- For transitions, identify the required thickness at each end.
- Confirm bevel/end preparation and seamless or welded construction if specified.
3. Align the inspection basis
The purchase specification should connect the geometry to the material and inspection requirements.
- State the fitting standard, material specification and grade.
- Include drawing revisions and dimensional tolerances when applicable.
- Specify material records, marking, packing and quantity by item.
